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Sample records for hemlock tsuga heterophylla

  1. The concurrent kinetics of N uptake by soil microbes and western hemlock (Tsuga heterophylla) seedlings: a microcosm study

    NASA Astrophysics Data System (ADS)

    Grenon, Frank; Bradley, Robert; Titus, Brian

    2014-05-01

    There is disagreement over the relative ability of microbes and plants to compete for soil N. Empirical data are needed, therefore, to develop models that can be applied for specific plant species across different soil conditions. We grew western hemlock (Tsuga heterophylla (Raf.) Sarg) seedlings in humus collected from old-growth forest plots (high available C) and from adjacent clearcut plots (low available C). We injected the rhizospheres with either 15N-labelled NH4+ or 15N-labelled amino acid solutions, over a wide range of N concentrations. The uptake of these N compounds by soil microbes and seedlings was assessed 4 h after injection. Microbial uptake rates of NH4+-N were best described by a linear models, whereas microbial uptake of amino acid-N as well as seedling N uptake were best described by asymptotic models. Microbial uptake rates were several orders of magnitude greater than seedling uptake rates, except at low concentrations that are typical under field situations. The provenance of the humus also had significant effects on N uptake kinetics by microbes and seedlings, which were consistent with the available C status of each humus type. Results suggest that differences in N uptake kinetics between plants and microbes are complementary functions that may confer resistance and resilience to forest ecosystems.

  2. The effect of fertilization on the below-ground diversity and community composition of ectomycorrhizal fungi associated with western hemlock (Tsuga heterophylla).

    PubMed

    Wright, Shannon H A; Berch, Shannon M; Berbee, Mary L

    2009-04-01

    Fertilization typically reduces ectomycorrhizal diversity shortly after its application but less is known about its longer-term influence on fungal species. Long-term effects are important in forests where fertilizer is rarely applied. We compared fungal species composition in western hemlock control plots with plots last fertilized 7 years ago with nitrogen (N) or nitrogen plus phosphorus (N + P). The N + P fertilization had a significant lingering effect, increasing the tree size and foliar P content of the western hemlocks. From ectomycorrhizal roots of 24-year-old trees from northern Vancouver Island, Canada, we identified fungi from 12 samples per treatment, by amplifying, cloning, and sequencing fungal ribosomal DNA fragments, placing sequences with 97% or more identity in the same operational taxonomic unit (OTU). Diversity was high across treatments; we detected 77 fungal OTUs, 52 from ectomycorrhizal genera, among 922 clone sequences. The five most frequent OTUs were similar in abundance across treatments. Only 19 OTUs matched any of the 197 previously reported ectomycorrhizal species of western hemlock. Species composition but not diversity in nitrogen plus phosphorus plots differed significantly from control or nitrogen plots. Two Cortinarius OTUs were indicator species for nitrogen plus phosphorus plots and presence of Cortinarius cinnamomeus was correlated with control or nitrogen plots. After 7 years, fertilization history had made no detectable difference in ectomycorrhizal fungal diversity, but long-lasting changes in environment resulting from fertilization had a lingering effect on fungal ectomycorrhizal species composition.

  3. Effects of fertilization of four hemlock species on Adelges tsugae (Hemiptera: Adelgidae) growth and feeding preference of predators.

    PubMed

    Joseph, S V; Braman, S K; Hanula, J L

    2011-02-01

    Understanding how fertilization affects host resistance to hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is important because fertilizers are often used to grow resistant selections to a suitable size for testing. We evaluated four hemlock species (Tsuga) under three different fertilizer regimes to assess whether fertility affected resistance to the adelgid and to determine whether it affected feeding preferences of the adelgid predators Laricobius nigrinus Fender and Sasajiscymnus tsugae (Sasaji & McClure). Treatments were long-term fertilization (from June 2008 to June 2009), short-term fertilization (from March to June 2009), and no fertilizer. Fertilizer was applied biweekly with 240 ppm N by using water-soluble fertilizer (N-P-K, 20:20:20). Plants (>1 yr old) were artificially infested with adelgids on 31 March 2009. Among unfertilized hemlocks (n=10 per species), foliar N was highest in Tsuga mertensiana (Bong.) CarriBre and lowest in T. chinensis (Franch.) E. Pritz. Significantly more progredien ovisacs or sisten eggs were present on T. mertensiana than on the other hemlock species with none on unfertilized T. chinensis. A. tsugae adults on T. heterophylla (Raf.) Sarg. were unaffected by fertility, but densities of developing A. tsugae nymphs were higher on unfertilized T. heterophylla plants than on fertilized T. heterophylla plants regardless of fertilizer treatment. Both L. nigrinus and S. tsugae consumed more adelgid eggs that developed on fertilized T. canadensis than from unfertilized plants. The predators did not exhibit this preference for adelgid eggs from females that developed on T. heterophylla or T. mertensiana.

  4. Potential feeding deterrents found in hemlock woolly adelgid, Adelges tsugae

    NASA Astrophysics Data System (ADS)

    Jones, Anne C.; Mullins, Donald E.; Jones, Tappey H.; Salom, Scott M.

    2012-07-01

    The nonnative hemlock woolly adelgid ( Adelges tsugae Annand, Hemiptera: Sternorrhyncha: Adelgidae) has been a significant mortality agent of eastern hemlock ( Tsuga canadensis Carriere) throughout a large portion of its geographic range. During a study investigating adelgid vigor in relation to host health, it was noted that adelgid extracts ranged from a yellow to a deep red color. Analysis by GC-MS identified the presence of the anthraquinone, chrysophanol and its anthrone precursor, chrysarobin in the extract. These compounds are predator deterrents in several other insects, including chrysomelid beetles. It is hypothesized that these compounds serve a similar purpose in the hemlock woolly adelgid.

  5. Isolation and characterization of microsatellite markers for Carolina hemlock (Tsuga caroliniana).

    PubMed

    Josserand, S A; Potter, K M; Echt, C S; Nelson, C D

    2008-11-01

    We describe the isolation and characterization of 31 polymorphic di- and trinucleotide microsatellite marker loci for Carolina hemlock (Tsuga caroliniana Englem.). In addition, primer pairs for 16 loci amplified scoreable alleles in six other Tsuga species. In eastern North America, both Carolina hemlock and eastern hemlock (Tsuga canadensis [L.] Carr.) populations are declining due to infestation by hemlock woolly adelgid, Adelges tsugae. The markers described here should enhance population genetic studies of hemlocks, providing valuable information for conserving and restoring these important forest tree species.

  6. Hemlock woolly adelgid (Adelges tsugae) infestation affects water and carbon relations of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana).

    PubMed

    Domec, Jean-Christophe; Rivera, Laura N; King, John S; Peszlen, Ilona; Hain, Fred; Smith, Benjamin; Frampton, John

    2013-07-01

    Hemlock woolly adelgid (HWA) is an exotic insect pest causing severe decimation of native hemlock trees. Extensive research has been conducted on the ecological impacts of HWA, but the exact physiological mechanisms that cause mortality are not known. Water relations, anatomy and gas exchange measurements were assessed on healthy and infested eastern (Tsuga canadensis) and Carolina (Tsuga caroliniana) hemlock trees. These data were then used in a mechanistic model to test whether the physiological responses to HWA infestation were sufficiently significant to induce changes in whole-plant water use and carbon uptake. The results indicated coordinated responses of functional traits governing water relations in infested relative to healthy trees. In response to HWA, leaf water potential, carbon isotope ratios, plant hydraulic properties and stomatal conductance were affected, inducing a reduction in tree water use by > 40% and gross primary productivity by 25%. Anatomical changes also appeared, including the activation of traumatic cells. HWA infestation had a direct effect on plant water relations. Despite some leaf compensatory mechanisms, such as an increase in leaf hydraulic conductance and nitrogen content, tree water use and carbon assimilation were diminished significantly in infested trees, which could contribute to tree mortality.

  7. Evaluation of hemlock (Tsuga) species and hybrids for resistance to Adelges tsugae (Hemiptera: Adelgidae) using artificial infestation.

    PubMed

    Montgomery, Michael E; Bentz, S E; Olsen, Richard T

    2009-06-01

    Hemlock (Tsuga) species and hybrids were evaluated for resistance to the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae). The adelgid was accidentally introduced from Asia to the eastern United States, where it is causing widespread mortality of the native hemlocks, Tsuga canadensis (L.) Carrière and Tsuga caroliniana Engelm. These two native species plus the Asian species Tsuga chinensis (Franch.) E. Pritz and T. dumosa (D.Don) Eichler and Tsuga sieboldii Carrière, and the hybrids T. chinensis x T. caroliniana and T. chinensis x T. sieboldii, were artificially infested with the crawler stage of A. tsugae in the early spring 2006 and 2007. After 8 or 9 wk-when the spring (progrediens) generation would be mature--counts were made of the adelgid. In both years, the density of A. tsugae was highest on T. canadensis, T. caroliniana, and T. sieboldii; lowest on T. chinensis; and intermediate on the hybrids. On T. chinensis and the T. chinensis hybrids, fewer adelgids settled, fewer of the settled adelgids survived, and the surviving adelgids grew slower. Thus, the nature of the host resistance is both nonpreference (antixenosis) and adverse effects on biology (antibiosis). Tree growth (height) was associated with resistance, but no association was found between time of budbreak and resistance that was independent of the taxa. Many of the hybrids grow well, have attractive form, and are promising as resistant landscape alternatives for the native hemlocks.

  8. Fitness and physiology of Adelges tsugae (Hemiptera: Adelgidae) in relation to the health of the eastern hemlock.

    PubMed

    Jones, Anne C; Mullins, Donald E; Brewster, Carlyle; Rhea, James P; Salom, Scott M

    2016-12-01

    The hemlock woolly adelgid, Adelges tsugae Annand is an invasive insect that frequently causes hemlock (Tsuga spp.) mortality in the eastern United States. Studies have shown that once healthy hemlocks become infested by the adelgid, nutrients are depleted from the tree, leading to both tree decline and a reduction of the adelgid population. Since A. tsugae is dependent on hemlock for nutrients, feeding on trees in poor health may affect the ability of the insect to obtain necessary nutrients and may consequently affect their physiological and population health. Trees were categorized as lightly or moderately impacted by A. tsugae based on quantitative and qualitative tree health measurements. Population health of A. tsugae on each tree was determined by measuring insect density and peak mean fecundity; A. tsugae physiological health was determined by measuring insect biomass, total carbon, carbohydrate, total nitrogen, and amino nitrogen levels. Adelges tsugae from moderately impacted trees exhibited significantly greater fecundity than from lightly impacted trees. However, A. tsugae from lightly impacted hemlocks contained significantly greater levels of carbohydrates, total nitrogen, and amino nitrogen. While the results of the physiological analysis generally support our hypothesis that A. tsugae on lightly impacted trees are healthier than those on moderately impacted trees, this was not reflected in the population health measurements. Adelges tsugae egg health in response to tree health should be verified. This study provides the first examination of A. tsugae physiological health in relation to standard A. tsugae population health measures on hemlocks of different health levels.

  9. Development of a rain down technique to artificially infest hemlocks with the hemlock woolly adelgid, Adelges tsugae.

    PubMed

    Jetton, Robert M; Mayfield, Albert E; Powers, Zaidee L

    2014-01-01

    The hemlock woolly adelgid Adelges tsugae Annand (Hemiptera: Adelgidae), is a non-native invasive pest that has caused widespread decline and mortality of eastern hemlock (Tsuga canadensis (L.) Carr. (Pinales: Pinaceae)) and Carolina hemlock (T. caroliniana Engelm.) in the eastern United States. Our preliminary experiments evaluated the utility of a rain-down technique to induce artificial infestations of A. tsugae on hemlock seedlings en masse. Experiments were conducted in PVC (1 m3) cages topped with poultry wire for placement of A. tsugae-infested branches, and with 1 m(2) gridded glue sheets and/or hemlock seedlings placed below to capture adelgid abundance, distribution, and infestation rate data. In the March 2011 experiment, the density of progrediens crawlers (adelgid nymphs, first instars) that rained down inside the PVC cages was significantly higher in the high ovisac treatment compared to the low ovisac treatment, with an estimated 513,000 and 289,000 crawlers per m(2) falling beneath each treatment, respectively. Resulting A. tsugae infestation rates on Carolina hemlock seedlings placed inside the cages did not differ between the treatments but were at or above established damage threshold densities for the adelgid. Infestation rates on eastern hemlock seedlings that were placed in cages nine days after the experiment started were below damage threshold levels and did not differ between the treatments. In the May 2011 experiment, the density of sistens crawlers raining down was substantially lower, with 17,000 and 33,000 falling per m(2) in the low and high ovisac treatments, respectively. Resulting infestation rates on Carolina hemlock seedlings were extremely low and well below damage threshold levels. Although A. tsugae crawlers were well distributed across the 1 m(2) gridded glue sheets placed at the bottom of each cage, hot spots of unusually high crawler density did occur in both experiments. This rain-down technique shows potential for use in

  10. Development of a rain down technique to artificially infest hemlocks with the hemlock woolly adelgid, Adelges tsugae.

    PubMed

    Jetton, Robert M; Mayfield, Albert E; Powers, Zaidee L

    2014-01-01

    The hemlock woolly adelgid Adelges tsugae Annand (Hemiptera: Adelgidae), is a non-native invasive pest that has caused widespread decline and mortality of eastern hemlock (Tsuga canadensis (L.) Carr. (Pinales: Pinaceae)) and Carolina hemlock (T. caroliniana Engelm.) in the eastern United States. Our preliminary experiments evaluated the utility of a rain-down technique to induce artificial infestations of A. tsugae on hemlock seedlings en masse. Experiments were conducted in PVC (1 m(3)) cages topped with poultry wire for placement of A. tsugae-infested branches, and with 1 m(2) gridded glue sheets and/or hemlock seedlings placed below to capture adelgid abundance, distribution, and infestation rate data. In the March 2011 experiment, the density of progrediens crawlers (adelgid nymphs, first instars) that rained down inside the PVC cages was significantly higher in the high ovisac treatment compared to the low ovisac treatment, with an estimated 513,000 and 289,000 crawlers per m(2) falling beneath each treatment, respectively. Resulting A. tsugae infestation rates on Carolina hemlock seedlings placed inside the cages did not differ between the treatments but were at or above established damage threshold densities for the adelgid. Infestation rates on eastern hemlock seedlings that were placed in cages nine days after the experiment started were below damage threshold levels and did not differ between the treatments. In the May 2011 experiment, the density of sistens crawlers raining down was substantially lower, with 17,000 and 33,000 falling per m(2) in the low and high ovisac treatments, respectively. Resulting infestation rates on Carolina hemlock seedlings were extremely low and well below damage threshold levels. Although A. tsugae crawlers were well distributed across the 1 m(2) gridded glue sheets placed at the bottom of each cage, hot spots of unusually high crawler density did occur in both experiments. This rain-down technique shows potential for use in

  11. Biophysical characteristics of Adelges tsugae feeding sites on six hemlock (Tsuga) species and a hybrid: implications for resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Characteristics of the plant surface significantly affect host-plant selection by phytophagous insects. Surface morphology of six hemlock species (Tsuga spp.) and a hybrid was investigated using low-temperature scanning electron microscopy. Observations focused on trichome presence and placement a...

  12. Development of a Hyperspectral Index for Detection of Initial Water Stress in Eastern Hemlock (Tsuga Canadensis)

    NASA Astrophysics Data System (ADS)

    Wiener, M. J.; Rock, B. N.

    2008-12-01

    Hemlock woolly adelgid (Adelges tsugae Annand) is an invasive insect pathogen that is causing significant mortality in existing eastern hemlock (Tsuga canadensis Carriere) stands across the Northeastern USA. Unchecked, A. tsugae will continue to decimate hemlock forests, initiating irreversible ecological alterations. Hemlock survival is dependent upon site conditions, where trees in mesic environments tend to decline at slower rates than trees in xeric ones. In addition, A. tsugae has been reported to restrict xylem flow in hemlock needles, potentially causing foliar drying. There has been little research on the ability of remote sensing tools to detect eastern hemlock water stress, a key factor in resistance to A. tsugae. In this study, 2007 hemlock needles were collected from 10 sites across the northeast and subjected to simulated water stress in order to determine the applicability of multispectral and hyperspectral indices in diagnosing hemlock water stress. Samples were dried in an oven at 65° C in two time groups: 60 minutes and 300 minutes. Spectral scans by a Visible Infrared Intelligent Spectrometer (VIRIS) in addition to percent water loss measurements were made at regular intervals throughout the drying period. Results include the rapid formation of reflectance peaks at 530 nm, 590 nm, and 644 nm which may be used to create hyperspectral water stress indices tailored to hemlocks that are extremely accurate in predicting both initial (R644/R669 r2=.773, p<.0001; Normalized R644/R669 r2=.801, p<.0001) and long-term (R644/R669 r2=.864, p<.0001; Normalized R644/R669 r2=.889, p<.0001) water stress. These findings can provide a significant tool in current management efforts of the HWA, by identifying both hemlock stands under environmental water stress, which are likely prone to infestation, in addition to regions under the initial stages of infestation. As a result, conservationists and forest managers will be afforded an opportunity to direct control

  13. Distribution and abundance of Adelges tsugae (Hemiptera: Adelgidae) within hemlock trees.

    PubMed

    Joseph, S V; Hanula, J L; Braman, S K

    2011-12-01

    We studied the distribution of hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), within hemlock trees for three summer (progrediens) and two winter (sistens) generations in northern Georgia. Eastern hemlock, Tsuga canadensis (L.) Carrière, trees were treated with 0, 10, or 25% of 1.5 g of imidacloprid per 2.5 cm of tree diameter at breast height and fertilized or not in a factorial design. Adelgid ovisacs per centimeter of branch were more abundant from June 2007 to June 2008 in the upper tree crown of insecticide untreated trees and when all trees were combined and that was the general trend for most comparisons. However, ovisacs were more abundant in the lower crown of insecticide treated trees in June 2008. More sistens nymphs settled on the upper crown branches than on the lower branches in summers 2007 and 2008. Higher eggs per ovisac were observed in the upper crown in February 2008 and in both the winter and summer 2009. In contrast, adelgids were more fecund in the lower crown in June 2008. On fertilized trees, eggs laid per adult were higher in the upper crown in February 2008. In summer 2008, eggs per ovisac were higher in the lower crown, but this reversed again to the upper crown by summer 2009. New growth of branches also varied among sample dates. These data demonstrate the variable distribution of adelgid and hemlock growth within trees over time and suggest that sampling only one crown area will not provide accurate estimates of adelgid densities.

  14. Carbon exchange of an old-growth eastern hemlock (Tsuga canadensis) forest in central New England.

    PubMed

    Hadley, Julian L; Schedlbauer, Jessica L

    2002-11-01

    Carbon (C) exchange of an approximately 200-year-old eastern hemlock (Tsuga canadensis L.) forest in central Massachusetts, USA, was estimated from mid-October 2000 through October 2001 based on eddy covariance measurements and statistical modeling from microclimatic data. Measurements were made in 68% of the hours during the year of study, with > 50% coverage in all months except December and August. Data were filtered by wind direction and atmospheric turbulence to remove invalid measurements. Analysis of filtered data showed that photosynthetically active radiation (PAR) was significant in predicting C exchange, except during the winter. Daily minimum air temperature affected C exchange in autumn and winter, whereas time of day, water vapor pressure deficit and air temperature had significant effects on C storage in spring, summer and fall. Most C storage in the stand occurred in April through July and in October 2001, with maximum rates in April and May. Persistent cold weather prevented C storage in December through March. In early spring 2001, C uptake was sensitive to nocturnal frost: daily minimum air temperatures below 0 degrees C reduced C fixation, and minima below -5 degrees C caused its virtual cessation. Soil temperature was a poor predictor of C balance during this period. In August, high soil and air temperatures (averaging 16.7 and 21.1 degrees C, respectively) drove high ecosystem respiration, which approximately balanced C uptake. These patterns show potential for stimulated C storage in hemlock forests in a warmer climate with fewer spring and autumn frosts, but reduced C storage during warmer summers. Estimated annual C storage was 3.0 Mg ha(-1), which is higher than for younger coniferous and deciduous forests during earlier years in the northeastern USA. Long-term data are needed to determine if the estimated high C storage in this hemlock forest is a result of interannual climate variation or an effect of forest composition.

  15. Predators associated with the hemlock woolly adelgid (Hemiptera: Adelgidae) in the Pacific Northwest.

    PubMed

    Kohler, G R; Stiefel, V L; Wallin, K F; Ross, D W

    2008-04-01

    The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is causing widespread mortality of eastern hemlock, Tsuga canadensis L. Carrière, in the eastern United States. In western North America, feeding by A. tsugae results in negligible damage to western hemlock, Tsuga heterophylla (Raf.) Sargent. Host tolerance and presence of endemic predators may be contributing to the relatively low levels of injury to T. heterophylla caused by A. tsugae. Field surveys of the predator community associated with A. tsugae infestations on 116 T. heterophylla at 16 sites in Oregon and Washington were conducted every 4-6 wk from March 2005 through November 2006. Fourteen uninfested T. heterophylla were also surveyed across 5 of the 16 sites. Each sample tree was assigned an A. tsugae population score ranging from 0 to 3. Predators collected from A. tsugae-infested T. heterophylla represent 55 species in 14 families, listed in order of abundance: Derodontidae, Chamaemyiidae, Hemerobiidae, Coccinellidae, Cantharidae, Reduviidae, Miridae, Syrphidae, Chrysopidae, Coniopterygidae, Staphylinidae, Anthocoridae, Nabidae, and Raphidiidae. Laricobius nigrinus Fender (Coleoptera: Derodontidae), Leucopis argenticollis Zetterstedt (Diptera: Chamaemyiidae), and Leucopis atrifacies (Aldrich) (Chamaemyiidae) were the most abundant predators; together comprising 59% of predator specimens recovered. Relationships among predators and A. tsugae were determined through community structure analysis. The abundances of Laricobius spp. larvae, L. nigrinus adults, Leucopis spp. larvae, and L. argenticollis adults were found to be positively correlated to A. tsugae population score. Predators were most abundant when the two generations of A. tsugae eggs were present. L. argenticollis and L. atrifacies were reared on A. tsugae in the laboratory, and host records show them to feed exclusively on Adelgidae.

  16. Influence of eastern hemlock (Tsuga canadensis L.) on fish community structure and function in headwater streams of the Delaware River basin

    USGS Publications Warehouse

    Ross, R.M.; Bennett, R.M.; Snyder, C.D.; Young, J.A.; Smith, D.R.; Lemarie, D.P.

    2003-01-01

    Hemlock (Tsuga canadensis) forest of the eastern U.S. are in decline due to invasion by the exotic insect hemlock woolly adelgid (Adelges tsugae). Aquatic biodiversity in hemlock ecosystems has not been documented; thus the true impact of the infestation cannot be assessed. We compared ichthyofaunal assemblages and trophic structure of streams draining hemlock and hardwood forests by sampling first- and second-order streams draining 14 paired hemlock and hardwood stands during base flows in July 1997 at the Delaware Water Gap National Recreation Area of Pennsylvania and New Jersey. Over 1400 fish of 15 species and 7 families were collected, but hemlock and hardwood streams individually harbored only one to four species. Brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) were two to three times as prevalent in hemlock than hardwood streams. Insectivorous fishes occurred in significantly higher proportion in streams of hardwood (0.90) than hemlock (0.46) stands, while piscivores occurred more often in hemlock (0.85) than hardwood (0.54) stands. Functional (trophic) diversity of fishes in hemlock and second-order streams was numerically greater than that of hardwood and first-order streams. Species composition also differed by stream order and terrain type. Biodiversity is threatened at several levels within hemlock ecosystems at risk to the hemlock woolly adelgid in eastern U.S. forests.

  17. Variation in plant defense against invasive herbivores: evidence for a hypersensitive response in eastern hemlocks (Tsuga canadensis).

    PubMed

    Radville, Laura; Chaves, Arielle; Preisser, Evan L

    2011-06-01

    Herbivores can trigger a wide array of morphological and chemical changes in their host plants. Feeding by some insects induces a defensive hypersensitive response, a defense mechanism consisting of elevated H(2)O(2) levels and tissue death at the site of herbivore feeding. The invasive hemlock woolly adelgid Adelges tsugae ('HWA') and elongate hemlock scale Fiorinia externa ('EHS') feed on eastern hemlocks; although both are sessile sap feeders, HWA causes more damage than EHS. The rapid rate of tree death following HWA infestation has led to the suggestion that feeding induces a hypersensitive response in hemlock trees. We assessed the potential for an herbivore-induced hypersensitive response in eastern hemlocks by measuring H(2)O(2) levels in foliage from HWA-infested, EHS-infested, and uninfested trees. Needles with settled HWA or EHS had higher H(2)O(2) levels than control needles, suggesting a localized hypersensitive plant response. Needles with no direct contact to settled HWA also had high H(2)O(2) levels, suggesting that HWA infestation may induce a systemic defense response in eastern hemlocks. There was no similar systemic defensive response in the EHS treatment. Our results showed that two herbivores in the same feeding guild had dramatically different outcomes on the health of their shared host.

  18. Assessment of Imidacloprid and Its Metabolites in Foliage of Eastern Hemlock Multiple Years Following Treatment for Hemlock Woolly Adelgid, Adelges tsugae (Hemiptera: Adelgidae), in Forested Conditions.

    PubMed

    Benton, E P; Grant, J F; Webster, R J; Nichols, R J; Cowles, R S; Lagalante, A F; Coots, C I

    2015-12-01

    Widespread decline and mortality of eastern hemlock, Tsuga canadensis (L.) Carrière, have been caused by hemlock woolly adelgid, Adelges tsugae (Annand) (HWA) (Hemiptera: Adelgidae). The current study is a retrospective analysis conducted in collaboration with Great Smoky Mountains National Park (GRSM) to determine longevity of imidacloprid and its insecticidal metabolites (imidacloprid olefin, 5-hydroxy, and dihydroxy) in GRSM's HWA integrated pest management (IPM) program. Foliage samples were collected from three canopy strata of hemlocks that were given imidacloprid basal drench treatments 4-7 yr prior to sampling. Foliage was analyzed to assess concentrations in parts per billion (ppb) of imidacloprid and its metabolites. Imidacloprid and its olefin metabolite were present in most, 95 and 65%, respectively, branchlets 4-7 yr post-treatment, but the 5-hydroxy and dihydroxy metabolites were present in only 1.3 and 11.7%, respectively, of the branchlets. Imidacloprid and olefin concentrations significantly decreased between 4 and 7 yr post-treatment. Concentrations of both imidacloprid and olefin were below the LC50 for HWA 5-7 yr post-treatment. Knowledge of the longevity of imidacloprid treatments and its metabolite olefin can help maximize the use of imidacloprid in HWA IPM programs.

  19. Factors affecting establishment and recovery of Sasajiscymnus tsugae (Coleoptera: Coccinellidae), an introduced predator of hemlock woolly adelgid (Hemiptera: Adelgidae) on eastern hemlock (Pinales: Pinaceae).

    PubMed

    Hakeem, A; Grant, J F; Wiggins, G J; Lambdin, P L; Hale, F A; Buckley, D S; Rhea, J R; Parkman, J P; Taylor, G

    2013-12-01

    To reduce populations of hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), >500,000 Sasajiscymnus tsugae (Sasaji and McClure) (Coleoptera: Coccinellidae) have been released in the Great Smoky Mountains National Park since 2002. To determine factors affecting establishment and recovery of these predatory beetles, 65 single release sites were sampled using beat sheets from 2008 to 2012. Several abiotic and biotic factors were evaluated for their association with establishment and recovery of S. tsugae. Information on predatory beetle releases (location, year of release, number released, and season of release), topographic features (elevation, slope, Beers transformed aspect, and topographic relative moisture index), and temperature data (minimum and maximum temperatures 1 d after release and average minimum and maximum temperatures 7 d after release) were obtained from Great Smoky Mountains National Park personnel. These factors were evaluated using stepwise logistic regression and Pearson correlation. S. tsugae was recovered from 13 sites 2 to 10 yr after release, and the greatest number was recovered from 2002 release sites. Regression indicated establishment and recovery was negatively associated with year of release and positively associated with the average maximum temperature 7 d after release and elevation (generally, recovery increased as temperatures increased). Several significant correlations were found between presence and number of S. tsugae and year of release, season of release, and temperature variables. These results indicate that releases of S. tsugae should be made in warmer (≍10-25°C) temperatures and monitored for at least 5 yr after releases to enhance establishment and recovery efforts.

  20. Species richness and abundance of ectomycorrhizal basidiomycete sporocarps on a moisture gradient in the Tsuga heterophylla zone

    USGS Publications Warehouse

    O'Dell, Thomas E.; Ammirati, Joseph F.; Schreiner, Edward G.

    1999-01-01

    Sporocarps of epigeous ectomycorrhizal fungi and vegetation data were collected from eight Tsuga heterophylla (Raf.) Sarg. - Pseudotsuga menziesii (Mirb.) Franco stands along a wet to dry gradient in Olympic National Park, Washington, U.S.A. One hundred and fifty species of ectomycorrhizal fungi were collected from a total sample area of 2.08 ha. Over 2 years, fungal species richness ranged from 19 to 67 taxa per stand. Sporocarp standing crop ranged from 0 to 3.8 kg/ha, averaging 0.58 kg/ha, 0.06 kg/ha in spring and 0.97 kg/ha in fall. Sporocarp standing crop and fungal species richness were correlated with precipitation. These results demonstrated that ectomycorrhizal fungal sporocarp abundance and species richness can be partly explained in terms of an environmental gradient.

  1. Oribatid mite communities in the canopy of montane Abies amabilis and Tsuga heterophylla trees on Vancouver Island, British Columbia.

    PubMed

    Winchester, N N; Lindo, Z; Behan-Pelletier, V M

    2008-04-01

    To study the oribatid mite community inhabiting microhabitats in the canopy of montane Abies amabilis [(Douglas ex D. Don) Lindl.] and Tsuga heterophylla [(Raf.) Sarg] tree species across five elevational sites, we collected 180 branch tips and 180 foliose/crustose lichen samples over three time periods. Thirty-three species of oribatid mites were identified from the study area. Mite species richness and abundance was significantly affected by microhabitat, and this association was independent of sampling time. At the microhabitat scale, distinct species assemblages were associated with lichen and branch tip habitats, and to a lesser degree, tree species. Conifer specificity was most apparent in the closely related species of Jugatala, where Jugatala tuberosa Ewing was only found on branch tips from A. amabilis and Jugatala sp. was primarily found on branch tips from T. heterophylla. Microhabitat specificity was most pronounced in Dendrozetes sp. where most individuals were found on branch tips and Anachiperia geminus Lindo et al. that occurred primarily on lichens. Principal components analysis of oribatid mite community composition further showed a high degree of association with microhabitat and tree species. Habitat profiles are difficult to discern for many species because tree, microhabitat, and elevation preferences confound distribution patterns. Given the significant tree-microhabitat associations in species composition in this montane canopy study, we suggest that sampling multiple microhabitats across elevations to look for patterns in community structure offers opportunities to explicitly test organizing principles in community ecology.

  2. Testing the Climate Sensitivity of Mountain Hemlock (Tsuga mertensiana (Bong.) Carr.) Near the Southern Limit of Its Range

    NASA Astrophysics Data System (ADS)

    Appleton, S.; St George, S.

    2014-12-01

    This study investigates the climate sensitivity of mountain hemlock (Tsuga mertensiana (Bong.) Carr.) near the southern limit of its range, tests the stability of its climate-tree relations over the last few decades, and explores its potential as a hydroclimatic proxy for Crater Lake National Park. We collected tree cores at seven locations around the caldera rim, focusing on hemlock growing at higher elevations (2000-2400 masl). The median length of all ring-width series is 283 years, and the oldest hemlock sample extends back to C.E. 1450. Several types of anatomical anomalies, including frost rings, traumatic resin ducts, false rings, and light late-wood bands were observed within the specimens, the most common feature being a false ring in C.E. 1810. Each set of standardized ring-width measurements has a strong common signal, with between-tree correlations (r-bar) ranging from 0.31 to 0.49. Preliminary analysis suggests hemlock growth across the park is strongly and inversely related to total cool-season precipitation, and is also influenced positively (albeit more weakly) by mean summer temperature. Most sites are significantly and negatively correlated with total December-to-February precipitation (r = -0.41) and total precipitation from December to August (r = -0.48). Compared to other ring-width records exhibiting similar negative responses to winter precipitation, these hemlocks appear to track that specific signal quite clearly and, as a result, these data may be suitable to reconstruct past changes in cool-season moisture in Crater Lake National Park and across the broader southern Cascades.

  3. Influence of eastern hemlock (Tsuga canadensis) forests on aquatic invertebrate assemblages in headwater streams

    USGS Publications Warehouse

    Snyder, C.D.; Young, J.A.; Lemarie, D.P.; Smith, D.R.

    2002-01-01

    We conducted a comparative study in the Delaware Water Gap National Recreation Area to determine the potential long-term impacts of hemlock forest decline on stream benthic macroinvertebrate assemblages. Hemlock forests throughout eastern North America have been declining because of the hemlock woolly adelgid, an exotic insect pest. We found aquatic invertebrate community structure to be strongly correlated with forest composition. Streams draining hemlock forests supported significantly more total taxa than streams draining mixed hardwood forests, and over 8% of the taxa were strongly associated with hemlock. In addition, invertebrate taxa were more evenly distributed (i.e., higher Simpson's evenness values) in hemlock-drained streams. In contrast, the number of rare species and total densities were significantly lower in streams draining hemlock, suggesting that diversity differences observed between forest types were not related to stochastic factors associated with sampling and that streams draining mixed hardwood forests may be more productive. Analysis of stream habitat data indicated that streams draining hemlock forests had more stable thermal and hydrologic regimes. Our findings suggest that hemlock decline may result in long-term changes in headwater ecosystems leading to reductions in both within-stream (i.e., alpha) and park-wide (i.e., gamma) benthic community diversity.

  4. Censusing and modeling the dynamics of a population of eastern hemlock (Tsuga canadensis L.) using remote sensing

    NASA Astrophysics Data System (ADS)

    Lamar, W. Robert

    A population of eastern hemlock (Tsuga canadensis L.) was censused from the ground using traditional field methods and from the air using large scale, high-resolution, aerial imagery in the early spring of 1997, 1998 and 1999. A manual crown survey map of the population, prepared from aerial imagery, was compared to a traditional field census. Over 60% of the individuals measured on the ground were not detected in the aerial census. Tree size, crown density and crown position all played roles in determining a crown's visibility from the air. Nearly all large, upper canopy hemlocks were visible in the aerial census. An important minority of small, lower canopy hemlocks were also visible in the aerial census. An automated spatial segmentation procedure was developed to identify and measure individual population units, or blobs, within the forest population. A blob was defined as a distinct portion of crown segmented from its neighbors on the basis of size, shape, and connectivity. To ensure the comparability of multi-year segmentation maps, an automated blob reconciliation procedure was also developed to make certain that no hemlock pixels were assigned to different blobs in different years. Following spatial segmentation and reconciliation, a large majority of hemlock blobs (˜64--72%) were found to be closely associated with ground referenced, manually delineated, individual hemlock crowns. The remaining blobs consisted of spatially distinct parts of a crown or closely clumped multiple crowns. Matrix population models were constructed from the ground-derived and aerial-derived population data. Matrix analysis produced a number of useful population characteristics including overall population growth rate (lambda), stable stage distributions, reproductive values, and sensitivity values. lambda's calculated from the aerial and ground-derived matrices were compared using randomization tests. While providing a different perspective and description of a population than

  5. Convergence of leaf display and photosynthetic characteristics of understory Abies amabilis and Tsuga heterophylla in an old-growth forest in southwestern Washington State, USA.

    PubMed

    Ishii, Hiroaki; Yoshimura, Ken-Ichi; Mori, Akira

    2009-08-01

    We compared the morphological and physiological characteristics of understory trees of Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes and Tsuga heterophylla (Raf.) Sarg. growing adjacent to each other in an old-growth forest in southwestern Washington State, USA. We hypothesized that, despite contrasting branching patterns and crown architectures, the two species should exhibit convergence in leaf display and photosynthetic gain per light intercepting area, because these are important properties determining their survival in the light-limited understory. The branching pattern of A. amabilis was regular (normal shoot-length distribution, less variable branching angle and bifurcation ratio), whereas that of T. heterophylla was more plastic (positively skewed shoot-length distribution, more variable branching angle and bifurcation ratio). The two species had similar shoot morphologies: number of leaves per unit shoot length and leaf to axis dry mass ratio. Leaf morphology, in contrast, was significantly different. Leaves of A. amabilis were larger and heavier than those of T. heterophylla, which resulted in lower mass-based photosynthetic rate for A. amabilis. Despite these differences, the two species had similar levels of leaf overlap and area-based photosynthetic characteristics. Needle longevity of A. amabilis was nearly twice that of T. heterophylla. The leaf N contents of current and 1-year-old leaves were lower for A. amabilis than for T. heterophylla. However, the leaf N content of A. amabilis did not change from current leaves to 6-year-old leaves, whereas that of T. heterophylla decreased with increasing leaf age. Abies amabilis had deeper crowns than T. heterophylla and retained branches with low relative growth rates. Longer branch retention may compensate for the lower branch-level assimilation rate of A. amabilis. We inferred that the convergence of leaf display and photosynthetic characteristics between A. amabilis and T. heterophylla may

  6. Ancient and modern colonization of North America by hemlock woolly adelgid, Adelges tsugae (Hemiptera: Adelgidae), an invasive insect from East Asia.

    PubMed

    Havill, Nathan P; Shiyake, Shigehiko; Lamb Galloway, Ashley; Foottit, Robert G; Yu, Guoyue; Paradis, Annie; Elkinton, Joseph; Montgomery, Michael E; Sano, Masakazu; Caccone, Adalgisa

    2016-05-01

    Hemlock woolly adelgid, Adelges tsugae, is an invasive pest of hemlock trees (Tsuga) in eastern North America. We used 14 microsatellites and mitochondrial COI sequences to assess its worldwide genetic structure and reconstruct its colonization history. The resulting information about its life cycle, biogeography and host specialization could help predict invasion by insect herbivores. We identified eight endemic lineages of hemlock adelgids in central China, western China, Ulleung Island (South Korea), western North America, and two each in Taiwan and Japan, with the Japanese lineages specializing on different Tsuga species. Adelgid life cycles varied at local and continental scales with different sexual, obligately asexual and facultatively asexual lineages. Adelgids in western North America exhibited very high microsatellite heterozygosity, which suggests ancient asexuality. The earliest lineages diverged in Asia during Pleistocene glacial periods, as estimated using approximate Bayesian computation. Colonization of western North America was estimated to have occurred prior to the last glacial period by adelgids directly ancestral to those in southern Japan, perhaps carried by birds. The modern invasion from southern Japan to eastern North America caused an extreme genetic bottleneck with just two closely related clones detected throughout the introduced range. Both colonization events to North America involved host shifts to unrelated hemlock species. These results suggest that genetic diversity, host specialization and host phylogeny are not predictive of adelgid invasion. Monitoring non-native sentinel host trees and focusing on invasion pathways might be more effective methods of preventing invasion than making predictions using species traits or evolutionary history.

  7. Orientation behavior of the predator Laricobius nigrinus (Coleoptera: Derodontidae) to hemlock woolly adelgid and host tree odors in a multi-chambered olfactometer.

    PubMed

    Wallin, Kimberly F; Latty, Tanya M; Ross, Darrell W

    2011-08-01

    We studied the adult ambulatory response of the predator, Laricobius nigrinus Fender (Coleoptera: Derodontidae), to odors from its prey, Adelges tsugae Annand, the hemlock woolly adelgid, and foliage of hemlock woolly adelgid, host hemlocks (Tsuga spp.), and other conifers. Both the predator and hemlock woolly adelgid are apparently native to western North America, but the predator is being released in the eastern United States, which has different hemlock species, for biological control of a lineage of hemlock woolly adelgid inadvertently introduced from Japan. L. nigrinus responded to odors from hemlock woolly adelgid host trees, but not to odors from hemlock woolly adelgid. L. nigrinus collected from hemlock woolly adelgid-infested western hemlock were more strongly attracted to odors from western hemlock [Tsuga heterophylla (Rafinesque) Sargent] than eastern hemlock [Tsuga canadensis (L.) Carrière] in most trials. Odors from western white pine (Pinus monticola Douglas ex D. Don) and white spruce [Picea glauca (Moench) Voss] were as attractive as western hemlock odors whereas odors from Douglas-fir [Pseudotsuga menziesii variety menziesii (Mirbel)] and ponderosa pine (Pinus ponderosa Douglas ex Lawson) were avoided. L. nigrinus reared on hemlock woolly adelgid-infested eastern hemlock in the laboratory were lethargic and were not attracted to either eastern or western hemlock odors. Predators collected in the field and tested monthly from December to March responded similarly each month, except February, when they flew rather than walked in the olfactometer, suggesting a period of dispersal or mate finding at that time of year. The implications of these results for programs to release L. nigrinus in the eastern United States for control of hemlock woolly adelgid are discussed.

  8. Forest expansion and climate change in the Mountain Hemlock (Tsuga mertensiana) zone, Lassen Volcanic National Park, California, U.S.A.

    SciTech Connect

    Taylor, A.H.

    1995-08-01

    The relationship between climate change and the dynamics of ecotonal populations of mountain hemlock (Tsuga mertensiana [Bong.] Carr.) was determined by comparing climate and the age structure of trees from 24 plots and seedlings from 13 plots in the subalpine zone of Lassen Volcanic National Park, California. Tree establishment was greatest during periods with above normal annual and summer temperatures, and normal or above normal precipitation. Seedling establishment was positively correlated with above normal annual and summer temperatures and negatively correlated with April snowpack depth. The different responses of trees and seedlings to precipitation variation is probably related to site soil moisture conditions. Mountain hemlock populations began to expand in 1842 and establishment increased dramatically after 1880 and peaked during a warm mesic period between 1895 and 1910. The onset of forest expansion coincides with warming that began at the end of the Little Ice Age (1850-1880). These data indicate that stability of the mountain hemlock ecotone is strongly influenced by climate. If warming induced by greenhouse gases does occur as climate models predict, then the structure and dynamics of near timberline forests in the Pacific Northwest will change. 52 refs., 8 figs., 3 tabs.

  9. A case study: looking at the effects of fragmentation on genetic structure in different life history stages of old-growth mountain hemlock (Tsuga mertensiana).

    PubMed

    Ally, Dilara; Ritland, Kermit

    2007-01-01

    We examined fine-scale genetic structure of mountain hemlock (Tsuga mertensiana) in an old-growth stand and an adjacent seedling population, with the goal of detecting the effects of fragmentation. Three hundred and six old-growth trees and 195 naturally regenerating seedlings were genotyped at 5 microsatellite loci. Genetic diversity was similar across old-growth life stages and within the clear-cut seedlings. Significant inbreeding was found in the adult class (30+ cm diameter at breast height) of old-growth seedlings and in the adjacent natural regeneration. Relatedness was significantly associated with physical distance for both the oldest age class and for regenerating seedlings in the adjacent clear-cut, whereas intermediate classes showed no such association. As intermediate classes show no isolation by distance, the associations that arise probably occur from single cohort regeneration that clearly has taken place in the clear-cut, and possibly when the oldest old-growth trees were established. Parentage analysis suggested that large-scale fragmentation, such as this clear-cut, allowed for increased long-distance seed dispersal. We conclude that long-lived tree populations can consist of a cohort mosaic, reflecting the effects of fragmentation, and resulting in a complex, age-dependent, local population structure with high levels of genetic diversity.

  10. Effects of hemlock woolly adelgid and elongate hemlock scale on eastern hemlock growth and foliar chemistry.

    PubMed

    Miller-Pierce, Mailea R; Orwig, David A; Preisser, Evan

    2010-04-01

    In the eastern United States, two invasive specialist insects share a native host plant, Eastern hemlock, Tsuga canadensis. In recent years, much research has focused on the impacts of the hemlock woolly adelgid (Adelges tsugae) because of the detrimental effects it has on hemlock growth and survival. In contrast, the invasive elongate hemlock scale (Fiorinia externa) is thought to have only minor impacts on hemlock. We infested hemlock saplings with each insect and compared them with control (i.e., neither insect herbivore) saplings to assess how early infestations impact Eastern hemlock health (measured using new branch growth, foliar %N, and C:N ratio). Our study showed that, at equal densities, the two insects differed in their effect on Eastern hemlock. F. externa did not impact plant growth or foliar chemistry over the course of the 2-yr experiment. A. tsugae significantly reduced plant growth and caused a reduction of %N in the first year of the experiment. By the end of the experiment, A. tsugae trees had the same %N in their foliage as control and F. externa trees but drastically reduced growth patterns. The most likely explanation for this result is the greater growth in control and F. externa saplings during the second year resulted in the dilution of available foliar N over a larger amount of newly produced plant tissue. For early infestations of both insects, our study suggests that management plans should focus on the more detrimental A. tsugae.

  11. Arboreal spiders in eastern hemlock.

    PubMed

    Mallis, Rachael E; Rieske, Lynne K

    2011-12-01

    Eastern hemlock [Tsuga canadensis (L.) Carrière] is a foundation species in forests of eastern North America that plays a key role in ecosystem function. It is highly susceptible to the exotic invasive hemlock woolly adelgid (Adelges tsugae Annand), which is causing widespread hemlock mortality. We surveyed the spider communities of eastern hemlock and deciduous canopies over 2 yr, collecting over 4,000 spiders from 21 families. We found that eastern hemlock canopies harbored a more abundant, rich, and diverse spider community than did deciduous canopies. Five spider families were present in our hemlock collections that were absent from the deciduous collections, including Mysmenidae, Theridiosomatidae, Mimetidae, Lycosidae, and Agelenidae. In hemlock canopies there were 4× the number of web builders, consisting primarily of the Tetragnathidae and Araneidae, than active hunters, consisting primarily of the Anyphaenidae and the Salticidae. Ours is the first in depth study of the spider community in eastern hemlock. Spider abundance in hemlock canopies suggest that they may play a role regulating herbivore populations, and could possibly affect the invasive hemlock woolly adelgid, either through direct consumption of the adelgids themselves or through interactions with classical biological control agents.

  12. False ring formation in eastern hemlock branches: impacts of hemlock woolly adelgid and elongate hemlock scale.

    PubMed

    Gonda-King, Liahna; Radville, Laura; Preisser, Evan L

    2012-06-01

    Herbivores can alter plant physiology through the induction of abnormal wood formation. Feeding by some insects induces the formation of false rings, a band of thick-walled latewood cells within the earlywood portion of the tree ring that reduces water transport. Hemlock woolly adelgid (Adelges tsugae Annand) and elongate hemlock scale (Fiorinia externa Ferris) are invasive insects that both feed on eastern hemlock [Tsuga canadensis (L.) Carrière]. Adelges tsugae has a greater effect on tree health than F. externa, but the mechanism underlying their differential effect is unknown. We explored the effects of these herbivores by assessing growth ring formation in branches of trees that had been experimentally infested for 4 yr with A. tsugae, F. externa, or neither insect. We measured false ring density, ring growth, and earlywood: latewood ratios in the two most recently deposited growth rings. Branches from A. tsugae-infested trees had 30% more false rings than branches from F. externa-infested trees and 50% more than branches from uninfested trees. In contrast, branches from F. externa-infested trees and control trees did not differ in false ring formation. Radial growth and earlywood: latewood ratios did not differ among treatments. Our results show that two invasive herbivores with piercing-sucking mouth parts have differing effects on false ring formation in eastern hemlock. These false rings may be the product of a systemic plant hypersensitive response to feeding by A. tsugae on hemlock stems. If false rings are responsible for or symptomatic of hemlock water stress, this may provide a potential explanation for the relatively large effect of A. tsugae infestations on tree health.

  13. Organic and inorganic nitrogen nutrition of western red cedar, western hemlock and salal in mineral N-limited cedar-hemlock forests.

    PubMed

    Bennett, Jennifer N; Prescott, Cindy E

    2004-11-01

    Western red cedar (Thuja plicata Donn.), western hemlock (Tsuga heterophylla Raf. Sarge) and salal (Gaultheria shallon Pursh) are the main species growing in cedar-hemlock forests on Vancouver Island, Canada. Based on the dominance of organic N in these systems, we tested the hypotheses that: (1) organic N can be utilized by the three plant species; and (2) salal, which is ericoid mycorrhizal and has high tannin concentration in its tissues, would absorb more N from the complex organic N compounds than the other two species. The abilities of cedar, hemlock and salal to take up 15N,13C-labelled glutamic acid were measured and the capacities of the three species to use nitrate (NO3-), ammonium (NH4+), glutamic acid, protein and protein-tannin N were compared over a 20-day period. Based on 13C enrichment, all three species absorbed at least a portion of glutamic acid intact. Cedar, hemlock and salal also showed similar patterns of N uptake from the NO3-, NH4+, glutamic acid, protein and protein-tannin treatments. The largest proportions of applied N were taken up from the NO3- and NH4+ treatments while smaller amounts of N were absorbed from the organic N compounds. Thus organic N was accessed to a modest degree by all three species, and salal did not have a greater capacity to utilize protein and protein-tannin-N.

  14. Impacts of dwarf mistletoe on the physiology of host Tsuga heterophylla trees as recorded in tree-ring C and O stable isotopes.

    PubMed

    Marias, Danielle E; Meinzer, Frederick C; Woodruff, David R; Shaw, David C; Voelker, Steven L; Brooks, J Renée; Lachenbruch, Barbara; Falk, Kristen; McKay, Jennifer

    2014-06-01

    Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture and photosynthetic gas exchange and can eventually induce tree death. To investigate the long-term (1886-2010) impacts of dwarf mistletoe on the growth and gas exchange characteristics of host western hemlock, we compared the diameter growth and tree-ring cellulose stable carbon (C) and oxygen (O) isotope ratios (δ(13)Ccell, δ(18)Ocell) of heavily infected and uninfected trees. The relative basal area growth of infected trees was significantly greater than that of uninfected trees in 1886-90, but declined more rapidly in infected than uninfected trees through time and became significantly lower in infected than uninfected trees in 2006-10. Infected trees had significantly lower δ(13)Ccell and δ(18)Ocell than uninfected trees. Differences in δ(18)Ocell between infected and uninfected trees were unexpected given that stomatal conductance and environmental variables that were expected to influence the δ(18)O values of leaf water were similar for both groups. However, estimates of mesophyll conductance (gm) were significantly lower and estimates of effective path length for water movement (L) were significantly higher in leaves of infected trees, consistent with their lower values of δ(18)Ocell. This study reconstructs the long-term physiological responses of western hemlock to dwarf mistletoe infection. The long-term diameter growth and δ(13)Ccell trajectories suggested that infected trees were growing faster than uninfected trees prior to becoming infected and subsequently declined in growth and leaf-level photosynthetic capacity compared with uninfected trees as the dwarf mistletoe infection became severe. This study further points to limitations of the dual-isotope approach for identifying sources of variation in δ(13)Ccell and indicates that changes in leaf internal properties such as gm and L that affect

  15. Binomial sequential sampling plan for hemlock woolly adelgid (Hemiptera: Adelgidae) sistens infesting individual eastern hemlock trees.

    PubMed

    Fidgen, Jeffrey G; Legg, David E; Salom, Scott M

    2006-08-01

    The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an exotic insect pest that is killing eastern hemlock, Tsuga canadensis (L.) Carrière, and Carolina hemlock, Tsuga caroliniana Engelmann, in the eastern United States. We used the sequential interval procedure to develop a binomial sequential sampling plan for A. tsugae sistens on individual eastern hemlock trees that uses nondestructive sampling of new shoots. The actual a (type I) and beta (type II) error rates were essentially 5 and 10%, respectively. Tallies of new shoots infested by at least one A. tsugae sistens were compared with stop values for thresholds of 10 and 30% of new hemlock shoots infested. Twenty to 80 new shoots had to be examined per tree to render a low, high, or indeterminate classification, which took < 2 min per tree regardless of the threshold used. This plan should be an efficient and cost-effective tool in the management of A. tsugae infestations on individual, high-value eastern hemlock trees.

  16. Stem Densities of Trees from Overstocked Mixed Conifer Stands of Western Hemlock, Douglas-fir and Western Redcedar.

    SciTech Connect

    Pong, W.Y.; Waddell, Dale R.; Biomass and Energy Project

    1985-03-15

    This report presents results from a stem density (wood and bark combined) study conducted on trees from overstocked mixed conifer stands of Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla) and western redcedar (Thuja plicata) located on the Quilcene Ranger District, Olympic National Forest in the State of Washington. Information on the density of stem wood that is available in literature generally have been derived from trees growing in stands of normal stocking levels. Stem densities, an essential parameter in the determination of stem biomass, have not been investigated for trees growing in overstocked conditions. Predictive estimators of density based on data derived from studies of normally stocked stands can not be applied to trees growing in an overstocked condition with any reliability. There is need to specifically examine stem densities in trees grown under these adverse conditions. 3 refs., 3 tabs.

  17. Hemlock woolly adelgid (Hemiptera: Adelgidae) induces twig volatiles of eastern hemlock in a forest setting.

    PubMed

    Pezet, Joshua; Elkinton, Joseph S

    2014-10-01

    The hemlock woolly adelgid (Adelges tsugae Annand) is an invasive species causing high mortality of eastern hemlock (Tsuga canadensis (L) Carriere) in the forests of eastern North America. Recent findings revealed that sapling eastern hemlocks artificially infested with hemlock woolly adelgid in a plantation setting responded to the insect with an array of induced resin volatile changes. Here we determine if eastern hemlocks growing beneath a forest canopy respond to hemlock woolly adelgid infestation with the same patterns of constitutive and inducible volatile resin production as those plantation specimens. We inoculated previously uninfested branches of mature and immature hemlocks in a central New England forest with hemlock woolly adelgid. We then sampled twig tissue of infested and uninfested trees in late spring, early summer, and mid-autumn, after known intervals of adelgid activity when an induced response might be expected. We identified and quantified resin volatiles by gas chromatography-mass spectrometry. Constitutive levels of total monoterpenoids, sesquiterpenoids, and combined resin volatiles were all several-fold more abundant in forest trees than those previously measured in a plantation setting, pointing to further study of the influence of site factors on hemlock volatile production. Hemlock woolly adelgid infestation induced an array of changes in eastern hemlock's volatile profile, including many-fold increases in benzyl alcohol and methyl salicylate accumulation. Despite differences in constitutive concentrations of volatiles between the two sites, our findings verify that hemlock woolly adelgid elicits patterns of resin volatile induction in forest-grown eastern hemlocks quite similar to those previously observed in plantation grown trees.

  18. Genetic evaluation of alternative silvicultural systems in coastal montane forests: western hemlock and amabilis fir.

    PubMed

    El-Kassaby, Y A; Dunsworth, B G; Krakowski, J

    2003-08-01

    Genetic diversity and mating system were quantified for shelterwood, patch cut and green tree-retention silvicultural systems, and compared to adjacent old-growth. This is a component of a larger study conducted in montane old-growth forests of coastal British Columbia to evaluate the feasibility and ecological consequences of alternative silvicultural systems. The experiment includes replicated treatments representing a range of overstory removal adjacent to old-growth and clearcut areas. Based on 22 electrophoretically assayed loci, the effects of silvicultural systems on genetic parameters of amabilis fir (Abies amabilis and western hemlock (Tsuga heterophylla were assessed by comparing an average number of alleles per locus, the percent polymorphic loci, and observed and expected heterozygosity between parental populations and naturally regenerated progeny as well as among treatments. Genetic variation in natural regeneration was greater than in parental populations, especially for low-frequency alleles. Silvicultural treatments caused no significant differences in amabilis fir genetic-diversity parameters, while the shelterwood system resulted in lower observed and expected heterozygosity in western hemlock. Nei's genetic distance revealed that all parental populations were extremely similar. The two species had contrasting mating system dynamics with amabilis fir producing higher levels of correlated paternity and inbreeding with wider variation among individual tree outcrossing-rate estimates. Western hemlock had significant levels of correlated paternity only for the green tree and shelterwood treatments demonstrating family structuring inversely related to stand density. Inbreeding in western hemlock was significant but lower than that observed for amabilis fir with a J-shaped distribution for individual tree multilocus outcrossing-rate estimates. The pollination and dispersal mechanisms of the two species represent the most-likely factors causing these

  19. Hemlock woolly adelgid and elongate hemlock scale induce changes in foliar and twig volatiles of eastern hemlock.

    PubMed

    Pezet, Joshua; Elkinton, Joseph; Gomez, Sara; McKenzie, E Alexa; Lavine, Michael; Preisser, Evan

    2013-08-01

    Eastern hemlock (Tsuga canadensis) is in rapid decline because of infestation by the invasive hemlock woolly adelgid (Adelges tsugae; 'HWA') and, to a lesser extent, the invasive elongate hemlock scale (Fiorinia externa; 'EHS'). For many conifers, induced oleoresin-based defenses play a central role in their response to herbivorous insects; however, it is unknown whether eastern hemlock mobilizes these inducible defenses. We conducted a study to determine if feeding by HWA or EHS induced changes in the volatile resin compounds of eastern hemlock. Young trees were experimentally infested for 3 years with HWA, EHS, or neither insect. Twig and needle resin volatiles were identified and quantified by gas chromatography/mass spectrometry. We observed a suite of changes in eastern hemlock's volatile profile markedly different from the largely terpenoid-based defense response of similar conifers. Overall, both insects produced a similar effect: most twig volatiles decreased slightly, while most needle volatiles increased slightly. Only HWA feeding led to elevated levels of methyl salicylate, a signal for systemic acquired resistance in many plants, and benzyl alcohol, a strong antimicrobial and aphid deterrent. Green leaf volatiles, often induced in wounded plants, were increased by both insects, but more strongly by EHS. The array of phytochemical changes we observed may reflect manipulation of the tree's biochemistry by HWA, or simply the absence of functional defenses against piercing-sucking insects due to the lack of evolutionary contact with these species. Our findings verify that HWA and EHS both induce changes in eastern hemlock's resin chemistry, and represent the first important step toward understanding the effects of inducible chemical defenses on hemlock susceptibility to these exotic pests.

  20. Laboratory studies of feeding and oviposition preference, developmental performance, and survival of the predatory beetle, Sasajiscymnus tsugae on diets of the woolly adelgids, Adelges tsugae and Adelges piceae.

    PubMed

    Jetton, Robert M; Monahan, John F; Hain, Fred P

    2011-01-01

    The suitability of the balsam woolly adelgid, Adelges piceae Ratzeburg (Hemiptera: Adelgidae) as an alternate mass rearing host for the adelgid predator, Sasajiscymnus tsugae Sasaji and McClure (Coleoptera: Coccinellidae) was studied in the laboratory. This predator is native to Japan and has been introduced to eastern hemlock, Tsuga canadensis (L.) Carrière (Pinales: Pinaceae), forests throughout the eastern United States for biological control of the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), also of Japanese origin. Feeding, oviposition, immature development, and adult long-term survival of S. tsugae were tested in a series of no choice (single-prey) and paired-choice experiments between the primary host prey, A. tsugae, and the alternate host prey, A. piceae. In paired-choice feeding tests, the predator did not discriminate between eggs of the two adelgid species, but in the no choice tests the predator did eat significantly more eggs of A. piceae than those of A. tsugae. S. tsugae accepted both test prey for oviposition and preferred to lay eggs on adelgid infested versus noninfested host plants. Overall oviposition rates were very low (< 1 egg per predator female) in the oviposition preference tests. Predator immature development rates did not differ between the two test prey, but only 60% of S. tsugae survived egg to adult development when fed A. piceae compared to 86% when fed A. tsugae. S. tsugae adult long-term survival was significantly influenced (positively and negatively) by prey type and the availability of a supplemental food source (diluted honey) when offered aestivating A. tsugae sistens nymphs or ovipositing aestivosistens A. piceae adults, but not when offered ovipositing A. tsugae sistens adults. These results suggest that the development of S. tsugae laboratory colonies reared on a diet consisting only of A. piceae may be possible, and that the biological control potential of the predator might be expanded to

  1. Impacts of trunk and soil injections of low rates of imidacloprid on hemlock woolly adelgid (Hemiptera: Adelgidae) and eastern hemlock (Pinales: Pinaceae) health.

    PubMed

    Eisenback, Brian M; Salom, Scott M; Kok, Loke T; Lagalante, Anthony F

    2014-02-01

    Eastern hemlocks (Tsuga canadensis Carrière) at two sites in southwestern Virginia were treated by trunk and soil injections of imidacloprid to determine the insecticide's impact on hemlock woolly adelgid, Adelges tsugae Annand. Treatments were 25, 50, and 100% of the highest labeled dosage rates for both stem and soil injection. Three and 4 yr after treatment, the half and full rates had significantly reduced A. tsugae populations, which were accompanied by increased new hemlock shoot growth and higher hemlock health scores on a visual rating of tree appearance. Imidacloprid and metabolite concentrations in tissue of treated trees were determined by liquid chromatography-tandem mass spectrometry, and A. tsugae density decreased as imidacloprid concentrations increased in wood tissue. There were no observed A. tsugae populations in all trees with imidacloprid tissue concentrations >413 ppb. Olefin, di-hydroxy, and 6-chloro-nicotinic-acid metabolites were the imidacloprid metabolites recovered in the highest concentrations. This suggests that hemlock metabolism of imidacloprid may increase efficacy of the parent compound. Stem and soil treatments of low rates of systemic imidacloprid reduce adelgid populations and promote hemlock health, but still may provide a remnant food source for beneficial predators.

  2. Comparison of numerical response and predation effects of two coccinellid species on hemlock woolly adelgid (Homoptera: Adelgidae).

    PubMed

    Butin, Elizabeth; Elkinton, Joseph; Havill, Nathan; Montgomery, Michael

    2003-06-01

    The hemlock woolly adelgid, Adelges tsugae Annand, is an introduced pest in North America that is native to Asia, and is causing extensive damage to eastern hemlock (Tsuga canadensis Carriere) and Carolina hemlock (Tsuga caroliniana Englemann) in the eastern United States. We compared two coccinellids imported for biological control of the adelgid: Scymnus ningshanensis Yu et Yao from China and Pseudoscymnus tsugae Sasaji and McClure from Japan. In a laboratory study, we measured the numerical response of each beetle species to a range of prey densities, and in field studies we examined the reproductive success and ability of the coccinellids to reduce populations of the hemlock woolly adelgid. In the laboratory, S. ningshanensis showed a positive numerical response as hemlock woolly adelgid density increased, and P. tsugae showed a density-independent response. In field cages, the presence of S. ningshanensis resulted in negative hemlock woolly adelgid population growth, in contrast to positive growth in both control cages and cages containing P. tsugae. Both our laboratory and field experiments suggest that S. ningshanensis has good potential as a biological control agent of hemlock woolly adelgid.

  3. Mid-Holocene Hemlock Decline in Eastern North America Linked with Phytophagous Insect Activity

    NASA Astrophysics Data System (ADS)

    Bhiry, Najat; Filion, Louise

    1996-05-01

    Macrofossil evidence indicates that the mid-Holocene hemlock [ Tsuga canadensisL. (Carr.)] decline that occurred over a wide area in eastern North America was associated with phytophagous insect activity. In situhemlock macrofossils and insect remains found in a paludified dunefield at the northern limit of hemlock testify that two defoliation events occurred at 4910 ± 90 and 4200 ± 100 yr B.P., respectively. The sharp coincidence of remains from hemlock needles with chewing damage typical of hemlock looper feeding, head capsules from the hemlock looper ( Lambdina fiscellaria) and the spruce budworm ( Choristoneura fumiferana), absence of hemlock fruiting remains, and tree-ring anomalies in fossil hemlocks that died prematurely (<165 yr) suggest that defoliation affected hemlock reproductive capacity and pollen productivity, or more likely caused mass mortality. Our findings indicate that defoliation can affect ecosystems for centuries, especially when long-lived tree species are involved.

  4. Hydraulic architecture and photosynthetic capacity as constraints on release from suppression in Douglas-fir and western hemlock.

    PubMed

    Renninger, Heidi J; Meinzer, Frederick C; Gartner, Barbara L

    2007-01-01

    We compared hydraulic architecture, photosynthesis and growth in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), a shade-intolerant species, and western hemlock (Tsuga heterophylla (Raf.) Sarg.), a shade-tolerant species, to study the temporal pattern of release from suppressive shade. In particular, we sought to determine whether hydraulic architecture or photosynthetic capacity is most important in constraining release. The study was conducted at two sites with mixed stands of 10- to 20-year-old Douglas-fir and western hemlock. At one site, the stand had been thinned allowing release of the understory trees, whereas at the other site, the stand remained unthinned. Douglas-fir had lower height growth (from 1998-2003) and lower relative height growth (height growth from 1998 to 2003/height in 1998) than western hemlock. However, relative height growth of released versus suppressed trees was higher in Douglas-fir (130%) than in western hemlock (65%), indicating that, although absolute height growth was less, Douglas-fir did release from suppression. Release seemed to be constrained initially by a limited photosynthetic capacity in both species. Five years after release, Douglas-fir trees had 14 times the leaf area and 1.5 times the leaf nitrogen concentration (N (area)) of suppressed trees. Needles of released western hemlock trees had about twice the maximum assimilation rate (A (max)) at ambient [CO(2)] as needles of suppressed trees and exhibited no photoinhibition at the highest irradiances. After release, trees increased in leaf area, leaf N concentration and overall photosynthetic capacity. Subsequently, hydraulic architecture appeared to constrain release in Douglas-fir and, to a lesser extent, in western hemlock. Released trees had significantly less negative foliar delta(13)C values than suppressed trees and showed a positive relationship between leaf area:sapwood area ratio (A (L)/A (S)) and delta(13)C, suggesting that trees with more leaf area for a

  5. Water use and carbon exchange of red oak- and eastern hemlock-dominated forests in the northeastern USA: implications for ecosystem-level effects of hemlock woolly adelgid.

    PubMed

    Hadley, Julian L; Kuzeja, Paul S; Daley, Michael J; Phillips, Nathan G; Mulcahy, Thomas; Singh, Safina

    2008-04-01

    Water use and carbon exchange of a red oak-dominated (Quercus rubra L.) forest and an eastern hemlock-dominated (Tsuga canadensis L.) forest, each located within the Harvard Forest in north-central Massachusetts, were measured for 2 years by the eddy flux method. Water use by the red oak forest reached 4 mm day(-1), compared to a maximum of 2 mm day(-1) by the eastern hemlock forest. Maximal carbon (C) uptake rate was also higher in the red oak forest than in the eastern hemlock forest (about 25 versus 15 micromol m(-2) s(-1)). Sap flux measurements indicated that transpiration of red oak, and also of black birch (Betula lenta L.), which frequently replaces eastern hemlock killed by hemlock woolly adelgid (Adelges tsugae Annand.), were almost twice that of eastern hemlock. Despite the difference between species in maximum summertime C assimilation rate, annual C storage of the eastern hemlock forest almost equaled that of the red oak forest because of net C uptake by eastern hemlock during unusually warm fall and spring weather, and a near-zero C balance during the winter. Thus, the effect on C storage of replacing eastern hemlock forest with a forest dominated by deciduous species is unclear. Carbon storage by eastern hemlock forests during fall, winter and spring is likely to increase in the event of climate warming, although this may be offset by C loss during hotter summers. Our results indicate that, although forest water use will decrease immediately following eastern hemlock mortality due to the hemlock woolly adelgid, the replacement of eastern hemlock by deciduous species such as red oak will likely increase summertime water use over current rates in areas where hemlock is a major forest species.

  6. Canopy light transmittance in Douglas-fir--western hemlock stands.

    PubMed

    Parker, Geoffrey G; Davis, Melinda M; Chapotin, Saharah Moon

    2002-02-01

    We measured vertical and horizontal variation in canopy transmittance of photosynthetically active radiation in five Pseudotsuga menziesii (Mirb.) Franco-Tsuga heterophylla (Raf.) Sarg. (Douglas-fir-western hemlock) stands in the central Cascades of southern Washington to determine how stand structure and age affect the forest light environment. The shape of the mean transmittance profile was related to stand height, but height of mean maximum transmittance was progressively lower than maximum tree height in older stands. The vertical rate of attenuation declined with stand age in both the overstory and understory. A classification of vertical light zones based on the mean and variance of transmittance showed a progressive widening of the bright (low variance and high mean) and transition (high variance and rapid vertical change) zones in older stands, whereas the dim zone (low variance and mean) narrowed. The zone of maximum canopy surface area in height profiles, estimated by inversion of transmittance profiles, changed from relatively high in the canopy in most young stands ("top-heavy") to lower in the canopy in older stands ("bottom-heavy"). In the understory, all stands had similar mean transmittances, but the spatial scale of variation increased with stand age and increasing crown size. The angular distribution of openness was similar in all stands, though the older stands were less open at all angles than the younger stands. Understory openness was generally unrelated to transmittance in the canopy above. Whole-canopy leaf area indices, estimated using three methods of inverting light measurements, showed little correspondence across methods. The observed patterns in light environment are consistent with structural changes occurring during stand development, particularly the diversification of crowns, the creation of openings of various sizes and the elaboration of the outer canopy surface. The ensemble of measurements has potential use in distinguishing

  7. Biomass Distribution in Western Hemlock, Douglas-Fir and Western Redcedar.

    SciTech Connect

    Pong, W.Y.; Waddell, Dale R.; Biomass and Energy Project

    1986-05-30

    This report presents results from a study characterizing the weight and volume of trees from overstocked (doghair) mixed conifer stands of Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla) and western redcedar (Thuja plicata) located on the Quilcene Ranger District, Olympic National Forest. There are approximately 20,000 acres classed as doghair on the Quilcene District. In order to evaluate their harvesting and utilization potential accurate estimates of volume and weight of entire trees and stands are needed. The objective of this study was to characterize the biomass of the three major tree species located in overstocked stands by providing estimators to predict the green and dry weight of the total tree, as well as separate predictions for the components of stem and crown. Additional objectives included estimates for the weight of the 'standing dead', the weight of the dead material on the forest floor, and estimators to predict the cubic volume of the wood and bark in the stems. 11 refs., 9 figs., 15 tabs.

  8. Assessing the potential impacts to riparian ecosystems resulting from hemlock mortality in Great Smoky Mountains National Park.

    PubMed

    Roberts, Scott W; Tankersley, Roger; Orvis, Kenneth H

    2009-08-01

    Hemlock Woolly Adelgid (Adelges tsugae) is spreading across forests in eastern North America, causing mortality of eastern hemlock (Tsuga canadensis [L.] Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.). The loss of hemlock from riparian forests in Great Smoky Mountains National Park (GSMNP) may result in significant physical, chemical, and biological alterations to stream environments. To assess the influence of riparian hemlock stands on stream conditions and estimate possible impacts from hemlock loss in GSMNP, we paired hardwood- and hemlock-dominated streams to examine differences in water temperature, nitrate concentrations, pH, discharge, and available photosynthetic light. We used a Geographic Information System (GIS) to identify stream pairs that were similar in topography, geology, land use, and disturbance history in order to isolate forest type as a variable. Differences between hemlock- and hardwood-dominated streams could not be explained by dominant forest type alone as forest type yields no consistent signal on measured conditions of headwater streams in GSMNP. The variability in the results indicate that other landscape variables, such as the influence of understory Rhododendron species, may exert more control on stream conditions than canopy composition. The results of this study suggest that the replacement of hemlock overstory with hardwood species will have minimal impact on long-term stream conditions, however disturbance during the transition is likely to have significant impacts. Management of riparian forests undergoing hemlock decline should, therefore, focus on facilitating a faster transition to hardwood-dominated stands to minimize long-term effects on water quality.

  9. Carbon isotope discrimination in western hemlock and its relationship to mineral nutrition and growth.

    PubMed

    Walia, Ankit; Guy, Robert D; White, Barry

    2010-06-01

    Western hemlock (Tsuga heterophylla [Raf.] Sarg.) is a major component of temperate rainforests in coastal British Columbia. Forest fertilization can enhance the growth of forest trees, but results are inconsistent for western hemlock. We investigated the relationship between delta13C (foliage and stemwood), growth response and tree nutritional status in this species. To establish a sampling protocol for stemwood, we first assessed spot-to-spot variation around and along the bole, which exceeded 1 per thousand. We utilized the reaction wood (high lignin content) and adjacent normal wood in two curved western hemlock stems to evaluate whether this variation was related to wood composition. There was a consistent 3.43 per thousand difference between lignin and holocellulose, but the isotopic mass balance of whole wood was conserved and, therefore, did not vary with lignin content. Therefore, extraction of cellulose or holocellulose prior to analysis can introduce (not remove) bias. In a detailed study of a third stem, circumferential and longitudinal variation in delta13C was associated with spiral grain indicating limited physiological mixing of isotopic signatures originating from the crown. Wood was subsequently pooled from four cardinal positions around each stem. Eight even-aged western hemlock stands were selected and fertilized with different combinations of nitrogen (N), phosphorous (P) and a blend of S, K, Mg, Zn and Cu. Fertilization was effective in increasing foliar N, P, K and S depending on treatment. At the end of the first growing season after fertilization, the effect of treatments on foliar delta13C was nearly significant (P = 0.054), but did not persist into a second year. Effects on tree-ring delta13C were more obvious and persisted for about 3 years, averaging approximately 0.2-0.4 per thousand over this period, depending on treatment. Combinations of N, P and blend had the greatest effect, consistent with relative increases in basal area

  10. Ganodone, a bioactive benzofuran from the fruiting bodies of Ganoderma tsugae.

    PubMed

    La Clair, James J; Rheingold, Arnold L; Burkart, Michael D

    2011-10-28

    Extracts of Ganoderma tsugae, also known as the Hemlock varnish shelf mushroom, and related Reishi mushrooms are well documented in traditional Chinese medicine. Several Ganoderma sp. are currently cultivated for use in coffee, teas, and dietary supplements. We now report on the isolation and characterization of an unprecedented benzofuran, ganodone (1), from the fruiting bodies of mature growth G. tsugae. This discovery provides a key next step in evaluating the active components in their associated herbal supplements.

  11. Oak seedling growth and ectomycorrhizal colonization are less in eastern hemlock stands infested with hemlock woolly adelgid than in adjacent oak stands.

    PubMed

    Lewis, James D; Licitra, Jeff; Tuininga, Amy R; Sirulnik, Abby; Turner, Gregory D; Johnson, Jacqui

    2008-04-01

    Invasive, non-indigenous, phytophagous insects have caused widespread declines in several dominant tree species. The decline in dominant tree species may lead to cascading effects on other tree and microbial species and their interactions, affecting forest recovery following the decline. In the eastern USA, eastern hemlock (Tsuga canadensis (L.) Carr) is declining because of infestation by the hemlock woolly adelgid (HWA; Adelges tsugae Annand). Northern red oak (Quercus rubra L.) is a common replacement species in declining hemlock stands, but reduced mycorrhizal inoculum potential in infested hemlock stands may cause oak to grow more slowly compared with oak in oak stands. We grew red oak seedlings for one growing season in declining hemlock-dominated stands infested with HWA and in adjacent oak-dominated stands. Ectomycorrhizal root tip density and morphotype richness in soil cores were 63 and 27% less, respectively, in declining hemlock stands than in oak stands. Similarly, ectomycorrhizal percent colonization and morphotype richness on oak seedlings were 33 and 30% less, respectively, in declining hemlock stands than in oak stands. In addition, oak seedlings in declining hemlock stands had 29% less dry mass than oak seedlings in oak stands. Analysis of covariance indicated that morphotype richness could account for differences in oak seedling dry mass between declining hemlock stands and oak stands. Additionally, oak seedling dry mass in declining hemlock stands significantly decreased with decreasing ectomycorrhizal percent colonization and morphotype richness. These results suggest that oak seedling growth in declining hemlock stands is affected by reduced ectomycorrhizal inoculum potential. Further, the rate of forest recovery following hemlock decline associated with HWA infestation may be slowed by indirect effects of HWA on the growth of replacement species, through effects on ectomycorrhizal colonization and morphotype richness.

  12. Prey suitability and phenology of Leucopis spp. (Diptera: Chamaemyiidae) associated with hemlock woolly adelgid (Hemiptera: Adelgidae) in the Pacific Northwest.

    PubMed

    Grubin, Sarah M; Ross, Darrell W; Wallin, Kimberly F

    2011-12-01

    Leucopis spp. (Diptera: Chamaemyiidae) from the Pacific Northwest previously were identified as potential biological control agents for the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in the eastern United States. We collected Leucopis spp. larvae from A. tsugae infested western hemlocks in Oregon and Washington and reared them on an unidentified Pineus spp., Pineus strobi (Hartig), Adelges cooleyi (Gillette), Adelges piceae (Ratzeburg), and A. tsugae in three no-choice tests. Leucopis spp. survival on A. tsugae was significantly higher than on A. piceae during the 2010 progrediens generation test and significantly higher than on P. strobi and A. cooleyi during the 2010 sistens generation test. However, across all three tests, some larvae completed development to adult on all four of the alternative adelgid species. Larvae that survived to the adult stage were identified as Leucopis argenticollis Zetterstedt and Leucopis piniperda Malloch. These results suggest that populations of L. argenticollis and L. piniperda in the Pacific Northwest may not be specific to A. tsugae. We also studied the phenology of Leucopis spp. on fourteen A. tsugae infested western hemlock trees in Oregon and Washington over a period of 14 mo. Leucopis spp. larvae were collected year-round, but highest densities coincided with the presence of progrediens and sistens eggs and adults of A. tsugae. There was a positive correlation between Leucopis spp. and A. tsugae abundance.

  13. Hydraulic responses to environmental perturbations in Tsuga canadensis and Betula lenta.

    PubMed

    Daley, Michael J; Phillips, Nathan G; Pettijohn, Justin C; Hadley, Julian

    2008-09-01

    Eastern hemlock (Tsuga canadensis (L). Carr.) is a late-successional species found across the northeastern United States of America that is currently threatened by the exotic pest, hemlock woolly adelgid (Adelges tsugae Annand). Because whole-tree physiological characteristics may scale to influence ecosystem processes, we considered whole-tree hydraulic controls in eastern hemlock and the replacement species black birch (Betula lenta L.). Through a series of misting perturbations, whole-tree resistances (R), capacitances (C) and time constants (tau) were determined from time series sap flux data in eastern hemlock and black birch. Black birch trees responded more rapidly to environmental perturbations than eastern hemlock. Utilizing the step function after applied treatments, whole-tree tau ranged between 9.4 and 24.8 min in eastern hemlock trees compared with 5.9 to 10.5 min in black birch. Species was not a significant predictor of R or C when controlling for tree size. In both species, R decreased with sapwood area and C increased. Our tau results indicate that the loss and replacement of eastern hemlock by black birch will decrease the lag between transpiration and absorption of water from the soil and potentially alter the diurnal pattern of carbon and water uptake.

  14. Web orientation and prey resources for web-building spiders in eastern hemlock.

    PubMed

    Mallis, Rachael E; Rieske, Lynne K

    2010-10-01

    We examined the arthropod community on eastern hemlock, Tsuga canadensis (L.) Carr, in the context of its role in providing potential prey items for hemlock-associated web-weaving spiders. Using sticky traps simulating spider webs, we evaluated what prey items are available to web-weaving spiders in eastern hemlock based on web orientation (horizontal versus vertical) and cardinal direction. We found that the overwhelming majority (>70%) of prey items available to spiders in hemlock canopies were Diptera. Psocoptera, Hymenoptera, and Hemiptera comprised most of the remaining potential prey. A significant direction × orientation interaction, and greater trap capture in some direction-orientation combinations, suggests that spiders might locate their webs in eastern hemlock canopies for thermoregulatory purposes, ultimately optimizing prey capture. We also evaluated these findings in the context of hemlock infestation by the invasive hemlock woolly adelgid, Adelges tsugae Annand. The adelgid is a sedentary insect with a mobile crawler stage that provides a readily available, easily obtained food source for predators in hemlock canopies. However, an abundance of alternative prey will affect within canopy spider distribution and the potential intensity with which spiders consume these prey. Understanding the response of spiders to potential prey availability is essential to understanding the trophic interactions involving these predators and their potential for influencing herbivore populations.

  15. Spatial tools for managing hemlock woolly adelgid in the southern Appalachians

    NASA Astrophysics Data System (ADS)

    Koch, Frank Henry, Jr.

    The hemlock woolly adelgid (Adelges tsugae) has recently spread into the southern Appalachians. This insect attacks both native hemlock species (Tsuga canadensis and T. caroliniana ), has no natural enemies, and can kill hemlocks within four years. Biological control displays promise for combating the pest, but counter-measures are impeded because adelgid and hemlock distribution patterns have been detailed poorly. We developed a spatial management system to better target control efforts, with two components: (1) a protocol for mapping hemlock stands, and (2) a technique to map areas at risk of imminent infestation. To construct a hemlock classifier, we used topographically normalized satellite images from Great Smoky Mountains National Park. Employing a decision tree approach that supplemented image spectral data with several environmental variables, we generated rules distinguishing hemlock areas from other forest types. We then implemented these rules in a geographic information system and generated hemlock distribution maps. Assessment yielded an overall thematic accuracy of 90% for one study area, and 75% accuracy in capturing hemlocks in a second study area. To map areas at risk, we combined first-year infestation locations from Great Smoky Mountains National Park and the Blue Ridge Parkway with points from uninfested hemlock stands, recording a suite of environmental variables for each point. We applied four different multivariate classification techniques to generate models from this sample predicting locations with high infestation risk, and used the resulting models to generate risk maps for the study region. All techniques performed well, accurately capturing 70--90% of training and validation samples, with the logistic regression model best balancing accuracy and regional applicability. Areas close to trails, roads, and streams appear to have the highest initial risk, perhaps due to bird- or human-mediated dispersal. Both components of our management

  16. The ecology of energy and nutrient fluxes in hemlock forests invaded by hemlock woolly adelgid.

    PubMed

    Stadler, Bernhard; Müller, Thomas; Orwig, David

    2006-07-01

    The hemlock woolly adelgid (HWA, Adelges tsugae Annand) is currently causing a severe decline in vitality and survival of eastern hemlock in North American forests. We analyzed the effects of light HWA infestation on vertical energy and nutrient fluxes from the canopy to the forest floor. Canopy throughfall, litter lysimeters, and laboratory litter microcosms were used to examine the effects of HWA-affected and unaffected throughfall on litter type, leachate, and litter chemistry. Early in the season adelgid infestation caused higher dissolved organic carbon (DOC; +24.6%), dissolved organic nitrogen (DON; +28.5%), and K (+39.3%) fluxes and lower inorganic nitrogen fluxes (-39.8%) in throughfall and in adjacent litter solutions collected beneath infested compared to uninfested trees. Needle litter collected beneath uninfested hemlock had significantly lower N concentrations compared to needles collected beneath infested trees, while no difference in N concentrations was found in birch litter. Bacteria were significantly more abundant on hemlock and birch litter beneath infested trees, while yeasts and filamentous fungi showed no consistent response to HWA throughfall. Litter microcosms showed that less DOC was leaching from birch than from hemlock needles when exposed to HWA throughfall. Overall, NH4-N and DON leachate concentrations were higher from birch than from hemlock litter. Thus, HWA-affected throughfall leads to qualitative and quantitative differences in nitrogen export from the litter layer. The N concentration of hemlock litter did not change with time, but the N concentration in birch litter increased significantly during the course of the experiment, especially when HWA-affected throughfall was applied. We suggest a nonlinear conceptual model for the temporal and vertical transition of energy and nutrient fluxes relative to progressing HWA infestation from a pure hemlock to a birch/maple-dominated forest. Progressive needle loss and changes in needle

  17. Spatial and temporal distribution of imidacloprid in eastern hemlock in the southern Appalachians.

    PubMed

    Dilling, Carla; Lambdin, Paris; Grant, Jerome; Rhea, Rusty

    2010-04-01

    The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an exotic insect species dramatically reducing populations of eastern hemlock, Tsuga canadensis (L.) Carrieré, throughout the eastern United States. Systemic imidacloprid is one of the primary chemicals used to successfully control infestations of the hemlock woolly adelgid. The concentration levels for this systemic insecticide present in the sap of eastern hemlocks were evaluated from three strata within the canopy over a two year time span. Enzyme-linked immunosorbent assays were conducted every three months posttreatment to assess imidacloprid concentration within the sap. The effect of application timing (fall versus spring) and application method (soil drench, soil injection, and tree injection) on the translocation of imidacloprid throughout the canopy, and the quantity of imidacloprid translocated in the sap of eastern hemlock branches and the terminal twig and needle tissue was determined. Concentration levels progressively declined from the bottom strata to the top strata of the canopy. This trend was consistent in all chemically treated trees. Tree injections provided the lowest concentration and the most nonuniform distribution of imidacloprid throughout the canopy. The highest insecticide concentrations within the tree across all strata over the two year period were consistently associated with the soil drench method followed by the soil injection method. Imidacloprid concentrations peaked between month 9 and 12 posttreatment, and then declined; however, at two years posttreatment, soil drench and soil injected trees contained concentrations reported as being effective for control of the hemlock woolly adelgid.

  18. Effects of fertilizer and low rates of imidacloprid on Adelges tsugae (Hemiptera: Adelgidae).

    PubMed

    Joseph, S V; Hanula, J L; Braman, S K; Byrne, F J

    2011-06-01

    Healthy hemlock trees, Tsuga canadensis (L.) Carrière, and hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), populations should favor retention and population growth of adelgid predators such as Laricobius nigrinus Fender (Coleoptera: Derodontidae) and Sasajiscymnus tsugae (Sasaji & McClure) (Coleoptera: Coccinellidae). Eastern hemlock trees between 15 and 38 cm diameter at breast height (dbh) were treated with 0, 10, or 25% of 1.5 g imidacloprid (Merit 75 WP) per 2.5 cm dbh and were either fertilized or not, in a 3 by 2 factorial design. After 2 yr, imidacloprid reduced the numbers of ovisacs and eggs found on trees in a dosage-dependent manner, while enhancing tree growth parameters such as new shoots or needles and the length of new shoots. Fertilized trees had greater adelgid fecundity, which was positively correlated with total foliar N in both winter generations. In February 2009 (27 mo after imidacloprid treatment), higher imidacloprid dosages to unfertilized trees resulted in reduced adelgid fecundity. Concentrations of N, P, and K were higher in the foliage of trees treated with insecticide, whereas foliar aluminum concentrations were consistently lower in trees with higher insecticide dosages. Trees treated with low rates of imidacloprid were healthier than untreated trees, but only trees treated with the 0.1 x dosage had sufficient adelgids to possibly sustain predators over extended periods.

  19. Spatial and Temporal Distribution of Imidacloprid Within the Crown of Eastern Hemlock

    PubMed Central

    Turcotte, Richard M.; Lagalante, Anthony; Jones, Jonathan; Cook, Frank; Elliott, Thomas; Billings, Anthony A.; Park, Yong-Lak

    2017-01-01

    Systemic imidacloprid is the most widely used insecticide to control the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), an exotic pest of eastern hemlock, Tsuga canadensis (L.) Carriére in the United States. This study was conducted to 1) determine the effect of treatment timing (spring vs. fall) and application method (trunk injection vs. soil injection) on the spatial and temporal distribution of imidacloprid within the crown of A. tsugae-free eastern hemlock using a competitive enzyme-linked immunosorbent assay (ELISA), 2) compare ELISA to gas chromatography-mass spectrometry (GC/MS) for the detection of imidacloprid in xylem fluid, and 3) determine the concentration of imidacloprid in leaf tissue using high performance liquid chromatography with tandem mass spectrometric (LC/MS/MS) detection methods. Xylem fluid concentrations of imidacloprid were found to be significantly higher for spring applications than for fall applications and for trunk injections than soil injections in the first year posttreatment. A total of 69% of samples analyzed by ELISA gave 1.8 times higher concentrations of imidacloprid than those found by GC/MS, leading to evidence of a matrix effect and overestimation of imidacloprid in xylem fluid by ELISA. A comparison of the presence of imidacloprid with xylem fluid and in leaf tissue on the same branch showed significant differences, suggesting that imidacloprid moved intermittently within the crown of eastern hemlock. PMID:28130463

  20. Spatial and Temporal Distribution of Imidacloprid Within the Crown of Eastern Hemlock.

    PubMed

    Turcotte, Richard M; Lagalante, Anthony; Jones, Jonathan; Cook, Frank; Elliott, Thomas; Billings, Anthony A; Park, Yong-Lak

    2017-01-01

    Systemic imidacloprid is the most widely used insecticide to control the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), an exotic pest of eastern hemlock, Tsuga canadensis (L.) Carriére in the United States. This study was conducted to 1) determine the effect of treatment timing (spring vs. fall) and application method (trunk injection vs. soil injection) on the spatial and temporal distribution of imidacloprid within the crown of A. tsugae-free eastern hemlock using a competitive enzyme-linked immunosorbent assay (ELISA), 2) compare ELISA to gas chromatography-mass spectrometry (GC/MS) for the detection of imidacloprid in xylem fluid, and 3) determine the concentration of imidacloprid in leaf tissue using high performance liquid chromatography with tandem mass spectrometric (LC/MS/MS) detection methods. Xylem fluid concentrations of imidacloprid were found to be significantly higher for spring applications than for fall applications and for trunk injections than soil injections in the first year posttreatment. A total of 69% of samples analyzed by ELISA gave 1.8 times higher concentrations of imidacloprid than those found by GC/MS, leading to evidence of a matrix effect and overestimation of imidacloprid in xylem fluid by ELISA. A comparison of the presence of imidacloprid with xylem fluid and in leaf tissue on the same branch showed significant differences, suggesting that imidacloprid moved intermittently within the crown of eastern hemlock.

  1. Host Range Specificity of Scymnus camptodromus (Coleoptera: Coccinellidae), A Predator of Hemlock Woolly Adelgid (Hemiptera: Adelgidae).

    PubMed

    Limbu, Samita; Cassidy, Katie; Keena, Melody; Tobin, Patrick; Hoover, Kelli

    2016-02-01

    Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae) was brought to the United States from China as a potential biological control agent for hemlock woolly adelgid (Adelges tsugae Annand) (Hemiptera: Adelgidae). Scymnus camptodromus phenology is closely synchronized with that of A. tsugae and has several characteristics of a promising biological control agent. As a prerequisite to field release, S. camptodromus was evaluated for potential nontarget impacts. In host range studies, the predator was given the choice of sympatric adelgid and nonadelgid prey items. Nontarget testing showed that S. camptodromus will feed to some degree on other adelgid species, but highly prefers A. tsugae. We also evaluated larval development of S. camptodromus on pine bark adelgid (Pineus strobi (Hartig)) (Hemiptera: Adelgidae) and larch adelgid (Adelges laricis Vallot) (Hemiptera: Adelgidae); a small proportion of predator larvae was able to develop to adulthood on P. strobi or A. laricis alone. Scymnus camptodromus showed no interest in feeding on woolly alder aphid (Paraprociphilus tessellatus Fitch) (Hemiptera: Aphididae) or woolly apple aphid (Eriosoma lanigerum (Hausmann)) (Hemiptera: Aphididae), and minimal interest in cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) in choice and no-choice experiments. Scymnus camptodromus females did not oviposit on any host material other than A. tsugae-infested hemlock. Under the circumstances of the study, S. camptodromus appears to be a specific predator of A. tsugae, with minimal risk to nontarget species. Although the predator can develop on P. strobi, the likelihood that S. camptodromus would oviposit on pine hosts of this adelgid is small.

  2. Density-dependent survival and fecundity of hemlock woolly adelgid (Hemiptera: Adelgidae).

    PubMed

    Sussky, Elizabeth M; Elkinton, Joseph S

    2014-10-01

    The hemlock woolly adelgid (Adelges tsugae Annand) has decimated eastern hemlocks (Tsuga canadensis Carrière) in forests throughout the eastern United Sates, but its densities in central New England appear to have stabilized. To find out why, we infested 64 eastern hemlocks with varying densities of adelgid ovisacs in a typical eastern hemlock forest in western Massachusetts. We subsequently documented adelgid density, fecundity, and the amount of new growth on experimental trees over two consecutive years. We used a 2 by 2 randomized block design using previously and newly infested hemlocks that were either 1-m tall saplings or branches of mature trees. There was a density-dependent decline in the survival and fecundity of adelgid in both the spring and winter generations. This response was a function of both previous infestation by adelgid and current year's crawler density in the spring generation. Additionally, the production of sexuparae in the spring generation played a key role in the overall density-dependent survival of adelgid, suggesting that sexuparae production is strongly linked to developing crawler density.

  3. Future species composition will affect forest water use after loss of eastern hemlock from southern Appalachian forests.

    PubMed

    Brantley, Steven; Ford, Chelcy R; Vose, James M

    2013-06-01

    Infestation of eastern hemlock (Tsuga canadensis (L.) Carr.) with hemlock woolly adelgid (HWA, Adelges tsugae) has caused widespread mortality of this key canopy species throughout much of the southern Appalachian Mountains in the past decade. Because eastern hemlock is heavily concentrated in riparian habitats, maintains a dense canopy, and has an evergreen leaf habit, its loss is expected to have a major impact on forest processes, including transpiration (E(t)). Our goal was to estimate changes in stand-level E(t) since HWA infestation, and predict future effects of forest regeneration on forest E(t) in declining eastern hemlock stands where hemlock represented 50-60% of forest basal area. We used a combination of community surveys, sap flux measurements, and empirical models relating sap flux-scaled leaf-level transpiration (E(L)) to climate to estimate the change in E(t) after hemlock mortality and forecast how forest E(t) will change in the future in response to eastern hemlock loss. From 2004 to 2011, eastern hemlock mortality reduced annual forest E(t) by 22% and reduced winter E(t) by 74%. As hemlock mortality increased, growth of deciduous tree species--especially sweet birch (Betula lenta L.), red maple (Acer rubrum L.), yellow poplar (Liriodendron tulipifera L.), and the evergreen understory shrub rosebay rhododendron (Rhododendron maximum L.)--also increased, and these species will probably dominate post-hemlock riparian forests. All of these species have higher daytime E(L) rates than hemlock, and replacement of hemlock with species that have less conservative transpiration rates will result in rapid recovery of annual stand E(t). Further, we predict that annual stand E(t) will eventually surpass E(t) levels observed before hemlock was infested with HWA. This long-term increase in forest E(t) may eventually reduce stream discharge, especially during the growing season. However, the dominance of deciduous species in the canopy will result in a

  4. Spatially nonrandom tree mortality and ingrowth maintain equilibrium pattern in an old-growth Pseudotsuga-Tsuga forest.

    PubMed

    Lutz, James A; Larson, Andrew J; Furniss, Tucker J; Donato, Daniel C; Freund, James A; Swanson, Mark E; Bible, Kenneth J; Chen, Jiquan; Franklin, Jerry F

    2014-08-01

    Mortality processes in old-growth forests are generally assumed to be driven by gap-scale disturbance, with only a limited role ascribed to density-dependent mortality, but these assumptions are rarely tested with data sets incorporating repeated measurements. Using a 12-ha spatially explicit plot censused 13 years apart in an approximately 500-year-old Pseudotsuga-Tsuga forest, we demonstrate significant density-dependent mortality and spatially aggregated tree recruitment. However, the combined effect of these strongly nonrandom demographic processes was to maintain tree patterns in a state of dynamic equilibrium. Density-dependent mortality was most pronounced for the dominant late-successional species, Tsuga heterophylla. The long-lived, early-seral Pseudotsuga menziesii experienced an annual stem mortality rate of 0.84% and no new recruitment. Late-seral species Tsuga and Abies amabilis had nearly balanced demographic rates of ingrowth and mortality. The 2.34% mortality rate for Taxus brevifolia was higher than expected, notably less than ingrowth, and strongly affected by proximity to Tsuga. Large-diameter Tsuga structured both the regenerating conspecific and heterospecific cohorts with recruitment of Tsuga and Abies unlikely in neighborhoods crowded with large-diameter competitors (P < 0.001). Density-dependent competitive interactions strongly shape forest communities even five centuries after stand initiation, underscoring the dynamic nature of even equilibrial old-growth forests.

  5. Visual ability and searching behavior of adult Laricobius nigrinus, a hemlock woolly adelgid predator.

    PubMed

    Mausel, D L; Salom, S M; Kok, L T

    2011-01-01

    Very little is known about the searching behavior and sensory cues that Laricobius spp. (Coleoptera: Derodontidae) predators use to locate suitable habitats and prey, which limits our ability to collect and monitor them for classical biological control of adelgids (Hemiptera: Adelgidae). The aim of this study was to examine the visual ability and the searching behavior of newly emerged L. nigrinus Fender, a host-specific predator of the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Phylloxeroidea: Adelgidae). In a laboratory bioassay, individual adults attempting to locate an uninfested eastern hemlock seedling under either light or dark conditions were observed in an arena. In another bioassay, individual adults searching for prey on hemlock seedlings (infested or uninfested) were continuously video-recorded. Beetles located and began climbing the seedling stem in light significantly more than in dark, indicating that vision is an important sensory modality. Our primary finding was that searching behavior of L. nigrinus, as in most species, was related to food abundance. Beetles did not fly in the presence of high A. tsugae densities and flew when A. tsugae was absent, which agrees with observed aggregations of beetles on heavily infested trees in the field. At close range of prey, slow crawling and frequent turning suggest the use of non-visual cues such as olfaction and contact chemoreception. Based on the beetles' visual ability to locate tree stems and their climbing behavior, a bole trap may be an effective collection and monitoring tool.

  6. Biomechanical Properties of Hemlocks: A Novel Approach to Evaluating Physical Barriers of the Plant–Insect Interface and Resistance to a Phloem-Feeding Herbivore

    PubMed Central

    Ayayee, Paul; Yang, Fuqian; Rieske, Lynne K.

    2014-01-01

    Micromechanical properties that help mediate herbivore access may be particularly important when considering herbivorous insects that feed with piercing-sucking stylets. We used microindentation to quantify the micromechanical properties of hemlock, Tsuga spp., to quantify the hardness of the feeding site of the invasive hemlock woolly adelgid, Adelges tsugae. We measured hardness of the hemlock leaf cushion, the stylet insertion point of the adelgid, across four seasons in a 1 y period for four hemlock species growing in a common garden, including eastern, western, mountain, and northern Japanese hemlocks. Leaf cushion hardness was highest in the fall and winter and lowest in summer for all species. Northern Japanese hemlock had relatively greater hardness than the remaining species. Our data contributes an additional perspective to the existing framework within which greater susceptibility and subsequent mortality of eastern hemlocks is observed. The potential application of microindentation to understanding the nature and relevance of plant mechanical defenses in plant–herbivore interactions is also demonstrated and highlighted. PMID:26462689

  7. Tsuga canadensis (L.) Carr. mortality will impact hydrologic processes in southern Appalachian forest ecosystems.

    PubMed

    Ford, Chelcy R; Vose, James M

    2007-06-01

    Eastern hemlock (Tsuga canadensis (L.) Carr.) is one of the principal riparian and cove canopy species in the southern Appalachian Mountains. Throughout its range, eastern hemlock is facing potential widespread mortality from the hemlock woolly adelgid (HWA). If HWA-induced eastern hemlock mortality alters hydrologic function, land managers will be challenged to develop management strategies that restore function or mitigate impacts. To estimate the impact that the loss of this forest species will have on the hydrologic budget, we quantified and modeled transpiration over a range of tree sizes and environmental conditions. We used heat dissipation probes, leaf-level gas-exchange measurements, allometric scaling, and time series modeling techniques to quantify whole-tree and leaf-level transpiration (E(L)) of eastern hemlock. We monitored trees ranging from 9.5 to 67.5 cm in diameter along a riparian corridor in western North Carolina, USA during 2004 and 2005. Maximum rates of daily tree water use varied by diameter and height, with large trees transpiring a maximum of 178-186 kg H2O x tree(-1) x d(-1). Values of E(L) could be predicted from current and lagged environmental variables. We forecasted eastern hemlock E(L) for inventoried stands and estimated a mean annual transpiration rate of 63.3 mm/yr for the hemlock component, with 50% being transpired in the winter and spring. In typical southern Appalachian stands, eastern hemlock mortality would thus reduce annual stand-level transpiration by approximately 10% and reduce winter and spring stand-level transpiration by approximately 30%. Eastern hemlock in the southern Appalachians has two distinct ecohydrological roles: an evergreen tree that maintains year-round transpiration rates and a riparian tree that has high transpiration rates in the spring. No other native evergreen in the southern Appalachians will likely fill the ecohydrological role of eastern hemlock if widespread mortality occurs. With the loss of

  8. Functional response of ungulate browsers in disturbed eastern hemlock forests

    USGS Publications Warehouse

    Destefano, Stephen

    2015-01-01

    Ungulate browsing in predator depleted North American landscapes is believed to be causing widespread tree recruitment failures. However, canopy disturbances and variations in ungulate densities are sources of heterogeneity that can buffer ecosystems against herbivory. Relatively little is known about the functional response (the rate of consumption in relation to food availability) of ungulates in eastern temperate forests, and therefore how “top down” control of vegetation may vary with disturbance type, intensity, and timing. This knowledge gap is relevant in the Northeastern United States today with the recent arrival of hemlock woolly adelgid (HWA; Adelges tsugae) that is killing eastern hemlocks (Tsuga canadensis) and initiating salvage logging as a management response. We used an existing experiment in central New England begun in 2005, which simulated severe adelgid infestation and intensive logging of intact hemlock forest, to examine the functional response of combined moose (Alces americanus) and white-tailed deer (Odocoileus virginianus) foraging in two different time periods after disturbance (3 and 7 years). We predicted that browsing impacts would be linear or accelerating (Type I or Type III response) in year 3 when regenerating stem densities were relatively low and decelerating (Type II response) in year 7 when stem densities increased. We sampled and compared woody regeneration and browsing among logged and simulated insect attack treatments and two intact controls (hemlock and hardwood forest) in 2008 and again in 2012. We then used AIC model selection to compare the three major functional response models (Types I, II, and III) of ungulate browsing in relation to forage density. We also examined relative use of the different stand types by comparing pellet group density and remote camera images. In 2008, total and proportional browse consumption increased with stem density, and peaked in logged plots, revealing a Type I response. In 2012

  9. Effect of hemlock and deciduous forest canopy on chemistry of throughfall, West Whately, Massachusetts

    NASA Astrophysics Data System (ADS)

    Rhodes, A. L.; Guswa, A. J.; McNicholas, J.; Mehter, S.; Spence, C.

    2009-12-01

    Ecological forest successions associated with climate change and human disturbance may alter chemical loads to forested New England watersheds. Spread of the invasive insect hemlock wooly adelgid (Adelges tsugae) to eastern North America is causing decline and mortality of the eastern hemlock (Tsuga Canadensis). To begin an evaluation of whether changes in nutrient cycling and rainfall amounts could be altered by this disturbance, we investigated differences in chemistry and volume of rain and throughfall between predominately hemlock and deciduous tree stands in a secondary growth forest located in West Whately, Massachusetts. From 3 June to 25 July 2009, we sampled 14 rain events from two plots: one dominated by eastern hemlock (LAI = 5.6 with 64% of stems as hemlock) and the other dominated by a mix of deciduous species (LAI = 4.7 with 47% of stems as maple and 42% of basal area accounted as white ash). Plots consisted of a 5 x 6 meter grid of 30 collectors for measuring throughfall volume. Half of these were combined into a composite sample and analyzed for pH, acid neutralizing capacity (ANC), dissolved organic carbon (DOC), base cations (Ca2+, Mg2+, Na+, K+), anions (Cl-, NO3-, SO42+), dissolved silica, and specific conductance. Throughfall results were compared against precipitation sampled from a collector located in a nearby field. Over the period of the study, rainfall totaled 311 mm. Throughfall amounted to 242 mm (78%) in the hemlock plot and 276 mm (89%) in the deciduous plot. On an event-by-event basis, the fraction of precipitation that appears as throughfall increases with amount. Throughfall from both hemlock and deciduous plots showed significantly (p < 0.05) higher pH, ANC, DOC, K+, Ca2+, and Mg2+ concentrations than open precipitation, suggesting that the canopy counteracts some acidity in rain and adds organic carbon and nutrients to throughfall. ANC is positively correlated with K+, Ca2+, Mg2+, and DOC, indicating that cation exchange between

  10. Effects of Light and Water Availability on the Performance of Hemlock Woolly Adelgid (Hemiptera: Adelgidae).

    PubMed

    Hickin, Mauri; Preisser, Evan L

    2015-02-01

    Eastern hemlock (Tsuga canadensis (L.) Carriere) is a dominant shade-tolerant tree in northeastern United States that has been declining since the arrival of the hemlock woolly adelgid (Adelges tsugae Annand). Determining where A. tsugae settles under different abiotic conditions is important in understanding the insect's expansion. Resource availability such as light and water can affect herbivore selectivity and damage. We examined how A. tsugae settlement and survival were affected by differences in light intensity and water availability, and how adelgid affected tree performance growing in these different abiotic treatments. In a greenhouse at the University of Rhode Island, we conducted an experiment in which the factors light (full-sun, shaded), water (water-stressed, watered), and adelgid (infested, insect-free) were fully crossed for a total of eight treatments (20 two-year-old hemlock saplings per treatment). We measured photosynthesis, transpiration, water potential, relative water content, adelgid density, and survival throughout the experiment. Adelgid settlement was higher on the old-growth foliage of shaded and water-stressed trees, but their survival was not altered by foliage age or either abiotic factor. The trees responded more to the light treatments than the water treatments. Light treatments caused a difference in relative water content, photosynthetic rate, transpiration, and water potential; however, water availability did not alter these variables. Adelgid did not enhance the impact of these abiotic treatments. Further studies are needed to get a better understanding of how these abiotic factors impact adelgid densities and tree health, and to determine why adelgid settlement was higher in the shaded treatments.

  11. Spatial and temporal distribution of residues of imidacloprid and its insecticidal 5-hydroxy and olefin and metabolites in eastern hemlock (Pinales: Pinaceae) in the southern Appalachians.

    PubMed

    Coots, Carla; Lambdin, Paris; Grant, Jerome; Rhea, Rusty

    2013-12-01

    Widespread mortality of eastern hemlock, Tsuga canadensis (L.) Carrière, resulting from infestation by hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), has occurred throughout the native range of eastern hemlock within the eastern United States. Imidacloprid, a systemic insecticide, is one of the primary chemical compounds used to control hemlock woolly adelgid in both urban and, in a limited manner, in natural forest environments. The metabolism of imidacloprid in eastern hemlock produces 12 metabolites; two of these, imidacloprid 5-hydroxy and imidacloprid olefin, are considered toxicologically important metabolites. However, little is known about the persistence of these metabolites in eastern hemlock in the southern Appalachians. Concentrations ofimidacloprid, olefin, and 5-hydroxy were quantified by using HPLC/MS/MS techniques. Over the 3-yr study, concentrations of imidacloprid and consequent 5-hydroxy and olefin were highest in trees treated with a soil injection in the spring. Imidacloprid and 5-hydroxy concentrations in sap were highest at 12 mo posttreatment and in tissue at 15 mo posttreatment. Imidacloprid was detected through 36 mo posttreatment and 5-hydroxy was detected through 15 mo posttreatment. Olefin concentrations in both sap and tissue were highest at 36 mo posttreatment and were detected in high concentrations through 36 mo posttreatment. Concentrations of imidacloprid were highest in the bottom stratum of the canopy and lowest in the top stratum. Concentrations of olefin and 5-hydroxy were highest in the top stratum and lowest in the bottom stratum.

  12. Sharing rotting wood in the shade: ectomycorrhizal communities of co-occurring birch and hemlock seedlings.

    PubMed

    Poznanovic, Sarah K; Lilleskov, Erik A; Webster, Christopher R

    2015-02-01

    Coarse woody debris (CWD) is an important nursery environment for many tree species. Understanding the communities of ectomycorrhizal fungi (ECMF)and the effect of ECMF species on tree seedling condition in CWD will elucidate the potential for ECMF-mediated effects on seedling dynamics. In hemlock-dominated stands, we characterized ECMF communities associated with eastern hemlock (Tsuga canadensis (L.) Carr) and yellow birch (Betula alleghaniensis Britt) seedling pairs growing on CWD. Seedling foliage and CWD were analyzed chemically, and seedling growth, canopy cover, and canopy species determined. Thirteen fungal taxa, 12 associated with birch, and 6 with hemlock, were identified based on morphology and ITS sequencing. Five species were shared by co-occurring birch and hemlock, representing 75% of ectomycorrhizal root tips. Rarified ECMF taxon richness per seedling was higher on birch than hemlock. Nonmetric multidimensional scaling revealed significant correlations between ordination axes, the mutually exclusive ECMF Tomentella and Lactarius spp., foliar N and K, CWD pH, and exchangeable Ca and Mg. Seedlings colonized by Lactarius and T. sublilacina differed significantly in foliar K and N, and CWD differed in exchangeable Ca and Mg. CWD pH and nutrient concentrations were low but foliar macro-nutrient concentrations were not. We hypothesize that the dominant ECMF are adapted to low root carbohydrate availability typical in shaded environments but differ in their relative supply of different nutrients.

  13. Spatial pulses of water inputs in deciduous and hemlock forest stands

    NASA Astrophysics Data System (ADS)

    Guswa, A. J.; Mussehl, M.; Pecht, A.; Spence, C.

    2010-12-01

    Trees intercept and redistribute precipitation in time and space. While spatial patterns of throughfall are challenging to link to plant and canopy characteristics, many studies have shown that the spatial patterns persist through time. This persistence leads to wet and dry spots under the trees, creating spatial pulses of moisture that can affect infiltration, transpiration, and biogeochemical processes. In the northeast, the invasive hemlock woolly adelgid poses a significant threat to eastern hemlock (Tsuga canadensis), and replacement of hemlock forests by other species, such as birch, maple, and oak, has the potential to alter throughfall patterns and hydrologic processes. During the summers of 2009 and 2010, we measured throughfall in both hemlock and deciduous plots to assess its spatial distribution and temporal persistence. From 3 June to 25 July 2009, we measured throughfall in one hemlock and one deciduous plot over fourteen events with rainfall totaling 311 mm. From 8 June through 28 July 2010, we measured throughfall in the same two plots plus an additional hemlock stand and a young black birch stand, and rainfall totaled 148 mm over eight events. Averaged over space and time, throughfall was 81% of open precipitation in the hemlock stands, 88% in the mixed deciduous stand, and 100% in the young black birch stand. On an event basis, spatial coefficients of variation are similar among the stands and range from 11% to 49% for rain events greater than 5 mm. With the exception of very light events, coefficients of variation are insensitive to precipitation amount. Spatial patterns of throughfall persist through time, and seasonal coefficients of variation range from 13% to 33%. All stands indicate localized concentrations of water inputs, and there were individual collectors in the deciduous stands that regularly received more than twice the stand-average throughfall.

  14. Community response of insects associated with eastern hemlock to imidacloprid and horticultural oil treatments.

    PubMed

    Dilling, Carla; Lambdin, Paris; Grant, Jerome; Rhea, Rusty

    2009-02-01

    The hemlock woolly adelgid, Adelges tsugae Annand, is an invasive species reducing the populations of eastern hemlock, Tsuga canadensis L. Carrière, throughout the eastern United States. Systemic imidacloprid and horticultural oil are the primary chemicals used to control infestations of this invasive pest; however, the impact of these two chemicals on nontarget canopy insects is unknown. This study was initiated in November 2005 to assess the effects of (1) imidacloprid soil drench, (2) imidacloprid soil injection, (3) imidacloprid tree injections, and (4) horticultural oil applications on multiple levels of organization (composition, overall specimen abundance and species richness, guild specimen abundance and species richness, and individual species) within the phytophagous and transient canopy insect community. Community composition differed significantly among treatments based on analysis of similarity. Mean species richness and specimen abundance were significantly reduced by one or more treatments. Soil drench applications significantly reduced species richness for the detritivore and phytophaga guilds. Furthermore, specimen abundance for species in the detritivore, fungivore, phytophaga, scavenger, and transient phytophaga guilds was significantly lower in the soil drench treatment. This trend was consistent in all insect guilds examined, with the exception of the hematophaga guild that was not significantly lower than for species on the control trees. Of the 293 species documented to be associated with eastern hemlocks, 33 species were found to be directly effected by one or more of the chemical treatments.

  15. Post-disturbance plant community dynamics following a rare natural-origin fire in a Tsuga canadensis forest.

    PubMed

    Murray, Bryan D; Holmes, Stacie A; Webster, Christopher R; Witt, Jill C

    2012-01-01

    Opportunities to directly study infrequent forest disturbance events often lead to valuable information about vegetation dynamics. In mesic temperate forests of North America, stand-replacing crown fire occurs infrequently, with a return interval of 2000-3000 years. Rare chance events, however, may have profound impacts on the developmental trajectories of forest ecosystems. For example, it has been postulated that stand-replacing fire may have been an important factor in the establishment of eastern hemlock (Tsuga canadensis) stands in the northern Great Lakes region. Nevertheless, experimental evidence linking hemlock regeneration to non-anthropogenic fire is limited. To clarify this potential relationship, we monitored vegetation dynamics following a rare lightning-origin crown fire in a Wisconsin hemlock-hardwood forest. We also studied vegetation in bulldozer-created fire breaks and adjacent undisturbed forest. Our results indicate that hemlock establishment was rare in the burned area but moderately common in the scarified bulldozer lines compared to the reference area. Early-successional, non-arboreal species including Rubus spp., Vaccinium angustifolium, sedges (Carex spp.), grasses, Epilobium ciliatum, and Pteridium aquilinium were the most abundant post-fire species. Collectively, our results suggest that competing vegetation and moisture stress resulting from drought may reduce the efficacy of scarification treatments as well as the usefulness of fire for preparing a suitable seedbed for hemlock. The increasing prevalence of growing-season drought suggests that silvicultural strategies based on historic disturbance regimes may need to be reevaluated for mesic species.

  16. Post-Disturbance Plant Community Dynamics following a Rare Natural-Origin Fire in a Tsuga canadensis Forest

    PubMed Central

    Murray, Bryan D.; Holmes, Stacie A.; Webster, Christopher R.; Witt, Jill C.

    2012-01-01

    Opportunities to directly study infrequent forest disturbance events often lead to valuable information about vegetation dynamics. In mesic temperate forests of North America, stand-replacing crown fire occurs infrequently, with a return interval of 2000–3000 years. Rare chance events, however, may have profound impacts on the developmental trajectories of forest ecosystems. For example, it has been postulated that stand-replacing fire may have been an important factor in the establishment of eastern hemlock (Tsuga canadensis) stands in the northern Great Lakes region. Nevertheless, experimental evidence linking hemlock regeneration to non-anthropogenic fire is limited. To clarify this potential relationship, we monitored vegetation dynamics following a rare lightning-origin crown fire in a Wisconsin hemlock-hardwood forest. We also studied vegetation in bulldozer-created fire breaks and adjacent undisturbed forest. Our results indicate that hemlock establishment was rare in the burned area but moderately common in the scarified bulldozer lines compared to the reference area. Early-successional, non-arboreal species including Rubus spp., Vaccinium angustifolium, sedges (Carex spp.), grasses, Epilobium ciliatum, and Pteridium aquilinium were the most abundant post-fire species. Collectively, our results suggest that competing vegetation and moisture stress resulting from drought may reduce the efficacy of scarification treatments as well as the usefulness of fire for preparing a suitable seedbed for hemlock. The increasing prevalence of growing-season drought suggests that silvicultural strategies based on historic disturbance regimes may need to be reevaluated for mesic species. PMID:22928044

  17. Nuclei of Tsuga canadensis: Role of Flavanols in Chromatin Organization

    PubMed Central

    Feucht, Walter; Schmid, Markus; Treutter, Dieter

    2011-01-01

    Needle primordia of Tsuga canadensis (hemlock) arising from flank meristems of a shoot apex, form cell lineages consisting of four or eight cells. Within a recently established lineage there is striking uniformity in the pattern of nuclear flavanols. This fact points to an identical transcriptional expression of these flavanols during cell cycling. However two lineages, even if located close together within the same meristem, can be very different in the expression of both cell shape and nuclear flavanol pattern, indicating that epigenetic positional signals are operating in a collective specification of cell lineage development. There is a wide range of nuclear flavanol patterning from a mosaic-like distribution in an activated cell type to a homogenous appearance in silenced cell types. Single cells deriving from lineages are desynchronized because they underlie a signaling network at a higher tissue level which results in stronger epigenetic modifications of their nuclear flavanols. As an extreme case of epigenetic modulation, transient drought conditions caused a drastic reduction of nuclear flavanols. Upon treatment with sucrose or cytokinin, these nuclear flavanols could be fully restored. Analytical determination of the flavanols revealed 3.4 mg/g DW for newly sprouting needles and 19.6 mg/g DW for anthers during meiosis. The roughly 6-fold difference in flavanols is apparently a reflection of the highly diverging organogenetic processes. Collectively, the studies provide strong evidence for combinatorial interplay between cell fate and nuclear flavanols. PMID:22072922

  18. Terpene chemistry of eastern hemlocks resistant to hemlock woolly adelgid.

    PubMed

    McKenzie, E Alexa; Elkinton, Joseph S; Casagrande, Richard A; Preisser, Evan L; Mayer, Mark

    2014-09-01

    Recent studies have identified a small number of individual eastern hemlock trees that demonstrate relative resistance to the introduced sap-feeding insect, the hemlock woolly adelgid. Using gas chromatography, we compared concentrations of twenty-two terpenoids in susceptible and relatively resistant trees, both in the forest and in propagated cuttings in a common-garden setting. Terpenoid concentrations were higher in twig tissue of resistant versus susceptible trees, across six sampling dates and at both sites. These changes may be particularly important because the hemlock woolly adelgid feeds on twig tissue. Because the common-garden cuttings were free of herbivores, the higher terpenoid concentrations are interpreted as a constitutive defense. Increased levels of monoterpenes and sesquiterpenes imply an overall increase in the input of carbon precursors to both terpenoid synthesis pathways.

  19. Feeding by Leucopis argenticollis and Leucopis piniperda (Diptera: Chamaemyiidae) from the western USA on Adelges tsugae (Hemiptera: Adelgidae) in the eastern USA.

    PubMed

    Motley, K; Havill, N P; Arsenault-Benoit, A L; Mayfield, A E; Ott, D S; Ross, D; Whitmore, M C; Wallin, K F

    2017-03-14

    Leucopis argenticollis (Zetterstedt) and Leucopis piniperda (Malloch) are known to feed on the lineage of Adelges tsugae Annand that is native to western North America, but it is not known if they will survive on the lineage that was introduced from Japan to the eastern USA. In 2014, western Leucopis spp. larvae were brought to the laboratory and placed on A. tsugae collected in either Washington (North American A. tsugae lineage) or Connecticut (Japanese lineage). There were no significant differences in survival or developmental times between flies reared on the two different adelgid lineages. In 2015 and 2016, western Leucopis spp. adults were released at two different densities onto enclosed branches of A. tsugae infested eastern hemlock (Tsuga canadensis (L.) Carr.) in Tennessee and New York. Cages were recovered and their contents examined 4 weeks after release at each location. Leucopis spp. larvae and puparia of the F1 generation were recovered at both release locations and adults of the F1 generation were collected at the Tennessee location. The number of Leucopis spp. offspring collected increased with increasing adelgid density, but did not differ by the number of adult flies released. Flies recovered from cages and flies collected from the source colony were identified as L.argenticollis and L. piniperda using DNA barcoding. These results demonstrate that Leucopis spp. from the Pacific Northwest are capable of feeding and developing to the adult stage on A. tsugae in the eastern USA and they are able to tolerate environmental conditions during late spring and early summer at the southern and northern extent of the area invaded by A. tsugae in the eastern USA.

  20. Ecohydrologic implications of differences in throughfall between hemlock and deciduous forest plots, West Whately, MA

    NASA Astrophysics Data System (ADS)

    Guswa, A. J.; Rhodes, A. L.; McNicholas, J.; Mehter, S.; Spence, C.

    2009-12-01

    Invasive pests, especially in conjunction with climate change, have the potential to transform the species composition of many forests. In the northeastern United States, the hemlock woolly adelgid poses a significant threat to eastern hemlock (Tsuga Canadensis), a tree known for its ecological role more than its timber value. To begin to assess the effect on the water cycle of converting hemlock to deciduous forest, we carried out a throughfall investigation in West Whately, MA during the summer of 2009. From 3 June to 25 July, we measured the volume and chemistry of throughfall in two forest plots: one dominated by hemlock (LAI = 5.6) and one comprising a variety of deciduous species (LAI = 4.7), including many saplings and sub-canopy trees. Over the period of the study, rainfall totaled 311 mm and throughfall amounted to 276 mm (89%) in the deciduous plot and 242 mm (78%) in the hemlock stand. When compared to open precipitation, throughfall from both plots showed significantly higher levels of acid neutralizing capacity, pH, and concentrations of K+, Ca2+, and Mg2+. On an event-by-event basis, the fraction of precipitation that shows up as throughfall increases with amount, and representing interception as a constant depth, Δ, provides a reasonable fit (Δdeciduous = 2.5 mm, R2 = 0.99; Δhemlock = 5 mm, R2 = 0.96). Analysis of variance and time-stability plots indicate a strong persistent effect of collector position on throughfall depth, leading to potential efficiencies in measurement strategies. In both stands, the spatial variability of throughfall depths is higher for lower intensity events, and the coefficient of variation has a value around 30% for larger events. The skewness of throughfall depths among collectors within the hemlock plot is generally small. Throughfall depths are positively skewed in the deciduous plot, and one collector consistently received throughfall equal to twice the incident rainfall. Should hemlock stands be eliminated and

  1. Mountain hemlock growth responds to climatic variability at annual and decadal time scales

    USGS Publications Warehouse

    Peterson, D.W.; Peterson, D.L.

    2001-01-01

    Improved understanding of tree growth responses to climate is needed to model and predict forest ecosystem responses to current and future climatic variability. We used dendroecological methods to study the effects of climatic variability on radial growth of a subalpine conifer, mountain hemlock (Tsuga mertensiana). Tree-ring chronologies were developed for 31 sites, spanning the latitudinal and elevational ranges of mountain hemlock in the Pacific Northwest. Factor analysis was used to identify common patterns of inter-annual growth variability among the chronologies, and correlation and regression analyses were used to identify climatic factors associated with that variability. Factor analysis identified three common growth patterns, representing groups of sites with different climate-growth relationships. At high-elevation and midrange sites in Washington and northern Oregon, growth was negatively correlated with spring snowpack depth, and positively correlated with growth-year summer temperature and the winter Pacific Decadal Oscillation index (PDO). In southern Oregon, growth was negatively correlated with spring snowpack depth and previous summer temperature, and positively correlated with previous summer precipitation. At the low-elevation sites, growth was mostly insensitive to annual climatic variability but displayed sensitivity to decadal variability in the PDO opposite to that found at high-elevation sites. Mountain hemlock growth appears to be limited by late snowmelt, short growing seasons, and cool summer temperatures throughout much of its range in the Pacific Northwest. Earlier snowmelt, higher summer temperatures, and lower summer precipitation in southern Oregon produce conditions under which growth is limited by summer temperature and/or soil water availability. Increasing atmospheric CO2 concentrations could produce warmer temperatures and reduced snowpack depths in the next century. Such changes would likely increase mountain hemlock growth

  2. Variation in winter survival of the invasive hemlock woolly adelgid (Hemiptera: Adelgidae) across the eastern United States.

    PubMed

    Trotter, R Talbot; Shields, Kathleen S

    2009-06-01

    The hemlock woolly adelgid (Adelges tsugae Annand) is a small, aphid-like insect native to East Asia and western North America. First documented in the eastern United States in Richmond, VA, in 1951, it has spread to at least 17 states, where it causes increased mortality among both eastern and Carolina hemlocks (Tsuga canadensis Carrière and T. caroliniana Engelmann., respectively). Previous work has suggested low temperatures may limit northward spread of the adelgid. Using recent surveys of A. tsugae mortality across the infested latitudinal gradient of the eastern United States, we show there is a significant positive relationship between minimum winter temperatures and winter survival at the landscape scale. The strength and nature of this relationship, however, varies through time, with absolute minimum winter temperatures explaining almost one half of the tree-level variance in survival in the spring of 2004 but only 9% in 2003. Post hoc analyses of the data suggest the explanatory power of temperature can be improved in ongoing studies by examining seasonal temperature profiles. Previous studies have also suggested adelgid survival may be density dependent, and although these data support this observation, contemporary density is a poor predictor of adelgid survival at the landscape scale. Using landscape estimates of minimum winter temperature, we show two simple methods of estimating landscape-scale adelgid survival rates. Both methods suggest much of the range of T. canadensis in the eastern United States, and the entire range of T. caroliniana falls in areas where winter temperatures will not impose critical limits on A. tsugae populations.

  3. Activity and residues of imidacloprid applied to soil and tree trunks to control hemlock woolly adelgid (Hemiptera: Adelgidae) in forests.

    PubMed

    Cowles, R S; Montgomery, M E; Cheah, C A S J

    2006-08-01

    We studied imidacloprid application methods and timing to control the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in forests. The methods compared were 1) soil injection near the trunk; 2) soil injection dispersed throughout the area under the canopy; 3) soil drench near the base of the trunk; and trunk injection with the 4) Arborjet, 5) Wedgle, and 6) Mauget systems. The applications were made in the fall and the following spring. Adelgid populations on the hemlocks (Tsuga spp.) were assessed in the fall of two successive years after the treatments. Relative to the untreated control trees, all the soil applications resulted in population reductions, but none of the trunk injections resulted in reductions. Fall and spring treatment efficacy did not differ. Reductions by the soil treatments were between 50 and 100% (avg 80%) by the first fall and 83-100% (avg 98.5%) by the second fall. Analysis of imidacloprid residues using enzyme-linked immunosorbent assay found residues in sap, needles, and twigs 1 mo to 3-yr after application. A laboratory dose-response bioassay using excised, adelgid-infested hemlock branches with cut ends immersed in serial dilutions of imidacloprid determined the LC50 value to be 300 ppb, based on an exposure of 20 d. A high degree of suppression of the adelgid on forest trees was associated with residues in hemlock tissue > 120 ppb 2 yr after soil treatment. Although precise relationships between residues and efficacy are elusive, it is clear that soil application of imidacloprid resulted in chronic residues of imidacloprid in tissues and suppression of adelgid populations for > 2 yr.

  4. A terrain-based paired-site sampling design to assess biodiversity losses from eastern hemlock decline

    USGS Publications Warehouse

    Young, J.A.; Smith, D.R.; Snyder, C.D.; Lemarie, D.P.

    2002-01-01

    Biodiversity surveys are often hampered by the inability to control extraneous sources of variability introduced into comparisons of populations across a heterogenous landscape. If not specifically accounted for a priori, this noise can weaken comparisons between sites, and can make it difficult to draw inferences about specific ecological processes. We developed a terrain-based, paired-site sampling design to analyze differences in aquatic biodiversity between streams draining eastern hemlock (Tsuga canadensis) forests, and those draining mixed hardwood forests in Delaware Water Gap National Recreation Area (USA). The goal of this design was to minimize variance due to terrain influences on stream communities, while representing the range of hemlock dominated stream environments present in the park. We used geographic information systems (GIS) and cluster analysis to define and partition hemlock dominated streams into terrain types based on topographic variables and stream order. We computed similarity of forest stands within terrain types and used this information to pair hemlock-dominated streams with hardwood counterparts prior to sampling. We evaluated the effectiveness of the design through power analysis and found that power to detect differences in aquatic invertebrate taxa richness was highest when sites were paired and terrain type was included as a factor in the analysis. Precision of the estimated difference in mean richness was nearly doubled using the terrain-based, paired site design in comparison to other evaluated designs. Use of this method allowed us to sample stream communities representative of park-wide forest conditions while effectively controlling for landscape variability.

  5. A terrain-based paired-site sampling design to assess biodiversity losses from eastern hemlock decline.

    PubMed

    Young, John A; Smith, David R; Snyder, Craig D; Lemarie, David P

    2002-06-01

    Biodiversity surveys are often hampered by the inability to control extraneous sources of variability introduced into comparisons of populations across a heterogenous landscape. If not specifically accounted for a priori, this noise can weaken comparisons between sites, and can make it difficult to draw inferences about specific ecological processes. We developed a terrain-based, paired-site sampling design to analyze differences in aquatic biodiversity between streams draining eastern hemlock (Tsuga canadensis) forests, and those draining mixed hardwood forests in Delaware Water Gap National Recreation Area (USA). The goal of this design was to minimize variance due to terrain influences on stream communities, while representing the range of hemlock dominated stream environments present in the park. We used geographic information systems (GIS) and cluster analysis to define and partition hemlock dominated streams into terrain types based on topographic variables and stream order. We computed similarity of forest stands within terrain types and used this information to pair hemlock-dominated streams with hardwood counterparts prior to sampling. We evaluated the effectiveness of the design through power analysis and found that power to detect differences in aquatic invertebrate taxa richness was highest when sites were paired and terrain type was included as a factor in the analysis. Precision of the estimated difference in mean richness was nearly doubled using the terrain-based, paired site design in comparison to other evaluated designs. Use of this method allowed us to sample stream communities representative of park-wide forest conditions while effectively controlling for landscape variability.

  6. 78 FR 21344 - Grant of Authority for Subzone Status, Hemlock Semiconductor Corporation, (Polysilicon), Hemlock...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... Foreign-Trade Zones Board Grant of Authority for Subzone Status, Hemlock Semiconductor Corporation... Semiconductor Corporation, located in Hemlock, Michigan (FTZ Docket 61-2011, filed 10-5-2011); Whereas, notice... Semiconductor Corporation, located in Hemlock, Michigan (Subzone 140C), as described in the application...

  7. Establishment of the hemlock woolly adelgid predator, Laricobius nigrinus (Coleoptera: Derodontidae), in the Eastern United States.

    PubMed

    Mausel, D L; Salom, S M; Kok, L T; Davis, G A

    2010-04-01

    The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), native to western North America and Asia, was accidentally introduced from Japan to the eastern United States. To potentially establish biological control of A. tsugae, we released a predator endemic to western North America, Laricobius nigrinus Fender (Coleoptera: Derodontidae), from 2003 to 2005, in 22 localities from Georgia to Massachusetts. Release sites spanned the invasive range of the adelgid across five United States Department of Agriculture plant hardiness zones (5a to 7a). Release sizes were 75, 150, 300, 600, or 1,200 adult L. nigrinus per site in the fall, winter, early spring, or sequentially (i.e., fall or winter and early spring). We monitored establishment by annual sampling for L. nigrinus adults with beat sheets and for L. nigrinus larvae by branch clipping. At the end of 3 yr, L. nigrinus was established in 13 of the 22 sites. The following variables were evaluated for their correlation with the numbers of L. nigrinus larvae and adults recovered and for their effect on establishment (scored as F(3) presence/absence): (1) Minimum winter temperature at the release site, (2) A. tsugae density at the time of release, (3) release size, and (4) release season. Only minimum winter temperature was correlated with larval recoveries and no variables were correlated with adult recoveries. Logistic regression modeling found that establishment was positively related to minimum winter temperature and release size. We recommend smaller release sizes in warm areas where establishment probability was high (i.e., zones 7a, 6b, and 6a) and larger release sizes in cold areas where establishment probability was low (i.e., zones 5b and 5a). Releases during fall-early spring and across the range of A. tsugae densities tested were successful.

  8. Seasonal phenology and abundance of Leucopis argenticollis, Leucopis piniperda (Diptera: Chamaemyiidae), Laricobius nigrinus (Coleoptera: Deridontidae) and Adelges tsugae (Hemiptera: Adelgidae) in the Pacific Northwest USA.

    PubMed

    Kohler, G R; Wallin, K F; Ross, D W

    2016-08-01

    Adelges tsugae infested western hemlock trees were sampled periodically for 1 year at two locations in Oregon and Washington to compare the phenology and abundance of three associated predators (Leucopis argenticollis, Leucopis piniperda, and Laricobius nigrinus) and their host. On each sample date, two 3-10 cm long terminal twigs were collected from each tree and brought to the laboratory to count all life stages of A. tsugae and the three predators. Peak larval abundance of Leucopis spp. and La. nigrinus coincided with the presence of A. tsugae adults and eggs. Leucopis spp. larvae were present for a much longer period of time than were La. nigrinus larvae. Furthermore, Leucopis spp. larvae were present during both the progrediens and sistens egg stages, while La. nigrinus larvae were only present during the progrediens egg stage. Overall, we collected 2.3-3.5 times more Leucopis spp. of all life stages than La. nigrinus. These results support the continued study of Leucopis spp. from the Pacific Northwest as biological control agents for A. tsugae in the Eastern USA.

  9. Comparison of Soil Geochemistry and Nitrogen Cycling beneath Eastern Hemlock and Black Birch Regrowth Forest, West Whately, MA, U.S.A

    NASA Astrophysics Data System (ADS)

    Rhodes, A. L.; Blanchett, S.; Sweezy, T.; Mansen, S.

    2011-12-01

    Ecological forest successions associated with introduction of invasive species, human disturbance, and climate change may alter biogeochemical cycles within forested New England watersheds. Spread of the invasive insect hemlock wooly adelgid (Adelges tsungae, HWA) to eastern North America is causing decline and mortality of the eastern hemlock (Tsuga canadensis). To evaluate whether changes in nutrient cycling could be altered by this disturbance, we investigated differences in soil geochemistry in secondary growth forest located at the MacLeish Field Station, Whately, MA, where HWA occurrences recently have been observed. Eastern hemlock on this property was selectively logged 20 years ago, with black birch regrowth succeeding hemlock. We hypothesize that such a succession could repeat should hemlock on the property experience mortality due to the HWA. Between 2010-2011, we measured soil pH, exchangeable acidity (Al3+ and H+), exchangeable base cations (Ca2+, Mg2+, Na+, and K+), and nitrogen mineralization rates of soil cores collected beneath a hemlock stand and beneath an adjacent, younger black birch stand that succeeded hemlock following logging. Although soil pH of organic horizons between hemlock and black birch are both acidic (pH<4.5), the concentration of exchangeable base cations in the organic horizon beneath black birch is approximately 1.5 times higher than hemlock, reflecting its higher total cation exchange capacity. These results suggest that the acidity typically associated with soils that support hemlock forests has not been neutralized by black birch regrowth, and soil acidity may be stabilized by exchangeable Al3+, which is similar for the two sites. More base cations may be becoming available within the cation exchange pool of the black birch soil, possibly reflecting variation in inputs of base cations from throughfall and leaf litter. Net nitrogen mineralization and nitrification rates determined for incubated soil cores, measured between

  10. Behavioral Responses of Laricobius spp. and Hybrids (Coleoptera: Derodontidae) to Hemlock Woolly Adelgid and Adelgid Host Tree Odors in an Olfactometer.

    PubMed

    Arsenault, Arielle L; Havill, Nathan P; Mayfield, Albert E; Wallin, Kimberly F

    2015-12-01

    The predatory species Laricobius nigrinus (Fender) and Laricobius osakensis (Shiyake and Montgomery) (Coleoptera: Derodontidae) have been released for biological control of hemlock woolly adelgid (Adelges tsugae; Hemiptera: Adelgidae) in eastern North America. L. osakensis is native to Japan, whereas L. nigrinus is endemic to the Pacific Northwest of the United States and Canada. After release, L. nigrinus was found to hybridize with the native eastern species, Laricobius rubidus (LeConte). The purpose of this study is to observe prey location behaviors of these three Laricobius species and L. nigrinus × L. rubidus (Ln × Lr) hybrids. Olfactometer bioassays were used to test response to host odors of adelgid-infested eastern hemlock, uninfested eastern hemlock, and uninfested eastern white pine. Predators reacted in the olfactometer more quickly when adelgid-infested foliage was included as a choice. L. nigrinus preferred infested eastern hemlock over uninfested eastern white pine, and L. rubidus preferred uninfested eastern white pine over uninfested eastern hemlock. Laricobius hybrids did not show a preference for foliage types known to be primary adelgid hosts (eastern hemlock and eastern white pine). Unequal preference by species of Laricobius for host trees of different adelgid prey could therefore be maintaining Laricobius species barriers despite hybridization. L. osakensis for this study were reared in the laboratory, whereas other species in this study were collected from the field, yet still were attracted to infested and uninfested eastern hemlock. This species also responded most quickly in the olfactometer, which is encouraging for successful biological control with this species.

  11. Comparison of throughfall chemistry in a mature hemlock forest and an early-successional deciduous forest resulting from salvage logging in Whately, Massachusetts

    NASA Astrophysics Data System (ADS)

    Zukswert, J. M.; Rhodes, A. L.; Dwyer, C. H.; Sweezy, T.

    2012-12-01

    Removal of foundation species as a result of disturbance events such as exotic species invasions can alter community composition and ecosystem function. The current hemlock woolly adelgid (Adelges tsugae) infestation in eastern North America that threatens the eastern hemlock (Tsuga canadensis), a foundation species, has motivated salvage logging efforts. Ecological succession resulting from salvage logging of hemlock would eventually produce a deciduous hardwood forest. The chemistry of throughfall beneath a mature hemlock forest canopy is expected to be more acidic than throughfall from a mature deciduous forest canopy because hemlock foliage releases more organic acids and fewer base cations. The chemical composition of throughfall during the early successional transition from hemlock to deciduous is less understood. We hypothesize that throughfall chemistry in a deciduous forest consisting primarily of juvenile trees may be more similar to direct precipitation because leaf area index is smaller. Differences between hemlock throughfall and direct precipitation may be larger due to the denser canopy of these mature trees. We compared the chemical composition of precipitation, hemlock throughfall, and black birch throughfall for 26 precipitation events from 4 March to 30 July 2012. The black birch (Betula lenta) forest patch resulted from salvage logging of hemlocks twenty years ago at the MacLeish Field Station in Whately, MA. From the three plots we measured the volume of water collected and pH, acid neutralizing capacity, dissolved organic carbon (DOC), and concentrations of cations (Ca2+, K+, Na+, Mg2+, NH4+), anions (Cl-, NO3-, SO42-), and dissolved silica. Precipitation totaled 405 mm during the course of the study. Throughfall totaled 347 mm in the black birch plot and 315 mm in the hemlock plot. The proportion of precipitation passing through the forest canopy was smaller in hemlock throughfall than black birch throughfall during small precipitation events

  12. Ion cycling in hemlock-northern hardwood forests of the southern Lake Superior region: a preliminary study.

    PubMed

    Bockheim, J G; Crowley, S E

    2002-01-01

    Upland forests of the southern Lake Superior region are diverse and contain a shifting mosaic of eastern hemlock [Tsuga canadensis (L.) Carr.] and northern hardwood forests dominated by sugar maple (Acer saccharum Marsh.). In this study, we survey the relative effects of management practice (old growth vs. managed), forest cover type (hemlock vs. northern hardwood), and soil great group (Entic Haplorthod vs. Alfic Oxyaquic Fragiorthod) on ion cycling as a precursor to a longer-term, more detailed study. Bulk precipitation, throughfall, and soil leachates at three depths were collected for two growing seasons in eight stands on the Ottawa National Forest in the Upper Peninsula of Michigan. A total of 1210 solutions were analyzed for pH, Na, K, Mg, Ca, Cl, NO3, and SO4. Losses of base cations (Ca, Mg, K) and SO4 from the bottom of the rooting zone generally were greater in old-growth than in managed northern hardwoods on both fragic and nonfragic soils. Leaching losses of base cations and NO3 usually were greater beneath old-growth northern hardwoods than beneath old-growth hemlock on both soil types and for both forest cover types and management practices on fragic than nonfragic soils. Management practice, forest cover type, and soil type all appear to affect ion cycling within these forests. All of the stands featured striking losses of base cations that probably are influenced strongly by NO3 and SO4 in atmospheric deposition.

  13. Induction of Cold Hardiness in an Invasive Herbivore: The Case of Hemlock Woolly Adelgid (Hemiptera: Adelgidae).

    PubMed

    Elkinton, Joseph S; Lombardo, Jeffrey A; Roehrig, Artemis D; McAvoy, Thomas J; Mayfield, Albert; Whitmore, Mark

    2016-12-19

    As a measure of cold hardiness, we tested the supercooling points or freezing temperatures of individual hemlock woolly adelgids (Adelges tsugae Annand) collected from 15 locations across the north to south range of the adelgid in eastern North America at different times during two winters. Adelgids from the northern interior locations with USDA hardiness zones of 5B-6B had lower supercooling points than adelgids from more southern or more coastal locations (zones 7A and 6B), where minimum winter temperatures were higher. Supercooling points reached a minimum in February in northern but not in southern locations. Laboratory experiments demonstrated that adelgids exposed to colder temperatures (-12 °C) had lower supercooling points after 3 d and adelgids held at 10 °C had higher supercooling points than did adelgids held at 2 °C for the same period. Extending these periods to 7 d produced no further change in supercooling points. Adelgids at northern sites had much lower supercooling points in February 2015 following at least 10 d of much colder weather than adelgids from those same sites in February 2016 following much warmer weather. The induction of cold hardiness produced much year-to-year variation in cold hardiness, especially in northern sites, in addition to concurrently and previously demonstrated genetic differences in cold hardiness between northern and southern adelgid populations. Consequently, the cold temperatures required to kill hemlock woolly adelgids will vary year to year and week to week based on exposure to prior temperatures.

  14. Characterization of the Soil Hydromorphic Conditions in a Paludified Dunefield during the Mid-Holocene Hemlock Decline near Québec City, Québec

    NASA Astrophysics Data System (ADS)

    Bhiry, Najat; Filion, Louise

    1996-11-01

    The mid-Holocene eastern hemlock [ Tsuga canadensisL. (Carr.)] decline has been recently attributed to the activity of insect defoliators. N. Bihiry and L. Filion, Quaternary Research45,312-320 (1996). In this study, soil hydromorphic conditions were investigated for the period 6800-3200 yr B.P. using micromorphological data from a peat section from a swale in a paludified dunefield in southern Québec. After a short period of plant colonization in shallow pools between 6800 and 6400 yr B.P., mesic conditions predominated in the interdune before the decline (6400-4900 yr B.P.), as evidenced by strong bioturbation and abundance of excrements from the soil fauna. During the decline, a shift from mesic to wet conditions occurred (4900-4100 yr B.P.), although xeric to mesic conditions persisted on dune ridges until at least 4200 yr B.P. Wetness culminated when beaver occupied the site (4100-3750 yr B.P.). Hemlock needles with chewing damage typical of hemlock looper ( Lambdina fiscellaria) feeding were identified at levels dated 4900, 4600, and 4200 yr B.P., respectively, implying that the hemlock decline was associated with at least three defoliation events. The ca. 400-yr interval between these events likely represents the time required for this late-sucessional tree species to recover.

  15. Integrating spatial modeling, climate change scenarios, invasive species risk, and public perceptions to inform sustainable management in mixed hemlock-hardwood forests in Maine

    NASA Astrophysics Data System (ADS)

    Dunckel, Kathleen Lois

    Introduced invasive pests and climate change are perhaps the most important and persistent catalyst for changes in forest composition. Infestation and outbreak of the hemlock woolly adelgid (HWA, Adelges tsugae) along the eastern coast of the USA, has led to widespread loss of hemlock (Tsuga canadensis (L.) Carr.), and a shift in tree species composition towards hardwood stands. Maine's forest dominated landscape and position at the leading edge of the HWA invasion provides an excellent opportunity to inform sustainable forest management (SFM) practices by using spatially explicit models to predict current tree species distribution, future range shifts, and solicit broad based feedback from Maine residents about forest management goals and preferences. This paper describes an interdisciplinary study of the ecological and social implications of changes in mixed northern hardwood forests due to disturbance. A two stage mapping approach was used where presence/absence of eastern hemlock is predicted with an overall accuracy of 85% and the continuous distribution (% basal area) was predicted with an accuracy of 83%. Given the importance of climate variables in predicting eastern hemlock, forecasts of future range shifts are possible using data generated through climate scenarios. The NASA Earth Exchange (NEX) Downscaled Climate Projections (NEX-DCP30) dataset was used to model future shifts in the geographic range of eastern hemlock throughout the state of Maine. The results clearly describe a significant shift in eastern hemlock range with gains in total geographic area that is suitable habitat. Sustaining forest systems across the landscape requires not only ecological knowledge, but also the integration of multiple socio-economic criteria as well, including data obtained through broad-based public participation approaches. Here, 3000 Maine residents were surveyed and asked how they: (1) value local forests; (2) view forest management goals and threats to forest

  16. Bioactive compounds from Iostephane heterophylla (Asteraceae).

    PubMed

    Aguilar, M I; Delgado, G; Hernández, M L; Villarreal, M L

    2001-01-01

    The novel bisabolene sesquiterpenes 3-6, were isolated from Iostephane heterophylla, using bioguided fractionation. The new compounds were determined to be (12R/12S)-12,13-epoxy-xanthorrhizols (3,4) and (12R/12S)-12,13-dihydro-12,13-dihydroxy-xanthorrizols (5,6) and their structures were characterized by analysis of spectroscopic data and by chemical correlation from xanthorrhizol (2). The stereochemistry at C-12 of 5 was deduced using the modified Mosher experiment. Some of the isolated compounds elicited activity against gram positive and gram negative bacteria, levadura and dermatophytes.

  17. RELATING FINE ROOT BIOMASS TO SOIL AND CLIMATE CONDITIONS IN THE PACIFIC NORTHWEST

    EPA Science Inventory

    The additive contribution of fine root biomass for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) to the stand average fine root biomass were estimated for eight conifer stands in the Pacific Northwest. Base...

  18. Forest floor bryophytes of Pseudotsuga menziesii-Tsuga heterophylla stand in Oregon: Influences of substrate and overstory

    USGS Publications Warehouse

    Rambo, T.; Muir, Patricia S.

    1998-01-01

    Species richness and abundance of bryophytes inhabiting forest floor substrates were assessed at two sites in western Oregon. Bryophyte diversity, abundance, and community composition were compared between sites, and between young forest stands (~55 yrs) and old-growth stands (400 + yrs) within each site. Relationships of stand structural features to diversity and community composition were assessed by stratifying sampling between 'diversity' plots placed in areas of greater structural diversity, such as hardwood openings and remnant old-growth trees, and 'matrix' plots situated within the remaining more homogeneous conifer-dominated forest matrix. Richness, particularly for liverworts, was significantly higher in old-growth than young stands, and the two ages differed significantly in community composition. Substrate (ground versus coarse woody debris) and overstory (conifers versus hardwoods) were most strongly correlated with variation in community composition. Relatively open hardwood-dominated diversity plots differed in composition from matrix plots. Bryophyte abundance was lower in denser stands and plots, and positively correlated with canopy gaps, percentage of hardwoods, and incident solar radiation. These results suggest that availability of light may limit bryophyte productivity in these stands.

  19. Effects of Forest Succession on Exchangeable Cation Concentrations and Nitrogen Mineralization Rates in Soils Following Logging of Eastern Hemlock Forest, Whately, Massachusetts

    NASA Astrophysics Data System (ADS)

    Rhodes, A. L.; Sweezy, T.; Zukswert, J. M.; Dwyer, C. H.

    2012-12-01

    Ecological forest successions associated with invasive species and human disturbance may alter biogeochemical cycles within New England forests. Spread of the invasive insect hemlock woolly adelgid (Adelges tsugae) to eastern North America is causing mortality of the eastern hemlock (Tsuga canadensis), prompting salvage logging. Regrowth by deciduous hardwood trees is often observed. To evaluate whether changes in nutrient cycling could be altered by forest succession, we investigated exchangeable cation chemistry and nitrogen mineralization rates for soil in a mature, eastern hemlock forest and in a juvenile black birch (Betula lenta) forest in western MA. Eastern hemlock on this property was selectively logged 20 years ago, with black birch regrowth succeeding hemlock. We measured soil pH, exchangeable acidity (Al3+ and H+), exchangeable base cations (Ca2+, Mg2+, Na+, and K+), and nitrogen mineralization rates of organic and mineral horizons for 7 incubation periods between May 2011 - July 2012. We also measured the cation exchange capacity and nitrogen mineralization rates of soils from May - July 2012 (2 incubations) in a mature deciduous forest composed primarily of black birch. At each field site, 7 soil cores were collected. Soil horizons (organic and mineral) were separated and homogenized, and 3 replicates of each composite sample were analyzed for soil geochemistry. Organic soils within the juvenile black birch plot (BB) exhibit a low pH (4.3) similar to hemlock organic soils (HEM, pH=4.2). Surprisingly, exchangeable Al3+—the dominant cation in both plots—is significantly greater in organic soils at BB than at HEM (p<.001), and base saturation is less at BB (29%) than at HEM (46%, p<0.001) due to less Ca2+. There are no significant differences in the exchangeable cation chemistry of the mineral horizons at both sites, suggesting that the acidity difference of organic matter is not due to different soil mineralogy. In comparison, organic soil at the

  20. Windthrow and salvage logging in an old-growth hemlock-northern hardwoods forest

    USGS Publications Warehouse

    Lang, K.D.; Schulte, L.A.; Guntenspergen, G.R.

    2009-01-01

    Although the initial response to salvage (also known as, post-disturbance or sanitary) logging is known to vary among system components, little is known about longer term forest recovery. We examine forest overstory, understory, soil, and microtopographic response 25 years after a 1977 severe wind disturbance on the Flambeau River State Forest in Wisconsin, USA, a portion of which was salvage logged. Within this former old-growth hemlock-northern hardwoods forest, tree dominance has shifted from Eastern hemlock (Tsuga canadensis) to broad-leaf deciduous species (Ulmus americana, Acer saccharum, Tilia americana, Populus tremuloides, and Betula alleghaniensis) in both the salvaged and unsalvaged areas. While the biological legacies of pre-disturbance seedlings, saplings, and mature trees were initially more abundant in the unsalvaged area, regeneration through root suckers and stump sprouts was common in both areas. After 25 years, tree basal area, sapling density, shrub layer density, and seedling cover had converged between unsalvaged and salvaged areas. In contrast, understory herb communities differed between salvaged and unsalvaged forest, with salvaged forest containing significantly higher understory herb richness and cover, and greater dominance of species benefiting from disturbance, especially Solidago species. Soil bulk density, pH, organic carbon content, and organic nitrogen content were also significantly higher in the salvaged area. The structural legacy of tip-up microtopography remains more pronounced in the unsalvaged area, with significantly taller tip-up mounds and deeper pits. Mosses and some forest herbs, including Athyrium filix-femina and Hydrophyllum virginianum, showed strong positive responses to this tip-up microrelief, highlighting the importance of these structural legacies for understory biodiversity. In sum, although the pathways of recovery differed, this forest appeared to be as resilient to the compound disturbances of windthrow

  1. Responses of sugar maple and hemlock seedlings to elevated carbon dioxide under altered above- and belowground nitrogen sources.

    PubMed

    Eller, Allyson S D; McGuire, Krista L; Sparks, Jed P

    2011-04-01

    Various human-induced changes to the atmosphere have caused carbon dioxide (CO₂), nitrogen dioxide (NO₂) and nitrate deposition (NO₃⁻) to increase in many regions of the world. The goal of this study was to examine the simultaneous influence of these three factors on tree seedlings. We used open-top chambers to fumigate sugar maple (Acer saccharum) and eastern hemlock (Tsuga canadensis) with ambient or elevated CO₂ and NO₂ (elevated concentrations were 760 ppm and 40 ppb, respectively). In addition, we applied an artificial wet deposition of 30 kg ha⁻¹ year⁻¹ NO₃⁻ to half of the open-top chambers. After two growing seasons, hemlocks showed a stimulation of growth under elevated CO₂, but the addition of elevated NO₂ or NO₃⁻ eliminated this effect. In contrast, sugar maple seedlings showed no growth enhancement under elevated CO₂ alone and decreased growth in the presence of NO₂ or NO₃⁻, and the combined treatments of elevated CO₂ with increased NO₂ or NO₃⁻ were similar to control plants. Elevated CO₂ induced changes in the leaf characteristics of both species, including decreased specific leaf area, decreased %N and increased C:N. The effects of elevated CO₂, NO₂ and NO₃⁻ on growth were not additive and treatments that singly had no effect often modified the effects of other treatments. The growth of both maple and hemlock seedlings under the full combination of treatments (CO₂ + NO₂ + NO₃⁻) was similar to that of seedlings grown under control conditions, suggesting that models predicting increased seedling growth under future atmospheric conditions may be overestimating the growth and carbon storage potential of young trees.

  2. The phytotoxic effect of exogenous ethanol on Euphorbia heterophylla L.

    PubMed

    Kern, Kátia Aparecida; Pergo, Erica Marusa; Kagami, Fernanda Lima; Arraes, Luis Saraiva; Sert, Maria Aparecida; Ishii-Iwamoto, Emy Luiza

    2009-01-01

    This study investigated the effects of exogenously applied ethanol on Euphorbia heterophylla L., a troublesome weed in field and plantation crops. Ethanol at concentrations ranging from 0.25 to 1.5% caused a dose-dependent inhibition of germination and growth of E. heterophylla. Measurements of respiratory activity and alcohol dehydrogenase (E.C. 1.1.1.1) activity during seed imbibition and initial seedling growth revealed that ethanol induces a prolongation of hypoxic conditions in the growing tissues. In isolated mitochondria, ethanol inhibited the respiration coupled to ADP phosphorylation, an action that probably contributed to modifications observed in the respiratory activity of embryos. A comparison of the effects of methanol, ethanol, propanol and acetaldehyde on germination and growth of E. heterophylla indicates that alcohol dehydrogenase activity is required for the observed effects, with the conversion of ethanol to acetaldehyde playing a role in the ethanol-induced injuries.

  3. Species-specific partitioning of soil water resources in an old-growth Douglas-fir-western hemlock forest.

    PubMed

    Meinzer, Frederick C; Warren, Jeffrey M; Brooks, J Renée

    2007-06-01

    Although tree- and stand-level estimates of forest water use are increasingly common, relatively little is known about partitioning of soil water resources among co-occurring tree species. We studied seasonal courses of soil water utilization in a 450-year-old Pseudotsuga menziesii (Mirb.) Franco-Tsuga heterophylla (Raf.) Sarg. forest in southwestern Washington State. Soil volumetric water content (theta) was continuously monitored with frequency domain capacitance sensors installed at eight depths from 0.2 to 2 m at four locations in the vicinity of each species. Vertical profiles of root distribution and seasonal and daily courses of hydraulic redistribution (HR), sap flow and tree water status were also measured. Mean root area in the upper 60 cm of soil was significantly greater in the vicinity of T. heterophylla trees. However, seasonal water extraction on a root area basis was significantly greater near P. menziesii trees at all depths between 15 and 65 cm, leading to significantly lower water storage in the upper 65 cm of soil near P. menziesii trees at the end of the summer dry season. Greater apparent efficiency of P. menziesii roots at extracting soil water was attributable to a greater driving force for water uptake rather than to differences in root hydraulic properties between the species. The dependence of HR on theta was similar in soil near individuals of both species, but seasonal maximum rates of HR were greater in soil near P. menziesii because minimum values of theta were lower, implying a steeper water potential gradient between the upper and lower soil that acted as a driving force for water efflux from shallow roots. The results provide information on functional traits relevant for understanding the ecological distributions of these species and have implications for spatial variability of processes such as soil respiration and nutrient cycling.

  4. Survival and Near Extinction of Hemlock Woolly Adelgid (Hemiptera: Adelgidae) During Summer Aestivation in a Hemlock Plantation.

    PubMed

    Sussky, Elizabeth M; Elkinton, Joseph S

    2015-02-01

    Varying densities of the spring generation of the hemlock woolly adelgid were manipulated on 16 previously uninfested eastern hemlocks in an open-field plantation in Massachusetts. In contrast to experimentally created hemlock woolly adelgid populations in a forest, as reported previously, there was no evidence of density-dependent survival on a tree-wide basis in the plantation in the spring (progrediens) generation. There was, however, comparable density-dependent survival of settled crawlers and sexupara production when samples of the population were examined from branches with high density. Plantation hemlocks had 9.3 times more foliage and 10 times lower adelgid densities per cm than the forest hemlocks. These results show that density-dependent processes in the progrediens generation may only be evident when hemlock woolly adelgid density reaches a critical threshold. In the sistens generation that begins in midsummer, we counted a mean of 126 settled crawlers on marked branch on all 16 trees, but none of these adelgids survived the mid-summer aestivation phase, perhaps due to higher temperatures that were recorded in the plantation compared with a nearby hemlock forest, where 16% of the adelgids survived the aestivation phase. Whole tree counts of overwintering adelgids revealed that the adelgid populations had gone extinct on 13 out of the 16 trees. Mortality in the midsummer aestivation phase often exceeds overwintering mortality that has been widely thought to be the main factor that limits adelgid population growth and spread, particularly in northern states.

  5. Entomopathogenic activity of a variety of the fungus, Colletotrichum acutatum, recovered from the elongate hemlock scale, Fiorinia externa.

    PubMed

    Marcelino, José A P; Gouli, Svetlana; Parker, Bruce L; Skinner, Margaret; Giordano, Rosanna

    2009-01-01

    A fungal epizootic in populations of Fiorinia externa Ferris (Hemiptera: Diaspididae) infesting hemlock trees, Tsuga canadensis (L.) Carrière (Pinales: Pinaceae) in forests of the Northeastern US has been recently detected. The current known distribution of the epizootic spans 36 sites in New York, Pennsylvania, New Jersey and Connecticut. Colletotrichum acutatum Simmonds var. fioriniae Marcelino and Gouli var. nov. inedit. (Phyllachorales: Phyllachoraceae) was the most prevalent fungus recovered from infected scales. Bioassays indicated that this C. acutatum variety is highly pathogenic to F. externa. Mortality rates of >90 and >55% were obtained for F. externa crawlers and settlers, respectively. Significantly lower mortality levels,

  6. Hemlock alkaloids from Socrates to poison aloes.

    PubMed

    Reynolds, Tom

    2005-06-01

    Hemlock (Conium maculatum L. Umbelliferae) has long been known as a poisonous plant. Toxicity is due to a group of piperidine alkaloids of which the representative members are coniine and gamma-coniceine. The latter is the more toxic and is the first formed biosynthetically. Its levels in relation to coniine vary widely according to environmental conditions and to provenance of the plants. Surprisingly, these piperidine alkaloids have turned up in quite unrelated species in the monocotyledons as well as the dicotyledons. Aloes, for instance, important medicinal plants, are not regarded as poisonous although some species are very bitter. Nevertheless a small number of mostly local species contain the alkaloids, especially gamma-coniceine and there have been records of human poisoning. The compounds are recognized by their characteristic mousy smell. Both acute and chronic symptoms have been described. The compounds are neurotoxins and death results from respiratory failure, recalling the effects of curare. Chronic non-lethal ingestion by pregnant livestock leads to foetal malformation. Both acute and chronic toxicity are seen with stock in damp meadows and have been recorded as problems especially in North America. The alkaloids derive biosynthetically from acetate units via the polyketide pathway in contrast to other piperidine alkaloids which derive from lysine.

  7. Impacts of dwarf mistletoe on the physiology of host Tsuga heterophylla trees as recorded in tree ring C and O stable isotopes

    EPA Science Inventory

    • Dwarf mistletoes, obligate, parasitic plants with diminutive aerial shoots, have long-term effects on host tree water relations, hydraulic architecture, and photosynthetic gas exchange and can eventually induce tree death. • To investigate long-term impacts of dwarf mistletoe...

  8. De Novo Sequencing and Assembly Analysis of the Pseudostellaria heterophylla Transcriptome

    PubMed Central

    Li, Jun; Zhen, Wei; Long, Dengkai; Ding, Ling; Gong, Anhui; Xiao, Chenghong; Jiang, Weike; Liu, Xiaoqing; Zhou, Tao; Huang, Luqi

    2016-01-01

    Pseudostellaria heterophylla (Miq.) Pax is a mild tonic herb widely cultivated in the Southern part of China. The tuberous roots of P. heterophylla accumulate high levels of secondary metabolism products of medicinal value such as saponins, flavonoids, and isoquinoline alkaloids. Despite numerous studies on the pharmacological importance and purification of these compounds in P. heterophylla, their biosynthesis is not well understood. In the present study, we used Illumina HiSeq 4000 sequencing platform to sequence the RNA from flowers, leaves, stem, root cortex and xylem tissues of P. heterophylla. We obtained 616,413,316 clean reads that we assembled into 127, 334 unique sequences with an N50 length of 951 bp. Among these unigenes, 53,184 unigenes (41.76%) were annotated in a public database and 39, 795 unigenes were assigned to 356 KEGG pathways; 23,714 unigenes (8.82%) had high homology with the genes from Beta vulgaris. We discovered 32, 095 DEGs in different tissues and performed GO and KEGG enrichment analysis. The most enriched KEGG pathway of secondary metabolism showed up-regulated expression in tuberous roots as compared with the ground parts of P. heterophylla. Moreover, we identified 72 candidate genes involved in triterpenoids saponins biosynthesis in P. heterophylla. The expression profiles of 11 candidate unigenes were analyzed by quantitative real-time PCR (RT-qPCR). Our study established a global transcriptome database of P. heterophylla for gene identification and regulation. We also identified the candidate unigenes involved in triterpenoids saponins biosynthesis. Our results provide an invaluable resource for the secondary metabolites and physiological processes in different tissues of P. heterophylla. PMID:27764127

  9. Maytenus heterophylla and Maytenus senegalensis, two traditional herbal medicines.

    PubMed

    da Silva, G; Serrano, R; Silva, O

    2011-01-01

    Maytenus heterophylla (Eckl. and Zeyh.) N.K.B. Robson and Maytenus senegalensis (Lam.) Exell are two African shrubs or trees that go under the common name of spike thorn, which belong to the Celastraceae family. Different plant parts of this species are largely used in traditional medicine for infectious and inflammatory diseases treatment. Several studies have been reported for both these species, but there are no recent review articles focusing microscopic, phytochemistry and pharmacological studies. The aim of this review is to summarize the information about these two African traditional medicines. Such kind of data can be applied in future experimental work and may guide future studies, namely in the field of validation of traditional medicine.

  10. Maytenus heterophylla and Maytenus senegalensis, two traditional herbal medicines

    PubMed Central

    da Silva, G.; Serrano, R.; Silva, O.

    2011-01-01

    Maytenus heterophylla (Eckl. and Zeyh.) N.K.B. Robson and Maytenus senegalensis (Lam.) Exell are two African shrubs or trees that go under the common name of spike thorn, which belong to the Celastraceae family. Different plant parts of this species are largely used in traditional medicine for infectious and inflammatory diseases treatment. Several studies have been reported for both these species, but there are no recent review articles focusing microscopic, phytochemistry and pharmacological studies. The aim of this review is to summarize the information about these two African traditional medicines. Such kind of data can be applied in future experimental work and may guide future studies, namely in the field of validation of traditional medicine. PMID:22470236

  11. Emergence, Seasonality, and Hybridization of Laricobius nigrinus (Coleoptera: Derodontidae), an Introduced Predator of Hemlock Woolly Adelgid (Hemiptera: Adelgidae), in the Tennessee Appalachians.

    PubMed

    Wiggins, Gregory J; Grant, Jerome F; Rhea, James R; Mayfield, Albert E; Hakeem, Abdul; Lambdin, Paris L; Galloway, A B Lamb

    2016-09-29

    From 2010 through 2013, adult emergence and seasonality of Laricobius nigrinus Fender, an introduced predatory species native to western North America, as well as hybridization with the native species Laricobius rubidus (LeConte), were evaluated using emergence traps and beat-sheet sampling in areas of previous release against hemlock woolly adelgid, Adelges tsugae Annand. The shortest emergence period of adult L. nigrinus was 7 wk beginning 22 October 2010, and the longest emergence was 15 wk beginning 17 October 2012. Native L. rubidus also were collected from emergence traps placed on the ground surface and beat-sheet samples all 3 yr, with emergence of L. rubidus initiating later than L. nigrinus each season. Seasonality of both Laricobius species was similar across a 44-mo study period. Adult L. nigrinus were present from October through April, and larvae of Laricobius spp. were collected from February to May. The average number of L. nigrinus from emergence traps was significantly greater than the average number of beetles collected from beat-sheet samples in 2010, while the converse was observed during 2012. Hybridization between L. nigrinus and L. rubidus was documented from 10.75% of specimens collected during 2010 and 2011, indicating periodic interbreeding between the introduced and native species. These findings suggest emergence trapping may be a useful method to assess establishment, population densities, and seasonality of Laricobius species in areas of release to enhance their use in management of A. tsuage.

  12. Emergence, Seasonality, and Hybridization of Laricobius nigrinus (Coleoptera: Derodontidae), an Introduced Predator of Hemlock Woolly Adelgid (Hemiptera: Adelgidae), in the Tennessee Appalachians.

    PubMed

    Wiggins, Gregory J; Grant, Jerome F; Rhea, James R; Mayfield, Albert E; Hakeem, Abdul; Lambdin, Paris L; Galloway, A B Lamb

    2016-12-01

    From 2010 through 2013, adult emergence and seasonality of Laricobius nigrinus Fender, an introduced predatory species native to western North America, as well as hybridization with the native species Laricobius rubidus (LeConte), were evaluated using emergence traps and beat-sheet sampling in areas of previous release against hemlock woolly adelgid, Adelges tsugae Annand. The shortest emergence period of adult L. nigrinus was 7 wk beginning 22 October 2010, and the longest emergence was 15 wk beginning 17 October 2012. Native L. rubidus also were collected from emergence traps placed on the ground surface and beat-sheet samples all 3 yr, with emergence of L. rubidus initiating later than L. nigrinus each season. Seasonality of both Laricobius species was similar across a 44-mo study period. Adult L. nigrinus were present from October through April, and larvae of Laricobius spp. were collected from February to May. The average number of L. nigrinus from emergence traps was significantly greater than the average number of beetles collected from beat-sheet samples in 2010, while the converse was observed during 2012. Hybridization between L. nigrinus and L. rubidus was documented from 10.75% of specimens collected during 2010 and 2011, indicating periodic interbreeding between the introduced and native species. These findings suggest emergence trapping may be a useful method to assess establishment, population densities, and seasonality of Laricobius species in areas of release to enhance their use in management of A. tsuage.

  13. 78 FR 21099 - Grant of Authority for Subzone Status, Hemlock Semiconductor, L.L.C., (Polysilicon), Clarksville, TN

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-09

    ... Foreign-Trade Zones Board Grant of Authority for Subzone Status, Hemlock Semiconductor, L.L.C... manufacturing facility of Hemlock Semiconductor, L.L.C., located in Clarksville, Tennessee (FTZ Docket 62-2011... polysilicon at the facility of Hemlock Semiconductor, L.L.C., located in Clarksville, Tennessee (Subzone...

  14. From dusk till dawn: nocturnal and diurnal pollination in the epiphyte Tillandsia heterophylla (Bromeliaceae).

    PubMed

    Aguilar-Rodríguez, P A; Krömer, T; García-Franco, J G; MacSwiney G, M C

    2016-01-01

    In order to compare the effectiveness of diurnal and nocturnal pollinators, we studied the reproductive biology and pollinators of Tillandsia heterophylla E. Morren, an epiphytic tank bromeliad endemic to southeastern Mexico. Since anthesis in T. heterophylla is predominantly nocturnal but lasts until the following day, we hypothesised that this bromeliad would receive visits from both diurnal and nocturnal visitors, but that nocturnal visitors would be the most effective pollinators, since they arrive first to the receptive flower, and that bats would be the most frequent nocturnal visitors, given the characteristics of the nectar. Flowering of T. heterophylla began in May and lasted until July. The species is fully self-compatible, with an anthesis that lasts for ca. 15-16 h. Mean volume of nectar produced per flower was 82.21 μl, with a mean sugar concentration of 6.33%. The highest volume and concentration of nectar were found at 20:00 h, with a subsequent decline in both to almost zero over the following 12-h period. T. heterophylla has a generalist pollination system, since at least four different morphospecies of visitors pollinate its flowers: bats, moths, hummingbirds and bees. Most of the pollinating visits corresponded to bats and took place in the early evening, when stigma receptivity had already begun; making bats the probable pollinator on most occasions. However, diurnal pollinators may be important as a 'fail-safe' system by which to guarantee the pollination of T. heterophylla.

  15. Multi-decade biomass dynamics in an old-growth hemlock-northern hardwood forest, Michigan, USA.

    PubMed

    Woods, Kerry D

    2014-01-01

    Trends in living aboveground biomass and inputs to the pool of coarse woody debris (CWD) in an undisturbed, old-growth hemlock-northern hardwood forest in northern MI were estimated from multi-decade observations of permanent plots. Growth and demographic data from seven plot censuses over 47 years (1962-2009), combined with one-time measurement of CWD pools, help assess biomass/carbon status of this landscape. Are trends consistent with traditional notions of late-successional forests as equilibrial ecosystems? Specifically, do biomass pools and CWD inputs show consistent long-term trends and relationships, and can living and dead biomass pools and trends be related to forest composition and history? Aboveground living biomass densities, estimated using standard allometric relationships, range from 360-450 Mg/ha among sampled stands and types; these values are among the highest recorded for northeastern North American forests. Biomass densities showed significant decade-scale variation, but no consistent trends over the full study period (one stand, originating following an 1830 fire, showed an aggrading trend during the first 25 years of the study). Even though total above-ground biomass pools are neither increasing nor decreasing, they have been increasingly dominated, over the full study period, by very large (>70 cm dbh) stems and by the most shade-tolerant species (Acer saccharum and Tsuga canadensis). CWD pools measured in 2007 averaged 151 m(3)/ha, with highest values in Acer-dominated stands. Snag densities averaged 27/ha, but varied nearly ten-fold with canopy composition (highest in Tsuga-dominated stands, lowest in Acer-dominated); snags constituted 10-50% of CWD biomass. Annualized CWD inputs from tree mortality over the full study period averaged 1.9-3.2 Mg/ha/yr, depending on stand and species composition. CWD input rates tended to increase over the course of the study. Input rates may be expected to increase over longer-term observations because, (a

  16. Relatedness defies biogeography: the tale of two island endemics (Acacia heterophylla and A. koa).

    PubMed

    Le Roux, Johannes J; Strasberg, Dominique; Rouget, Mathieu; Morden, Clifford W; Koordom, Megan; Richardson, David M

    2014-10-01

    Despite the normally strong link between geographic proximity and relatedness of recently diverged taxa, truly puzzling biogeographic anomalies to this expectation exist in nature. Using a dated phylogeny, population genetic structure and estimates of ecological niche overlap, we tested the hypothesis that two geographically very disjunct, but morphologically very similar, island endemics (Acacia heterophylla from Réunion Island and A. koa from the Hawaiian archipelago) are the result of dispersal between these two island groups, rather than independent colonization events from Australia followed by convergent evolution. Our genetic results indicated that A. heterophylla renders A. koa paraphyletic and that the former colonized the Mascarene archipelago directly from the Hawaiian Islands ≤ 1.4 million yr ago. This colonization sequence was corroborated by similar ecological niches between the two island taxa, but not between A. melanoxylon from Australia (a sister, and presumed ancestral, taxon to A. koa and A. heterophylla) and Hawaiian A. koa. It is widely accepted that the long-distance dispersal of plants occurs more frequently than previously thought. Here, however, we document one of the most exceptional examples of such dispersal. Despite c. 18 000 km separating A. heterophylla and A. koa, these two island endemics from two different oceans probably represent a single taxon as a result of recent extreme long-distance dispersal.

  17. Effects of consecutive monoculture of Pseudostellaria heterophylla on soil fungal community as determined by pyrosequencing

    PubMed Central

    Wu, Linkun; Chen, Jun; Wu, Hongmiao; Wang, Juanying; Wu, Yanhong; Lin, Sheng; Khan, Muhammad Umar; Zhang, Zhongyi; Lin, Wenxiong

    2016-01-01

    Under consecutive monoculture, the biomass and quality of Pseudostellaria heterophylla declines significantly. In this study, a three-year field experiment was conducted to identify typical growth inhibition effects caused by extended monoculturing of P. heterophylla. Deep pyrosequencing was used to examine changes in the structure and composition of soil fungal community along a three-year gradient of monoculture. The results revealed a distinct separation between the newly planted plot and the two-year, three-year monocultured plots. The Shannon and Simpson diversity indices were significantly higher in the two-year and three-year monoculture soils than in the newly planted soil. Consecutive monoculture of this plant led to a significant increase in relative abundance of Fusarium, Trichocladium and Myrothecium and Simplicillium, etc., but a significant decrease in the relative abundance of Penicillium. Quantitative PCR analysis confirmed a significant increase in Fusarium oxysporum, an agent known to cause wilt and rot disease of P. heterophylla. Furthermore, phenolic acid mixture at a ratio similar to that found in the rhizosphere could promote mycelial growth of pathogenic F. oxysporum. Overall, this study demonstrated that consecutive monoculture of P. heterophylla can alter the fungal community in the rhizosphere, including enrichment of host-specific pathogenic fungi at the expense of plant-beneficial fungi. PMID:27216019

  18. Genome Sequence of Euphorbia mosaic virus from Passionfruit and Euphorbia heterophylla in Florida

    PubMed Central

    Londoño, M. A.; Cohen, A. L.; Padilla-Rodriguez, M.; Rosario, K.; Breitbart, M.

    2017-01-01

    ABSTRACT Euphorbia mosaic virus (EuMV) was found in a symptomatic passionfruit (Passiflora edulis) plant from Homestead, Florida, USA, as well as in the symptomatic weed Euphorbia heterophylla. This is the first identification of EuMV in Florida and the United States and the first report of a natural infection of passionfruit by EuMV. PMID:28254981

  19. Genome Sequence of Euphorbia mosaic virus from Passionfruit and Euphorbia heterophylla in Florida.

    PubMed

    Polston, J E; Londoño, M A; Cohen, A L; Padilla-Rodriguez, M; Rosario, K; Breitbart, M

    2017-03-02

    Euphorbia mosaic virus (EuMV) was found in a symptomatic passionfruit (Passiflora edulis) plant from Homestead, Florida, USA, as well as in the symptomatic weed Euphorbia heterophylla This is the first identification of EuMV in Florida and the United States and the first report of a natural infection of passionfruit by EuMV.

  20. Effects of consecutive monoculture of Pseudostellaria heterophylla on soil fungal community as determined by pyrosequencing

    NASA Astrophysics Data System (ADS)

    Wu, Linkun; Chen, Jun; Wu, Hongmiao; Wang, Juanying; Wu, Yanhong; Lin, Sheng; Khan, Muhammad Umar; Zhang, Zhongyi; Lin, Wenxiong

    2016-05-01

    Under consecutive monoculture, the biomass and quality of Pseudostellaria heterophylla declines significantly. In this study, a three-year field experiment was conducted to identify typical growth inhibition effects caused by extended monoculturing of P. heterophylla. Deep pyrosequencing was used to examine changes in the structure and composition of soil fungal community along a three-year gradient of monoculture. The results revealed a distinct separation between the newly planted plot and the two-year, three-year monocultured plots. The Shannon and Simpson diversity indices were significantly higher in the two-year and three-year monoculture soils than in the newly planted soil. Consecutive monoculture of this plant led to a significant increase in relative abundance of Fusarium, Trichocladium and Myrothecium and Simplicillium, etc., but a significant decrease in the relative abundance of Penicillium. Quantitative PCR analysis confirmed a significant increase in Fusarium oxysporum, an agent known to cause wilt and rot disease of P. heterophylla. Furthermore, phenolic acid mixture at a ratio similar to that found in the rhizosphere could promote mycelial growth of pathogenic F. oxysporum. Overall, this study demonstrated that consecutive monoculture of P. heterophylla can alter the fungal community in the rhizosphere, including enrichment of host-specific pathogenic fungi at the expense of plant-beneficial fungi.

  1. AmeriFlux US-Ha2 Harvard Forest Hemlock Site

    DOE Data Explorer

    Munger, William [Harvard University

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Ha2 Harvard Forest Hemlock Site. Site Description - The forest surrounding the Hemlock site has remained pristine with two exceptions. In the early to mid-1700s, European settlers cleared the majority of the forest for agricultural purposes. Selective harvesting of hemlock and chestnut trees occurred up until the early 1900s, when the chestnut blight killed all of the chestnut trees. In the current forest, about 83% of the total basal area of trees is hemlock. The remainder is equally divided between eastern white pine (Pinus strobus L.) and deciduous species, including red maple (Acer rubrum), red oak (Quercus rubra) and black birch (Betula lenta). A very thick organic layer (10-20 cm or more) covers the soil surface, and highly decayed coarse woody debris is abundant.

  2. Inclination distributions and size measurements of hemlock and red spruce needles

    NASA Technical Reports Server (NTRS)

    Kimes, Daniel S.; Smith, J. A.

    1991-01-01

    Needle inclination angle distributions were plotted for 5 and 10 deg intervals for two hemlock trees and one red spruce. The distributions for the hemlock and spruce were similar, with the peak normal angle occurring between 10 and 20 deg. These distributions are between two theoretical (planophile and spherical) leaf angle distributions. The results can be used as an input to radiative transfer models that require a distribution of the orientation of the scattering elements of the canopy.

  3. Large wood dynamics in central Appalachian hemlock headwater ravines

    NASA Astrophysics Data System (ADS)

    Costigan, K. H.; Soltesz, P.; Jaeger, K. L.

    2014-12-01

    Large wood (LW) is a critical component to forested mountain headwater streams contributing significantly to geomorphic and ecological processes. The character of LW is a function of valley recruitment processes that influence LW entering the channel and instream retention processes that influence LW transport through the channel reach. In the central Appalachian Mountains, US, LW dynamics in eastern hemlock-dominated ravines may change due to the invasive insect Hemlock Wooly Adelgid (HWA). However, quantitative LW studies are lacking for this region, which are necessary for effective management of projected HWA-associated change. We examined LW dynamics across central Appalachian headwater streams to identify 1) the current state of LW load, 2) the relative environmental factors that influence LW load, 3) potential signs of HWA impact on LW dynamics, and 4) functional grouping patterns of LW pieces in these systems. In a field study that included 24 sites in Ohio, West Virginia, and Virginia, mean wood density was 36 pieces/100m ± 21 and mean wood volume was 5.6 m3/100m ± 3.5. Most pieces were less than bankfull width suggesting high transportability, but large pieces (>10m) contributed significantly to wood volume, jam formation, and geomorphic function. Central Appalachian LW load was on the lower end of mountain headwater streams, but comparable to the northeastern US. A mixture of recruitment and retention processes influence wood dynamics, but channel retention processes better explain jam dynamics. Specifically, higher wood load was associated with lower forest basal area, smaller channel dimensions, and lower hydraulic driving forces, which is consistent with other studies. We did not detect a significant influence on wood load as a result of HWA infestation of ~20 years, which may reflect a lag period between tree mortality, toppling, and LW load. Pieces clustered in three functional groups of 1) larger, stable pieces that store sediment, stabilize the

  4. [Study on seed quality test and quality standard of Pesudostellaria heterophylla].

    PubMed

    Xiao, Cheng-Hong; Zhou, Tao; Jiang, Wei-Ke; Chen, Min; Xiong, Hou-Xi; Liao, Ming-Wu

    2014-08-01

    Referring to the rules for agricultural seed testing (GB /T 3543-1995) issued by China, the test of sampling, seed purity, weight per 1 000 seeds, seed moisture, seed viability and germination rate had been studied for screening seed quality test methods of Pesudostellaria heterophylla. The seed quality from different collection areas was measured. The results showed that at least 6.5 g seeds should be sampled and passed through 10-mesh sieve for purity analysis. The weight of 1 000 seeds was determined by using the 500-seed method. The phenotypic observation and size measurement were used for authenticity testing. The seed moisture was determined under the higher temperature (130 ± 2) degrees C for 5 hours. The seeds were dipped into 0.2% TTC sustaining 1 hour at 40 degrees C, then the viability could be determined. The break dormancy seeds were cultured on sand at 10 degrees C. K cluster analysis was applied for the data analysis, the seed quality from different collection areas grading of P. Heterophylla was described as three grades. The seed quality of each grade should reach following requirements: for first grade seeds, germination rate ≥ 86%, 1 000-grain weight ≥ 2.59 g, purity ≥ 87%, moisture ≤ 13.1%; for second grade seeds, germination rate ≥ 70%, 1 000-grain weight ≥ 2.40 g, purity ≥ 77%, moisture ≤ 14.3%; for third grade seeds, germination rate ≥ 41%, 1 000-grain weight ≥ 2.29 g, purity ≥ 76%, moisture ≤ 15.8%. The seed testing methods for quality items of P. heterophylla had been initially established, as well as the primary P. heterophylla seed quality classification standard.

  5. Highly stocked coniferous stands on the Olympic Peninsula: chemical composition and implications for harvest strategy. Forest Service research paper

    SciTech Connect

    Little, S.N.; Waddell, D.R.

    1987-10-01

    This report presents an assessment of macronutrients and their distribution within highly stocked, stagnant stands of mixed conifers on the Quilcene Ranger District, Olympic National Forest, northwest Washington. These stands consisted of predominantly three species: western hemlock (Tsuga heterophylla), coast Douglas-fir (Pseudotsuga menzeisii), and western redcedar (Thuja plicata). Preliminary investigation suggests that the living crown contains a small portion of the nutrient capital on the site. Extracting this material from the site during harvest or site preparation should not pose a threat to future production of biomass. Bioassays suggested that no macronutrients were deficient for growth of Douglas-fir seedlings.

  6. Effect of temperature and host tree on cold hardiness of hemlock looper eggs along a latitudinal gradient.

    PubMed

    Rochefort, Sophie; Berthiaume, Richard; Hébert, Christian; Charest, Martin; Bauce, Eric

    2011-06-01

    The hemlock looper, Lambdina fiscellaria, is an economically important insect pest of Canadian forests which overwinters as eggs. Although the hemlock looper causes extensive damages, no information on the mechanisms related to its cold tolerance is known. The objective of this study was to determine the effect of temperature and exposure duration on hemlock looper winter survival but also to identify seasonal supercooling capacity and cryoprotectant levels of three populations along a latitudinal gradient. As host plant may contribute to offspring overwintering success, cold tolerance of hemlock looper eggs from parents whose larvae were fed on three different tree species was also measured. Mean supercooling point (SCP) of hemlock looper eggs was lower than -30 °C from October through the following spring with values being as low as -47 °C in February. Trehalose was the most abundant sugar found in hemlock looper eggs with a peak concentration of 0.3 μg mg⁻¹ DW⁻¹. Glycerol, a polyol, was more often absent in eggs of the different populations and tree species tested in the study. When exposed to different temperature regimes for various periods of time, significant mortality of hemlock looper eggs occurred at higher temperatures than the mean SCP. Thus, hemlock looper could be considered as a chill tolerant species. No clear pattern of population and host plant effects on SCP and cryoprotectants was detected in this study. However, when exposed to different winter temperatures and exposure duration, hemlock looper from higher latitudes survived better (survival rates ranging between 0 and 89% at -20 °C) than those from lower latitudes (survival rates ranging between 0 and 56% at -20 °C). Our results may contribute to a better understanding of hemlock looper winter biology and thus facilitate predictions of outbreaks and range expansion.

  7. Revisiting the Plastid Phylogenomics of Pinaceae with Two Complete Plastomes of Pseudolarix and Tsuga.

    PubMed

    Sudianto, Edi; Wu, Chung-Shien; Lin, Ching-Ping; Chaw, Shu-Miaw

    2016-06-27

    Phylogeny of the ten Pinaceous genera has long been contentious. Plastid genomes (plastomes) provide an opportunity to resolve this problem because they contain rich evolutionary information. To comprehend the plastid phylogenomics of all ten Pinaceous genera, we sequenced the plastomes of two previously unavailable genera, Pseudolarix amabilis (122,234 bp) and Tsuga chinensis (120,859 bp). Both plastomes share similar gene repertoire and order. Here for the first time we report a unique insertion of tandem repeats in accD of T. chinensis From the 65 plastid protein-coding genes common to all Pinaceous genera, we re-examined the phylogenetic relationship among all Pinaceous genera. Our two phylogenetic trees are congruent in an identical tree topology, with the five genera of the Abietoideae subfamily constituting a monophyletic clade separate from the other three subfamilies: Pinoideae, Piceoideae, and Laricoideae. The five genera of Abietoideae were grouped into two sister clades consisting of (1) Cedrus alone and (2) two sister subclades of Pseudolarix-Tsuga and Abies-Keteleeria, with the former uniquely losing the gene psaM and the latter specifically excluding the 3 psbA from the residual inverted repeat.

  8. Revisiting the Plastid Phylogenomics of Pinaceae with Two Complete Plastomes of Pseudolarix and Tsuga

    PubMed Central

    Sudianto, Edi; Wu, Chung-Shien; Lin, Ching-Ping; Chaw, Shu-Miaw

    2016-01-01

    Phylogeny of the ten Pinaceous genera has long been contentious. Plastid genomes (plastomes) provide an opportunity to resolve this problem because they contain rich evolutionary information. To comprehend the plastid phylogenomics of all ten Pinaceous genera, we sequenced the plastomes of two previously unavailable genera, Pseudolarix amabilis (122,234 bp) and Tsuga chinensis (120,859 bp). Both plastomes share similar gene repertoire and order. Here for the first time we report a unique insertion of tandem repeats in accD of T. chinensis. From the 65 plastid protein-coding genes common to all Pinaceous genera, we re-examined the phylogenetic relationship among all Pinaceous genera. Our two phylogenetic trees are congruent in an identical tree topology, with the five genera of the Abietoideae subfamily constituting a monophyletic clade separate from the other three subfamilies: Pinoideae, Piceoideae, and Laricoideae. The five genera of Abietoideae were grouped into two sister clades consisting of (1) Cedrus alone and (2) two sister subclades of Pseudolarix—Tsuga and Abies—Keteleeria, with the former uniquely losing the gene psaM and the latter specifically excluding the 3 psbA from the residual inverted repeat. PMID:27352945

  9. 77 FR 46373 - Availability of an Environmental Assessment for a Biological Control Agent for Hemlock Woolly...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE... predators similar to that found in areas in which it is native is needed in order to provide more efficient... provide a predator that the spring generation of hemlock woolly adelgid currently lacks in the...

  10. Assessing hemlock decline using visible and near-infrared spectroscopy: indices comparison and algorithm development.

    PubMed

    Pontius, Jennifer; Hallett, Richard; Martin, Mary

    2005-06-01

    Near-infrared reflectance spectroscopy was evaluated for its effectiveness at predicting pre-visual decline in eastern hemlock trees. An ASD FieldSpec Pro FR field spectroradiometer measuring 2100 contiguous 1-nm-wide channels from 350 nm to 2500 nm was used to collect spectra from fresh hemlock foliage. Full spectrum partial least squares (PLS) regression equations and reduced stepwise linear regression equations were compared. The best decline predictive model was a 6-term linear regression equation (R2= 0.71, RMSE = 0.591) based on: Carter Miller Stress Index (R694/R760), Derivative Chlorophyll Index (FD705/FD723), Normalized Difference Vegetation Index ((R800 - R680)/(R800 + R680)), R950, R1922, and FD1388. Accuracy assessment showed that this equation predicted an 11-class decline rating with a 1-class tolerance accuracy of 96% and differentiated healthy trees from those in very early decline with 72% accuracy. These results indicate that narrow-band sensors could be developed to detect very early stages of hemlock decline, before visual symptoms are apparent. This capability would enable land managers to identify early hemlock woolly adelgid infestations and monitor forest health over large areas of the landscape.

  11. The non-competitive blockade of GABAA receptors by an aqueous extract of water hemlock (Cicuta douglasii) tubers.

    PubMed

    Green, Benedict T; Goulart, Camila; Welch, Kevin D; Pfister, James A; McCollum, Isabelle; Gardner, Dale R

    2015-12-15

    Water hemlocks (Cicuta spp.) are acutely toxic members of the Umbellierae family; the toxicity is due to the presence of C17-polyacetylenes such as cicutoxin. There is only limited evidence of noncompetitive antagonism by C17-polyacetylenes at GABAA receptors. In this work with WSS-1 cells, we documented the noncompetitive blockade of GABAA receptors by an aqueous extract of water hemlock (Cicuta douglasii) and modulated the actions of the extract with a pretreatment of 10 μM midazolam.

  12. Triterpenoids and Polysaccharide Fractions of Ganoderma tsugae Exert Different Effects on Antiallergic Activities

    PubMed Central

    Chen, Miaw-Ling; Hsieh, Chia-Chien; Chiang, Bor-Luen; Lin, Bi-Fong

    2015-01-01

    This study was to investigate antiallergic effects of triterpenoids (Gt-TRE) and polysaccharide (Gt-PS) extracts from Ganoderma tsugae, using mast cell line RBL-2H3, T cell line EL4, primary T cells, and transfected RAW264.7 macrophage cells. The results showed that histamine secreted from activated RBL-2H3 mast cells was significantly suppressed by Gt-TRE but not Gt-PS. Interleukin- (IL-) 4 secreted from activated EL4 cells was significantly suppressed by Gt-TRE but not Gt-PS. Further primary CD4+ T cells cultures also confirmed that Gt-TRE (5 ~ 50 µg/mL) significantly suppressed Th2 cytokines IL-4 and IL-5 secretions but had no effect on Th1 cytokines IL-2 and interferon (IFN)-γ. Gt-PS did not affect IL-4 and IL-5 secretions until higher doses (400, 500 µg/mL) and significantly suppressed IFNγ secretions but enhanced IL-2 at these high doses. The reporter gene assay indicated that Gt-TRE inhibited but Gt-PS enhanced the transcriptional activity of NF-κB in activated transfected RAW264.7 cells and transfected EL4 cells. IL-4 secreted by this transfected EL-4 cells was also significantly decreased by Gt-TRE but not by Gt-PS, suggesting that these two fractions may exert different effects on NF-κB related cytokines expression. These data suggested that triterpenoids fraction of Ganoderma tsugae might be the main constituents to alleviate allergic asthma. PMID:25960757

  13. Interaction of Pseudostellaria heterophylla with Quorum Sensing and Quorum Quenching Bacteria Mediated by Root Exudates in a Consecutive Monoculture System.

    PubMed

    Zhang, Liaoyuan; Guo, Zewang; Gao, Huifang; Peng, Xiaoqian; Li, Yongyu; Sun, Shujing; Lee, Jung-Kul; Lin, Wenxiong

    2016-12-28

    Many plant-pathogenic bacteria are dependent on quorum sensing (QS) to evoke disease. In this study, the population of QS and quorum quenching (QQ) bacteria was analyzed in a consecutive monoculture system of Pseudostellaria heterophylla. The isolated QS strains were identified as Serratia marcescens with SwrIR-type QS system and exhibited a significant increase over the years of monoculture. Only one QQ strain was isolated from newly planted soil sample and was identified as Bacillus thuringiensis, which secreted lactonase to degrade QS signal molecules. Inoculation of S. marcescens to P. heterophylla root could rapidly cause wilt disease, which was alleviated by B. thuringiensis. Furthermore, the expression of lactonase encoded by the aiiA gene in S. marcescens resulted in reduction of its pathogenicity, implying that the toxic effect of S. marcescens on the seedlings was QS-regulated. Meanwhile, excess lactonase in S. marcescens led to reduction in antibacterial substances, exoenzymes, and swarming motility, which might contribute to pathogensis on the seedlings. Root exudates and root tuber extracts of P. heterophylla significantly promoted the growth of S. marcescens, whereas a slight increase of B. thuringiensis was observed in both samples. These results demonstrated that QS-regulated behaviors in S. marcescens mediated by root exudates played an important role in replanting diseases of P. heterophylla.

  14. Macrofossil and Tree-Ring Evidence for a Long-Term Forest Succession and Mid-Holocene Hemlock Decline

    NASA Astrophysics Data System (ADS)

    Filion, Louise; Quinty, François

    1993-07-01

    Paludified dune fields in southern Québec provided a unique opportunity to analyze a mid-Holocene forest succession, ranging from xero-mesophilous forests to treed peatlands, which registered the hemlock decline, a major biostratigraphic event in eastern North America. Our fossil-tree chronology established from 66 radiocarbon dates of tree stems indicates that white pine and hemlock were present at the study site about 6000-5700 yr B.P. Hemlock reached a maximum 4900-4800 yr B.P. and then declined between 4600 and 3800 yr B.P.; the species recovered around 3700 yr B.P. and then decreased when white pine and eastern latch dominated the site after 3000 yr B.P. and between 2600 and 2200 yr B.P., respectively. Tree-ring signatures of fossil hemlocks suggest the continuous influence of biotic factors, possibly insect defoliators, throughout the record, as shown by recurrent suppressed-growth pattern. Microscopic examination of the hemlock fossil stems disclosed no evidence of fungal disease. The hemlock decline was probably caused by regional posthypsithermal climatic changes, toward moister conditions.

  15. Phylogenetic structure of ectomycorrhizal fungal communities of western hemlock changes with forest age and stand type.

    PubMed

    Lim, SeaRa; Berbee, Mary L

    2013-08-01

    On Vancouver Island, British Columbia, fertilization with nitrogen (N) and phosphorus (P) following clearcutting increases growth of western hemlock. To explore whether fertilization also resulted in ectomycorrhizal fungal communities that were more or less similar to neighboring unlogged stands, we sampled roots from western hemlock from three replicate plots from each of five different, well-characterized, forest stand types that differed in site type, and in logging and fertilization history. We harvested four samples of 100 ectomycorrhizal root tips from each plot, a total of 60 samples per stand type. From each sample, we analyzed fungal ribosomal internal transcribed spacers and 28S DNA, sequencing 15-29 clones per sample and 60-116 clones per plot. We detected 147 fungal operational taxonomic units among a total of 1435 sequences. Craterellus tubaeformis was frequently present and resulted in a pattern of phylogenetic overdispersion in the fungal communities. Fungal species composition was strongly correlated with foliar nitrogen concentration. However, other site quality factors were also important because the fertilized regenerating hemlock and mature hemlock-amabilis fir forests had similar foliar nitrogen content but little overlap in fungal species. Compared with unfertilized regenerating forests, fungal communities in N + P-fertilized regenerating forests had significantly more species overlap with old growth forests. However, the fungal communities of all regenerating forest were similar to one another and all differed significantly from older forests. By correlating fungal clades with habitats, this research improves understanding of how forest management can contribute to maintaining diverse ectomycorrhizal fungal communities across a landscape.

  16. Purification and Characterization of a Thermostable Caseinolytic Serine Protease from the Latex of Euphorbia heterophylla L.

    PubMed

    Singh, Sorokhaibam J; Singh, Laishram R; Devi, Sanjenbam K; Singh, Senjam S; Devi, Chingsubam B; Rully, Huidrom

    2015-01-01

    A new thermostable caseinolytic serine protease was purified from the latex of Euphorbia heterophylla L. to electrophoretic homogeneity by a procedure involving successive steps of pretreatment of the latex, PEG fractionation, CM-cellulose chromatography and DEAE-cellulose chromatography. The purified protease was found to be a monomeric protein of molecular weight 77.2 kDa. It exhibited caseinolytic activity with hyperbolic azocasein saturation with Vmax and Km values of 0.11 units.mL(-1) and 0.55 mg.mL(-1) respectively. Specific inhibitory studies revealed the enzyme to be a serine protease. The protease was characterized by pH optimum of 8.0 and high thermostability with T1/2 of 75°C. Based on the results of peptide mass fingerprinting analysis, the protease was shown to be a new protein not characterized earlier.

  17. Molecular characterization of a new begomovirus that infects Euphorbia heterophylla and Solanum lycopersicum in Venezuela.

    PubMed

    Zambrano, Karla; Fernández-Rodríguez, Thaly; Marys, Edgloris

    2012-02-01

    We report the complete nucleotide sequence of a begomovirus isolate infecting Euphorbia heterophylla and tomato (Solanum lycopersicum) in central Venezuela. Based on the current taxonomic criteria for the genus Begomovirus, the isolate was shown to represent a novel species, tentatively named Euphorbia mosaic Venezuela virus (EuMVV). Its DNA-A is most closely related to those of Euphorbia-infecting begomoviruses from the Caribbean and Central America. The DNA B component forms a phylogenetic cluster with Euphorbia and Sida-infecting begomoviruses from the squash leaf curl virus (SLCV) cluster. EuMVV is transmissible to S. lycopersicum and Capsicum annuum by biolistics of infectious cloned DNA-A and DNA-B components and induces characteristic leaf downward curling and yellowing in S. lycopersicum and and yellowing and leaf distortion in Capsicum annuum.

  18. The influence of successional processes and disturbance on the structure of Tsuga canadensis forests.

    PubMed

    D'Amato, Anthony W; Orwig, David A; Foster, David R

    2008-07-01

    Old-growth forests are valuable sources of ecological, conservation, and management information, yet these ecosystems have received little study in New England, due in large part to their regional scarcity. To increase our understanding of the structures and processes common in these rare forests, we studied the abundance of downed coarse woody debris (CWD) and snags and live-tree size-class distributions in 16 old-growth hemlock forests in western Massachusetts. Old-growth stands were compared with eight adjacent second-growth hemlock forests to gain a better understanding of the structural differences between these two classes of forests resulting from contrasting histories. In addition, we used stand-level dendroecological reconstructions to investigate the linkages between disturbance history and old-growth forest structure using an information-theoretic model selection framework. Old-growth stands exhibit a much higher degree of structural complexity than second-growth forests. In particular, old-growth stands had larger overstory trees and greater volumes of downed coarse woody debris (135.2 vs. 33.2 m3/ha) and snags (21.2 vs. 10.7 m3/ha). Second-growth stands were characterized by either skewed unimodal or reverse-J shaped diameter distributions, while old-growth forests contained bell-shaped, skewed unimodal, rotated sigmoid, and reverse J-shaped distributions. The variation in structural attributes among old-growth stands, particularly the abundance of downed CWD, was closely related to disturbance history. In particular, old-growth stands experiencing moderate levels of canopy disturbance during the last century (1930s and 1980s) had greater accumulations of CWD, highlighting the importance of gap-scale disturbances in shaping the long-term development and structural characteristics of old-growth forests. These findings are important for the development of natural disturbance-based silvicultural systems that may be used to restore important forest

  19. Chemical characteristics and anti-proliferation activities of Ganoderma tsugae polysaccharides.

    PubMed

    Chien, Rao-Chi; Yen, Ming-Tsung; Tseng, Yu-Hsiu; Mau, Jeng-Leun

    2015-09-05

    Polysaccharides were extracted by hot-water and hot-alkali from four forms of Ganoderma tsugae including mature and baby Ling chih, mycelium and filtrate. Different profiles of proximate composition and monosaccharide constituents, and element contents were found in the extracted polysaccharides from different extractions and different forms. The molecular weight distributions of polysaccharides were 2.8×10(4)-6.5×10(5)Da and their infrared spectra were comparable. The hot-alkali extracted polysaccharides exhibited better anti-proliferation on IMR32 cells than the hot-water extracted polysaccharides, which were in turn more effective than the hot-water extracts. Besides, most hot-water extracts and both extracted polysaccharides exhibited an anti-proliferation effect on Hep G2 cells. However, the hot-water extracts showed less effective in anti-proliferation of IMR32 and Hep G2 cells. Based on the anti-tumor effects, both polysaccharides could be prepared for use in the formulation of nutraceuticals and functional foods.

  20. Novel microsatellites for Calibrachoa heterophylla (Solanaceae) endemic to the South Atlantic Coastal Plain of South America1

    PubMed Central

    Silva-Arias, Gustavo Adolfo; Mäder, Geraldo; Bonatto, Sandro L.; Freitas, Loreta B.

    2015-01-01

    Premise of the study: Calibrachoa heterophylla (Solanaceae) is a petunia species restricted to the South Atlantic Coastal Plain of South America and presents a recent history of colonization from continental to coastal environments and diversification following the formation of the Coastal Plain during the Quaternary period. Methods and Results: This study reports a suite of 16 microsatellite loci for C. heterophylla. The applicability of these markers was assessed by genotyping 57 individuals from two natural populations. Of the 16 described loci, 12 were found to be polymorphic. Successful cross-amplification tests were obtained using 12 Calibrachoa species. Conclusions: The development of microsatellite markers will be useful to recover the contemporary history of the colonization of the Coastal Plain and to provide information for the conservation of this endemic species. PMID:26191462

  1. Postglacial vegetation history of Mitkof Island, Alexander Archipelago, southeastern Alaska

    USGS Publications Warehouse

    Ager, T.A.; Carrara, P.E.; Smith, Jody L.; Anne, V.; Johnson, J.

    2010-01-01

    An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ???12,900??cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400??cal yr BP. The earliest known vegetation to develop on the island (???12,900??cal yr BP) was pine woodland (Pinus contorta) with alder (Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ???12,240??cal yr BP, Sitka spruce (Picea sitchensis) began to colonize the island while pine woodland declined. By ???11,200??cal yr BP, mountain hemlock (Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ???10,180??cal yr BP, when western hemlock (Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ???7100??cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars (Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene.

  2. Postglacial vegetation history of Mitkof Island, Alexander Archipelago, southeastern Alaska

    NASA Astrophysics Data System (ADS)

    Ager, Thomas A.; Carrara, Paul E.; Smith, Jane L.; Anne, Victoria; Johnson, Joni

    2010-03-01

    An AMS radiocarbon-dated pollen record from a peat deposit on Mitkof Island, southeastern Alaska provides a vegetation history spanning ˜12,900 cal yr BP to the present. Late Wisconsin glaciers covered the entire island; deglaciation occurred > 15,400 cal yr BP. The earliest known vegetation to develop on the island (˜12,900 cal yr BP) was pine woodland ( Pinus contorta) with alder ( Alnus), sedges (Cyperaceae) and ferns (Polypodiaceae type). By ˜12,240 cal yr BP, Sitka spruce ( Picea sitchensis) began to colonize the island while pine woodland declined. By ˜11,200 cal yr BP, mountain hemlock ( Tsuga mertensiana) began to spread across the island. Sitka spruce-mountain hemlock forests dominated the lowland landscapes of the island until ˜10,180 cal yr BP, when western hemlock ( Tsuga heterophylla) began to colonize, and soon became the dominant tree species. Rising percentages of pine, sedge, and sphagnum after ˜7100 cal yr BP may reflect an expansion of peat bog habitats as regional climate began to shift to cooler, wetter conditions. A decline in alders at that time suggests that coastal forests had spread into the island's uplands, replacing large areas of alder thickets. Cedars ( Chamaecyparis nootkatensis, Thuja plicata) appeared on Mitkof Island during the late Holocene.

  3. Phenology, natural enemies, and efficacy of horticultural oil for control of Chionaspis heterophyllae (Homoptera: Diaspididae) on Christmas tree plantations.

    PubMed

    Fondren, Kirsten M; McCullough, Deborah G

    2005-10-01

    Pine needle scale, Chionaspis pinifoliae (Fitch), and Chionaspis heterophyllae Cooley are important pests of Scots pine, Pinus sylvestris L., and other conifers in much of North America. On Christmas tree plantations, these insects are typically controlled by spraying broad-spectrum insecticides when the vulnerable immature stages are present. However, effective control of bivoltine populations can be difficult to achieve due to asynchronous hatch and development of the second generation. Our objectives were to 1) determine the phenology of the second generation of C. heterophyllae in Michigan; 2) characterize the natural enemy complex; and 3) assess the effectiveness of horticultural oil for control of C. heterophyllae on P. sylvestris Christmas tree plantations. We monitored scale populations in three counties in lower Michigan for 3 yr. Scale phenology was consistently associated with cumulative degree-days base 10 degrees C (DD(10 degrees C)). Second-generation egg hatch began at approximately 1230-1300 DD(10 degrees C), and continued for approximately 3 wk. The peak of the second instar coincided with 1500-1600 DD(10 degrees C). Common predators included the coccinellids Chilocorus stigma (Say) and Microweisia misella (LeConte). On average, 70% of the C. heterophyllae population in unsprayed fields was killed by predators in 1999. Two endoparasitic wasps, Encarsia bella Gahan and Marietta mexicana Howard (Hymenoptera: Aphelinidae), also were recovered. In 2000 and 2001, we applied a highly refined horticultural spray oil with a backpack mist blower at 1500-1600 DD(10 degrees). Scale mortality on trees treated with oil ranged from 66 to 80% and was similar to control achieved using conventional insecticides in both years.

  4. Effects of ammonium and nitrate on nutrient uptake and activity of nitrogen assimilating enzymes in western hemlock

    SciTech Connect

    Knoepp, J.D.; Turner, D.P.; Tingey, D.T.

    1993-01-01

    Western hemlock seedlings were grown in nutrient solutions with ammonium, nitrate or ammonium plus nitrate as nitrogen sources. The objectives were to examine (1) possible selectivity for ammonium or nitrate as an N source, (2) the maintenance of charge balance during ammonium and nitrate uptake, and (3) the activity of the nitrogen assimilating enzymes, nitrate reductase, glutamine synthetase, and glutamine dehydrogenase, in relation to the uptake of different nitrogen sources. The uptake studies revealed that western hemlock takes up ammonium faster than nitrate and that ammonium partially inhibits nitrate uptake. Nitrate reductase activity varied with nitrate availability in root tissue, but showed no response in needles, indicating that most nitrate is reduced in the roots. Results indicate that western hemlock may be adapted to sites where NH(4+) is the predominate N source.

  5. A climatic driver for abrupt mid-Holocene vegetation dynamics and the hemlock decline in New England.

    PubMed

    Foster, David R; Oswald, W Wyatt; Faison, Edward K; Doughty, Elaine D; Hansen, Barbara C S

    2006-12-01

    The mid-Holocene decline of eastern hemlock is widely viewed as the sole prehistorical example of an insect- or pathogen-mediated collapse of a North American tree species and has been extensively studied for insights into pest-host dynamics and the consequences to terrestrial and aquatic ecosystems of dominant-species removal. We report paleoecological evidence implicating climate as a major driver of this episode. Data drawn from sites across a gradient in hemlock abundance from dominant to absent demonstrate: a synchronous, dramatic decline in a contrasting taxon (oak); changes in lake sediments and aquatic taxa indicating low water levels; and one or more intervals of intense drought at regional to continental scales. These results, which accord well with emerging climate reconstructions, challenge the interpretation of a biotically driven hemlock decline and highlight the potential for climate change to generate major, abrupt dynamics in forest ecosystems.

  6. Effect of simulated fall heat waves on cold hardiness and winter survival of hemlock looper, Lambdina fiscellaria (Lepidoptera: Geometridae).

    PubMed

    Vallières, Rosemarie; Rochefort, Sophie; Berthiaume, Richard; Hébert, Christian; Bauce, Éric

    2015-02-01

    The hemlock looper (Lambdina fiscellaria) is an important pest of eastern Canadian forests. The ongoing climate warming could modify the seasonal ecology of this univoltine species that lays eggs at the end of summer and overwinters at this stage. Indeed, the increase in frequency and intensity of extreme climatic events such as fall heat waves could interfere with the winter metabolism of the hemlock looper. Moreover, the host plant quality, which influences the quantity of insect energetic reserves, the geographic origin of populations and the conditions prevailing during the cold acclimation period, could cause various responses of this pest to climate warming. The main objective of this study is to determine the impact of these factors on hemlock looper winter biology. In October 2010, hemlock looper eggs initially collected from two geographic areas in the province of Québec, and from parents reared on two host plants, were exposed to fall heat waves of different intensities during 5 consecutive days. Supercooling points and cryoprotectant levels were measured on eggs on four different dates in 2010-2011 and survival rate was measured in April 2011. Our results show that hemlock looper eggs have a very low supercooling point and high levels of trehalose, glucose and mannitol in September and November. However, there is no clear relationship between the concentration of these compounds and the decrease in supercooling points. Contents in trehalose, glucose and mannitol were significantly influenced by fall heat waves and by the origin of the population. Winter survival of eggs from the temperate population was negatively affected by strong heat waves while the boreal population was not affected. This study suggests that the metabolism and winter survival of temperate hemlock looper populations in Québec will be more affected by fall heat waves that will increase in frequency due to climate change, than boreal populations.

  7. Douglas-fir ectomycorrhizae in 40- and 400-year-old stands: mycobiont availability to late successional western hemlock.

    PubMed

    Horton, T R; Molina, R; Hood, K

    2005-09-01

    We investigated ectomycorrhizal (EM) fungi in forest stands containing both early successional Douglas-fir and late successional western hemlock at two points in the typical stand development by identifying EM fungi from roots of Douglas-fir and western hemlock in mixed stands. In an early seral stage forest, EM roots of western hemlock seedlings and intermingling 40-year-old Douglas-fir were sampled. In a late seral stage forest, EM roots of trees of both species were sampled in a 400-year-old stand. We use molecular approaches to identify the symbionts from field samples in this descriptive study. In the early seral stage study, >95% of the western hemlock root tips by biomass were colonized by fungi also colonizing Douglas-fir roots. This result supports the prediction that western hemlock can associate with fungi in Douglas-fir EM networks. In the same study, fungi specific to Douglas-fir colonized 14% of its EM root tips. In the late seral stage study, 14% of the western hemlock root tips were colonized by fungi also observed in association with Douglas-fir, a result strongly influenced by sampling issues and likely represents a conservative estimate of multiple host fungi in this old growth setting. Fungi specific to Douglas-fir colonized 25% of its root tip biomass in the old growth study, in tight coralloid clusters within five of the 24 soil samples. The trends revealed in this study corroborate earlier studies suggesting a predominance of multiple host fungi in mixed communities of EM plants. The role of host-specific fungi in these stands remains unclear.

  8. DNA and Flavonoids Leach out from Active Nuclei of Taxus and Tsuga after Extreme Climate Stresses

    PubMed Central

    Feucht, Walter; Schmid, Markus; Treutter, Dieter

    2015-01-01

    Severe over-stresses of climate caused dramatic changes in the intracellular distribution of the flavonoids. This was studied in needles from the current year’s growth of the following species and varieties: Tsuga canadensis, Taxus baccata, T. aurea, T. repens, T. nana, and T. compacta. The mode of steady changes in flavonoids was evaluated by microscopic techniques. Most of the flavonoids stain visibly yellow by themselves. The colorless flavanol subgroup can be stained blue by the DMACA reagent. In mid-summer 2013, outstanding high temperatures and intense photo-oxidative irradiation caused in a free-standing tree of Taxus baccata dramatic heat damage in a limited number of cells of the palisade layers. In these cells, the cytoplasm was burned brown. However, the nucleus maintained its healthy “blue” colored appearance which apparently was a result of antioxidant barrier effects by these flavanols. In late May 2014, excessive rainfall greatly affected all study trees. Collectively, in all study trees, a limited number of the mesophyll nuclei from the needless grown in 2013 and 2014 became overly turgid, enlarged in size and the flavanols leached outward through the damaged nuclear membranes. This diffusive stress event was followed one to three days later by a similar efflux of DNA. Such a complete dissolution of the nuclei in young tissues was the most spectacular phenomenon of the present study. As a common feature, leaching of both flavanols and DNA was markedly enhanced with increasing size and age of the cells. There is evidence that signalling flavonoids are sensitized to provide in nuclei and cytoplasm multiple mutual protective mechanisms. However, this well-orchestrated flavonoid system is broken down by extreme climate events. PMID:27135348

  9. DNA and Flavonoids Leach out from Active Nuclei of Taxus and Tsuga after Extreme Climate Stresses.

    PubMed

    Feucht, Walter; Schmid, Markus; Treutter, Dieter

    2015-09-21

    Severe over-stresses of climate caused dramatic changes in the intracellular distribution of the flavonoids. This was studied in needles from the current year's growth of the following species and varieties: Tsuga canadensis, Taxus baccata, T. aurea, T. repens, T. nana, and T. compacta. The mode of steady changes in flavonoids was evaluated by microscopic techniques. Most of the flavonoids stain visibly yellow by themselves. The colorless flavanol subgroup can be stained blue by the DMACA reagent. In mid-summer 2013, outstanding high temperatures and intense photo-oxidative irradiation caused in a free-standing tree of Taxus baccata dramatic heat damage in a limited number of cells of the palisade layers. In these cells, the cytoplasm was burned brown. However, the nucleus maintained its healthy "blue" colored appearance which apparently was a result of antioxidant barrier effects by these flavanols. In late May 2014, excessive rainfall greatly affected all study trees. Collectively, in all study trees, a limited number of the mesophyll nuclei from the needless grown in 2013 and 2014 became overly turgid, enlarged in size and the flavanols leached outward through the damaged nuclear membranes. This diffusive stress event was followed one to three days later by a similar efflux of DNA. Such a complete dissolution of the nuclei in young tissues was the most spectacular phenomenon of the present study. As a common feature, leaching of both flavanols and DNA was markedly enhanced with increasing size and age of the cells. There is evidence that signalling flavonoids are sensitized to provide in nuclei and cytoplasm multiple mutual protective mechanisms. However, this well-orchestrated flavonoid system is broken down by extreme climate events.

  10. Developmental polymorphism in a Newfoundland population of the hemlock looper, Lambdina fiscellaria (Lepidoptera: Geometridae).

    PubMed

    Berthiaume, Richard; Bauce, Eric; Hébert, Christian; Brodeur, Jacques

    2007-08-01

    The hemlock looper [Lambdina fiscellaria (Guenée)], a widespread and highly polyphagous Geometridae, is considered one of the most economically important defoliators of North American coniferous forests. Variations in the number of larval instars between geographic populations of this species have been previously reported in the literature. However, whether such developmental polymorphism occurs within a given population is unknown. In this study, we report the presence of both four and five larval instar individuals within a population of hemlock looper in Newfoundland when reared on balsam fir. For both sexes, the majority of individuals reared on balsam fir shoots went through four larval instars, but more than one third of the females (35.3%) went through five larval instars. Females with four larval instars developed faster and had smaller pupal weight than females with five larval instars. However, a growth-related index (weight gain per unit of time) was similar for the two ecotypes (four or five larval instars). No significant difference was observed between the two ecotypes in terms of reproductive capacity (fecundity and egg size). We also found significant differences in life history traits between males and females. Results indicate that developmental polymorphism, in this case, the variation in the number of larval instars, might provide some adaptive attributes that allowed exploitation of a broader ecological niche.

  11. Imidacloprid movement in soils and impacts on soil microarthropods in southern Appalachian eastern hemlock stands.

    PubMed

    Knoepp, Jennifer D; Vose, James M; Michael, Jerry L; Reynolds, Barbara C

    2012-01-01

    Imidacloprid is a systemic insecticide effective in controlling the exotic pest (hemlock woolly adelgid) in eastern hemlock () trees. Concerns over imidacloprid impacts on nontarget species have limited its application in southern Appalachian ecosystems. We quantified the movement and adsorption of imidacloprid in forest soils after soil injection in two sites at Coweeta Hydrologic Laboratory in western North Carolina. Soils differed in profile depth, total carbon and nitrogen content, and effective cation exchange capacity. We injected imidacloprid 5 cm into mineral soil, 1.5 m from infested trees, using a Kioritz soil injector. We tracked the horizontal and vertical movement of imidacloprid by collecting soil solution and soil samples at 1 m, 2 m, and at the drip line from each tree periodically for 1 yr. Soil solution was collected 20 cm below the surface and just above the saprolite, and acetonitrile-extractable imidacloprid was determined through the profile. Soil solution and extractable imidacloprid concentrations were determined by high-performance liquid chromatography. Soil solution and extractable imidacloprid concentrations were greater in the site with greater soil organic matter. Imidacloprid moved vertically and horizontally in both sites; concentrations generally declined downward in the soil profile, but preferential flow paths allowed rapid vertical movement. Horizontal movement was limited, and imidacloprid did not move to the tree drip line. We found a negative relationship between adsorbed imidacloprid concentrations and soil microarthropod populations largely in the low-organic-matter site; however, population counts were similar to other studies at Coweeta.

  12. Ecosystem function in Appalachian headwater streams during an active invasion by the hemlock woolly adelgid.

    PubMed

    Northington, Robert M; Webster, Jackson R; Benfield, Ernest F; Cheever, Beth M; Niederlehner, Barbara R

    2013-01-01

    Forested ecosystems in the southeastern United States are currently undergoing an invasion by the hemlock woolly adelgid (HWA). Previous studies in this area have shown changes to forest structure, decreases in canopy cover, increases in organic matter, and changes to nutrient cycling on the forest floor and soil. Here, we were interested in how the effects of canopy loss and nutrient leakage from terrestrial areas would translate into functional changes in streams draining affected watersheds. We addressed these questions in HWA-infested watersheds at the Coweeta Hydrologic Laboratory in North Carolina. Specifically, we measured stream metabolism (gross primary production and ecosystem respiration) and nitrogen uptake from 2008 to 2011 in five streams across the Coweeta basin. Over the course of our study, we found no change to in-stream nutrient concentrations. While canopy cover decreased annually in these watersheds, this change in light penetration did not translate to higher rates of in-stream primary production during the summer months of our study. We found a trend towards greater heterotrophy within our watersheds, where in-stream respiration accounted for a much larger component of net ecosystem production than GPP. Additionally, increases in rhododendron cover may counteract changes in light and nutrient availability that occurred with hemlock loss. The variability in our metabolic and uptake parameters suggests an actively-infested ecosystem in transition between steady states.

  13. Microbial communities and bacterial diversity of spruce, hemlock and grassland soils of Tatachia Forest, Taiwan.

    PubMed

    Selvam, Ammaiyappan; Tsai, Shu-Hsien; Liu, Ching-Piao; Chen, I-Chu; Chang, Cheng-Hsiung; Yang, Shang-Shyng

    2010-07-01

    To evaluate the bacterial diversity of Tatachia Forest soils, 16S rDNA clone libraries of the spruce, hemlock and grassland soils were constructed. Further, the influence of physicochemical and biological properties of soil on microbial ecology, pH, moisture content, microbial population and biomass were also analyzed. The soil pH increased with the increasing of soil depth; whereas the microbial population, biomass, moisture content, total organic carbon and total nitrogen were reverse. Microbial populations were the highest in the summer season which also correlated with the highest moisture content. The phylogenetic analyses revealed that the clones from nine 16S rDNA clone libraries represented Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Gemmatimonadetes, Planctomycetes, Verrucomicrobia, candidate division TG1 and candidate division TM7. Members of Proteobacteria, Acidobacteria and Actinobacteria constituted 42.2, 35.1 and 7.8 % of the clone libraries, respectively; whereas the remaining bacterial divisions each comprised <3 %. The spruce site had the highest bacterial diversity among the tested sites, followed by the hemlock sites and the grassland sites with the least. The bacterial community is the more diverse in the organic layer than that in deeper horizons. Further, bacterial diversity through the gradient horizons was different, indicating that the bacterial diversity in the deeper horizons is not simply the diluted analogs of the surface soils and some microbes dominate only in the deeper horizons.

  14. Floral longevity and autonomous selfing are altered by pollination and water availability in Collinsia heterophylla

    PubMed Central

    Jorgensen, Rachael; Arathi, H. S.

    2013-01-01

    Background and Aims A plant investing in reproduction partitions resources between flowering and seed production. Under resource limitation, altered allocations may result in floral trait variations, leading to compromised fecundity. Floral longevity and timing of selfing are often the traits most likely to be affected. The duration of corolla retention determines whether fecundity results from outcrossing or by delayed selfing-mediated reproductive assurance. In this study, the role of pollination schedules and soil water availability on floral longevity and seed production is tested in Collinsia heterophylla (Plantaginaceae). Methods Using three different watering regimes and pollination schedules, effects on floral longevity and seed production were studied in this protandrous, flowering annual. Key Results The results reveal that soil water status and pollination together influence floral longevity with low soil water and hand-pollinations early in the floral lifespan reducing longevity. However, early pollinations under excess water did not extend longevity, implying that resource surplus does not lengthen the outcrossing period. The results also indicate that pollen receipt, a reliable cue for fecundity, accelerates flower drop. Early corolla abscission under drought stress could potentially exacerbate sexual conflict in this protandrous, hermaphroditic species by ensuring self-pollen paternity and enabling male control of floral longevity. While pollination schedules did not affect fecundity, water stress reduced per-capita seed numbers. Unmanipulated flowers underwent delayed autonomous selfing, producing very few seeds, suggesting that inbreeding depression may limit benefits of selfing. Conclusions In plants where herkogamy and dichogamy facilitate outcrossing, floral longevity determines reproductive success and mating system. Reduction in longevity under drought suggests a strong environmental effect that could potentially alter the preferred breeding

  15. Expression and Functional Analysis of WRKY Transcription Factors in Chinese Wild Hazel, Corylus heterophylla Fisch

    PubMed Central

    Liang, Li-Song; Ma, Qing-Hua; Chen, Xin; Zong, Jian-Wei; Wang, Gui-Xi

    2015-01-01

    Plant WRKY transcription factors are known to regulate various biotic and abiotic stress responses. In this study we identified a total of 30 putative WRKY unigenes in a transcriptome dataset of the Chinese wild Hazel, Corylus heterophylla, a species that is noted for its cold tolerance. Thirteen full-length of these ChWRKY genes were cloned and found to encode complete protein sequences, and they were divided into three groups, based on the number of WRKY domains and the pattern of zinc finger structures. Representatives of each of the groups, Unigene25835 (group I), Unigene37641 (group II) and Unigene20441 (group III), were transiently expressed as fusion proteins with yellow fluorescent fusion protein in Nicotiana benthamiana, where they were observed to accumulate in the nucleus, in accordance with their predicted roles as transcriptional activators. An analysis of the expression patterns of all 30 WRKY genes revealed differences in transcript abundance profiles following exposure to cold, drought and high salinity conditions. Among the stress-inducible genes, 23 were up-regulated by all three abiotic stresses and the WRKY genes collectively exhibited four different patterns of expression in flower buds during the overwintering period from November to April. The organ/tissue related expression analysis showed that 18 WRKY genes were highly expressed in stem but only 2 (Unigene9262 and Unigene43101) were greatest in male anthotaxies. The expression of Unigene37641, a member of the group II WRKY genes, was substantially up-regulated by cold, drought and salinity treatments, and its overexpression in Arabidopsis thaliana resulted in better seedling growth, compared with wild type plants, under cold treatment conditions. The transgenic lines also had exhibited higher soluble protein content, superoxide dismutase and peroxidase activiety and lower levels of malondialdehyde, which collectively suggets that Unigene37641 expression promotes cold tolerance. PMID

  16. Expression and Functional Analysis of WRKY Transcription Factors in Chinese Wild Hazel, Corylus heterophylla Fisch.

    PubMed

    Zhao, Tian-Tian; Zhang, Jin; Liang, Li-Song; Ma, Qing-Hua; Chen, Xin; Zong, Jian-Wei; Wang, Gui-Xi

    2015-01-01

    Plant WRKY transcription factors are known to regulate various biotic and abiotic stress responses. In this study we identified a total of 30 putative WRKY unigenes in a transcriptome dataset of the Chinese wild Hazel, Corylus heterophylla, a species that is noted for its cold tolerance. Thirteen full-length of these ChWRKY genes were cloned and found to encode complete protein sequences, and they were divided into three groups, based on the number of WRKY domains and the pattern of zinc finger structures. Representatives of each of the groups, Unigene25835 (group I), Unigene37641 (group II) and Unigene20441 (group III), were transiently expressed as fusion proteins with yellow fluorescent fusion protein in Nicotiana benthamiana, where they were observed to accumulate in the nucleus, in accordance with their predicted roles as transcriptional activators. An analysis of the expression patterns of all 30 WRKY genes revealed differences in transcript abundance profiles following exposure to cold, drought and high salinity conditions. Among the stress-inducible genes, 23 were up-regulated by all three abiotic stresses and the WRKY genes collectively exhibited four different patterns of expression in flower buds during the overwintering period from November to April. The organ/tissue related expression analysis showed that 18 WRKY genes were highly expressed in stem but only 2 (Unigene9262 and Unigene43101) were greatest in male anthotaxies. The expression of Unigene37641, a member of the group II WRKY genes, was substantially up-regulated by cold, drought and salinity treatments, and its overexpression in Arabidopsis thaliana resulted in better seedling growth, compared with wild type plants, under cold treatment conditions. The transgenic lines also had exhibited higher soluble protein content, superoxide dismutase and peroxidase activiety and lower levels of malondialdehyde, which collectively suggets that Unigene37641 expression promotes cold tolerance.

  17. Density-Dependent Recruitment and Diapause in the Spring-Feeding Generation of Hemlock Woolly Adelgid (Hemiptera: Adelgidae) in Western North America.

    PubMed

    Weed, Aaron S; Elkinton, Joseph S; Lany, Nina K

    2016-12-01

    Insect populations are affected by density-dependent and density-independent factors, and knowing how these factors affect long-term population growth is critical to pest management. In this study, we experimentally manipulated densities of the hemlock woolly adelgid on eastern and western hemlock trees in the western USA to evaluate the effects of density and host species on hemlock woolly adelgid crawler colonization. We then followed development of hemlock woolly adelgid on each hemlock species. Settlement of crawlers was strongly density-dependent and consistent between host species. In addition, a period of hot days that coincided with the settlement of hemlock woolly adelgid crawlers put our experimental and naturally occurring populations into diapause during April. Diapause resulted in one generation that yr in our experimental population. Analyses of long-term air temperature records indicated that diapause-inducing temperatures in April similar to those observed in our experiment have occurred rarely since 1909 and the frequency of these events has not changed over time. Prior work suggests that hemlock woolly adelgid completes two generations per yr in the western USA with a diapause occurring in the summer. This typical life history reflects the long-term influence of regional average seasonal temperature patterns on development and the timing of diapause-inducing temperatures. However, the timing of unseasonal weather, such as the hot days observed in our experiment, occasionally changes life history trajectories from this normal pattern. Our results show that density-dependent and density-independent factors have strong effects on generational mortality and life history of hemlock woolly adelgid that are important to its population dynamics and management.

  18. Density-Dependent Recruitment and Diapause in the Spring-Feeding Generation of Hemlock Woolly Adelgid (Hemiptera: Adelgidae) in Western North America.

    PubMed

    Weed, Aaron S; Elkinton, Joseph S; Lany, Nina K

    2016-09-30

    Insect populations are affected by density-dependent and density-independent factors, and knowing how these factors affect long-term population growth is critical to pest management. In this study, we experimentally manipulated densities of the hemlock woolly adelgid on eastern and western hemlock trees in the western USA to evaluate the effects of density and host species on hemlock woolly adelgid crawler colonization. We then followed development of hemlock woolly adelgid on each hemlock species. Settlement of crawlers was strongly density-dependent and consistent between host species. In addition, a period of hot days that coincided with the settlement of hemlock woolly adelgid crawlers put our experimental and naturally occurring populations into diapause during April. Diapause resulted in one generation that yr in our experimental population. Analyses of long-term air temperature records indicated that diapause-inducing temperatures in April similar to those observed in our experiment have occurred rarely since 1909 and the frequency of these events has not changed over time. Prior work suggests that hemlock woolly adelgid completes two generations per yr in the western USA with a diapause occurring in the summer. This typical life history reflects the long-term influence of regional average seasonal temperature patterns on development and the timing of diapause-inducing temperatures. However, the timing of unseasonal weather, such as the hot days observed in our experiment, occasionally changes life history trajectories from this normal pattern. Our results show that density-dependent and density-independent factors have strong effects on generational mortality and life history of hemlock woolly adelgid that are important to its population dynamics and management.

  19. Estimating structural attributes of Douglas-fir/western hemlock forest stands from Landsat and SPOT imagery

    NASA Technical Reports Server (NTRS)

    Cohen, Warren B.; Spies, Thomas A.

    1992-01-01

    Relationships between spectral and texture variables derived from SPOT HRV 10 m panchromatic and Landsat TM 30 m multispectral data and 16 forest stand structural attributes is evaluated to determine the utility of satellite data for analysis of hemlock forests west of the Cascade Mountains crest in Oregon and Washington, USA. Texture of the HRV data was found to be strongly related to many of the stand attributes evaluated, whereas TM texture was weakly related to all attributes. Data analysis based on regression models indicates that both TM and HRV imagery should yield equally accurate estimates of forest age class and stand structure. It is concluded that the satellite data are a valuable source for estimation of the standard deviation of tree sizes, mean size and density of trees in the upper canopy layers, a structural complexity index, and stand age.

  20. Insights into the Regulation of Rhizosphere Bacterial Communities by Application of Bio-organic Fertilizer in Pseudostellaria heterophylla Monoculture Regime

    PubMed Central

    Wu, Linkun; Chen, Jun; Wu, Hongmiao; Qin, Xianjin; Wang, Juanying; Wu, Yanhong; Khan, Muhammad U.; Lin, Sheng; Xiao, Zhigang; Luo, Xiaomian; Zhang, Zhongyi; Lin, Wenxiong

    2016-01-01

    The biomass and quality of Pseudostellariae heterophylla suffers a significant decline under monoculture. Since rhizosphere miobiome plays crucial roles in soil health, deep pyrosequencing combined with qPCR was applied to characterize the composition and structure of soil bacterial community under monoculture and different amendments. The results showed compared with the 1st-year planted (FP), 2nd-year monoculture of P. heterophylla (SP) led to a significant decline in yield and resulted in a significant increase in Fusarium oxysporum but a decline in Burkholderia spp. Bio-organic fertilizer (MT) formulated by combining antagonistic bacteria with organic matter could significantly promote the yield by regulating rhizosphere bacterial community. However, organic fertilizer (MO) without antagonistic bacteria could not suppress Fusarium wilt. Multivariate statistics analysis showed a distinct separation between the healthy samples (FP and MT) and the unhealthy samples (SP and MO), suggesting a strong relationship between soil microbial community and plant performance. Furthermore, we found the application of bio-organic fertilizer MT could significantly increase the bacterial community diversity and restructure microbial community with relatively fewer pathogenic F. oxysporum and more beneficial Burkholderia spp. In conclusion, the application of novel bio-organic fertilizer could effectively suppress Fusarium wilt by enriching the antagonistic bacteria and enhancing the bacterial diversity. PMID:27899917

  1. Antitussive activity of Pseudostellaria heterophylla (Miq.) Pax extracts and improvement in lung function via adjustment of multi-cytokine levels.

    PubMed

    Pang, Wensheng; Lin, Siding; Dai, Qiwen; Zhang, Hongcheng; Hu, Juan

    2011-04-19

    Pseudostellaria heterophylla (Miq.) Pax is one of the most widespread herbal and healthcare products in China. Extensive clinical use has shown that it has functions which "strengthens qi and generates saliva, moistens the lung and relieves cough". The ethyl acetate fraction extracted from the roots of the plant Pseudostellaria heterophylla exhibited a dose-dependent antitussive effect between 100 to 500 mg/kg. At a dose of 400 mg/kg, the ethyl acetate fraction treatment markedly prolonged the cough latent period and reduced the number of coughs in a guinea pig model induced by citric acid. Fall lung airway resistance, rise in dynamic lung compliance, decreased serum levels of IL-8, GM-CSF, TNF-α, and ET-1 in rat model of stable phase chronic obstructive pulmonary disease induced by cigarette smoke exposure were also observed. These results suggest that ethyl acetate fraction has antitussive activity related to its improvement in lung function via attenuation of airway inflammation by adjustment of multi-cytokine levels.

  2. LC-ESI-MS/MS analysis and pharmacokinetics of heterophyllin B, a cyclic octapeptide from Pseudostellaria heterophylla in rat plasma.

    PubMed

    Zhao, Wai-Ou; Pang, Li; Dong, Ning; Yang, Shu

    2015-11-01

    Heterophyllin B (HB) is a cyclic octapeptide isolated from Pseudostellaria heterophylla. HB is used as the quality control index for evaluating P. heterophylla in the Chinese Pharmacopoeia. A rapid and sensitive LC-ESI-MS/MS method was developed and validated for the analysis of HB in rat plasma. Sample preparation consisted of a solid-phase extraction step for the removal of interference and preconcentration of the target analyte HB and the internal standard N-acetylcysteine before chromatographic analysis by MS/MS detection. The separation of HB and N-acetylcysteine was performed using a Hypersil GOLD™ C18 column and a mixture of methanol-water (60:40, v/v) containing 10 mmol/L ammonium formate and 0.1% formic acid as the mobile phase. The determination step was optimized in the selected reaction monitoring mode for the highly selective and sensitive quantitation of HB in rat plasma. Intra- and inter-assay precision (as relative standard deviation) was ≤9.1%, and accuracy was between 92.6 and 102.7%. The validated method was successfully applied to quantify HB concentrations up to 7 h after tail intravenous injections of 2.08, 4.16 and 8.32 mg/kg HB in rats. The LC-MS/MS method identified the relevant pharmacokinetic parameters of HB and its studied analog.

  3. Seasonal ecology and thermal constraints of Telenomus spp. (Hymenoptera: Scelionidae), egg parasitoids of the hemlock looper (Lepidoptera: Geometridae).

    PubMed

    Legault, Simon; Hébert, Christian; Blais, Julie; Berthiaume, Richard; Bauce, Eric; Brodeur, Jacques

    2012-12-01

    We describe seasonal patterns of parasitism by Telenomus coloradensis Crawford, Telenomus droozi Muesebeck, Telenomus flavotibiae Pelletier (Hymenoptera: Scelionidae), and Trichogramma spp. (Hymenoptera: Trichogrammatidae), egg parasitoids of the hemlock looper, Lambdina fiscellaria (Guenée) (Lepidoptera: Geometridae), after a 3-yr survey of defoliated stands in the lower St. Lawrence region (Quebec, Canada). Results from sentinel trap sampling indicate that T. coloradensis and T. droozi are the most common species, whereas parasitism by T. flavotibiae and Trichogramma spp. is rare. Telenomus coloradensis and T. droozi show similar seasonal periods of parasitism, both species being active in early spring (late April) at temperatures as low as 4°C. Using thermal threshold (T(0)) and thermal constant (K) for immature development of T. coloradensis males and females from egg to adult emergence, we estimated that the spring progeny emerges in the middle of the summer while hemlock looper eggs are absent from the forest environment. Parasitoid females would then mate and remain in the environment to 1) exploit alternate host species, 2) enter into quiescence and later parasitize eggs laid by hemlock looper females in the fall, 3) enter into a reproductive diapause and parasitize hemlock looper eggs only the next spring, or all of these. Although previous studies have shown that T. coloradensis can overwinter in its immature form within the host egg, our field and laboratory results indicate that in the lower St. Lawrence region, this species principally enters diapause as fertilized females, with a mean supercooling point of -30.6°C in the fall.

  4. Diurnal changes in the dielectric properties and water status of eastern hemlock and red spruce from Howland, ME

    NASA Technical Reports Server (NTRS)

    Salas, W. A.; Ranson, K. J.; Rock, B. N.; Moss, D. M.

    1991-01-01

    The diurnal characteristics of microwave dielectric properties and water potential of two conifer species were investigated in July and September, 1990. P-band and C-band radial dielectric profiles of hemlock and red spruce, as well as hemlock diurnal water potential and dielectric profiles, are presented. The resulting radial dielectric profiles matched the regions of the functional sapwood (water transport component of the active xylem) in both species such that the sapwood was characterized by a higher dielectric than the bark and heartwood tissues. This is probably due to characteristic differences in the water content of each tissue. As the hemlocks progressed through their diurnal water potential pattern, the dielectric profile remained static until mid-afternoon. As the tension in the water column relaxed (2 to 3 bars) the dielectric constant decreased by 30 to 40 percent. There are several possible explanations for this phenomenon, and these may relate to the dependency of the dielectric measurements on temperature, salinity, and volumetric water content.

  5. Polysaccharide-degrading complex produced in wood and in liquid media by the brown-rot fungus Poria placenta

    SciTech Connect

    Highley, T.L.; Wolter, K.E.; Evans, F.J.

    1981-01-01

    P.placenda produced the same type of enzyme activities when grown in liquid culture with simple sugars, hemlock (Tsuga heterophylla), or Liquidambar styraciflua sawdust and inoculated in decayed L. styraciflua blocks. However, there were differences in amounts of enzyme activity produced per mg of protein from decayed wood and liquid media; beta-, alpha-galactosidase, and xylanase activities were higher in liquid culture than in extracts from decayed wood, while beta-xylosidase activities were slightly higher in extracts than in liquid culture. Despite these quantitative differences, the extracellular carbohydrolase complex from liquid culture must be structurally similar to that of decayed wood because of similar isoelectric points and electrophoretic and molecular sieving properties.

  6. Levels-of-growing-stock cooperative study in douglas-fir: Report No. 13. The Francis study, 1963-90. Forest Service research paper

    SciTech Connect

    Hoyer, G.E.; Andersen, N.A.; Marshall, D.

    1996-04-01

    The levels-of-growing-stock studies in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), were designed to test the influence of treatment regimes by using a wide range of retained growing stock on the development of forest growth, yield, and stand structure. Results of the Francis installation located in the headwaters of the Willapa River in Pacific County, Washington, are summarized from calibration at age 15 through age 42 (completion of 60 feet of height growth from calibration, and the planned course of the experimental thinnings plus 5 years). In addition to the eight basic treatments and control common to the other eight study installations in the region, five additional treatments were added at Francis; four late first thinnings (at age 25), which matched the level of growing stock of four standard fixed treatments, and an unthinned western hemlock (Tsuga heterophylla (Raf.) Sarg.). Estimated Douglas-fir site index (50-year base) of this plantation is 124, a mid site II.

  7. Relative density, equilibrium moisture content, and dimensional stability of western hemlock bark

    SciTech Connect

    Meyer, R.W.; Kellogg, R.M.; Warren, W.G.

    1980-04-01

    The measurement of western hemlock bark samples from three coastal sites in British Columbia revealed that inner bark relative density (0.382) is less than that of the adjacent sapwood (0.413) and markedly less than that of outer bark (0.463). The equilibrium moisture content of the inner and outer bark are equivalent at both 70 and 30% relative humidity, and slightly higher than that of the sapwood. The generally higher shrinkage of bark compared with wood is the result of bark cell collapse during drying. In the outer bark, some collapse or crushing takes place in the standing tree. This compacting of tissue reduces the shrinkage of outer bark relative to the inner bark. The actual shrinkage per unit change in moisture content of the inner bark is the same as that for the sapwood. The outer bark appears to be more dimensionally stable. The longitudinal shrinkage of both inner (2.9%) and outer (2.2%) bark is markedly greater than that of the sapwood (0.1-0.2%). (Refs. 10).

  8. Aerially released spray penetration of a tall coniferous canopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An aerial spray deposition project was designed to evaluate aerial application to an Eastern Hemlock (Tsuga canadensis) canopy to combat Hemlock Woolly Adelgid (Adelges tsugae). This adelgid offers a difficult target residing in the forest canopy at the nodes of branchlets. The study collected 1680 ...

  9. Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

    USGS Publications Warehouse

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.

  10. Evaluation of volatiles from Ampelopsis brevipedunculata var. heterophylla using GC-olfactometry, GC-MS and GC-pulsed flame photometric detector.

    PubMed

    Nakamura, Atsuhiko; Miyazawa, Mitsuo

    2013-01-01

    Ampelopsis brevipedunculata var. heterophylla is extensively cultivated in Asia, and the dried leaves and branches have a characteristic odor and have been used as a tea. To investigate the odorants contributing to the characteristic odor of A. brevipedunculata var. heterophylla, the aroma extraction dilution analysis method was performed through gas chromatography olfactometry. In addition, volatile sulfur compounds were evaluated using pulsed flame photometric detector. As a result, 86 compounds were identified in the oils of leaves and 78 in branches, accounting for 80.0% and 68.3%, respectively, of the compounds identified. The main compounds in the essential oil of leaves were palmitic acid (12.5%), phenylacetaldehyde (4.1%) and hexahydrofarnesyl acetone (3.9%). On the other hand, the essential oil of branches contained palmitic acid (12.7%), terpinen-4-ol (4.4%) and α-cadinol (3.7%). The total number of odor-active compounds identified in the leaf and branch oils was 39. The most odorous compounds of leaves and branches of A. brevipedunculata var. heterophylla were (E, Z)-2,6-nonadienal (melon, green odor), (E)-2-nonenal (grassy odor), phenylacetaldehyde (honey-like) and (E)-linalool oxide (woody odor).

  11. Loss of Homeostatic Gas Exchange in Eastern Hemlock in Response to Pollution and Rising CO2?

    NASA Astrophysics Data System (ADS)

    Rayback, S. A.; Gagen, M. H.; Lini, A.; Cogbill, C. V.

    2014-12-01

    In eastern North American, multiple environmental effects, natural and anthropogenic, may impinge upon tree-ring based stable carbon isotope ratios when examined over long time periods. Investigation of relationships between a Vermont (USA) eastern hemlock δ¹³C (1849-2010) chronology and local and regional climate variables, as well as a regional sulfur dioxide time series revealed the decoupling of δ¹³C from significant climate drivers such as May-August maximum temperature (r=0.50, p<0.01) and, raise the possibility that this decoupling can be attributed to foliar and soil leaching of calcium due to acidic deposition since the 1960s. Further, investigation of derived photosynthetic isotope discrimination (Δ¹³C) time series showed an overall decreasing trend in Δ¹³C in response to rising atmospheric carbon dioxide (ca), but with a slight rise in Δ¹³C in the last decade. Comparison of time series of leaf intercellular CO2 concentration (ci), ci/ca, and intrinsic water use efficiency (iWUE) showed homeostatic maintenance of ci levels against ca until 1965 and rising iWUE. Then, ci increased proportional (1965-2000) and later at the same rate as ca (2001-2010) and iWUE leveled off indicating a potential loss of sensitivity to increasing atmospheric carbon dioxide. This more recent passive response may be an indication of a loss of homeostatic maintenance of stomatal control and/or may be linked to changing climate in the region (e.g., wetter conditions).

  12. Pesticide residues in Hemlock and Canadice Lakes and their tributaries in western New York, 1997-98

    USGS Publications Warehouse

    Eckhardt, David A.; Burke, Sarah

    2000-01-01

    In 1997, the U.S.Geological Survey (USGS) and the City of Rochester began a cooperative program to study the presence of pesticides (herbicides and insecticides) that occur at trace levels in Hemlock and Canadice Lakes and their tributaries. The most frequently detected pesticides in streamflow and lake-water samples were herbicides commonly used in agriculture ? atrazine, metolachlor, and simazine. None of the concentrations of these compounds in the samples exceeded Federal or State water-quality standards. Differences in the concentrations among stream samples can be attributed to land use and streamflow, and the timing of rainfall in relation to herbicide application. The north (lower) end of Hemlock Lake can receive pesticides in agricultural runoff from northern parts of its watershed and Canadice Creek. These pesticide inputs bypass most of the lake and could periodically affect the water quality periodically affect the water quality at the City of Rochester intake. Pesticide concentrations in samples from the intake during this study, however, were about 100 times less than current Federal and State standards for drinking water. Residues of DDT, dieldrin, and mirex are present in low concentrations in the bottom sediments of both lakes, but none were detected in water samples. The use of these insecticides was banned in 1972,and their persistence in the lakebed sediments is probably due to erosion of contaminated soils from agricultural lands.

  13. The effects of partial cutting on stand structure and growth of western hemlock-Sitka spruce stands in southeast Alaska

    USGS Publications Warehouse

    Deal, R.L.; Tappeiner, J.C.

    2002-01-01

    The effects of partial cutting on species composition, new and residual-tree cohorts, tree size distribution, and tree growth was evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 12-96 years ago, when 16-96% of the former stand basal area was removed. Partial cutting maintained stand structures similar to uncut old-growth stands, and the cutting had no significant effects on tree species composition. The establishment of new-tree cohorts was positively related to the proportion of basal-area cut. The current stand basal area, tree species composition, and stand growth were significantly related to trees left after harvest (p < 0.001). Trees that were 20-80 cm dbh at the time of cutting had the greatest tree-diameter and basal-area growth and contributed the most to stand growth. Diameter growth of Sitka spruce and western hemlock was similar, and the proportion of stand basal-area growth between species was consistent for different cutting intensities. Concerns about changing tree species composition, lack of spruce regeneration, and greatly reduced stand growth and vigor with partial cuts were largely unsubstantiated. Silvicultural systems based on partial cutting can provide rapidly growing trees for timber production while maintaining complex stand structures with mixtures of spruce and hemlock trees similar to oldgrowth stands.

  14. Pesticide residues in Hemlock and Canadice Lakes and their tributaries in western New York, 1997–98

    USGS Publications Warehouse

    Eckhardt, David A.; Burke, Sarah

    2000-01-01

    In 1997, the U.S.Geological Survey (USGS) and the City of Rochester began a cooperative program to study the presence of pesticides (herbicides and insecticides) that occur at trace levels in Hemlock and Canadice Lakes and their tributaries. The most frequently detected pesticides in streamflow and lake-water samples were herbicides commonly used in agriculture — atrazine, metolachlor, and simazine. None of the concentrations of these compounds in the samples exceeded Federal or State water-quality standards. Differences in the concentrations among stream samples can be attributed to land use and streamflow, and the timing of rainfall in relation to herbicide application.The north (lower) end of Hemlock Lake can receive pesticides in agricultural runoff from northern parts of its watershed and Canadice Creek. These pesticide inputs bypass most of the lake and could periodically affect the water quality periodically affect the water quality at the City of Rochester intake. Pesticide concentrations in samples from the intake during this study, however, were about 100 times less than current Federal and State standards for drinking water.Residues of DDT, dieldrin, and mirex are present in low concentrations in the bottom sediments of both lakes, but none were detected in water samples. The use of these insecticides was banned in 1972,and their persistence in the lakebed sediments is probably due to erosion of contaminated soils from agricultural lands.

  15. Abietoid seed fatty acid compositions--a review of the genera Abies, Cedrus, Hesperopeuce, Keteleeria, Pseudolarix, and Tsuga and preliminary inferences on the taxonomy of Pinaceae.

    PubMed

    Wolff, Robert L; Lavialle, Olivier; Pédrono, Frédérique; Pasquier, Elodie; Destaillats, Frederic; Marpeau, Anne M; Angers, Paul; Aitzetmüller, Kurt

    2002-01-01

    The seed fatty acid (FA) compositions of Abietoids (Abies, Cedrus, Hesperopeuce, Keteleeria, Pseudolarix, and Tsuga) are reviewed in the present study in conclusion to our survey of Pinaceae seed FA compositions. Many unpublished data are given. Abietoids and Pinoids (Pinus, Larix, Picea, and Pseudotsuga)-constituting the family Pinaceae-are united by the presence of several delta5-olefinic acids, taxoleic (5,9-18:2), pinolenic (5,9,12-18:3), coniferonic (5,9,12,15-1 8:4), keteleeronic (5,11-20:2), and sciadonic (5,11,14-20:3) acids, and of 14-methyl hexadecanoic (anteiso-17:0) acid. These acids seldom occur in angiosperm seeds. The proportions of individual delta5-olefinic acids, however, differ between Pinoids and Abietoids. In the first group, pinolenic acid is much greater than taxoleic acid, whereas in the second group, pinolenic acid is greater than or equal to taxoleic acid. Moreover, taxoleic acid in Abietoids is much greater than taxoleic acid in Pinoids, an apparent limit between the two subfamilies being about 4.5% of that acid relative to total FA. Tsuga spp. appear to be a major exception, as their seed FA compositions are much like those of species from the Pinoid group. In this respect, Hesperopeuce mertensiana, also known as Tsuga mertensiana, has little in common with Abietoids and fits the general FA pattern of Pinoids well. Tsuga spp. and H. mertensiana, from their seed FA compositions, should perhaps be separated from the Abietoid group and their taxonomic position revised. It is suggested that a "Tsugoid" subfamily be created, with seed FA in compliance with the Pinoid pattern and other botanical and immunological criteria of the Abietoid type. All Pinaceae genera, with the exception of Pinus, are quite homogeneous when considering their overall seed FA compositions, including delta5-olefinic acids. In all cases but one (Pinus), variations from one species to another inside a given genus are of small amplitude. Pinus spp., on the other hand

  16. Geological and climatic changes in quaternary shaped the evolutionary history of Calibrachoa heterophylla, an endemic South-Atlantic species of petunia

    PubMed Central

    2013-01-01

    Background The glacial and interglacial cycles that characterized the Quaternary greatly affected the distribution and genetic diversity of plants. In the Neotropics, few phylogeographic studies have focused on coastal species outside of the Atlantic Rainforest. Climatic and sea level changes during the Quaternary played an important role in the evolutionary history of many organisms found in coastal regions. To contribute to a better understanding of plant evolution in this environment in Southern South America, we focused on Calibrachoa heterophylla (Solanaceae), an endemic and vulnerable wild petunia species from the South Atlantic Coastal Plain (SACP). Results We assessed DNA sequences from two cpDNA intergenic spacers and analyzed them using a phylogeographic approach. The present phylogeographic study reveals the influence of complex geologic and climatic events on patterns of genetic diversification. The results indicate that C. heterophylla originated inland and subsequently colonized the SACP; the data show that the inland haplogroup is more ancient than the coastal one and that the inland was not affected by sea level changes in the Quaternary. The major diversification of C. heterophylla that occurred after 0.4 Myr was linked to sea level oscillations in the Quaternary, and any diversification that occurred before this time was obscured by marine transgressions that occurred before the coastal sand barrier’s formation. Results of the Bayesian skyline plot showed a recent population expansion detected in C. heterophylla seems to be related to an increase in temperature and humidity that occurred at the beginning of the Holocene. Conclusions The geographic clades have been formed when the coastal plain was deeply dissected by paleochannels and these correlate very well with the distributional limits of the clades. The four major sea transgressions formed a series of four sand barriers parallel to the coast that progressively increased the availability of

  17. [Technology of extraction of essential oil from leaves of Vitex negundo L. var. heterophylla (Franch.) Rehd. by supercritical CO2 apparatus].

    PubMed

    Xie, Jianchun; Sun, Baoguo; Zheng, Fuping; Yu, Min

    2005-12-01

    By the designation of mono-factor experiments and orthogonal multifactor experiments, influences of extraction temperature, extraction pressure, CO2 flow rate and extraction times on the yield of oil from the leaves of Vitex negundo L. var. heterophylla (Franch.) Rehd. in the supercritical CO2 extraction process were investigated. The obtained optimal extraction technology was: the extraction pressure: 22 MPa; the extraction temperature: 45 degrees C; the CO2 flow rate: 25 L/h and the extraction time: 3h. The oil yield on the above supercritical CO2 extraction conditions was 3.22%.

  18. Inhibitory effects of antioxidant constituents from Melothria heterophylla on matrix metalloproteinase-1 expression in UVA-irradiated human dermal fibroblasts.

    PubMed

    Cho, Y H; Kim, J H; Sim, G S; Lee, B C; Pyo, H B; Park, H D

    2006-01-01

    Matrix metalloproteinases (MMPs) are known to play an important role in photoaging by mediating the degradation of extracellular matrix proteins. To develop a new anti-aging agent for cosmetics from natural products, Melothria heterophylla (Lour.) Cogn. was selected for its antioxidant activity and inhibitory effect on expression of MMP-1 in UVA-irradiated human skin fibroblasts. Two compounds (compounds 1 and 2 ) were isolated from an ethyl acetate soluble fraction of the ethanolic extracts; they were identified as 1,2,4,6-tetra-O-galloyl-beta-(D)-glucopyranose (1) and 3,4,5-trihydroxybenzoic acid (2). These compounds were found to scavenge radicals and reactive oxygen species (ROS) and were measured to have SC50 values of 3.9 microM and 13.3 microM against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and values of 4.3 microM and 4.0 microM against superoxide radicals in the xanthine/xanthine oxidase system, respectively. Compounds 1 and 2 showed a dose-dependent inhibitory effect on the expression and activity of MMP-1 in UVA-induced human skin fibroblasts, but no inhibition of MMP-1 mRNA expression. Therefore, we concluded that compounds 1 and 2 significantly inhibited MMP-1 expression at the protein level. Also, these compounds were determined to have a potent antioxidant activity. From these results, we suggest that these compounds might be useful as a new anti-aging agent for photodamaged skin, but the in vitro findings must be verified in in vivo studies.

  19. Ent-trachyloban-19-oic acid isolated from Iostephane heterophylla as a promising antibacterial agent against Streptococcus mutans biofilms.

    PubMed

    Hernández, Dulce M; Díaz-Ruiz, Gloria; Rivero-Cruz, Blanca E; Bye, Robert A; Aguilar, María Isabel; Rivero-Cruz, J Fausto

    2012-04-01

    From the roots of Iostephane heterophylla, six known compounds, namely, ent-trachyloban-19-oic acid (1), the mixture of ent-kaur-16-en-19-oic acid (2) and ent-beyer-15-en-19-oic acid (3), xanthorrhizol (4), 16α-hydroxy-ent-kaurane (5) and 16α-hydroxy-ent-kaur-11-en-19-oic acid (6) were isolated using a bioassay-guided fractionation method. The known compounds (1-6) were identified by comparison of their spectroscopic data with reported values in the literature. In an attempt to increase the resultant antimicrobial activity of 1 and 4, a series of reactions was performed on ent-trachyloban-19-oic acid (1) and xanthorrhizol (4), to obtain derivatives 1a, 1b, and 4a-4d. All the isolated compounds (1-6) and the derivatives 1a, 1b, and 4a-4d were evaluated for their antimicrobial activity against two oral pathogens, Streptococcus mutans and Porphyromonas gingivalis associated with caries and periodontal disease, respectively. Compounds 1, 1b, 2+3, 4 and 4d inhibited the growth of S. mutans with concentrations ranging from 4.1 μg/mL to 70.5 μg/mL. No significant activity was found on P. gingivalis except for 4 with an MIC of 6.8 μg/mL. The ability of 1, 1b, 2+3, 4 and 4d to inhibit biofilm formation by S. mutans was evaluated. It was found that 1, 1b, 4 and 4d interfered with the establishment of S. mutans biofilms, inhibiting their development at 32.5, 125.0, 14.1 and 24.4 μg/mL, respectively.

  20. Effects of elevated nitrogen dioxide and carbon dioxide on the growth of Sugar Maple and Hemlock seedlings

    NASA Astrophysics Data System (ADS)

    Eller, A. S.; McGuire, K. L.; Sparks, J. P.

    2005-12-01

    The partial pressure of nitrogen dioxide (NO2) in the earth's atmosphere has been rising since the industrial revolution and is likely to continue rising due to the burning of fossil fuels. When NO2 enters plant leaves, it can undergo reactions that produce nitrate, which can be a source of nutrient nitrogen for the plant. However, NO2 is also an oxidant with the potential to damage cell membranes and decrease growth. The goals of this study were to examine the effect of NO2 on plant productivity alone and in combination with elevated CO2 under both nitrogen- and non-nitrogen-limiting conditions. To assess these effects, we conducted CO2, NO2, and CO2 + NO2 fumigations of sugar maple and eastern hemlock seedlings in open-topped chambers and measured relative growth rate, specific leaf area, root:shoot, and C:N of the leaves, stems, and roots. Sugar maple growth was reduced by 7% under elevated NO2 when nitrogen was limiting. When nitrogen was not limiting and CO2 was ambient, elevated NO2 caused a 4% decrease in growth and when CO2 was elevated there was no growth effect. Hemlock growth was increased by elevated NO2 regardless of nitrogen status and under both partial pressures of CO2; 3 and 8% increase in growth under ambient and elevated CO2, respectively. These data suggest gaseous reactive nitrogen may augment or decrease the future growth effects of elevated CO2 depending on plant species identity. In addition, perhaps because of differences in nitrogen metabolism and physiology, deciduous and evergreen tree species appear to have different responses to reactive nitrogen fumigation. These results underscore the need for examining the responses of vegetation to mixtures of gases representative of the future atmosphere rather than examining the influence of carbon dioxide alone.

  1. Thuja plicata exclusion in ectomycorrhiza-dominated forests: testing the role of inoculum potential of arbuscular mycorrhizal fungi.

    PubMed

    Weber, Adrian; Karst, Justine; Gilbert, Benjamin; Kimmins, J P

    2005-03-01

    The ability of trees dependent on arbuscular mycorrhizal (AM) fungi to establish in ectomycorrhizal forests is unknown. On northern Vancouver Island, Canada, there are sharp boundaries between mixed red cedar (Thuja plicata)-hemlock (Tsuga heterophylla) (CH) stands, and stands of hemlock and amabilis fir (Abies amabilis) (HA). We tested differences in AM colonization of red cedar between ectomycorrhiza-dominated (HA) stands and stands containing red cedar (CH), across a range of light levels. We used a soil bioassay approach to determine whether there was sufficient AM fungal inoculum in the HA tree stands to colonize red cedar seedlings. Seeds of hemlock and red cedar were sown in forest floor samples collected from the two types of forests, and shade treatments ranging from < 1 to 53% of full sunlight were imposed. After 6 months, seedling survival and root and shoot biomass were quantified, and red cedar seedlings were sampled for AM fungal colonization. Hemlock survival and growth did not differ between soil types, suggesting there was no substrate-associated limitation to its establishment in either forest type. Red cedar colonization by AM fungi was significantly correlated with light levels in CH soils but arbuscular mycorrhizas were absent in roots of red cedar seedlings grown in HA soil. Red cedar survival and relative growth rate were significantly greater in the CH than in HA soil; higher growth was due primarily to greater shoot growth in CH soils at high light levels. The low soil inoculum potential for red cedar in ectomycorrhiza-dominated stands may account for the virtual exclusion of red cedar seedlings from these forests.

  2. Long-term structural and biomass dynamics of virgin Tsuga canadensis-Pinus strobus forests after hurricane disturbance.

    PubMed

    D'Amato, Anthony W; Orwig, David A; Foster, David R; Barker Plotkin, Audrey; Schoonmaker, Peter K; Wagner, Maggie R

    2017-03-01

    The development of old-growth forests in northeastern North America has largely been within the context of gap-scale disturbances given the rarity of stand-replacing disturbances. Using the 10-ha old-growth Harvard Tract and its associated 90-year history of measurements, including detailed surveys in 1989 and 2009, we document the long-term structural and biomass development of an old-growth Tsuga canadensis-Pinus strobus forest in southern New Hampshire, USA following a stand-replacing hurricane in 1938. Measurements of aboveground biomass pools were integrated with data from second- and old-growth T. canadensis forests to evaluate long-term patterns in biomass development following this disturbance. Ecosystem structure across the Tract prior to the hurricane exhibited a high degree of spatial heterogeneity with the greatest levels of live tree basal area (70-129 m(2) /ha) on upper west-facing slopes where P. strobus was dominant and intermixed with T. canadensis. Live-tree biomass estimates for these stratified mixtures ranged from 159 to 503 Mg/ha at the localized, plot scale (100 m(2) ) and averaged 367 Mg/ha across these portions of the landscape approaching the upper bounds for eastern forests. Live-tree biomass 71 years after the hurricane is more uniform and lower in magnitude, with T. canadensis currently the dominant overstory tree species throughout much of the landscape. Despite only one living P. strobus stem in the 2009 plots (and fewer than five stems known across the entire 10-ha area), the detrital legacy of this species is pronounced with localized accumulations of coarse woody debris exceeding 237.7-404.2 m(3) /ha where this species once dominated the canopy. These patterns underscore the great sizes P. strobus attained in pre-European landscapes and its great decay resistance relative to its forest associates. Total aboveground biomass pools in this 71-year-old forest (255 Mg/ha) are comparable to those in modern old

  3. Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO(2) assimilation and growth in Douglas-fir.

    PubMed

    Saffell, Brandy J; Meinzer, Frederick C; Voelker, Steven L; Shaw, David C; Brooks, J Renée; Lachenbruch, Barbara; McKay, Jennifer

    2014-07-01

    Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC infection, particularly in relation to potential explanatory climate factors. We sampled trees from an Oregon site where a fungicide trial took place from 1996 to 2000, which enabled the comparison of stable isotope values between trees with and without disease. Carbon stable isotope discrimination (Δ(13)C) of treated Douglas-fir tree-rings was greater than that of untreated Douglas-fir tree-rings during the fungicide treatment period. Both annual growth and tree-ring Δ(13)C increased with treatment such that treated Douglas-fir had values similar to co-occurring western hemlock during the treatment period. There was no difference in the tree-ring oxygen stable isotope ratio between treated and untreated Douglas-fir. Tree-ring Δ(13)C of diseased Douglas-fir was negatively correlated with relative humidity during the two previous summers, consistent with increased leaf colonization by SNC under high humidity conditions that leads to greater disease severity in following years.

  4. Quantitative determination of benzalkonium chloride in treated wood by solid-phase extraction followed by liquid chromatography with ultraviolet detection.

    PubMed

    Miyauchi, Teruhisa; Mori, Mitsunori; Ito, Katsuhiko

    2005-11-18

    Ammoniacal copper quat (ACQ) compound wood preservative is comprised of copper and quaternary ammonium compounds with benzalkonium chloride (BAC) as the active ingredient. Solid-phase extraction (SPE) followed by liquid chromatography with ultraviolet detection (LC-UV) was developed for quantitative determination of BAC in treated wood. Five species of wood were used, Japanese cedar (Cryptomeria japonica), Japanese larch (Larix leptolepis), Yezo spruce (Picea jezoensis), Sakhalin fir (Abies sachalinensis), and western hemlock (Tsuga heterophylla). BAC used in the present study was composed of 66% C12, 33% C14 and less than 1% C16. BAC was added to each wood species (500 mg) then extracted with HCl-ethanol (20 ml) and quantitatively determined with LC-UV (262 nm). Wood extractives from the heartwood of each species, except western hemlock, interfered with quantitative determination of BAC, but SPE with an Oasis MCX cartridge was effective in preventing this. Using the present methods, BAC homologue peaks were clearly confirmed without interference. Recoveries from wood ranged from 92 to 101% and the limit of quantitation was approximately 240 microg/g wood for the C12 and C14 homologues.

  5. The Application of Stomatal Frequency Analysis As A Proxy For Paleo-atmospheric Co2: Calibration and Proxy-validation

    NASA Astrophysics Data System (ADS)

    Kouwenberg, L. L. R.; Wagner, F.; Kürschner, W. M.; Visscher, H.

    Stomata regulate gas-exchange in leaves and their frequency on leaves has a profound influence on the intake of CO2 and the loss of water through the stomata. Experiments and analysis of leaves that have grown naturally under the historical CO2 levels of the past 200 years have demonstrated that many plant species, especially woody an- giosperms, show a reduction in stomatal frequency in relation to a rise in atmospheric CO2. This decrease in stomatal frequency restricts water loss, while the CO2 intake is not substantially reduced due to the higher CO2 concentration in the atmosphere. This species-specific response has been successfully used to reconstruct past CO2 lev- els from the stomatal frequency on fossil leaves after careful calibration to a series of known atmospheric CO2 levels. Methods to obtain such a calibration, are discussed by example of two tree taxa, the tree birch (Betula pubescens/pendula) and the west- ern hemlock (Tsuga heterophylla). The effective use of stomatal frequency analysis as a proxy of atmospheric CO2 requires validation by determination of the influence of other factors such as light availability, humidity, temperature and leaf age on stom- atal frequency. The (dis)advantages of using experiments vs material from naturally grown trees for validation and calibration will be discussed. For angiosperm species, such as Betula, the influence of other factors besides CO2 on stomatal frequency is shown to be of a lesser magnitude when the stomatal index (the number of stomata as a proportion of epidermal cells) is used instead of the stomatal density (the number of stomata per mm2 leaf area). Stomatal frequency in Tsuga heterophylla is not influ- enced by light regime or leaf age, and the observed reduction in stomatal frequency related to the CO2 rise of the last century cannot be explained by trends in precip- itation or temperature as apparent in local climate records. Thus, these two species are considered highly suitable as proxies

  6. Armored scale insect endosymbiont diversity at the species level: genealogical patterns of Uzinura diasipipdicola in the Chionaspis pinifoliae-Chionaspis heterophyllae species complex (Hemiptera: Coccoidea: Diaspididae).

    PubMed

    Andersen, J C; Gwiazdowski, R A; Gdanetz, K; Gruwell, M E

    2015-02-01

    Armored scale insects and their primary bacterial endosymbionts show nearly identical patterns of co-diversification when viewed at the family level, though the persistence of these patterns at the species level has not been explored in this group. Therefore we investigated genealogical patterns of co-diversification near the species level between the primary endosymbiont Uzinura diaspidicola and its hosts in the Chionaspis pinifoliae-Chionaspis heterophyllae species complex. To do this we generated DNA sequence data from three endosymbiont loci (rspB, GroEL, and 16S) and analyzed each locus independently using statistical parsimony network analyses and as a concatenated dataset using Bayesian phylogenetic reconstructions. We found that for two endosymbiont loci, 16S and GroEL, sequences from U. diaspidicola were broadly associated with host species designations, while for rspB this pattern was less clear as C. heterophyllae (species S1) shared haplotypes with several other Chionaspis species. We then compared the topological congruence of the phylogenetic reconstructions generated from a concatenated dataset of endosymbiont loci (including all three loci, above) to that from a concatenated dataset of armored scale hosts, using published data from two nuclear loci (28S and EF1α) and one mitochondrial locus (COI-COII) from the armored scale hosts. We calculated whether the two topologies were congruent using the Shimodaira-Hasegawa test. We found no significant differences (P = 0.4892) between the topologies suggesting that, at least at this level of resolution, co-diversification of U. diaspidicola with its armored scale hosts also occurs near the species level. This is the first such study of co-speciation at the species level between U. diaspidicola and a group of armored scale insects.

  7. Fire-mediated pathways of stand development in Douglas-fir/ western hemlock forests of the Pacific Northwest, USA.

    PubMed

    Tepley, Alan J; Swanson, Frederick J; Spies, Thomas A

    2013-08-01

    Forests dominated by Douglas-fir and western hemlock in the Pacific Northwest of the United States have strongly influenced concepts and policy concerning old-growth forest conservation. Despite the attention to their old-growth characteristics, a tendency remains to view their disturbance ecology in relatively simple terms, emphasizing infrequent, stand-replacing (SR) fire and an associated linear pathway toward development of those old-growth characteristics. This study uses forest stand- and age-structure data from 124 stands in the central western Cascades of Oregon to construct a conceptual model of stand development under the mixed-severity fire regime that has operated extensively in this region. Hierarchical clustering of variables describing the age distributions of shade-intolerant and shade-tolerant species identified six groups, representing different influences of fire frequency and severity on stand development. Douglas-fir trees > 400 years old were found in 84% of stands, yet only 18% of these stands (15% overall) lack evidence of fire since the establishment of these old trees, whereas 73% of all stands show evidence of at least one non-stand-replacing (NSR) fire. Differences in fire frequency and severity have contributed to multiple development pathways and associated variation in contemporary stand structure and the successional roles of the major tree species. Shade-intolerant species form a single cohort following SR fire, or up to four cohorts per stand in response to recurring NSR fires that left living trees at densities up to 45 trees/ha. Where the surviving trees persist at densities of 60-65 trees/ha, the postfire cohort is composed only of shade-tolerant species. This study reveals that fire history and the development of old-growth forests in this region are more complex than characterized in current stand-development models, with important implications for maintaining existing old-growth forests and restoring stands subject to timber

  8. Distribution of nitrogen-15 tracers applied to the canopy of a mature spruce-hemlock stand, Howland, Maine, USA.

    PubMed

    Dail, David Bryan; Hollinger, David Y; Davidson, Eric A; Fernandez, Ivan; Sievering, Herman C; Scott, Neal A; Gaige, Elizabeth

    2009-06-01

    In N-limited ecosystems, fertilization by N deposition may enhance plant growth and thus impact C sequestration. In many N deposition-C sequestration experiments, N is added directly to the soil, bypassing canopy processes and potentially favoring N immobilization by the soil. To understand the impact of enhanced N deposition on a low fertility unmanaged forest and better emulate natural N deposition processes, we added 18 kg N ha(-1) year(-1) as dissolved NH(4)NO(3) directly to the canopy of 21 ha of spruce-hemlock forest. In two 0.3-ha subplots, the added N was isotopically labeled as (15)NH(4) (+) or (15)NO(3) (-) (1% final enrichment). Among ecosystem pools, we recovered 38 and 67% of the (15)N added as (15)NH(4) (+) and (15)NO(3) (-), respectively. Of (15)N recoverable in plant biomass, only 3-6% was recovered in live foliage and bole wood. Tree twigs, branches, and bark constituted the most important plant sinks for both NO(3) (-) and NH(4) (+), together accounting for 25-50% of (15)N recovery for these ions, respectively. Forest floor and soil (15)N retention was small compared to previous studies; the litter layer and well-humified O horizon were important sinks for NH(4) (+) (9%) and NO(3) (-) (7%). Retention by canopy elements (surfaces of branches and boles) provided a substantial sink for N that may have been through physico-chemical processes rather than by N assimilation as indicated by poor recoveries in wood tissues. Canopy retention of precipitation-borne N added in this particular manner may thus not become plant-available N for several years. Despite a large canopy N retention potential in this forest, C sequestration into new wood growth as a result of the N addition was only ~16 g C m(-2) year(-1) or about 10% above the current net annual C sequestration for this site.

  9. Recovery of ergosterol from the medicinal mushroom, Ganoderma tsugae var. Janniae, with a molecularly imprinted polymer derived from a cleavable monomer-template composite.

    PubMed

    Hashim, Shima N N S; Schwarz, Lachlan J; Danylec, Basil; Mitri, Khosse; Yang, Yuanzhong; Boysen, Reinhard I; Hearn, Milton T W

    2016-10-14

    A semi-covalent imprinting strategy has been developed for the synthesis of molecularly-imprinted polymers specific for the fungal sterol, ergosterol, a biological precursor of vitamin D2. This imprinting approach involved a novel post-synthesis cleavable monomer-template composite, namely ergosteryl methacrylate, and resulted in the formation of an imprinted polymer that selectively and efficiently recognized ergosterol through non-covalent interactions. The derived molecularly-imprinted polymer and the corresponding non-imprinted polymer were systematically evaluated for their selectivity towards ergosterol via static and dynamic binding studies using various ergosteryl esters (e.g. ergosteryl-cinnamate, -ferulate, -coumarate, -ferulate acetate and -acetate, respectively) as competitors. Moreover, the binding capacity of the molecularly imprinted polymer for ergosterol was enhanced when the sample loading conditions involved the use of partially aqueous solvent mixtures, such as acetonitrile/water (9:1 (v/v) or 8:2 (v/v)). These attributes were exploited in a solid-phase extraction format, whereby ergosterol was obtained with excellent recoveries from an extract of the fruiting body powder of the medicinal fungus Ganoderma tsugae var. Janniae.

  10. 76 FR 42675 - Availability of an Environmental Assessment and Finding of No Significant Impact for a Biological...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-19

    ... Significant Impact for a Biological Control Agent for Hemlock Woolly Adelgid AGENCY: Animal and Plant Health... biological control agent to reduce the severity of hemlock woolly adelgid (Adelges tsugae, HWA) infestations... release of this biological control agent into the continental United States. \\1\\ To view the notice,...

  11. Multielemental analysis of tree rings: a survey of coniferous trees in the Great Smoky Mountains National Park. [Picea rubens; Abies fraseri; Tsuga canadensis; Pinus rigida; Pinus strobus

    SciTech Connect

    Baes, C.F. III; McLaughlin, S.B.

    1986-01-01

    Conifers were sampled at various locations in the Great Smoky Mountains National Park (GSMNP) to examine changes in growth rate and elemental composition of the tree rings as a function of tree species and location. Earlier studies in the park had indicated (1) recent increases in deposition of trace metals at high-elevation sites and (2) decreased tree ring widths and increased iron accumulation in short-leaf pine between 1863 and 1912 in trees at Cades Cove, which were thought to be influenced by emissions from copper smelters at Copperhill, Tennessee, 88 km upwind of the cove. Conifers were cored for multielement analysis growth analysis at nine locations throughout the GSMNP. Multielement analysis was performed for 31 elements, 21 of which were generally detected in the xylem: Al, B, Ba, Be, Ca, Cd, Cu, Fe, Hf, K, Li, Mg, Mn, Na, Ni, P, Pb, Si, Sr, Ti, and Zn. There was little evidence of a synchronous growth decline in conifers between 1863 and 1912 at the sites sampled. A comparison between raw ring widths averaged over the periods 1974 to 1983 and 1929 to 1958 showed that approximately 77, 83, and 88% of all red spruce, Fraser fir, and hemlock, respectively, had lower growth rates during the latter time period. The elemental concentrations found in wood suggest that the trees in the GSMNP are not exposed to levels of trace metals as high as are trees immediately downwind of smelters or fossil fuel plants. However, the patterns of Mn and Zn in Fraser fir at high-elevation sites and the temporal similarity between increases of Al, B, Cu, Fe, and Ni in wood and increases in fossil fuel emissions upwind of the GSMNP suggest that forests in the park are exposed to increasing levels of trace metal deposition or that trace metals are made more available for uptake by trees as a result of anthropogenic influences. 48 refs., 22 figs., 11 tabs.

  12. Pollen-tube growth rates in Collinsia heterophylla (Plantaginaceae): one-donor crosses reveal heritability but no effect on sporophytic-offspring fitness

    PubMed Central

    Lankinen, Åsa; Maad, Johanne; Armbruster, W. Scott

    2009-01-01

    Background and Aims Evolutionary change in response to natural selection will occur only if a trait confers a selective advantage and there is heritable variation. Positive connections between pollen traits and fitness have been found, but few studies of heritability have been conducted, and they have yielded conflicting results. To understand better the evolutionary significance of pollen competition and its potential role in sexual selection, the heritability of pollen tube-growth rate and the relationship between this trait and sporophytic offspring fitness were investigated in Collinsia heterophylla. Methods Because the question being asked was if female function benefited from obtaining genetically superior fathers by enhancing pollen competition, one-donor (per flower) crosses were used in order to exclude confounding effects of post-fertilization competition/allocation caused by multiple paternity. Each recipient plant was crossed with an average of five pollen donors. Pollen-tube growth rate and sporophytic traits were measured in both generations. Key Results Pollen-tube growth rate in vitro differed among donors, and the differences were correlated with in vivo growth rate averaged over two to four maternal plants. Pollen-tube growth rate showed significant narrow-sense heritability and evolvability in a father–offspring regression. However, this pollen trait did not correlate significantly with sporophytic-offspring fitness. Conclusions These results suggest that pollen-tube growth rate can respond to selection via male function. The data presented here do not provide any support for the hypothesis that intense pollen competition enhances maternal plant fitness through increased paternity by higher-quality sporophytic fathers, although this advantage cannot be ruled out. These data are, however, consistent with the hypothesis that pollen competition is itself selectively advantageous, through both male and female function, by reducing the genetic load

  13. Late Glacial-Holocene Pollen-Based Vegetation History from Pass Lake, Prince of Wales Island, Southeastern Alaska

    USGS Publications Warehouse

    Ager, Thomas A.; Rosenbaum, Joseph G.

    2009-01-01

    A radiocarbon-dated history of vegetation development since late Wisconsin deglaciation has been reconstructed from pollen evidence preserved in a sediment core from Pass Lake on Prince of Wales Island, southeastern Alaska. The shallow lake is in the south-central part of the island and occupies a low pass that was filled by glacial ice of local origin during the late Wisconsin glaciation. The oldest pollen assemblages indicate that pine woodland (Pinus contorta) had developed in the area by ~13,715 cal yr B.P. An abrupt decline in the pine population, coinciding with expansion of alder (Alnus) and ferns (mostly Polypodiaceae) began ~12,875 yr B.P., and may have been a response to colder, drier climates during the Younger Dryas climatic interval. Mountain hemlock (Tsuga mertensiana) began to colonize central Prince of Wales Island by ~11,920 yr B.P. and was soon followed by Sitka spruce (Picea sitchensis). Pollen of western hemlock (Tsuga heterophylla) began to appear in Pass Lake sediments soon after 11,200 yr B.P. The abundance of western hemlock pollen in the Pass Lake core during most of the Holocene appears to be the result of wind transport from trees growing at lower altitudes on the island. The late Holocene pollen record from Pass Lake is incomplete because of one or more unconformities, but the available record suggests that a vegetation change occurred during the late Holocene. Increases in pollen percentages of pine, cedar (probably yellow cedar, Chamaecyparis nootkatensis), and heaths (Ericales) suggest an expansion of muskeg vegetation occurred in the area during the late Holocene. This vegetation change may be related to the onset of cooler, wetter climates that began as early as ~3,774 yr B.P. in the region. This vegetation history provides the first radiocarbon-dated Late Glacial-Holocene terrestrial paleoecological framework for Prince of Wales Island. An analysis of magnetic properties of core sediments from Pass Lake suggests that unconformities

  14. National Dam Inspection Program. Lower Hemlock Dam (NDI-ID Number PA-00756, DER-ID Number 52-117) Delaware River Basin, Pike County, Pennsylvania. Phase I Inspection Report.

    DTIC Science & Technology

    1980-06-01

    is covered with a large overhanging concrete slab and is accessible by a footbridge from the crest of the dam,(Photograph 5, Appendix C). Lower Hemlock...Valve house located in the reservoir accessible from the top of dam by concrete footbridge . B. OUTLET STRUCTURE 24" 0 concrete pipe discharging at...Concrete footbridge to intake. A-3 NDI NO. PA-O_ 756 VISUAL INSPECTION SPILLWAY OBSERVATIONS AND REMARKS A. APPROACH CHANNEL Approach is-directly from

  15. Headwater riparian invertebrate communities associated with red alder and conifer wood and leaf litter in southeastern Alaska

    USGS Publications Warehouse

    LeSage, C.M.; Merritt, R.W.; Wipfli, M.S.

    2005-01-01

    We examined how management of young upland forests in southeastern Alaska affect riparian invertebrate taxa richness, density, and biomass, in turn, potentially influencing food abundance for fish and wildlife. Southeastern Alaska forests are dominated by coniferous trees including Sitka spruce (Picea sitchensis (Bong.) Carr.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), with mixed stands of red cedar (Thuja plicata Donn.). Red alder (Alnus rubra Bong.) is hypothesized to influence the productivity of young-growth conifer forests and through forest management may provide increased riparian invertebrate abundance. To compare and contrast invertebrate densities between coniferous and alder riparian habitats, leaf litter and wood debris (early and late decay classes) samples were collected along eleven headwater streams on Prince of Wales Island, Alaska, during the summers of 2000 and 2001. Members of Acarina and Collembola were the most abundant taxa collected in leaf litter with alder litter having significantly higher mean taxa richness than conifer litter. Members of Acarina were the most abundant group collected on wood debris and alder wood had significantly higher mean taxa richness and biomass than conifer wood. Alder wood debris in more advanced decay stages had the highest mean taxa richness and biomass, compared to other wood types, while conifer late decay wood debris had the highest densities of invertebrates. The inclusion of alder in young-growth conifer forests can benefit forest ecosystems by enhancing taxa richness and biomass of riparian forest invertebrates. ?? 2005 by the Northwest Scientific Association. All rights reserved.

  16. Development and testing of a snow interceptometer to quantify canopy water storage and interception processes in the rain/snow transition zone of the North Cascades, Washington, USA

    NASA Astrophysics Data System (ADS)

    Martin, Kael A.; Stan, John T.; Dickerson-Lange, Susan E.; Lutz, James A.; Berman, Jeffrey W.; Gersonde, Rolf; Lundquist, Jessica D.

    2013-06-01

    Tree canopy snow interception is a significant hydrological process, capable of removing up to 60% of snow from the ground snowpack. Our understanding of canopy interception has been limited by our ability to measure whole canopy water storage in an undisturbed forest setting. This study presents a relatively inexpensive technique for directly measuring snow canopy water storage using an interceptometer, adapted from Friesen et al. (2008). The interceptometer is composed of four linear motion position sensors distributed evenly around the tree trunk. We incorporate a trunk laser-mapping installation method for precise sensor placement to reduce signal error due to sensor misalignment. Through calibration techniques, the amount of canopy snow required to produce the measured displacements can be calculated. We demonstrate instrument performance on a western hemlock (Tsuga heterophylla) for a snow interception event in November 2011. We find a snow capture efficiency of 83 ± 15% of accumulated ground snowfall with a maximum storage capacity of 50 ± 8 mm snow water equivalent (SWE). The observed interception event is compared to simulated interception, represented by the variable infiltration capacity (VIC) hydrologic model. The model generally underreported interception magnitude by 33% using a leaf area index (LAI) of 5 and 16% using an LAI of 10. The interceptometer captured intrastorm accumulation and melt rates up to 3 and 0.75 mm SWE h-1, respectively, which the model failed to represent. While further implementation and validation is necessary, our preliminary results indicate that forest interception magnitude may be underestimated in maritime areas.

  17. Emission of biogenic VOCs from trees in the Lower Fraser Valley, B.C.

    SciTech Connect

    Drewitt, G.; Styen, D.G.; Gillespie, T.; Curren, K.

    1996-12-31

    Biogenic volatile organic compounds (VOC`s) are known to participate in the formation of ground level ozone. It is possible that in the areas with high emission rates from local vegetation, biogenic hydrocarbons can be of comparable importance to anthropogenic hydrocarbons in the production of this secondary air pollutant. In order to implement an effective abatement strategy, the relative importance of these biogenic emissions to the atmospheric chemistry of an area must be known. The Lower Fraser Valley located in the southwestern corner of British Columbia experiences episodes of elevated ground level ozone concentrations during the summer under the influence of a stationary high pressure system and characterized by lush coastal rain forest vegetation and extensive agriculture surfaces. During the summer of 1995 a field campaign to determine the emission rate from natural sources in the region was conducted. The emission rate from natural sources in the region was conducted. The mission rate of biogenic hydrocarbons from four tree species, Western Red Cedar (Thuja Plicata), Cottonwood (Populus Balsemifera), Douglass Fir (Pseudotsuga Menziesii) and Hemlock (Tsuga Heterophylla) was measured in the field. It was found that Cottonwood trees emit isoprene at a rate approaching 100 times greater than any of the other three species.

  18. Simulating secondary succession of elk forage values in a managed forest landscape, western Washington

    NASA Astrophysics Data System (ADS)

    Jenkins, Kurt; Starkey, Edward

    1996-09-01

    Modern timber management practices often influence forage production for elk ( Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir ( Pseudotsuga menziesii, PSME)-western hemlock ( Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.

  19. Simulating secondary succession of elk forage values in a managed forest landscape, western Washington

    USGS Publications Warehouse

    Jenkins, Kurt J.; Starkey, Edward E.

    1996-01-01

    Modern timber management practices often influence forage production for elk (Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir (Pseudotsuga menziesii, PSME)-western hemlock (Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.

  20. Simulating Secondary Succession of Elk Forage Values in a Managed Forest Landscape, Western Washington

    PubMed

    Jenkins; Starkey

    1996-09-01

    Modern timber management practices often influence forage production for elk (Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir (Pseudotsuga menziesii, PSME)-western hemlock (Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.KEY WORDS:Cervus elaphus; Elk; Forage; Forest management; Modeling; Secondary succession

  1. Euphorbia heterophylla leaf extract mediated green synthesis of Ag/TiO2 nanocomposite and investigation of its excellent catalytic activity for reduction of variety of dyes in water.

    PubMed

    Atarod, Monireh; Nasrollahzadeh, Mahmoud; Mohammad Sajadi, S

    2016-01-15

    This work reports a facile and green synthesis of Ag/TiO2 nanocomposite by extract of leaves of Euphorbia heterophylla without any stabilizer or surfactant. The green synthesized Ag/TiO2 nanocomposite was characterized by field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD) and UV-vis. The Ag/TiO2 nanocomposite was found to be effective catalyst for reduction of various dyes, such as 4-nitrophenol (4-NP), Methyl orange (MO), Congo red (CR) and Methylene blue (MB) in the presence of NaBH4 in water at room temperature. Catalysis reactions were monitored by employing UV-vis spectroscopy. Catalysis reactions followed pseudo-first order rate equation. The catalyst can be recovered and reused several times without significant loss of its catalytic activity.

  2. A High Resolution Late Holocene Paleo-atmospheric Co2 Reconstruction From Stomatal Frequency Analysis of Conifer Needles

    NASA Astrophysics Data System (ADS)

    Kouwenberg, L. L. R.; Kurschner, W. M.; Wagner, F.; Visscher, H.

    An inverse relation of stomatal frequency in leaves of many plant taxa and atmospheric CO2 concentration has been repeatedly demonstrated. Response curves based on this species-specific relation are increasingly used to reconstruct paleo-CO2 levels from stomatal frequency analysis on fossil leaves. This type of atmospheric CO2 records have been produced for a large part of geological history, varying from the Paleozoic to the Holocene. Quaternary glaciochemical records from Antarctica and Greenland suggest that CO2 concentration and temperature are strongly linked, in general CO2 appears to lag temperature change. However, in order to assess this relation, high res- olution records with a precise chronology are needed. During the Holocene, several century-scale climatic fluctuations took place, such as the 8.2 kyr event and the Lit- tle Ice age. Linking these temperature fluctuations to paleo-CO2 concentrations in glaciochemical records can be difficult, because the resolution of ice-cores is gen- erally low and the ice-gas age difference complicates accurate dating. An excellent alternative tool for high-resolution Holocene CO2 reconstructions can be provided by stomatal frequency analysis of leaves from Holocene peat and lake sediments. In this study, it is demonstrated that the western hemlock (Tsuga heterophylla) also ad- justs its stomatal frequency to the historical CO2 rise. After careful proxy-validation, a high resolution paleo-atmospheric CO2 record over the last 2000 years based on subfossil Tsuga heterophylla needles from Mount Rainier (Washington, USA) was re- constructed. Chronology is provided by a suite of AMS carbon isotope dates and the presence of tephra layers from nearby Mt. St Helens. The record reproduces CO2 lev- els around 280 ppmv for the Little Ice Age and the CO2 rise to 365 ppmv over the last 150 years. A prominent feature is a marked rise in CO2 at 350 years AD, gradu- ally declining over the next centuries. The CO2 record will be

  3. Using LiDAR Metrics to Characterize Forest Structural Complexity at Multiple Scales

    NASA Astrophysics Data System (ADS)

    Kane, V. R.; McGaughey, R. J.; Gersonde, R.; Franklin, J. F.

    2007-12-01

    Forest structure - the size and arrangement of trees and foliage - reflects a stand's history of initiation, growth, disturbance, and mortality. Because of this, studying the structure of forests can provide key insights into ecological processes, guides to silvicultural prescriptions to improve habitat, and assessments of forested landscapes. This study tested LiDAR metrics to characterize stands based on canopy structure. The study site was the 34,591 ha of forests in the Cedar River Watershed in western Washington State, USA. Stands ranged in age from <25 years old to >350 years old (including old-growth). Study sites spanned the western hemlock- Douglas fir (Tsuga heterophylla-Pseudotsuga menziesii), Pacific silver fir (Abies amabilis), and mountain hemlock (Tsuga mertansiana) forest zones. Eighty sample plots were used to ground truth the LiDAR data. A variety of structural indices were used to study canopy structural variations at the plot, stand, and landscape scales. The two most successful indices used the exposed geometry of the canopy surface: (1) the ratio of the canopy surface area to ground surface area (rumple index), and (2) the ratio of the volume beneath the canopy surface to maximum volume beneath the 95th percentile height (modified canopy volume method). These two indices integrated the spatial effects of tree heights, foliage distribution, and tree arrangement within 15m pixels. Variation between pixels revealed structural complexity at larger scales. Results: At the plot scale (~4 pixels), correlations with standard plot metrics (e.g., diameter at breast height) were similar to those reported by other studies. Comparison of structural complexity with age and height revealed a diversity of development pathways. The relationship between height and complexity allowed stands to be classified by the degree to which they have achieved their potential structural complexity, a new way to examine forest development. At the stand scale, the indices

  4. The importance of large-diameter trees to forest structural heterogeneity.

    PubMed

    Lutz, James A; Larson, Andrew J; Freund, James A; Swanson, Mark E; Bible, Kenneth J

    2013-01-01

    Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established the Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged and mapped all 30,973 woody stems ≥ 1 cm dbh, all 1,966 snags ≥ 10 cm dbh, and all shrub patches ≥ 2 m(2). Basal area of the 26 woody species was 62.18 m(2)/ha, of which 61.60 m(2)/ha was trees and 0.58 m(2)/ha was tall shrubs. Large-diameter trees (≥ 100 cm dbh) comprised 1.5% of stems, 31.8% of basal area, and 17.6% of the heterogeneity of basal area, with basal area dominated by Tsuga heterophylla and Pseudotsuga menziesii. Small-diameter subpopulations of Pseudotsuga menziesii, Tsuga heterophylla and Thuja plicata, as well as all tree species combined, exhibited significant aggregation relative to the null model of complete spatial randomness (CSR) up to 9 m (P ≤ 0.001). Patterns of large-diameter trees were either not different from CSR (Tsuga heterophylla), or exhibited slight aggregation (Pseudotsuga menziesii and Thuja plicata). Significant spatial repulsion between large-diameter and small-diameter Tsuga heterophylla suggests that large-diameter Tsuga heterophylla function as organizers of tree demography over decadal timescales through competitive interactions. Comparison among two forest dynamics plots suggests that forest structural diversity responds to intermediate-scale environmental heterogeneity and disturbances, similar to hypotheses about patterns of species richness, and richness- ecosystem function. Large mapped plots with detailed within-plot environmental spatial covariates will be required to test these hypotheses.

  5. The Importance of Large-Diameter Trees to Forest Structural Heterogeneity

    PubMed Central

    Lutz, James A.; Larson, Andrew J.; Freund, James A.; Swanson, Mark E.; Bible, Kenneth J.

    2013-01-01

    Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established the Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged and mapped all 30,973 woody stems ≥1 cm dbh, all 1,966 snags ≥10 cm dbh, and all shrub patches ≥2 m2. Basal area of the 26 woody species was 62.18 m2/ha, of which 61.60 m2/ha was trees and 0.58 m2/ha was tall shrubs. Large-diameter trees (≥100 cm dbh) comprised 1.5% of stems, 31.8% of basal area, and 17.6% of the heterogeneity of basal area, with basal area dominated by Tsuga heterophylla and Pseudotsuga menziesii. Small-diameter subpopulations of Pseudotsuga menziesii, Tsuga heterophylla and Thuja plicata, as well as all tree species combined, exhibited significant aggregation relative to the null model of complete spatial randomness (CSR) up to 9 m (P≤0.001). Patterns of large-diameter trees were either not different from CSR (Tsuga heterophylla), or exhibited slight aggregation (Pseudotsuga menziesii and Thuja plicata). Significant spatial repulsion between large-diameter and small-diameter Tsuga heterophylla suggests that large-diameter Tsuga heterophylla function as organizers of tree demography over decadal timescales through competitive interactions. Comparison among two forest dynamics plots suggests that forest structural diversity responds to intermediate-scale environmental heterogeneity and disturbances, similar to hypotheses about patterns of species richness, and richness- ecosystem function. Large mapped plots with detailed within-plot environmental spatial covariates will be required to test these hypotheses. PMID:24376579

  6. Impact of an Invasive Insect and Plant Defense on a Native Forest Defoliator

    PubMed Central

    Wilson, Claire M.; Vendettuoli, Justin F.; Orwig, David A.; Preisser, Evan L.

    2016-01-01

    Eastern hemlock (Tsuga canadensis [L.] Carriére) in the United States is threatened by the invasive hemlock woolly adelgid (Adelges tsugae Annand). The native hemlock looper (Lambdina fiscellaria Guenée) also appears to have played a role in previous population declines of this conifer. Although these two insects co-occur in much of the adelgid’s invaded range, their interactions remain unstudied. We assessed looper performance and preference on both uninfested and adelgid-infested foliage from adelgid-susceptible hemlocks, as well as on uninfested foliage from an eastern hemlock that is naturally adelgid-resistant. Larvae reared on uninfested foliage from adelgid-susceptible hemlocks experienced 60% mortality within the first two weeks of the experiment, and pupated at a lower weight than larvae fed adelgid-infested foliage. Despite differences in foliage source, this first look and strong pattern suggests that the hemlock looper performs better (pupates earlier, weighs more) on adelgid-infested foliage. In addition, trends suggested that larvae reared on foliage from the adelgid-resistant tree survived better, pupated earlier, and weighed more than in the other treatments. Larvae preferred adelgid-resistant over adelgid-susceptible foliage. Our results suggest that looper perform slightly better on adelgid-infested foliage and that plant resistance to xylem-feeding adelgid may increase susceptibility to foliar-feeding looper larvae. PMID:27649247

  7. Coast Range Ecoregion: Chapter 1 in Status and trends of land change in the Western United States--1973 to 2000

    USGS Publications Warehouse

    Sohl, Terry L.

    2012-01-01

    The Coast Range Ecoregion, which covers approximately 57,338 km2 (22,138 mi2), is a thin, linear ecoregion along the Pacific Coast, stretching roughly 1,300 km from the Olympic Peninsula, in northwest Washington, to an area south of San Francisco, California (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). It is bounded on the east by the Puget Lowland, the Willamette Valley, the Klamath Mountains, and the Southern and Central California Chaparral and Oak Woodlands Ecoregions. Almost the entire Coast Range Ecoregion lies within 100 km of the coast. Topography is highly variable, with coastal mountain ranges and valleys ranging from sea level to over 1,000 m in elevation (fig. 2). A maritime climate, along with high topographic relief, results in substantial, but regionally variable, amounts of rainfall, ranging from 130 cm to more than 350 cm per year. The favorable climate of the Coast Range Ecoregion has supported forests of Sitka spruce (Picea sitchensis) along its northern coast and coast redwoods (Sequoia sempervirens) along its southern coast, as well as Douglas-fir (Pseudotsuga menziesii), western red cedar (Thuja plicata), and western hemlock (Tsuga heterophylla) inland (Omernik, 1987). Today, however, much of the forest is heavily managed for logging (fig. 3), although the ecoregion still supports some of the largest remaining areas of old-growth forest in the Pacific Northwest. Agriculture is a minor component of the landscape, present locally in flat lands and valleys near the coast. Urban development is minimal; Eureka, California, is the only urban center in the ecoregion, with a population of over 26,000 (U.S. Census Bureau, 2000).

  8. Flux partitioning in an old-growth forest: seasonal and interannual dynamics.

    PubMed

    Falk, Matthias; Wharton, Sonia; Schroeder, Matt; Ustin, Susan; Paw U, Kyaw Tha

    2008-04-01

    Turbulent fluxes of carbon, water and energy were measured at the Wind River Canopy Crane, Washington, USA from 1999 to 2004 with eddy-covariance instrumentation above (67 m) and below (2.5 m) the forest canopy. Here we present the decomposition of net ecosystem exchange of carbon (NEE) into gross primary productivity (GPP), ecosystem respiration (R(eco)) and tree canopy net CO(2) exchange (DeltaC) for an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)-western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest. Significant amounts of carbon were recycled within the canopy because carbon flux measured at the below-canopy level was always upward. Maximum fluxes reached 4-6 micromol m(-2) s(-1) of CO(2) into the canopy air space during the summer months, often equaling the net downward fluxes measured at the above-canopy level. Ecosystem respiration rates deviated from the expected exponential relationship with temperature during the summer months. An empirical ecosystem stress term was derived from soil water content and understory flux data and was added to the R(eco) model to account for attenuated respiration during the summer drought. This attenuation term was not needed in 1999, a wet La Niña year. Years in which climate approximated the historical mean, were within the normal range in both NEE and R(eco), but enhanced or suppressed R(eco) had a significant influence on the carbon balance of the entire stand. In years with low respiration the forest acts as a strong carbon sink (-217 g C m(-2) year(-1)), whereas years in which respiration is high can turn the ecosystem into a weak to moderate carbon source (+100 g C m(-2) year(-1)).

  9. Diversity of Riparian Plants among and within Species Shapes River Communities

    PubMed Central

    Jackrel, Sara L.; Wootton, J. Timothy

    2015-01-01

    Organismal diversity among and within species may affect ecosystem function with effects transmitting across ecosystem boundaries. Whether recipient communities adjust their composition, in turn, to maximize their function in response to changes in donor composition at these two scales of diversity is unknown. We use small stream communities that rely on riparian subsidies as a model system. We used leaf pack experiments to ask how variation in plants growing beside streams in the Olympic Peninsula of Washington State, USA affects stream communities via leaf subsidies. Leaves from red alder (Alnus rubra), vine maple (Acer cinereus), bigleaf maple (Acer macrophyllum) and western hemlock (Tsuga heterophylla) were assembled in leaf packs to contrast low versus high diversity, and deployed in streams to compare local versus non-local leaf sources at the among and within species scales. Leaves from individuals within species decomposed at varying rates; most notably thin leaves decomposed rapidly. Among deciduous species, vine maple decomposed most rapidly, harbored the least algal abundance, and supported the greatest diversity of aquatic invertebrates, while bigleaf maple was at the opposite extreme for these three metrics. Recipient communities decomposed leaves from local species rapidly: leaves from early successional plants decomposed rapidly in stream reaches surrounded by early successional forest and leaves from later successional plants decomposed rapidly adjacent to later successional forest. The species diversity of leaves inconsistently affected decomposition, algal abundance and invertebrate metrics. Intraspecific diversity of leaf packs also did not affect decomposition or invertebrate diversity. However, locally sourced alder leaves decomposed more rapidly and harbored greater levels of algae than leaves sourced from conspecifics growing in other areas on the Olympic Peninsula, but did not harbor greater aquatic invertebrate diversity. In contrast to

  10. Holocene vegetational history of the Kootenai River Valley, Montana

    NASA Astrophysics Data System (ADS)

    Mack, Richard N.; Rutter, N. W.; Valastro, S.

    1983-09-01

    Pollen records in the Kootenai and Fisher River drainages in western Montana reveal a fivezone sequence of Holocene vegetation change. Deposition of Glacier Peak Ash-Layer G (ca. 10,540 ± 660 yr B.P.) in the lowermost sediments (clay intermixed with pebbles) at Tepee Lake gives a minimum date for the initiation of sedimentation. Initial vegetation on the newly deglaciated terrain was dominated by Pinus (probably white bark pine) with small amounts of Gramineae, Picea and Abies, reflecting a relatively cool, moist macroclimate. Two vegetation units appear to contribute to Pollen Zone II (ca. 11,000-7100 yr B.P.): arboreal communities with pines, along with Pseudotsuga or Larix, or both, and treeless vegetation dominated by Artemisia. Pollen Zone II represents an overall warmer macroclimate than occurred upon ice withdrawal. After ca. 7100 yr B.P. (Pollen Zone III) diploxylon pines became a major pollen contributor near both Tepee Lake and McKillop Creek Pond, indicating an expansion of xerophytic forest ( P. contorta and P. ponderosa) along with an increase in the prominence of Pseudotsuga menziesii or Larix occidentalis, or both. Artemisia briefly expanded coverage near Tepee Lake concomitant with the Mazama ashfall ca. 6700 yr B.P. A short-term climatic trend with more available water began after ca. 4000 yr B.P. as Abies (probably A. grandis) along with Picea engelmannii became a more regular component of the forest surrounding both sites. Emergence of the modern macroclimate is indicated primarily with the first regular appearance of Tsuga heterophylla in the pollen record by ca. 2700 yr B.P., synchronous with the development of western hemlock forest within the same latitudes in northern Idaho and northeastern Washington.

  11. Plants promote mating and dispersal of the human pathogenic fungus Cryptococcus.

    PubMed

    Springer, Deborah J; Mohan, Rajinikanth; Heitman, Joseph

    2017-01-01

    Infections due to Cryptococcus are a leading cause of fungal infections worldwide and are acquired as a result of environmental exposure to desiccated yeast or spores. The ability of Cryptococcus to grow, mate, and produce infectious propagules in association with plants is important for the maintenance of the genetic diversity and virulence factors important for infection of animals and humans. In the Western United States and Canada, Cryptococcus has been associated with conifers and tree species other than Eucalyptus; however, to date Cryptococcus has only been studied on live Arabidopsis thaliana, Eucalyptus sp., and Terminalia catappa (almond) seedlings. Previous research has demonstrated the ability of Cryptococcus to colonize live plants, leaves, and vasculature. We investigated the ability of Cryptococcus to grow on live seedlings of the angiosperms, A. thaliana, Eucalyptus camaldulensis, Colophospermum mopane, and the gymnosperms, Pseudotsuga menziesii (Douglas fir), and Tsuga heterophylla (Western hemlock). We observed a broad-range ability of Cryptococcus to colonize both traditional infection models as well as newly tested conifer species. Furthermore, C. neoformans, C. deneoformans, C. gattii (VGI), C. deuterogattii (VGII) and C. bacillisporus (VGIII) were able to colonize live plant leaves and needles but also undergo filamentation and mating on agar seeded with plant materials or in saprobic association with dead plant materials. The ability of Cryptococcus to grow and undergo filamentation and reproduction in saprobic association with both angiosperms and gymnosperms highlights an important role of plant debris in the sexual cycle and exposure to infectious propagules. This study highlights the broad importance of plants (and plant debris) as the ecological niche and reservoirs of infectious propagules of Cryptococcus in the environment.

  12. Diversity of Riparian Plants among and within Species Shapes River Communities.

    PubMed

    Jackrel, Sara L; Wootton, J Timothy

    2015-01-01

    Organismal diversity among and within species may affect ecosystem function with effects transmitting across ecosystem boundaries. Whether recipient communities adjust their composition, in turn, to maximize their function in response to changes in donor composition at these two scales of diversity is unknown. We use small stream communities that rely on riparian subsidies as a model system. We used leaf pack experiments to ask how variation in plants growing beside streams in the Olympic Peninsula of Washington State, USA affects stream communities via leaf subsidies. Leaves from red alder (Alnus rubra), vine maple (Acer cinereus), bigleaf maple (Acer macrophyllum) and western hemlock (Tsuga heterophylla) were assembled in leaf packs to contrast low versus high diversity, and deployed in streams to compare local versus non-local leaf sources at the among and within species scales. Leaves from individuals within species decomposed at varying rates; most notably thin leaves decomposed rapidly. Among deciduous species, vine maple decomposed most rapidly, harbored the least algal abundance, and supported the greatest diversity of aquatic invertebrates, while bigleaf maple was at the opposite extreme for these three metrics. Recipient communities decomposed leaves from local species rapidly: leaves from early successional plants decomposed rapidly in stream reaches surrounded by early successional forest and leaves from later successional plants decomposed rapidly adjacent to later successional forest. The species diversity of leaves inconsistently affected decomposition, algal abundance and invertebrate metrics. Intraspecific diversity of leaf packs also did not affect decomposition or invertebrate diversity. However, locally sourced alder leaves decomposed more rapidly and harbored greater levels of algae than leaves sourced from conspecifics growing in other areas on the Olympic Peninsula, but did not harbor greater aquatic invertebrate diversity. In contrast to

  13. Plants promote mating and dispersal of the human pathogenic fungus Cryptococcus

    PubMed Central

    Mohan, Rajinikanth; Heitman, Joseph

    2017-01-01

    Infections due to Cryptococcus are a leading cause of fungal infections worldwide and are acquired as a result of environmental exposure to desiccated yeast or spores. The ability of Cryptococcus to grow, mate, and produce infectious propagules in association with plants is important for the maintenance of the genetic diversity and virulence factors important for infection of animals and humans. In the Western United States and Canada, Cryptococcus has been associated with conifers and tree species other than Eucalyptus; however, to date Cryptococcus has only been studied on live Arabidopsis thaliana, Eucalyptus sp., and Terminalia catappa (almond) seedlings. Previous research has demonstrated the ability of Cryptococcus to colonize live plants, leaves, and vasculature. We investigated the ability of Cryptococcus to grow on live seedlings of the angiosperms, A. thaliana, Eucalyptus camaldulensis, Colophospermum mopane, and the gymnosperms, Pseudotsuga menziesii (Douglas fir), and Tsuga heterophylla (Western hemlock). We observed a broad-range ability of Cryptococcus to colonize both traditional infection models as well as newly tested conifer species. Furthermore, C. neoformans, C. deneoformans, C. gattii (VGI), C. deuterogattii (VGII) and C. bacillisporus (VGIII) were able to colonize live plant leaves and needles but also undergo filamentation and mating on agar seeded with plant materials or in saprobic association with dead plant materials. The ability of Cryptococcus to grow and undergo filamentation and reproduction in saprobic association with both angiosperms and gymnosperms highlights an important role of plant debris in the sexual cycle and exposure to infectious propagules. This study highlights the broad importance of plants (and plant debris) as the ecological niche and reservoirs of infectious propagules of Cryptococcus in the environment. PMID:28212396

  14. New Boston Air Force Station Environmental Assessment

    DTIC Science & Technology

    2007-11-02

    is the dominant broadleaf tree , but others include sugar maple (Acer saccharm), red maple (A. rubrum), yellow birch (Betula alleghaniensis), and...strobus) and eastern hemlock (Tsuga canadensis). Because of greatly sloping relief, drainage basins are well defined on NBAFS. For this reason

  15. A 26,600 yr record of climate and vegetation from Rice Lake in the Eel River drainage of the northern California Coast Range

    NASA Astrophysics Data System (ADS)

    Heusser, L. E.

    2014-12-01

    Rice Lake, (40'41" N; 123'30" W, 1109 m elev.) lies in the transition zone of the precipitation dipole in the western United States, which is reflected by the present vegetation - a mosaic of mesic northern mixed hardwood-evergreen forests (Quercus spp., Pinus spp., Calocedrus/Juniperus) and more arid southern oak foothill woodlands (Quercus spp.) that borders the westernmost edge of coastal redwoods (Sequoia sempervirens) forest. The site, which lies on the active Lake Mountain fault zone, is now a large (~15 ha) sagpond that dries in summer. Between ~26,600 yr - ~15,000 yr, a permanent lake with aquatic vegetation (Isoetes) occupied the core site. Montane conifer forests, with pine (Pinus, spp.), mountain hemlock (Tsuga mertensiana), spruce (Picea spp), and western hemlock (T. heterophylla) covered the region. Climatic parameters of modern montane coniferous forest and the continued presence of aquatic vegetation (Isoetes) suggest higher precipitation and lower temperatures during the last glacial. Charcoal (fire event frequency) was minimal. Rapid oscillations of oak, the riparian alder (Alnus), pine, Cupressaceae (Juniperus, Calocedrus), Douglas fir (Pseudotsuga menzeii), and fir (Abies) characterize the deglacial, and reflect rapid changes in precipitation and temperatures, e.g, Bølling-Allerød warming and Younger Dryas cooling. Between ~15,000 yr and ~13,000 yr, aquatic vegetation of the lake abruptly decreased. Expansion of oak, tanoak (Lithocarpus), shrubs (cf. Ceanothus) and decline of pine and montane conifers, along with the development of marshes with Typha and Cyperaceae on the former lakebed, imply early Holocene warming and decreasing precipitation. This is supported by an increase in charcoal, which is attributed to forest fires. Between ~5,000 yr - ~6,000 yr, a short interval of increased precipitation (inferred from a peak in alder and decrease in Cupressaceae) initiates the development of modern mixed hardwood-evergreen forest. Correlative data

  16. 2. View from the mansion formal entrance driveway toward the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. View from the mansion formal entrance driveway toward the big meadow at the Billings Farm & Museum. The driveway is flanked by granite gateposts surmounted by wrought iron urn lamps. The view includes a manicured hemlock hedge (Tsuga canadensis) retained by a stone wall at left, and white birch (Betula species) under-planted with ferns at center. - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

  17. Plants determine diversity and function of soil microbial and mesofaunal communities - results from a girdling experiments in a temperate coniferous forest

    NASA Astrophysics Data System (ADS)

    Subke, J.; Voke, N.; Leronni, V.; Briones, M. J. I.; Ineson, P.

    2009-04-01

    The potential for carbon (C) sequestration in soils depends on the rate of humification of C inputs to soils in relation to the decomposition of old soil organic matter. Recent results indicate a close connection between the input of fresh organic matter and the decomposition of old organic matter through soil priming. We conducted a tree girdling experiment in order to better understand the interdependence of soil microbial communities and plant belowground C allocation. A girdling experiment in a mature Western Hemlock (Tsuga heterophylla) stand near York (NE England) confirms the pattern observed in other girdling studies, with a reduction in total soil CO2 efflux (RS) to about 60% of control plots following a delay of about 2 weeks. High frequency measurements of RS immediately after girdling show a short-lived significant increase in RS in girdled plots between 3 and 8 hours after tree girdling, which have not been observed previously. The autotrophic flux contribution (calculated as the difference in RS between the control and girdled plots) declined throughout autumn, but in contrast to most girdling studies, remained significantly greater than zero throughout during December and January. This result indicates that tree belowground allocation continues throughout winter, despite regular night-time frosts in the period measurement were taken. Dominant mesofauna invertebrates (Enchytraeid worms) showed a positive response to girdling and higher abundances were recorded in the girdled plots when compared to the control ones, although differences were only significant on one sampling occasion. These results suggest that, in contrast to other components of the soil food-web, these organisms appear to be underpinned by detrital decomposition rather than by recent photosynthate-C deposition. Litterbag incubations showed no significant short-term treatment effect over the 4 months period following girdling, indicating no measurable interaction of decomposition and

  18. Influences of Forest Tree Species and Early Spring Temperature on Surface-Atmosphere Transfers of Water and Carbon in the Northeastern U.S.

    NASA Astrophysics Data System (ADS)

    Hadley, J. L.; Kuzeja, P.; Mulcahy, T.; Singh, S.

    2008-12-01

    Influences of Forest Tree Species and Early Spring Temperature on Surface-Atmosphere Transfers of Water and Carbon in the Northeastern U.S. Julian Hadley, Paul Kuzeja, Safina Singh and Thomas Mulcahy Transfers of water vapor from terrestrial ecosystems to the atmosphere affect regional hydrology, weather and climate over short time scales, and forest-atmosphere CO2 exchange affects global climate over long timescales. To better understand these effects for forests dominated by two very different tree species, we measured forest-atmosphere water vapor and CO2 transfers by the eddy flux technique to at two sites in central Massachusetts USA for three years. Average annual evapotranspiration (ET) for a young deciduous forest dominated by red oak (Quercus rubra L., the most abundant tree species in the area), was about 430 mm or 25 percent greater than for a coniferous forest dominated by 100 to 230 year old eastern hemlock (Tsuga canadensis L.). The difference in ET was most pronounced in July and August when the deciduous forest lost about 50 percent more water by ET in the average year (192 mm for oak forest versus 130 mm for hemlock). These data indicate that if deciduous trees with similar physiology to red oak replace hemlocks, summertime ET will increase while summer streamflow, soil water content and the extent of year- round wetlands will decrease. Increased summertime ET should also lead to slightly higher regional atmospheric humidity and precipitation. Hemlock-to-deciduous forest conversion has occurred from North Carolina to southern New England and is continuing northward as a lethal insect pest, the hemlock woolly adelgid (Adelges tsugae Annand) continues to kill hemlocks. Average annual carbon storage for the old hemlock forest in our study was about 3.3 Mg C/ha, nearly equal to the average for the deciduous forest, 3.5 Mg C/ha. This calls into question ecological theory that predicts large declines in the rate of carbon uptake for old forests, and

  19. Puget Lowland Ecoregion: Chapter 2 in Status and trends of land change in the Western United States--1973 to 2000

    USGS Publications Warehouse

    Sorenson, Daniel G.

    2012-01-01

    vegetation zone is named after the western hemlock (Tsuga heterophylla), Douglas-fir (Pseudotsuga menziesii) is the dominant tree species. Seattle, which had an estimated population of 563,376 in 2000, is the largest city in the Puget Lowland Ecoregion (Puget Sound Regional Council, 2001). The greater Seattle metropolitan area, comprising Seattle, Tacoma, Bellevue, and Bremerton, had an estimated population of 3.5 million people in 2000 (U.S. Census Bureau, 2000). Other sizable cities in the ecoregion include the state capital Olympia, as well as Tacoma, Bellingham, and Everett, Washington. The center of the Puget Lowland Ecoregion is dominated by the Seattle metropolitan area and developed land cover, whereas agriculture occurs mainly on river floodplains in the north and south. The remainder of the ecoregion area is dominated by forest land cover (fig. 1).

  20. Exotic herbivores on a shared native host: tissue quality after individual, simultaneous, and sequential attack.

    PubMed

    Gómez, Sara; Orians, Colin M; Preisser, Evan L

    2012-08-01

    Plants in nature are often attacked by multiple enemies whose effect on the plant cannot always be predicted based on the outcome of individual attacks. We investigated how two invasive herbivores, the hemlock woolly adelgid (Adelges tsugae) (HWA) and the elongate hemlock scale (Fiorinia externa) (EHS), alter host plant quality (measured as amino acid concentration and composition) when feeding individually or jointly on eastern hemlock (Tsuga canadensis), an important long-lived forest tree that is in severe decline. The joint herbivore treatments included both simultaneous and sequential infestations by the two herbivores. We expected resource depletion over time, particularly in response to feeding by HWA. In contrast, HWA dramatically increased the concentration and altered the composition of individual free amino acids. Compared to control trees, HWA increased total amino acid concentration by 330% after 1 year of infestation. Conversely, EHS had a negligible effect when feeding individually. Interestingly, there was a marginally significant HWA × EHS interaction that suggests the potential for EHS presence to reduce the impact of HWA on foliage quality when the two species co-occur. We suggest indirect effects of water stress as a possible physiological mechanism for our results. Understanding how species interactions change the physiology of a shared host is crucial to making more accurate predictions about host mortality and subsequent changes in affected communities and ecosystems, and to help design appropriate management plans.

  1. Deer herbivory alters forest response to canopy decline caused by an exotic insect pest.

    PubMed

    Eschtruth, Anne K; Battles, John J

    2008-03-01

    Hemlock woolly adelgid (HWA; Adelges tsugae) infestations have resulted in the continuing decline of eastern hemlock (Tsuga canadensis) throughout much of the eastern United States. While the initial impacts of HWA infestations have been documented, our understanding of forest response to this disturbance remains incomplete. HWA infestation is not occurring in isolation but within a complex ecological context. The role of potentially important interacting factors, such as elevated levels of white-tailed deer herbivory, is poorly understood. Despite the potential for herbivory to alter forest successional trajectories following a canopy disturbance, little is known about herbivory-disturbance interactions, and herbivory is rarely considered in assessing forest response to a co-occurring disturbance. We used repeated censuses of deer exclosures and paired controls (400 paired plots) to quantify the impact of deer herbivory on tree seedling species abundance in 10 eastern hemlock ravines that span a gradient in HWA-induced canopy decline severity. Use of a maximum likelihood estimation framework and information theoretics allowed us to quantify the strength of evidence for alternative models developed to estimate the impacts of herbivory on tree seedling abundance as a function of varying herbivore density and canopy decline severity. The exclusion of deer herbivory had marked impacts on the abundance of the studied seedling species: Acer rubrum, Acer saccharum, Betula lenta, Nyssa sylvatica, Quercus montana, and Tsuga canadensis. For all six species, the relationship between seedling abundance and deer density was either exponential or saturating. Although the functional form of the response varied among seedling species, the inclusion of both deer density and canopy decline severity measures consistently resulted in models with substantially greater support. Canopy decline resulted in higher proportional herbivory impacts and altered the ranking of herbivory impacts

  2. Foundation species loss affects vegetation structure more than ecosystem function in a northeastern USA forest

    PubMed Central

    Orwig, David A.; Barker Plotkin, Audrey A.; Davidson, Eric A.; Lux, Heidi; Savage, Kathleen E.

    2013-01-01

    Loss of foundation tree species rapidly alters ecological processes in forested ecosystems. Tsuga canadensis, an hypothesized foundation species of eastern North American forests, is declining throughout much of its range due to infestation by the nonnative insect Adelges tsugae and by removal through pre-emptive salvage logging. In replicate 0.81-ha plots, T. canadensis was cut and removed, or killed in place by girdling to simulate adelgid damage. Control plots included undisturbed hemlock and mid-successional hardwood stands that represent expected forest composition in 50–100 years. Vegetation richness, understory vegetation cover, soil carbon flux, and nitrogen cycling were measured for two years prior to, and five years following, application of experimental treatments. Litterfall and coarse woody debris (CWD), including snags, stumps, and fallen logs and branches, have been measured since treatments were applied. Overstory basal area was reduced 60%–70% in girdled and logged plots. Mean cover and richness did not change in hardwood or hemlock control plots but increased rapidly in girdled and logged plots. Following logging, litterfall immediately decreased then slowly increased, whereas in girdled plots, there was a short pulse of hemlock litterfall as trees died. CWD volume remained relatively constant throughout but was 3–4× higher in logged plots. Logging and girdling resulted in small, short-term changes in ecosystem dynamics due to rapid regrowth of vegetation but in general, interannual variability exceeded differences among treatments. Soil carbon flux in girdled plots showed the strongest response: 35% lower than controls after three years and slowly increasing thereafter. Ammonium availability increased immediately after logging and two years after girdling, due to increased light and soil temperatures and nutrient pulses from leaf-fall and reduced uptake following tree death. The results from this study illuminate ecological processes

  3. Foundation species loss affects vegetation structure more than ecosystem function in a northeastern USA forest.

    PubMed

    Orwig, David A; Barker Plotkin, Audrey A; Davidson, Eric A; Lux, Heidi; Savage, Kathleen E; Ellison, Aaron M

    2013-01-01

    Loss of foundation tree species rapidly alters ecological processes in forested ecosystems. Tsuga canadensis, an hypothesized foundation species of eastern North American forests, is declining throughout much of its range due to infestation by the nonnative insect Adelges tsugae and by removal through pre-emptive salvage logging. In replicate 0.81-ha plots, T. canadensis was cut and removed, or killed in place by girdling to simulate adelgid damage. Control plots included undisturbed hemlock and mid-successional hardwood stands that represent expected forest composition in 50-100 years. Vegetation richness, understory vegetation cover, soil carbon flux, and nitrogen cycling were measured for two years prior to, and five years following, application of experimental treatments. Litterfall and coarse woody debris (CWD), including snags, stumps, and fallen logs and branches, have been measured since treatments were applied. Overstory basal area was reduced 60%-70% in girdled and logged plots. Mean cover and richness did not change in hardwood or hemlock control plots but increased rapidly in girdled and logged plots. Following logging, litterfall immediately decreased then slowly increased, whereas in girdled plots, there was a short pulse of hemlock litterfall as trees died. CWD volume remained relatively constant throughout but was 3-4× higher in logged plots. Logging and girdling resulted in small, short-term changes in ecosystem dynamics due to rapid regrowth of vegetation but in general, interannual variability exceeded differences among treatments. Soil carbon flux in girdled plots showed the strongest response: 35% lower than controls after three years and slowly increasing thereafter. Ammonium availability increased immediately after logging and two years after girdling, due to increased light and soil temperatures and nutrient pulses from leaf-fall and reduced uptake following tree death. The results from this study illuminate ecological processes underlying

  4. Carbon Fluxes in a Managed Landscape: Assessing the Drivers of Temporal and Spatial Variability in Flux Tower, MODIS and Forest Inventory Data of the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Wharton, S.; Bible, K.; Falk, M.; Paw U, K.

    2010-12-01

    This research focuses on the Wind Late Successional Reserve of Southern Washington where clear-cut logging over the past 100 years has created a fragmented landscape of coniferous forests that range in age from 0 to 500 years. In this study, we integrate several datasets to examine the environmental drivers of carbon exchange in this region across time and space. These sources include: (1) network of flux towers across a disturbance choronosequence, (2) MODIS Enhanced Vegetation Index, (3) aboveground net primary production (ANPP) from forest inventories, (4) and regional precipitation and air temperature measurements from the NOAA network of weather stations and PRISM reanalysis data. Net ecosystem exchange of carbon (NEE) has been measured at the Wind River Canopy Crane AmeriFlux site since 1998. The canopy crane is located in an old-growth forest composed of late seral Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla). Two flux towers were erected in early seral stands to study the effects of silviculture on net ecosystem exchange. CO2 uptake at the old-growth stand is highest in the spring before bud break when air and soil temperatures and vapor pressure deficit are relatively low, and soil moisture and light levels are favorable for photosynthesis, while maximum CO2 uptake is observed two to three months later at the early seral stands and coincide with peak leaf area index. This CO2 pattern is driven by different water conserving strategies. A reduction in carbon exchange is observed at the old-growth forest when moisture becomes limiting and canopy conductance rates drop sharply after mid-morning in the summer. In contrast, inhibition in canopy conductance rates and CO2 exchange is not observed at the early seral stands until soil moisture levels become critically low at the very end of the summer. The regional MODIS data (200 km X 200 km area) from 2000-2008 show that annual variability in the Enhanced Vegetation Index (EVI) also

  5. Invasive insect effects on nitrogen cycling and host physiology are not tightly linked.

    PubMed

    Rubino, Lucy; Charles, Sherley; Sirulnik, Abby G; Tuininga, Amy R; Lewis, James D

    2015-02-01

    Invasive insects may dramatically alter resource cycling and productivity in forest ecosystems. Yet, although responses of individual trees should both reflect and affect ecosystem-scale responses, relationships between physiological- and ecosystem-scale responses to invasive insects have not been extensively studied. To address this issue, we examined changes in soil nitrogen (N) cycling, N uptake and allocation, and needle biochemistry and physiology in eastern hemlock (Tsuga canadensis (L) Carr) saplings, associated with infestation by the hemlock woolly adelgid (HWA) (Adelges tsugae Annand), an invasive insect causing widespread decline of eastern hemlock in the eastern USA. Compared with uninfested saplings, infested saplings had soils that exhibited faster nitrification rates, and more needle (15)N uptake, N and total protein concentrations. However, these variables did not clearly covary. Further, within infested saplings, needle N concentration did not vary with HWA density. Light-saturated net photosynthetic rates (Asat) declined by 42% as HWA density increased from 0 to 3 adelgids per needle, but did not vary with needle N concentration. Rather, Asat varied with stomatal conductance, which was highest at the lowest HWA density and accounted for 79% of the variation in Asat. Photosynthetic light response did not differ among HWA densities. Our results suggest that the effects of HWA infestation on soil N pools and fluxes, (15)N uptake, needle N and protein concentrations, and needle physiology may not be tightly coupled under at least some conditions. This pattern may reflect direct effects of the HWA on N uptake by host trees, as well as effects of other scale-dependent factors, such as tree hydrology, affected by HWA activity.

  6. A comparative toxicity assessment of materials used in aquatic construction.

    PubMed

    Lalonde, Benoit A; Ernst, William; Julien, Gary; Jackman, Paula; Doe, Ken; Schaefer, Rebecca

    2011-10-01

    Comparative toxicity testing was performed on selected materials that may be used in aquatic construction projects. The tests were conducted on the following materials: (1) untreated wood species (hemlock [Tsuga ssp], Western red cedar (Thuja plicata), red oak [Quercus rubra], Douglas fir [Pseudotsuga menziesii], red pine [Pinus resinosa], and tamarack [Larix ssp]); (2) plastic wood; (3) Ecothermo wood hemlock stakes treated with preservatives (e.g., chromated copper arsenate [CCA], creosote, alkaline copper quaternary [ACQ], zinc naphthenate, copper naphthenate, and Lifetime Wood Treatment); (4) epoxy-coated steel; (5) hot-rolled steel; (6) zinc-coated steel; and (7) concrete. Those materials were used in acute lethality tests with rainbow trout, Daphnia magna, Vibrio fischeri and threespine stickleback. The results indicated the following general ranking of the materials (from the lowest to highest LC(50) values); ACQ > creosote > zinc naphthenate > copper naphthenate > CCA (treated at 22.4 kg/m(3)) > concrete > red pine > western red cedar > red oak > zinc-coated steel > epoxy-coated steel > CCA (6.4 kg/m(3)). Furthermore, the toxicity results indicated that plastic wood, certain untreated wood species (hemlock, tamarack, Douglas fir, and red oak), hot-rolled steel, Ecothermo wood, and wood treated with Lifetime Wood Treatment were generally nontoxic to the test species.

  7. Reconstruction of annual temperature (1590?1979) for Longmire, Washington, derived from tree rings

    NASA Astrophysics Data System (ADS)

    Graumlich, Lisa J.; Brubaker, Linda B.

    1986-03-01

    Annual growth records from trees at timberline in the Cascade Range of Washington are correlated with variations in temperature and snow depth and used to reconstruct climatic variation in the past. Response surfaces indicate that growth of mountain hemlock ( Tsuga mertensiana) and subalpine larch ( Larix lyallii) is positively correlated with summer (July to September) temperature and negatively correlated with spring (March) snow depth when snow depth is at or below average. During years of above average snow depth, temperature has little effect on mountain hemlock but has a negative effect on growth in subalpine larch. These interactions make it difficult to reconstruct these climatic variables separately using standard methods. Mean annual temperature values, which combine information on both summer temperature and spring snow depth, were estimated from a regression model that reconstructs past temperature at Longmire, Washington, as a function of larch and hemlock tree-ring chronologies. The reconstruction of mean annual temperature shows temperatures between 1590 and 1900 to be approximately 1°C lower than those of the 20th century. Only during a short period from 1650 to 1690 did temperatures approach 20th-century values.

  8. Carbon exchange and quantum efficiency of ecosystem carbon storage in mature deciduous and old-growth coniferous forest in central New England in 2001

    NASA Astrophysics Data System (ADS)

    Hadley, J. L.; Urbanski, S. P.

    2002-12-01

    Carbon storage in forests of the northeastern U.S. and adjacent Canada may be a significant carbon sink, as forests and soils in this region have recovered after agricultural abandonment in the 19th century. Data collected during the 1990's showed that an area of 70 to 100 year old deciduous forest on abandoned farmland in central Massachusetts stored an average of 2.0 Mg C/ha/yr in trees and soil. During 2001 we measured carbon exchange and environmental parameters (above-canopy air temperature, atmospheric humidity, photosynthetically active radiation (PAR) and soil temperature) in both the 70-100 year old deciduous forest and in a nearby eastern hemlock (Tsuga canadensis L.)-dominated forest with trees up to 220 years old that was never cleared for agricultural use. The deciduous forest stored more than 4 Mg C/ ha in 2001, far higher than in any previous year since measurements started in 1991. Highest monthly deciduous forest carbon storage (1.8 - 1.9 Mg ha-1 month-1) occurred in July and August. The hemlock forest stored about 3 Mg C/ha, with peak storage in April and May (0.8 - 0.9Mg C ha-1 month-1), and little or no C storage during August. The differences in carbon storage between the two forests were related to differences in quantum use efficiency. Quantum efficiency of ecosystem carbon storage in the foliated deciduous forest averaged about 0.16 g C /mol PAR and was insensitive to temperature after leaf maturation. In contrast, the average hemlock forest quantum efficiency declined from about 0.10 g C /mol PAR at daily average above-canopy air temperature (T{a}{v}{g}) = 5 oC to zero quantum efficiency (no net carbon storage) at T{a}{v}{g} = 23 oC. Optimum temperatures for carbon storage in the hemlock forest occurred in April. Differences between the two forests are likely due primarily to a higher maximum photosynthetic rate and a more positive temperature response of leaf-level photosynthesis in red oak (the dominant deciduous species) as compared with

  9. Controls on Nitrogen Retention and Loss in Urban and Rural Forest Ecosystems.

    NASA Astrophysics Data System (ADS)

    Templer, P. H.

    2011-12-01

    Human activities, such as the burning of fossil fuels and production of fertilizer, have increased the amount of nitrogen deposited onto terrestrial ecosystems. In addition to changes in atmospheric deposition of nitrogen, other human-induced disturbances have led to dramatic shifts in forest composition of the United States over the last 100 years. Tree species composition of many forests is changing in response to introduced pests and pathogens, competition with introduced plant species and changes in climate. Understanding the combined effects of increased nitrogen inputs and changes in plant species composition on forest nitrogen cycling is critical to our understanding of forest biogeochemistry and nutrient budgets. Despite several decades of research on the effects of atmospheric nitrogen deposition, there is still significant uncertainty about the factors that regulate nitrogen retention and loss in forest ecosystems. The use of natural abundance stable isotopes of nitrogen and oxygen has proven to be a powerful tool for tracing the sources of nitrate in water, from inputs to leaching, as it moves through an ecosystem. The evaluation of natural abundance nitrogen values in atmospheric deposition has been used to partition sources of nitrogen, such as coal-fired power plants vs. tailpipe exhaust, since each of their isotopic signatures is distinct. Similarly, natural abundance oxygen values of nitrate in atmospheric inputs and soil leachate have been used as a tool to partition sources of nitrate between precipitation and nitrate produced microbially during nitrification. We measured the natural abundance isotopic composition of nitrate to quantify rates of nitrogen inputs to the forest and to determine rates of nitrogen losses from healthy, declining and preemptively cut eastern hemlock (Tsuga canadensis) stands in both an urban forest at the Arnold Arboretum in Boston, MA, and a rural forest at Harvard Forest in Petersham, MA. The hemlock woolly adelgid

  10. 6000-year record of forest history on Mount Rainier, Washington

    SciTech Connect

    Dunwiddie, P.W.

    1986-02-01

    Sediments in three ponds between 1300 - 1500 m on the south side of Mt. Rainier were examined for plant macrofossils and pollen. Macrofossils of seral species such as Abies lasiocarpa, Pseudotsuga menziesii, Pinus monticola, Abies procera, and Pinus contorta are conspicuous from 6000 to 3400 BP. These species suggest a climate that was warmer/drier than today and favored frequent fires. Neoglacial cooling may have begun 3700-3400 BP, as species typical of higher elevations became prominent; a decline in seral species after 3400 BP suggests less frequent fires. In the last 100 yr, Tsuga heterophylla became abundant and then declined at the highest elevation site. General trends in pollen percentages are similar to the macrofossil curves. Tephra deposition from Mt. Rainier and Mt. St. Helens did not produce conspicuous changes in forest composition. Few major fires are evident from charcoal and macrofossils at these sites.

  11. Recominant Pinoresino-Lariciresinol Reductase, Recombinant Dirigent Protein And Methods Of Use

    DOEpatents

    Lewis, Norman G.; Davin, Laurence B.; Dinkova-Kostova, Albena T.; Fujita, Masayuki , Gang; David R. , Sarkanen; Simo , Ford; Joshua D.

    2003-10-21

    Dirigent proteins and pinoresinol/lariciresinol reductases have been isolated, together with cDNAs encoding dirigent proteins and pinoresinol/lariciresinol reductases. Accordingly, isolated DNA sequences are provided from source species Forsythia intermedia, Thuja plicata, Tsuga heterophylla, Eucommia ulmoides, Linum usitatissimum, and Schisandra chinensis, which code for the expression of dirigent proteins and pinoresinol/lariciresinol reductases. In other aspects, replicable recombinant cloning vehicles are provided which code for dirigent proteins or pinoresinol/lariciresinol reductases or for a base sequence sufficiently complementary to at least a portion of dirigent protein or pinoresinol/lariciresinol reductase DNA or RNA to enable hybridization therewith. In yet other aspects, modified host cells are provided that have been transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence encoding dirigent protein or pinoresinol/lariciresinol reductase. Thus, systems and methods are provided for the recombinant expression of dirigent proteins and/or pinoresinol/lariciresinol reductases.

  12. Proteomic analysis of Corylus heterophylla fisch in Changbai Mountain by shotgun approach.

    PubMed

    Chunlei, Liu; Weihong, Min; Jingsheng, Liu; Yan, Liu; Jingxi, Ma; Jingjing, Li

    2015-07-01

    Total proteins of Changbai Mountain hazelnut were extracted and then enzymolysed in solution. The mixture of peptides was separated on chromatograph and identified by shotgun proteomics approach. The identified proteins were analyzed by bioinformatics, 303 proteins were identified, of which 237 proteins (78.2%) were mainly distributing in a range of 10-70 kDa and 85 proteins (28.1%) were around pI 5-6. Based on the biological process cellular component and molecular function, these proteins were classified by Gene Ontology, the results showed that 183 proteins (73.8%) had catalytic activity (e.g. oxidoreductase, kinase, peptidase, etc.), and 170 proteins (68.5%) had binding activity. The protein profile provided a valuable basis for further research of hazelnut proteins and opened up new research avenues related to the function of these proteins.

  13. Stand characteristics of 65-year-old planted and naturally regenerated stands near Sequim, Washington. Forest Service research paper

    SciTech Connect

    Miller, R.E.; Anderson, H.W.

    1995-04-01

    Tree numbers, height, and volume were determined in six 63- to 66-year-old plantations of coast Douglas-fir (Pseudotsunga menziesii) (Mirb.) Franco var. menziesii in northwest Washington. These stands resulted from the first extensive plantings of this species in the Pacific Northwest. Data from 0.25-acre plots in these plantations were compared to those from matched plots in adjacent, naturally regenerated stands with the same history of logging, wildfire, and absence of further siviculture after regeneration. Planting resulted in well-stocked Douglas-fir stands with volunteers of other tree species. Natural seeding resulted in similarly stocked stands of western hemlock (Tsunga heterophylla) (Raf.) (Sarg.) with Douglas-fir in the dominant crown class.

  14. Spatial variation of modern pollen in Oregon and southern Washington, USA.

    PubMed

    Minckley; Whitlock

    2000-10-01

    Surface sediments from 95 lakes provide information on the spatial variation of modern pollen spectra in Oregon and southern Washington. Percentages for 13 pollen types were compared within and between vegetation zones to characterize regional patterns of pollen spectra. The percentage data were also compared with climate variables to determine relationships between pollen percentages and regional climate gradients. The composition of modern pollen spectra corresponds well with the distribution of the pollen producers. Most pollen assemblages were generally dominated by Pinus, but those west of the Cascade Range were dominated by Alnus. Low percentages of Pseudotsuga/Larix, Tsuga mertensiana, Abies, and Picea pollen coincided with local occurrence of the trees. The distributions of the pollen data were arranged along gradients of temperature and effective moisture. West of the Cascade Range, Alnus, Tsuga heterophylla, Pseudotsuga/Larix, and Cupressaceae pollen were abundant and correlate well with moderate temperature and high effective moisture. In the shrub-steppe and woodlands east of the Cascade Range, where effective moisture is low, Artemisia, Cupressaceae, and Pinus pollen were dominant. At high elevations, Pinus, T. mertensiana, Abies, and Picea were common pollen types in areas with short growing seasons and high effective moisture. Pollen percentages collected from lake surface sediments, moss polsters, and soils were compared within a number of vegetation types to assess their similarity. The three types of sample yielded similar results for forested areas, but lake sediment samples from upper- and lower-treeline sites captured a more regional picture of the vegetation.

  15. A 14,000 year vegetation history of a hypermaritime island on the outer Pacific coast of Canada based on fossil pollen, spores and conifer stomata

    NASA Astrophysics Data System (ADS)

    Lacourse, Terri; Delepine, J. Michelle; Hoffman, Elizabeth H.; Mathewes, Rolf W.

    2012-11-01

    Pollen and conifer stomata analyses of lake sediments from Hippa Island on the north coast of British Columbia were used to reconstruct the vegetation history of this small hypermaritime island. Between 14,000 and 13,230 cal yr BP, the island supported diverse herb-shrub communities dominated by Cyperaceae, Artemisia and Salix. Pinus contorta and Picea sitchensis stomata indicate that these conifers were present among the herb-shrub communities, likely as scattered individuals. Transition to open P. contorta woodland by 13,000 cal yr BP was followed by increases in Alnus viridis, Alnus rubra and P. sitchensis. After 12,000 cal yr BP, Pinus-dominated communities were replaced by dense P. sitchensis and Tsuga heterophylla forest with Lysichiton americanus and fern understory. Thuja plicata stomata indicate that this species was present by 8700 cal yr BP, but the pollen record suggests that its populations did not expand to dominate regional rainforests, along with Tsuga and Picea, until after 6600 cal yr BP. Conifer stomata indicate that species may be locally present for hundreds to thousands of years before pollen exceed thresholds routinely used to infer local species arrival. When combined, pollen and conifer stomata can provide a more accurate record of paleovegetation than either when used alone.

  16. Postglacial vegetation history of Orcas Island, northwestern Washington

    NASA Astrophysics Data System (ADS)

    Leopold, Estella B.; Dunwiddie, Peter W.; Whitlock, Cathy; Nickmann, Rudy; Watts, William A.

    2016-05-01

    The revegetation of islands following retreat of Pleistocene glaciers is of great biogeographical interest. The San Juan Islands, Washington, feature regionally distinctive xerophytic plant communities, yet their vegetation history, as it relates to past climate and sea level, is poorly known. We describe a 13,700-year-old pollen record from Killebrew Lake Fen and compare the vegetation reconstruction with others from the region. The data suggest that the narrow channels surrounding Orcas Island were not a barrier to early postglacial immigration of plants. Between 13,700 and 12,000 cal yr BP, Pinus, Tsuga, Picea, Alnus viridis, and possibly Juniperus maritima were present in a mosaic that supported Bison antiquus and Megalonyx. The rise of Alnus rubra-type pollen and Pteridium spores at ca. 12,000 cal yr BP suggests a warming trend and probably more fires. Temperate conifer taxa, including Cupressaceae, Pseudotsuga, Tsuga heterophylla, and Abies, increased after 11,000 cal yr BP and especially in the last 7000 cal yr BP. After 6000 cal yr BP, Pseudotsuga and Cupressaceae dominated the vegetation. The last 1500 yr were the wettest period of the record. Due to its rain shadow location, Orcas Island experienced drier conditions than on the mainland during most of the postglacial period.

  17. Migration of tree species in New England based on elevational and regional analyses. Forest Service research paper (Final)

    SciTech Connect

    Solomon, D.S.; Leak, W.B.

    1994-07-20

    With field measurements of migration patterns, we used two complementary approaches to examine tree-species movement after a documented increase in temperature. The advancing-front theory was used to examine age trends over distance and elevation for both a mountain site in New Hampshire and a regional comparison across the State of Maine. Well-defined stationary fronts were identified for red spruce (Picea rubens) and beech (Fagus grandifolia), while a catastrophic front was depicted for sugar maple (Acer saccharum) and a constant slow-moving advancing front was exhibited by hemlock (Tsuga canadensis). The regional analysis, in Maine, indicated that white pine (Pinus strobus) and balsam fir (Abies balsamea) decreased significantly in average latitude and elevation over a 24-year period. The potential ranges of the major species in terms of elevation and regional position appear stable.

  18. 76 FR 81475 - Foreign-Trade Zones 140 and 78 Applications for Subzone Authority Dow Corning Corporation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-28

    ... Corporation, Hemlock Semiconductor Corporation and Hemlock Semiconductor, L.L.C.; Notice of Public Hearing and... Semiconductor Corporation facility in Hemlock, Michigan (76 FR 63282, 10/12/2011) and the Hemlock...

  19. Habitat classification: A comparison using avian species and guilds

    NASA Astrophysics Data System (ADS)

    Degraaf, Richard M.; Chadwick, Nan L.

    1984-11-01

    Results of breeding bird censuses in 1979 and 1980 were used to compare the relationships of both species and guilds to forest habitats in the White Mountains of New Hampshire. Several age classes of 11 forest cover types were studied: northern hard-woods ( Fagus-Betula-Acer), spruce ( Picea), spruce-fir ( Picea-Abies), birth ( Betula), swamp hardwoods ( Acer-Pinus-Tsuga), pine ( Pinus strobus and P. resinosa), balsam fir ( Abies), aspen ( Populus tremuloides and P. grandidentata), northern red oak ( Quercus), oak-pine ( Quercus-Pinus), and hemlock ( Tsuga). All types were even-aged; only northern hardwoods had an additional uneven-aged condition. Forest cover types were also pooled to consider generalized habitats: hardwoods, mixed forest, or softwoods. Results of ordinations based on censuses of 74 bird species indicate that foraging guilds are more related to general cover types than are nesting substrate guilds, but bird species reflect habitat differences to a greater degree than do either guild scheme. Also, considerable overlap occurs in bird species distribution between hardwoods and mixed forests; softwoods show little overlap with other types. Discriminant function and classification analyses revealed that bird species composition can be used to correctly classify general forest habitats more accurately (83.8%) than either foraging (63.2%) or nesting substrate guilds (58.4%). These results indicate that, of the habitats studied, avian species compositions are more characteristic than are foraging or nesting substrate guild composition, which tend to be similar across forest habitats.

  20. Climate, geography, and tree establishment in Subalpine Meadows of the Olympic Mountains, Washington, U.S.A.

    SciTech Connect

    Woodward, A.; Silsbee, D.G.; Schreiner, E.G.

    1995-08-01

    Noticeable changes in vegetation distribution have occurred in the Pacific Northwest during the last century as trees have established in some subalpine meadows. To study the relationship of this process to climate, recently established trees were aged in six subalpine meadows in the Olympic Mountains, Washington. The sites represent three points along a steep precipitation gradient. Subalpine fir (Abies lasiocarpa) has been establishing at the dry end of the gradient, mountain hemlock (Tsuga mertensiana) at the wet end, and both species in the center. Establishment patterns were compared with deviations from the century-long average for these weather variables: winter precipitation, Palmer Drought Severity Index, and winter, October and May temperatures. Results show that establishment occurred in dry areas when weather conditions were wetter than average, and in wet areas under drier than average conditions. Establishment at central sites did not show consistent relationships with climate. If future climatic conditions continue to warm, establishment of subalpine fir in subalpine meadows in dry areas may cease and mountain hemlock may resume in wet areas. 34 refs., 5 figs., 3 tabs.

  1. Microclimatic variation within sleeve cages used in ecological studies.

    PubMed

    Nelson, Lori A; Rieske, Lynne K

    2014-01-01

    Sleeve cages for enclosing or excluding arthropods are essential components of field studies evaluating trophic interactions. Microclimatic variation in sleeve cages was evaluated to characterize its potential effects on subsequent long-term experiments. Two sleeve cage materials, polyester and nylon, and two cage sizes, 400 and 6000 cm(2), were tested on eastern hemlock, Tsuga canadensis (L.) Carrière. Temperature and relative humidity inside and outside cages, and the cost and durability of the cage materials, were compared. Long-term effects of the sleeve cages were observed by measuring new growth on T. canadensis branches. The ultimate goal was to identify a material that minimizes bag-induced microclimatic variation. Bagged branches whose microclimates mimic those of surrounding unbagged branches should have minimal effects on plant growth and may prove ideal venues for assessing herbivore and predator behavior under natural conditions. No differences were found in temperature or humidity between caging materials. Small cages had higher average temperatures than large cages, especially in the winter, but this difference was confounded by the fact that small cages were positioned higher in trees than large cages. Differences in plant growth were detected. Eastern hemlock branches enclosed within polyester cages produced fewer new growth tips than uncaged controls. Both polyester and nylon cages reduced the length of new shoot growth relative to uncaged branches. In spite of higher costs, nylon cages were superior to polyester with respect to durability and ease of handling.

  2. Climate, geography, and tree establishment in subalpine meadows of the Olympic Mountains, Washington, USA

    USGS Publications Warehouse

    Woodward, Andrea; Schreiner, Edward G.; Silsbee, D.G.

    1995-01-01

    Noticeable changes in vegetation distribution have occurred in the Pacific Northwest during the last century as trees have established in some subalpine meadows. To study the relationship of this process to climate, recently established trees were aged in six subalpine meadows in the Olympic Mountains, Washington. The sites represent three points along a steep precipitation gradient. Subalpine fir (Abies lasiocarpa) has been establishing at the dry end of the gradient, mountain hemlock (Tsuga mertensiana) at the wet end, and both species in the center. Establishment patterns were compared with deviations from the century-long average for these weather variables: winter precipitation, Palmer Drought Severity Index, and winter, October, and May temperatures. Results show that establishment occurred in dry areas when weather conditions were wetter than average, and in wet areas under drier than average conditions. Establishment at central sites did not show consistent relationships with climate. If future climatic conditions continue to warm, establishment of subalpine fir in subalpine meadows in dry areas may cease and mountain hemlock may resume in wet areas.

  3. 75 FR 28232 - Availability of an Environmental Assessment for a Biological Control Agent for Hemlock Woolly...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... alternatives to, the release of an insect, Laricobius osakensis, into the continental United States for use as... Service (APHIS) is proposing to issue permits for the release of an insect, Laricobius osakensis, into the... adelgid (HWA) infestations. HWA, an introduced insect pest destructive to forest and ornamental...

  4. 76 FR 63282 - Foreign-Trade Zone 140-Flint, Michigan; Application for Subzone; Hemlock Semiconductor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-12

    ..., silicon tetrachloride, trichlorosilane, dichlorosilane, hydrogen chloride and direct process residue...: silicon metal, silicon tetrachloride, trichlorosilanes and dichlorosilanes (duty rate ranges from duty... foreign status silicon metal subject to an antidumping or countervailing duty order into the...

  5. Estimating nitrogen lost from forest floor during prescribed fires in Douglas-fir/western hemlock clearcuts

    SciTech Connect

    Little, S.N.; Ohmann, J.L. )

    1988-03-01

    Nitrogen loss from consumption of forest floor was studied on 33 treatment blocks burned on 11 clearcuts in western Washington and western Oregon. In most cases, nitrogen concentration in forest floor did not change significantly following prescribed fire. Change in the amount of nitrogen in forest floor ranged from an increase of 192 kg/ha to a loss of 666 kg/ha. In most cases, nitrogen loss was directly proportional to the amount of forest floor consumed. Total nitrogen loss can therefore be estimated by multiplying expected loss of forest floor by its nitrogen concentration before the burn.

  6. The future of bioethics: three dogmas and a cup of hemlock.

    PubMed

    Dawson, Angus

    2010-06-01

    In this paper I argue that bioethics is in crisis and that it will not have a future unless it begins to embrace a more Socratic approach to its leading assumptions. The absence of a critical and sceptical spirit has resulted in little more than a dominant ideology. I focus on three key issues. First, that too often bioethics collapses into medical ethics. Second, that medical ethics itself is beset by a lack of self-reflection that I characterize here as a commitment to three dogmas. Third, I offer a more positive perspective by suggesting how bioethics may benefit from looking towards public health ethics as a new source of inspiration and direction.

  7. Mineral waters, electricity, and hemlock: devising therapeutics for children in eighteenth-century institutions.

    PubMed

    Mathisen, Ashley

    2013-01-01

    The development of paediatric medicine as a formal field of medical specialisation is usually traced to the mid-nineteenth century at the earliest. While it is true that formal specialisation in children's medicine was not, on the whole, typical for eighteenth-century medical practitioners, many displayed a deep and lasting interest in the diseases of children, and were consequently eager to develop therapeutic practices which could be targeted at infants and children. This led to a variety of attempts at innovation, many of which benefitted from the co-operation of, and opportunities afforded by, institutions. By examining the efforts of several medical practitioners at the London Foundling Hospital and at the Dispensary for the Infant Poor, this article explores how eighteenth-century medical practitioners used their affiliations with institutions to address the problems of devising or adapting therapeutic practices and treatments for children. In tailoring medical practice to suit children and, more specifically, in using institutions to do so, medical practitioners were demonstrating that child patients required special consideration, that children's diseases could be managed medically and with the benefit of new approaches and methods, and that children's health, as a whole, was the province of medical practitioners.

  8. Pistillate flower development and pollen tube growth mode during the delayed fertilization stage in Corylus heterophylla Fisch.

    PubMed

    Liu, Jianfeng; Zhang, Huidi; Cheng, Yunqing; Kafkas, Salih; Güney, Murat

    2014-09-01

    Unlike most angiosperms, in which fertilization occurs within several days after pollination, fertilization in hazel (Corylus Spp.) is delayed by two to three and a half months. However, the female inflorescences or young fruits are too hard or lignified to be dissected according to regular paraffin sectioning technique. So, what the nature of development during the extended progamic phases of hazel remains unknown. The female inflorescence development and pollen tube growth mode during the delayed fertilization stage in hazel were investigated by improved paraffin sectioning and aniline blue staining of pollen tubes. The results showed ovaries and ovules of hazel were invisible at the time of blooming. Early ovary and ovule primordium began to form from 15 to 20 days after blooming, respectively. Integument and mature embryo sacs differentiated from the nucellus on 40th and 55th day after blooming, respectively. Pollen tubes were retarded in the bottom of the style or the pollen tube cavity (PTC, a specifical lignified cavity structure at the bottom of style for pollen tube to rest during progamic phase) for about 26 days. Then, the pollen tubes were observed to leave the PTC and began to enter the ovary. After that, a single pollen tube passed through the vicinity of the micropyle. Finally, pollen tubes turned a corner and penetrated the embryo sac through the tissue of the chalaza instead of micropyle on 52 and 55 days after blooming, respectively. The results of more in-depth information will be beneficial to better understanding of the delayed fertilization process in hazel.

  9. 76 FR 76934 - Foreign-Trade Zones 140 and 78; Applications for Subzone Authority; Dow Corning Corporation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-09

    ... Corporation, Hemlock Semiconductor Corporation and Hemlock Semiconductor, L.L.C.; Extension of Comment Periods... in Midland, Michigan (76 FR 63282- 63283, October 12, 2011), at the Hemlock Semiconductor Corporation facility in Hemlock, Michigan (76 FR 63282, October 12, 2011) and at the Hemlock Semiconductor,...

  10. 77 FR 21082 - Foreign-Trade Zones 140 and 78, Applications for Subzone Authority Dow Corning Corporation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-09

    ... Corporation, Hemlock Semiconductor Corporation, and Hemlock Semiconductor, L.L.C.; Reopening of Rebuttal... facility in Midland, Michigan (76 FR 63282- 63283, 10/12/2011), at the Hemlock Semiconductor Corporation facility in Hemlock, Michigan (76 FR 63282, 10/12/2011) and at the Hemlock Semiconductor, L.L.C....

  11. 77 FR 30500 - Foreign-Trade Zones 140 and 78, Applications for Subzone Authority, Dow Corning Corporation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-23

    ... Corporation, Hemlock Semiconductor Corporation, and Hemlock Semiconductor, L.L.C.; Reopening of Comment... facility in Midland, Michigan (76 FR 63282- 63283, 10/12/2011), at the Hemlock Semiconductor Corporation facility in Hemlock, Michigan (76 FR 63282, 10/12/2011) and at the Hemlock Semiconductor, L.L.C....

  12. Effects of late holocene forest disturbance and vegetation change on acidic mud pond, Maine, USA

    SciTech Connect

    Rhodes, T.E.; Davis, R.B.

    1995-04-01

    The limnological effects of natural forest disturbance and succession were studied by analyzing the chemistry, charcoal, pollen, chrysophytes, and diatoms in sediments deposited from {approx}3500 to {approx}700 yr BP in Mud Pond, Maine. Fine-grained sediments rich in organic matter are interrupted every 100-500 yr ({bar X} = 280) by coarser, more minerogenic sediments, reflecting soil erosion. The disturbance horizons contain high concentrations of charcoal, indicating forest fires, low percentages of pollen of late-successional trees such as Tsuga, and high percentages of pollen and spores of early-successional plants such as shrubs and ferns. Within a few decades, pollen percentages of Alnus peak, followed by Betula. Tsuga pollen percentages increase for 200-400 yr after disturbances, and generally stabilize or decrease several decades before the next disturbance. Limnological responses to these changes are indicated by high percentages of diatoms and chrysophytes of waters of near neutral pH. Diatom-inferred pH typically increases abruptly from {approx}5.0 to {approx}6.1, and chrysophyte-inferred pH from {approx}5.5 to {approx}5.8 at disturbance horizons. These increases may be caused by increased wood ash and mineral soils after disturbances. This pulse is followed by a two-step recovery. First the inferred pH decreases nearly to the pre-disturbance condition. This response likely results from soil stabilization and uptake of base cations by successional vegetation. Second, a slower acidification of {approx}0.1 pH unit per century occurs as early successional shrubs and hardwood forest are replaced by old-growth conifer forest. Increasing percentages of pollen of Picea, Alnus, and Salix by 1350 yr BP, and decreasing percentages of hemlock and beech around 1350 yr BP imply cooler conditions. Large changes in diatom and chrysophyte assemblages in approximately this period may be related. 64 refs., 8 figs., 3 tabs.

  13. A multi-scale conceptual model of fire and disease interactions in North American forests

    NASA Astrophysics Data System (ADS)

    Varner, J. M.; Kreye, J. K.; Sherriff, R.; Metz, M.

    2013-12-01

    One aspect of global change with increasing attention is the interactions between irruptive pests and diseases and wildland fire behavior and effects. These pests and diseases affect fire behavior and effects in spatially and temporally complex ways. Models of fire and pathogen interactions have been constructed for individual pests or diseases, but to date, no synthesis of this complexity has been attempted. Here we synthesize North American fire-pathogen interactions into syndromes with similarities in spatial extent and temporal duration. We base our models on fire interactions with three examples: sudden oak death (caused by the pathogen Phytopthora ramorum) and the native tree tanoak (Notholithocarpus densiflorus); mountain pine beetle (Dendroctonus ponderosae) and western Pinus spp.; and hemlock woolly adelgid (Adelges tsugae) on Tsuga spp. We evaluate each across spatial (severity of attack from branch to landscape scale) and temporal scales (from attack to decades after) and link each change to its coincident effects on fuels and potential fire behavior. These syndromes differ in their spatial and temporal severity, differentially affecting windows of increased or decreased community flammability. We evaluate these models with two examples: the recently emergent ambrosia beetle-vectored laurel wilt (caused by the pathogen Raffaelea lauricola) in native members of the Lauraceae and the early 20th century chestnut blight (caused by the pathogen Cryphonectria parasitica) that led to the decline of American chestnut (Castanea dentata). Some changes (e.g., reduced foliar moisture content) have short-term consequences for potential fire behavior while others (functional extirpation) have more complex indirect effects on community flammability. As non-native emergent diseases and pests continue, synthetic models that aid in prediction of fire behavior and effects will enable the research and management community to prioritize mitigation efforts to realized effects.

  14. Impacts of Invasive Pests on Forest Carbon and Nitrogen Dynamics

    NASA Astrophysics Data System (ADS)

    Lovett, G. M.; Crowley, K. F.

    2014-12-01

    Forests of the U.S. have been subject to repeated invasions of destructive insects and diseases imported from other continents. Like other disturbances, these pests can produce short-term ecosystem effects due to tree mortality, but unlike other disturbances, they often target individual species and therefore can cause long-term species change in the forest. Because tree species vary in their influence on carbon (C) and nitrogen (N) cycles, pest-induced species change can radically alter the biogeochemistry of a forest. In this paper we use both data and modeling to examine how pest-induced species change may alter the C and N cycling in forests of the eastern U.S. We describe a new forest ecosystem model that distinguishes individual tree species and allows species composition to shift over the course of the model run. Results indicate that the mortality of eastern hemlock (Tsuga canadensis) by hemlock woolly adelgid and its replacement by faster-growing species such as black birch (Betula lenta) will reduce forest floor C stocks but increase productivity as the birch become established. Decline of American beech (Fagus grandifolia) from beech bark disease and its replacement by sugar maple (Acer saccharum) is likely to decrease soil C storage and increase N leaching from the ecosystem. Responses to other invasive pests will also be discussed. The magnitude of these species-specific effects on C and N cycling is in many cases larger than direct effects expected from changes in climate and atmospheric N deposition, indicating that species change should be included in models that predict forest ecosystem function under future environmental conditions.

  15. Recognizing Non-Stationary Climate Response in Tree Growth for Southern Coastal Alaska, USA

    NASA Astrophysics Data System (ADS)

    Wiles, G. C.; Jarvis, S. K.; D'Arrigo, R.; Vargo, L. J.; Appleton, S. N.

    2012-12-01

    Stationarity in growth response of trees to climate over time is assumed in dendroclimatic studies. Recent studies of Alaskan yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) have identified warming-induced early loss of insulating snowpack and frost damage as a mechanism that can lead to decline in tree growth, which for this species is documented over the last century. A similar stress may be put on temperature-sensitive mountain hemlock (Tsuga mertensiana (Bong.) Carrière) trees at low elevations, which in some cases show a decline in tree growth with warming temperatures. One of the challenges of using tree-ring based SAT, SST, PDO and PNA-related reconstructions for southern coastal Alaska has been understanding the response of tree-ring chronologies to the warming temperatures over the past 50 years. Comparisons of tree growth with long meteorological records from Sitka Alaska that extend back to 1830 suggest many mountain hemlock sites at low elevations are showing decreasing ring-widths, at mid elevations most sites show a steady increasing growth tracking warming, and at treeline a release is documented. The recognition of this recent divergence or decoupling of tree-ring and temperature trends allows for divergence-free temperature reconstructions using trees from moderate elevations. These reconstructions now provide a better perspective for comparing recent warming to Medieval warming and a better understanding of forest dynamics as biomes shift in response to the transition from the Little Ice Age to contemporary warming. Reconstructed temperatures are consistent with well-established, entirely independent tree-ring dated ice advances of land-terminating glaciers along the Gulf of Alaska providing an additional check for stationarity in the reconstructed interval.

  16. Interactions of Carbon Gain and Nitrogen Addition in a Temperate Forest

    NASA Astrophysics Data System (ADS)

    Bazzaz, F. A.

    2001-12-01

    In plants, carbon and nitrogen are intimately related. The plant gains carbon using nitrogen because it is a major constituent of both the light reaction (chlorophyll) and dark reaction (Rubisco and PEP carboxylase). The plant also gains more nitrogen by using carbon to grow roots that can forage for nitrogen, especially the less mobile (NH4+). Rising CO2 and increased nitrogen deposition are important elements of global change, both of which may affect ecosystem structure and function. They may cause a particularly large shift in species composition in systems where contrasting groups of species co-occur, e.g. evergreen coniferous and deciduous broad-leaved tree species. We studied the impact of nitrogen deposition in a mixed forest in central Massachusetts (Harvard Forest). We found that the early-successional broad-leaved species, yellow birch (Betula alleghaniensis) and red maple (Acer rubrum), both showed large increases in biomass, while the late successional species sugar maple (Acer saccharum) and all the coniferous species, hemlock (Tsuga canadensis), red spruce (Picea rubens) and white pine (Pinus strobus), only showed slight increases. As a result, when these species wre grown together, there was a decrease in species diversity. There was a significant correlation between species growth rate and the growth enhancement following nitrogen addition. We used SORTIE, a spatially explicit forest model to speculate about the future of this community. In both hemlock and red oak stands, nitrogen deposition led to shift in forest composition towards further dominance of young forests by yellow birch. We conclude that seedling physiological and demographic responses to increased nitrogen availability will scale up to exaggerate successional dynamics in mixed temperate forests in the future

  17. Dendroclimatic estimates of a drought index for northern Virginia

    USGS Publications Warehouse

    Puckett, Larry J.

    1981-01-01

    A 230-year record of the Palmer drought-severity index (PDSI) was estimated for northern Virginia from variations in widths of tree rings. Increment cores were extracted from eastern hemlock, Tsuga canadensis (L.) Carr., at three locations in northern Virginia. Measurements of annual growth increments were made and converted to standardized indices of growth. A response function was derived for hemlock to determine the growth-climate relationship. Growth was positively correlated with precipitation and negatively correlated with temperature during the May-July growing season. Combined standardized indices of growth were calibrated with the July PDSI. Growth accounted for 20-30 percent of the PDSI variance. Further regressions using factor scores of combined tree growth indices resulted in a small but significant improvement. Greatest improvement was made by using factor scores of growth indices of individual trees, thereby accounting for 64 percent of the July PDSI variance in the regression. Comparison of the results with a 241-year reconstruction from New York showed good agreement between low-frequency climatic trends. Analysis of the estimated Central Mountain climatic division of Virginia PDSI record indicated that, relative to the long-term record (1746-1975), dry years have occurred in disproportionally larger numbers during the last half of the 19th century and the mid-20th century. This trend appears reversed for the last half of the 18th century and the first half of the 19th century. Although these results are considered first-generation products, they are encouraging, suggesting that once additional tree-ring chronologies are constructed and techniques are refined, it will be possible to obtain more accurate estimates of prior climatic conditions in the mid-Atlantic region.

  18. Sap flux-upscaled canopy transpiration, stomatal conductance, and water use efficiency in an old growth forest in the Great Lakes region of the United States

    NASA Astrophysics Data System (ADS)

    Tang, Jianwu; Bolstad, Paul V.; Ewers, Brent E.; Desai, Ankur R.; Davis, Kenneth J.; Carey, Eileen V.

    2006-06-01

    Combining sap flux and eddy covariance measurements provides a means to study plant stomatal conductance and the relationship between transpiration and photosynthesis. We measured sap flux using Granier-type sensors in a northern hardwood-dominated old growth forest in Michigan, upscaled to canopy transpiration, and calculated canopy conductance. We also measured carbon and water fluxes with the eddy covariance method and derived daytime gross primary production (GPP). The diurnal patterns of sap flux and canopy transpiration were mainly controlled by vapor pressure deficit (D) and photosynthetically active radiation (PAR). Daily sums of sap flux and canopy transpiration had exponential relationships to D that saturated at higher D and had linear relationships to PAR. Sugar maple (Acer saccharum) and yellow birch (Betula alleghaniesis) had higher sap flux per unit of sapwood area than eastern hemlock (Tsuga canadensis), while sugar maple and hemlock had higher canopy transpiration per unit of leaf area than yellow birch. Sugar maple dominated canopy transpiration per ground area. Canopy transpiration averaged 1.57 mm d-1, accounting for 65% of total evapotranspiration in the growing season. Canopy conductance was controlled by both D and PAR, but the day-to-day variation in canopy conductance mainly followed a negatively logarithmic relationship with D. By removing the influences of PAR, half-hourly canopy conductance was also negatively logarithmically correlated with D. Water use efficiency (WUE) had a strong exponential relationship with D on a daily basis and approached a minimum of 4.4 mg g-1. WUE provides an alternative to estimate GPP from measurements of sap flux.

  19. Bryophyte species associations with coarse woody debris and stand ages in Oregon

    USGS Publications Warehouse

    Rambo, T.; Muir, Patricia S.

    1998-01-01

    We quantified the relationships of 93 forest floor bryophyte species, including epiphytes from incorporated litterfall, to substrate and stand age in Pseudotsuga menziesii-Tsuga heterophylla stands at two sites in western Oregon. We used the method of Dufr??ne and Legendre that combines a species' relative abundance and relative frequency, to calculate that species' importance in relation to environmental variables. The resulting 'indicator value' describes a species' reliability for indicating the given environmental parameter. Thirty-nine species were indicative of either humus, a decay class of coarse woody debris, or stand age. Bryophyte community composition changed along the continuum of coarse woody debris decomposition from recently fallen trees with intact bark to forest floor humus. Richness of forest floor bryophytes will be enhanced when a full range of coarse woody debris decay classes is present. A suite of bryophytes indicated old-growth forest. These were mainly either epiphytes associated with older conifers or liverworts associated with coarse woody debris. Hardwood-associated epiphytes mainly indicated young stands. Mature conifers, hardwoods, and coarse woody debris are biological legacies that can be protected when thinning managed stands to foster habitat complexity and biodiversity, consistent with an ecosystem approach to forest management.

  20. Large wood recruitment and redistribution in headwater streams in the southern Oregon Coast Range, U.S.A

    USGS Publications Warehouse

    May, Christine L.; Gresswell, Robert E.

    2003-01-01

    Large wood recruitment and redistribution mechanisms were investigated in a 3.9 km2 basin with an old-growth Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. forest, located in the southern Coast Range of Oregon. Stream size and topographic setting strongly influenced processes that delivered wood to the channel network. In small colluvial channels draining steep hillslopes, processes associated with slope instability dominated large wood recruitment. In the larger alluvial channel, windthrow was the dominant recruitment process from the local riparian area. Consequently, colluvial channels received wood from further upslope than the alluvial channel. Input and redistribution processes influenced piece location relative to the direction of flow and thus, affected the functional role of wood. Wood recruited directly from local hillslopes and riparian areas was typically positioned adjacent to the channel or spanned its full width, and trapped sediment and wood in transport. In contrast, wood that had been fluvially redistributed was commonly located in mid-channel positions and was associated with scouring of the streambed and banks. Debris flows were a unique mechanism for creating large accumulations of wood in small streams that lacked the capacity for abundant fluvial transport of wood, and for transporting wood that was longer than the bank-full width of the channel.

  1. Evidence for millennial-scale climate change during marine isotope stages 2 and 3 at Little Lake, Western Oregon, U.S.A.

    USGS Publications Warehouse

    Grigg, L.D.; Whitlock, C.; Dean, W.E.

    2001-01-01

    Pollen and geochemical data from Little Lake, western Oregon, suggest several patterns of millennial-scale environmental change during marine isotope stage (MIS) 2 (14,100-27,600 cal yr B.P.) and the latter part of MIS 3 (27,600-42,500 cal yr B.P.). During MIS 3, a series of transitions between warm- and cold-adapted taxa indicate that temperatures oscillated by ca. 2??-4??C every 1000-3000 yr. Highs and lows in summer insolation during MIS 3 are generally associated with the warmest and coldest intervals. Warm periods at Little Lake correlate with warm sea-surface temperatures in the Santa Barbara Basin. Changes in the strength of the subtropical high and the jet stream may account for synchronous changes at the two sites. During MIS 2, shifts between mesic and xeric subalpine forests suggest changes in precipitation every 1000-3000 yr. Increases in Tsuga heterophylla pollen at 25,000 and 22,000 cal yr B.P. imply brief warmings. Minimum summer insolation and maximum global ice-volumes during MIS 2 correspond to cold and dry conditions. Fluctuations in precipitation at Little Lake do not correlate with changes in the Santa Barbara Basin and may be explained by variations in the strength of the glacial anticyclone and the position of the jet stream. ?? 2001 University of Washington.

  2. 76 FR 63281 - Foreign-Trade Zone 78-Nashville, TN, Application for Subzone, Hemlock Semiconductor, L.L.C...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-12

    ... manufacturing and distribution of polysilicon, silicon tetrachloride, trichlorosilane, dichlorosilane, hydrogen... value of the finished product) include: silicon metal, silicon tetrachloride, trichlorosilanes and... prohibiting the admission of foreign status silicon metal subject to an antidumping or countervailing...

  3. The non-competitive blockade of GABAA receptors by an aqueous extract of water hemlock (Cicuta douglassi) tubers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Teratogenic alkaloids can cause developmental defects due to the inhibition of fetal movement from the desensitization of fetal muscle-type nicotinic acetylcholine receptors (nAChR). In this study, we tested the hypothesis that the piperidine alkaloid anabaseine a 1,2-dehydropiperidine and anabasin...

  4. Quantifying canopy complexity and effects on productivity and resilience in late-successional hemlock-hardwood forests.

    PubMed

    Fahey, Robert T; Fotis, Alexander T; Woods, Kerry D

    2015-04-01

    The regrowing forests of eastern North America have been an important global C sink over the past 100+ years, but many are now transitioning into late succession. The consequences of this transition are unclear due to uncertainty around the C dynamics of old- growth forests. Canopy structural complexity (CSC) has been shown to be an important source of variability in C dynamics in younger forests (e.g., in productivity and resilience to disturbance), but its role in late-successional forests has not been widely addressed. We investigated patterns of CSC in two old-growth forest landscapes in the Upper Peninsula of Michigan, USA, to assess factors associated with CSC and its influence on productivity and disturbance resilience (to moderate-severity windstorm). CSC was quantified using a portable below-canopy LiDAR (PCL) system in 65 plots that also had long-term (50-70+ years). inventory data, which were used to quantify aboveground net primary productivity (ANPP), disturbance history, and stand characteristics. We found high and variable CSC relative to younger forests across a suite of PCL-derived metrics. Variation in CSC was driven by species composition and size structure, rather than disturbance history or site characteristics. Recent moderate severity wind disturbance decreased plot-scale CSC, but increased stand-scale variation in CSC. The strong positive correlation between CSC and productivity illustrated in younger forests was not present in undisturbed portions of these late-successional ecosystems. Moderate severity disturbance appeared to reestablish the positive link between CSC and productivity, but this relationship was scale and severity dependent. A positive CSC-productivity relationship was evident at the plot scale with low-severity, dispersed disturbance, but only at a patch scale in more severely disturbed areas. CSC does not appear to strongly correlate With variation in productivity in undisturbed old-growth forests, but may play a very important (and scale/severity-dependent) role in their response to disturbance. Understanding potential, drivers and consequences of CSC in late-successional forests will inform management focused on promoting complexity and old-growth conditions, and illustrate potential inipacts of such treatments on regional C dynamics.

  5. SPECIES-SPECIFIC PARTITIONING OF SOIL WATER RESOURCES IN AN OLD-GROWTH DOUGLAS-FIR/WESTERN HEMLOCK FOREST

    EPA Science Inventory

    Although tree- and stand-level estimates of forest water use are increasingly common, relatively little is known about partitioning of soil water resources among co-occurring tree species. We studied seasonal courses of soil water utilization in a 450-year-old Pseudotsuga menzies...

  6. Role of Nurse Logs in Forest Expansion at Timberline

    NASA Astrophysics Data System (ADS)

    Johnson, A. C.; Yeakley, A.

    2008-12-01

    Nurselogs, known to be key sites of forest regeneration in lower elevation temperate forests, may be important sites for seedling establishment at expanding timberline forests. To determine factors associated with seedling establishment and survival on nurselogs at timberline, fourteen sites, located across a precipitation gradient in the Washington North Cascades Mountains, were examined. Site attributes including seedling type and height, disturbance process introducing downed wood, wood decay type, shading, slope gradient, aspect, and temperature and water content of wood and adjacent soil were determined along 60 m long transects. Nurselogs were found at 13 out of 14 sites; sites typically associated with greater than 80% shade and downed wood having a high level of wood decay. Downed wood serving as nurselogs originated from blowdown, snow avalanches, and forest fires. In total, 46 of 136 downed wood pieces observed served as nurselogs. Seedlings on nurselogs included mountain hemlock (Tsuga mertensiana), Pacific silver fir (Abies amabilis), yellow cedar (Chamaecyparis nootkatensis), subalpine fir (Abies lasiocarpa), Engelmann spruce (Picea engelmannii), and western larch (Larix occidentalis). Nurselogs had significantly higher temperatures (p = 0.015) and higher moisture contents (p = 0.019) than the adjacent soil. Per equal volumes weighed, nurselogs had on average of 23.8 g more water than the adjacent soil. Given predictions of climate warming and associated summer drought conditions in Pacific Northwest forests, the moisture provided by nurselogs may be integral for conifer survival and subsequent timberline expansion in some landscapes.

  7. Patterns and Impacts of millennial-scale hydroclimatic change in North American during the Holocene

    NASA Astrophysics Data System (ADS)

    Shuman, B. N.

    2012-12-01

    A new database of >100 lake-level reconstructions spanning the Holocene from the United States and Canada reveals that long-term patterns of hydroclimatic change in the mid-latitudes were punctuated by a series of abrupt events, particularly at ca. 8 and 5.5 ka. New detailed reconstructions from the Rocky Mountains and the northeast U.S. show that the abrupt changes produced important changes in the gradient of moisture availability across the continent with the mid-continent drying and the Atlantic coast becoming wet at ca 8 ka, and then a reversal of this pattern at 5.5 ka. Both changes are associated with important abrupt changes in North American vegetation, including abrupt shifts in the boundaries of the Great Plains grasslands and including the classic collapse of eastern hemlock (Tsuga) species. Regression analyses indicate that the area of the Laurentide Ice Sheet and Atlantic sea surface temperatures drove the abrupt changes. Archeological data also reveal societal importance of the hydroclimatic changes, which included probably severe reductions in mid-continent river flows.

  8. Acid rain, air pollution, and tree growth in southeastern New York

    USGS Publications Warehouse

    Puckett, L.J.

    1982-01-01

    Whether dendroecological analyses could be used to detect changes in the relationship of tree growth to climate that might have resulted from chronic exposure to components of the acid rain-air pollution complex was determined. Tree-ring indices of white pine (Pinus strobus L.), eastern hemlock (Tsuga canadensis (L.) Cart.), pitch pine (Pinus rigida Mill.), and chestnut oak (Quercus prinus L.) were regressed against orthogonally transformed values of temperature and precipitation in order to derive a response-function relationship. Results of the regression analyses for three time periods, 1901–1920, 1926–1945, and 1954–1973 suggest that the relationship of tree growth to climate has been altered. Statistical tests of the temperature and precipitation data suggest that this change was nonclimatic. Temporally, the shift in growth response appears to correspond with the suspected increase in acid rain and air pollution in the Shawangunk Mountain area of southeastern New York in the early 1950's. This change could be the result of physiological stress induced by components of the acid rain-air pollution complex, causing climatic conditions to be more limiting to tree growth.

  9. Acid rain, air pollution, and tree growth in southeastern New York

    SciTech Connect

    Puckett, L.J.

    1982-07-01

    Whether dendroecological analyses could be used to detect changes in the relationship of tree growth to climate that might have resulted from chronic exposure to components of the acid rain-air pollution complex was determined. Tree-ring indices of white pine (Pinus strobus L.), eastern hemlock (Tsuga canadensis (L.) Carr.), pitch pine (Pinus rigida Mill.), and chestnut oak (Quercus prinus L.) were regressed against orthogonally transformed values of temperature and precipitation in order to derive a response-function relationship. Results of the regression analyses for three time periods, 1901-1920, 1926-1945, and 1954-1973 suggest that the relationship of tree growth to climate has been altered. Statistical tests of the temperature and precipitation data suggest that this change was nonclimatic. Temporally, the shift in growth response appears to correspond with the suspected increase in acid rain and air pollution in the Shawangunk Mountain area of southeastern New York in the early 1950's. This change could be the result of physiological stress induced by components of the acid rain-air pollution complex, causing climatic conditions to be more limiting to tree growth.

  10. Relationships among environmental variables and distribution of tree species at high elevation in the Olympic Mountains

    USGS Publications Warehouse

    Woodward, Andrea

    1998-01-01

    Relationships among environmental variables and occurrence of tree species were investigated at Hurricane Ridge in Olympic National Park, Washington, USA. A transect consisting of three plots was established down one north-and one south-facing slope in stands representing the typical elevational sequence of tree species. Tree species included subalpine fir (Abies lasiocarpa), Douglas-fir (Pseudotsuga menziesii), mountain hemlock (Tsuga mertensiana), and Pacific silver fir (Abies amabilis). Air and soil temperature, precipitation, and soil moisture were measured during three growing seasons. Snowmelt patterns, soil carbon and moisture release curves were also determined. The plots represented a wide range in soil water potential, a major determinant of tree species distribution (range of minimum values = -1.1 to -8.0 MPa for Pacific silver fir and Douglas-fir plots, respectively). Precipitation intercepted at plots depended on topographic location, storm direction and storm type. Differences in soil moisture among plots was related to soil properties, while annual differences at each plot were most often related to early season precipitation. Changes in climate due to a doubling of atmospheric CO2 will likely shift tree species distributions within, but not among aspects. Change will be buffered by innate tolerance of adult trees and the inertia of soil properties.

  11. Detecting long-term hydrological patterns at Crater Lake, Oregon

    USGS Publications Warehouse

    Peterson, D.L.; Silsbee, D.G.; Redmond, Kelly T.

    1999-01-01

    Tree-ring chronologies for mountain hemlock (Tsuga mertensiana) were used to reconstruct the water level of Crater Lake, a high-elevation lake in the southern Cascade Range of Oregon. Reconstructions indicate that lake level since the late 1980s has been lower than at any point in the last 300 years except the early 1930s to mid 1940s. Lake level was consistently higher during the Little Ice Age than during the late 20th century; during the late 17th century, lake level was up to 9 m higher than recent (1980s and 1990s) low levels, which is consistent with paleoclimalic reconstructions of regional precipitation and atmospheric pressure. Furthermore, instrumental data available for the 20th century suggest that there are strong teleconnections among atmospheric circulation (e.g., Pacific Decadal Oscillation), tree growth, and hydrology in southern Oregon. Crater Lake is sensitive to interannual, interdecadal and intercentenary variation in precipitation and atmospheric circulation, and can be expected to track both short-term and longterm variation in regional climatic patterns that may occur in the future.

  12. Energetic considerations and habitat quality for elk in arid grasslands and coniferous forests

    SciTech Connect

    McCorquodale, S.M. )

    1991-04-01

    The author used static modeling to explore the recent success of elk (Cervus elaphus) colonizing the arid shrub-steppe of Washington. Forage-based estimates of metabolizable energy available to elk in the shrub-steppe were compared to energy available in 2 mesic forest communities that historically have served as more typical summer elk habitat. Although precipitation and primary productivity were substantially lower in the shrub-steppe, the estimated calories available in shrub-steppe forage over a 300-km{sup 2} area were 271 and 86%, respectively, of lodgepole pine (Pinus contorta) and cedar-hemlock (Thuja-Tsuga) forests of similar size. Low intercommunity variability in forage production, lack of a significant nonforage overstory, and the large size and relative abundance of foraging areas in the shrub-steppe mitigated reduced primary production. In the shrub-steppe, 92% of the habitat represented potential foraging habitat as determined by minimum forage biomass, whereas only 10 and 40% of the forested habitats, respectively, could be considered prime foraging areas. Whereas forage energy was concentrated in openings within conifer forests, it was more uniformly dispersed over the habitat mosaic in the shrub-steppe. These results provide a bioenergetic framework for understanding the recent success of elk colonizing the arid shrub-steppe of Washington and are consistent with observed patterns of movement and habitat use for elk in shrub-steppe habitat.

  13. Growth responses of subalpine fir to climatic variability in the Pacific Northwest

    USGS Publications Warehouse

    Peterson, D.W.; Peterson, D.L.; Ettl, Gregory J.

    2002-01-01

    We studied regional variation in growth-limiting factors and responses to climatic variability in subalpine forests by analyzing growth patterns for 28 tree-ring growth chronologies from subalpine fir (Abies lasiocarpa (Hook.) Nutt.) stands in the Cascade and Olympic Mountains (Washington and Oregon, U.S.A.). Factor analysis identified four distinct time series of common growth patterns; the dominant growth pattern at any site varied with annual precipitation and temperature (elevation). Throughout much of the region, growth is negatively correlated with winter precipitation and spring snowpack depth, indicating that growth is limited primarily by short growing seasons. On the driest and warmest sites, growth is negatively correlated with previous summer temperature, suggesting that low summer soil moisture limits growth. Growth patterns in two regions were sensitive to climatic variability associated with the Pacific Decadal Oscillation, apparently responding to low-frequency variation in spring snowpack and summer soil moisture (one negatively, one positively). This regional-scale analysis shows that subalpine fir growth in the Cascades and Olympics is limited by different climatic factors in different subregional climates. Climatea??growth relationships are similar to those for a co-occurring species, mountain hemlock (Tsuga mertensiana (Bong.) Carri??re), suggesting broad biogeographic patterns of response to climatic variability and change by subalpine forest ecosystems in the Pacific Northwest.

  14. Observations of summer roosting and foraging behavior of a hoary bat (Lasiurus cinereus) in southern New Hampshire.

    SciTech Connect

    Veillieux, J. P.; Moosman, P. R.; Reynolds, D. S.; LaGory, K. E.; Walston, L. J.; Environmental Science Division; Franklin Pierce Univ.; Fitchburg State Coll.; St. Paul's School

    2009-01-01

    Few data are available that describe the roosting and foraging ecology of the Hoary Bat (Lasiurus cinereus), and no such data are available for the northeastern United States. We captured a juvenile Hoary Bat in south-central New Hampshire during July of 2007 and monitored its roosting behavior for ten days and its foraging behavior for one night. The bat roosted with two other bats, which we presumed were its mother and sibling. These bats roosted exclusively in Tsuga canadensis (Eastern Hemlock Tree) and tended to roost near tree tops in the forest canopy. The radiotagged bat used at least six roost trees and changed roost location eight times during the ten-day observation period. Although roost-tree fidelity was low, all roost trees were located within a maximum circular area of 0.5 ha. The bat foraged over an estimated 156-ha area of mostly forest habitat (68%), with additional open habitats (15%) and wetlands (17%). These data are the first observations of roosting and foraging behaviors by the Hoary Bat in the northeastern region of its geographic range.

  15. Photosynthetic differences between saplings and adult trees: an integration of field results by meta-analysis.

    PubMed

    Thomas, Sean C; Winner, William E

    2002-02-01

    Ontogenetic changes in gas exchange parameters provide both insight into mechanisms underlying tree growth patterns, and data necessary to scale environmental impacts on young trees to predict responses of older trees. We present a quantitative review and meta-analysis of field measurements of gas exchange parameters in saplings and mature trees of 35 tree species (seven conifers, seven temperate deciduous trees, and 21 tropical evergreen trees). Data for saplings were obtained in both understory environments and open areas or large gaps. We also present data on ontogenetic changes in photosynthesis for Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg., species of particular interest because of their large maximal heights and long life-spans. Among tree species, there is evidence for both ontogenetic increases and ontogenetic decreases in photosynthetic capacity on a leaf area basis (A(area)). Overall, A(area) is generally higher for upper-canopy leaves of adult trees than for saplings, especially in temperate deciduous trees. However, the pattern for photosynthetic capacity on a leaf mass basis (A(mass)) is the reverse of that observed for A(area). Saplings of both conifers and broad-leaved trees, even when acclimated to low-light conditions, characteristically have a higher A(mass) than adult trees. This pattern is driven largely by an ontogenetic increase in leaf mass per unit area (LMA), as found in 100% of studies reviewed. Data for Pacific Northwest conifers, although including measurements on some of the tallest trees studied, did not differ greatly from patterns found in other tree species. We conclude that ontogenetic changes in LMA are the single most consistent difference between saplings and adult trees, and that changes in LMA and related aspects of leaf morphology may be critical to understanding both variation in gas exchange during tree growth, and stage-dependent responses of trees to environmental change.

  16. Effects of dams and geomorphic context on riparian forests of the Elwha River, Washington

    USGS Publications Warehouse

    Shafroth, Patrick B.; Perry, Laura G; Rose, Chanoane A; Braatne, Jeffrey H

    2016-01-01

    Understanding how dams affect the shifting habitat mosaic of river bottomlands is key for protecting the many ecological functions and related goods and services that riparian forests provide and for informing approaches to riparian ecosystem restoration. We examined the downstream effects of two large dams on patterns of forest composition, structure, and dynamics within different geomorphic contexts and compared them to upstream reference conditions along the Elwha River, Washington, USA. Patterns of riparian vegetation in river segments downstream of the dams were driven largely by channel and bottomland geomorphic responses to a dramatically reduced sediment supply. The river segment upstream of both dams was the most geomorphically dynamic, whereas the segment between the dams was the least dynamic due to substantial channel armoring, and the segment downstream of both dams was intermediate due to some local sediment supply. These geomorphic differences were linked to altered characteristics of the shifting habitat mosaic, including older forest age structure and fewer young Populus balsamifera subsp. trichocarpa stands in the relatively static segment between the dams compared to more extensive early-successional forests (dominated by Alnus rubra and Salix spp.) and pioneer seedling recruitment upstream of the dams. Species composition of later-successional forest communities varied among river segments as well, with greater Pseudotsuga menziesii and Tsuga heterophylla abundance upstream of both dams, Acer spp. abundance between the dams, and P. balsamifera subsp. trichocarpa and Thuja plicata abundance below both dams. Riparian forest responses to the recent removal of the two dams on the Elwha River will depend largely on channel and geomorphic adjustments to the release, transport, and deposition of the large volume of sediment formerly stored in the reservoirs, together with changes in large wood dynamics.

  17. AmeriFlux US-Bar Bartlett Experimental Forest

    DOE Data Explorer

    Richardson, Andrew [Harvard University

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Bar Bartlett Experimental Forest. Site Description - The Bartlett Experimental Forest (448170 N, 71830 W) is located within the White Mountains National Forest in north-central New Hampshire, USA. The 1050 ha forest extends across an elevational range from 200 to 900 m a.s.l. It was established in 1931 and is managed by the USDA Forest Service Northeastern Research Station in Durham, NH. The climate is humid continental with short, cool summers (mean July temperature, 19.8C) and long, cold winters (mean January temperature, 9.8C). Annual precipitation averages 130 cm and is distributed evenly throughout the year. Soils are developed from glacial till and are predominantly shallow, well-drained spodosols. At lowto mid-elevation, vegetation is dominated by northern hardwoods (American beech, Fagus grandifolia; sugar maple, Acer saccharum; yellow birch, Betula alleghaniensis; with some red maple, Acer rubrum and paper birch, Betula papyrifera). Conifers (eastern hemlock, Tsuga canadensis; eastern white pine, Pinus strobus; red spruce, Picea rubens) are occasionally found intermixed with the more abundant deciduous species but are generally confined to the highest (red spruce) and lowest (hemlock and pine) elevations. In 2003, the site was adopted as a NASA North American Carbon Program (NACP) Tier-2 field research and validation site. A 26.5 m high tower was installed in a low-elevation northern hardwood stand in November, 2003, for the purpose of making eddy covariance measurements of the forest–atmosphere exchange of CO2, H2O and radiant energy. Continuous flux and meteorological measurements began in January, 2004, and are ongoing. Average canopy height in the vicinity of the tower is approximately 20–22 m. In the tower footprint, the forest is predominantly classified into red maple, sugar maple, and American beech forest types. Leaf area index in the vicinity of the tower is 3.6 as measured

  18. Fruiting body and soil rDNA sampling detects complementary assemblage of Agaricomycotina (Basidiomycota, Fungi) in a hemlock-dominated forest plot in southern Ontario.

    PubMed

    Porter, Teresita M; Skillman, Jane E; Moncalvo, Jean-Marc

    2008-07-01

    This is the first study to assess the diversity and community structure of the Agaricomycotina in an ectotrophic forest using above-ground fruiting body surveys as well as soil rDNA sampling. We recovered 132 molecular operational taxonomic units, or 'species', from fruiting bodies and 66 from soil, with little overlap. Fruiting body sampling primarily recovered fungi from the Agaricales, Russulales, Boletales and Cantharellales. Many of these species are ectomycorrhizal and form large fruiting bodies. Soil rDNA sampling recovered fungi from these groups in addition to taxa overlooked during the fruiting body survey from the Atheliales, Trechisporales and Sebacinales. Species from these groups form inconspicuous, resupinate and corticioid fruiting bodies. Soil sampling also detected fungi from the Hysterangiales that form fruiting bodies underground. Generally, fruiting body and soil rDNA samples recover a largely different assemblage of fungi at the species level; however, both methods identify the same dominant fungi at the genus-order level and ectomycorrhizal fungi as the prevailing type. Richness, abundance, and phylogenetic diversity (PD) identify the Agaricales as the dominant fungal group above- and below-ground; however, we find that molecularly highly divergent lineages may account for a greater proportion of total diversity using the PD measure compared with richness and abundance. Unless an exhaustive inventory is required, the rapidity and versatility of DNA-based sampling may be sufficient for a first assessment of the dominant taxonomic and ecological groups of fungi in forest soil.

  19. Dendrogeomorphic Assessment of the Rattlesnake Gulf Landslide in the Tully Valley, Onondaga County, New York

    USGS Publications Warehouse

    Tamulonis, Kathryn L.; Kappel, William M.

    2009-01-01

    Dendrogeomorphic techniques were used to assess soil movement within the Rattlesnake Gulf landslide in the Tully Valley of central New York during the last century. This landslide is a postglacial, slow-moving earth slide that covers 23 acres and consists primarily of rotated, laminated, glaciolacustrine silt and clay. Sixty-two increment cores were obtained from 30 hemlock (Tsuga canadensis) trees across the active part of the landslide and from 3 control sites to interpret the soil-displacement history. Annual growth rings were measured and reaction wood was identified to indicate years in which ring growth changed from concentric to eccentric, on the premise that soil movement triggered compensatory growth in displaced trees. These data provided a basis for an 'event index' to identify years of landslide activity over the 108 years of record represented by the oldest trees. Event-index values and total annual precipitation increased during this time, but years with sudden event-index increases did not necessarily correspond to years with above-average precipitation. Multiple-regression and residual-values analyses indicated a possible correlation between precipitation and movement within the landslide and a possible cyclic (decades-long) tree-ring response to displacement within the landslide area from the toe upward to, and possibly beyond, previously formed landslide features. The soil movement is triggered by a sequence of factors that include (1) periods of several months with below-average precipitation followed by persistent above-average precipitation, (2) the attendant increase in streamflow, which erodes the landslide toe and results in an upslope propagation of slumping, and (3) the harvesting of mature trees within this landslide during the last century and continuing to the present.

  20. Incorporating interspecific competition into species-distribution mapping by upward scaling of small-scale model projections to the landscape

    PubMed Central

    2017-01-01

    There are a number of overarching questions and debate in the scientific community concerning the importance of biotic interactions in species distribution models at large spatial scales. In this paper, we present a framework for revising the potential distribution of tree species native to the Western Ecoregion of Nova Scotia, Canada, by integrating the long-term effects of interspecific competition into an existing abiotic-factor-based definition of potential species distribution (PSD). The PSD model is developed by combining spatially explicit data of individualistic species’ response to normalized incident photosynthetically active radiation, soil water content, and growing degree days. A revised PSD model adds biomass output simulated over a 100-year timeframe with a robust forest gap model and scaled up to the landscape using a forestland classification technique. To demonstrate the method, we applied the calculation to the natural range of 16 target tree species as found in 1,240 provincial forest-inventory plots. The revised PSD model, with the long-term effects of interspecific competition accounted for, predicted that eastern hemlock (Tsuga canadensis), American beech (Fagus grandifolia), white birch (Betula papyrifera), red oak (Quercus rubra), sugar maple (Acer saccharum), and trembling aspen (Populus tremuloides) would experience a significant decline in their original distribution compared with balsam fir (Abies balsamea), black spruce (Picea mariana), red spruce (Picea rubens), red maple (Acer rubrum L.), and yellow birch (Betula alleghaniensis). True model accuracy improved from 64.2% with original PSD evaluations to 81.7% with revised PSD. Kappa statistics slightly increased from 0.26 (fair) to 0.41 (moderate) for original and revised PSDs, respectively. PMID:28207782

  1. Incorporating interspecific competition into species-distribution mapping by upward scaling of small-scale model projections to the landscape.

    PubMed

    Baah-Acheamfour, Mark; Bourque, Charles P-A; Meng, Fan-Rui; Swift, D Edwin

    2017-01-01

    There are a number of overarching questions and debate in the scientific community concerning the importance of biotic interactions in species distribution models at large spatial scales. In this paper, we present a framework for revising the potential distribution of tree species native to the Western Ecoregion of Nova Scotia, Canada, by integrating the long-term effects of interspecific competition into an existing abiotic-factor-based definition of potential species distribution (PSD). The PSD model is developed by combining spatially explicit data of individualistic species' response to normalized incident photosynthetically active radiation, soil water content, and growing degree days. A revised PSD model adds biomass output simulated over a 100-year timeframe with a robust forest gap model and scaled up to the landscape using a forestland classification technique. To demonstrate the method, we applied the calculation to the natural range of 16 target tree species as found in 1,240 provincial forest-inventory plots. The revised PSD model, with the long-term effects of interspecific competition accounted for, predicted that eastern hemlock (Tsuga canadensis), American beech (Fagus grandifolia), white birch (Betula papyrifera), red oak (Quercus rubra), sugar maple (Acer saccharum), and trembling aspen (Populus tremuloides) would experience a significant decline in their original distribution compared with balsam fir (Abies balsamea), black spruce (Picea mariana), red spruce (Picea rubens), red maple (Acer rubrum L.), and yellow birch (Betula alleghaniensis). True model accuracy improved from 64.2% with original PSD evaluations to 81.7% with revised PSD. Kappa statistics slightly increased from 0.26 (fair) to 0.41 (moderate) for original and revised PSDs, respectively.

  2. Calibrating abundance indices with population size estimators of red back salamanders (Plethodon cinereus) in a New England forest

    PubMed Central

    Ellison, Aaron M.; Jackson, Scott

    2015-01-01

    Herpetologists and conservation biologists frequently use convenient and cost-effective, but less accurate, abundance indices (e.g., number of individuals collected under artificial cover boards or during natural objects surveys) in lieu of more accurate, but costly and destructive, population size estimators to detect and monitor size, state, and trends of amphibian populations. Although there are advantages and disadvantages to each approach, reliable use of abundance indices requires that they be calibrated with accurate population estimators. Such calibrations, however, are rare. The red back salamander, Plethodon cinereus, is an ecologically useful indicator species of forest dynamics, and accurate calibration of indices of salamander abundance could increase the reliability of abundance indices used in monitoring programs. We calibrated abundance indices derived from surveys of P. cinereus under artificial cover boards or natural objects with a more accurate estimator of their population size in a New England forest. Average densities/m2 and capture probabilities of P. cinereus under natural objects or cover boards in independent, replicate sites at the Harvard Forest (Petersham, Massachusetts, USA) were similar in stands dominated by Tsuga canadensis (eastern hemlock) and deciduous hardwood species (predominantly Quercus rubra [red oak] and Acer rubrum [red maple]). The abundance index based on salamanders surveyed under natural objects was significantly associated with density estimates of P. cinereus derived from depletion (removal) surveys, but underestimated true density by 50%. In contrast, the abundance index based on cover-board surveys overestimated true density by a factor of 8 and the association between the cover-board index and the density estimates was not statistically significant. We conclude that when calibrated and used appropriately, some abundance indices may provide cost-effective and reliable measures of P. cinereus abundance that could

  3. Calibrating abundance indices with population size estimators of red back salamanders (Plethodon cinereus) in a New England forest.

    PubMed

    Siddig, Ahmed A; Ellison, Aaron M; Jackson, Scott

    2015-01-01

    Herpetologists and conservation biologists frequently use convenient and cost-effective, but less accurate, abundance indices (e.g., number of individuals collected under artificial cover boards or during natural objects surveys) in lieu of more accurate, but costly and destructive, population size estimators to detect and monitor size, state, and trends of amphibian populations. Although there are advantages and disadvantages to each approach, reliable use of abundance indices requires that they be calibrated with accurate population estimators. Such calibrations, however, are rare. The red back salamander, Plethodon cinereus, is an ecologically useful indicator species of forest dynamics, and accurate calibration of indices of salamander abundance could increase the reliability of abundance indices used in monitoring programs. We calibrated abundance indices derived from surveys of P. cinereus under artificial cover boards or natural objects with a more accurate estimator of their population size in a New England forest. Average densities/m(2) and capture probabilities of P. cinereus under natural objects or cover boards in independent, replicate sites at the Harvard Forest (Petersham, Massachusetts, USA) were similar in stands dominated by Tsuga canadensis (eastern hemlock) and deciduous hardwood species (predominantly Quercus rubra [red oak] and Acer rubrum [red maple]). The abundance index based on salamanders surveyed under natural objects was significantly associated with density estimates of P. cinereus derived from depletion (removal) surveys, but underestimated true density by 50%. In contrast, the abundance index based on cover-board surveys overestimated true density by a factor of 8 and the association between the cover-board index and the density estimates was not statistically significant. We conclude that when calibrated and used appropriately, some abundance indices may provide cost-effective and reliable measures of P. cinereus abundance that

  4. Forest responses to late Holocene climate change in north-central Wisconsin: a high- resolution study from Hell's Kitchen Lake.

    NASA Astrophysics Data System (ADS)

    Urban, M. A.; Booth, R. K.; Jackson, S. T.; Minckley, T. A.

    2007-12-01

    Forest dynamics at centennial to millennial timescales can be identified using paleoecological records with high spatial, temporal, and taxonomic resolution. These dynamics are linked to climate changes by comparing the paleoecological records with independent paleoclimate records of complementary sensitivity and temporal resolution. We analyzed plant macrofossils at contiguous 1cm intervals (representing 5 to 35 yr/cm) from late Holocene sediments of Hell's Kitchen Lake (3 ha) in north-central Wisconsin. Most of the plant macrofossils derive from trees growing on the slopes directly adjacent to the lake, and were identified to the species. We also analyzed pollen at an approximately100 year resolution to provide a regionally integrated record of forest composition. We then compared the macrofossil and pollen records with independent records of climate change in the region, particularly paleohydrological records from kettle bogs. The most notable feature of the late Holocene record occurs between 2300-2000 cal yr BP. During this period yellow birch (Betula alleghaniensis) macrofossils first appear in the record, along with a corresponding increase in pollen percentages. Hemlock (Tsuga canadensis) macrofossils and pollen also show a marked increase at this time. These changes coincide with a major transition towards wetter conditions recorded in the testate amoebae record of Hornet Bog (~200km northwest) and in a number of other kettle bog records from the region. Directly following this transition, tamarack (Larix laricina) and Sphagnum macrofossils at Hell's Kitchen Lake increase dramatically, likely representing the initiation of bog-mat growth along the southwest margin of the lake during the wet period. . We are continuing our high-resolution sampling downcore at Hell's Kitchen Lake. This will permit us to examine additional ecologic and climatic events in the early and mid-Holocene.

  5. Surface Soil Carbon, Nitrogen and Tree Species are Tightly Linked in Northeastern USA Forested Watersheds

    NASA Astrophysics Data System (ADS)

    Ross, D. S.; Juillerat, J.

    2008-12-01

    We measured C and N ratios in 608 surface soil horizons (primarily Oa) from ten small watersheds at seven established research sites in the northeastern USA. The dominant tree species included sugar maple (Acer saccharum), yellow birch (Betula alleghaniensis), American beech (Fagus grandifolia), red spruce (Picea rubens) and eastern hemlock (Tsuga canadensis). In the soil, both the C (50-530 g/kg) and C/N ratio (11.6- 45.3) had a wide distribution. In all but the Cone Pond watershed, both N concentration and the C/N ratio were positively and linearly related to C content. For these nine watersheds, the average N (g/kg) = 6.9 + 0.030 X C (g/kg), R2 = 0.97. The C/N ratios at Cone were much higher than would be predicted from the other data and charcoal was found in numerous samples, suggesting a source of recalcitrant C. Across all watersheds, C concentration was also positively correlated with forest floor depth (and therefore C pools). Although sugar maple dominance was negatively correlated with C/N ratio and C, better relationships were obtained by combining species. Carbon concentration of the humified surface horizon was negatively related to maple + birch dominance and positively related to conifer + beech dominance. Among nine of these ten watersheds, the average C concentration in the surface soil varied (187-441 g/kg) with a constant C/N ratio of 33. The remarkably tight relationships between C, N, and species suggest predicable patterns in C accumulation.

  6. Plant and Soil Natural Abundance delta-15N: Indicators of Nitrogen Cycling in the Catskill Mountains, New York, USA

    NASA Astrophysics Data System (ADS)

    Templer, P. H.; Lovett, G. M.; Weathers, K.; Arthur, M. A.

    2002-12-01

    We examined the potential use of natural abundance 15N of plants and soils as an indicator of forest nitrogen (N) cycling rates within the Catskill Mountains, NY. These watersheds receive among the highest rates of N deposition in the northeastern United States and are beginning to show signs of N saturation. Many studies have shown a link between increased N cycling rates and 15N enrichment of soil and plant pools. Faster rates of N cycling processes, especially nitrification, lead to fractionation of 14/15N, creating N products that are relatively depleted in 15N. This can lead to enrichment of soil pools, as lighter 14N is lost from the system via leaching or denitrification. Plant N pools can become increasingly enriched as they take up 15N-enriched soil N. Despite similar amounts of N deposition across the Catskill Mountains, forests dominated by different tree species appear to vary in the amount of N retained or lost to nearby streams. To determine if plant and soil 15N could be used as indicators of N cycling rates, we collected foliage, wood, litterfall, organic and mineral soil, and fine roots from single species stands of American beech (Fagus grandifolia), eastern hemlock (Tsuga canadensis), red oak (Quercus rubra), and sugar maple (Acer saccharum). Fine roots and soil 15N were highest within sugar maple stands (p<0.05). Sugar maple soils also had the highest rates of net nitrification and N leaching. Therefore, soil 15N appears to correlate with forest N retention and loss. However, 15N enrichment was highest within foliage, litterfall and wood of beech trees (p<0.05). The decoupling between foliage 15N and N cycling, as well as between 15N of foliage and fine roots, illustrates that it may not be possible to use a single plant pool as an indicator of N cycling rates.

  7. Element accumulation patterns of deciduous and evergreen tree seedlings on acid soils: implications for sensitivity to manganese toxicity.

    PubMed

    St Clair, Samuel B; Lynch, Jonathan P

    2005-01-01

    Foliar nutrient imbalances, including the hyperaccumulation of manganese (Mn), are correlated with symptoms of declining health in sensitive tree species growing on acidic forest soils. The objectives of this study were to: (1) compare foliar nutrient accumulation patterns of six deciduous (sugar maple (Acer saccharum Marsh.), red maple (Acer rubrum L.), red oak (Quercus rubra L.), white oak (Quercus alba L.), black cherry (Prunus serotina Ehrh.) and white ash (Fraxinus americana L.)) and three evergreen (eastern hemlock (Tsuga canadensis L.), white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss.)) tree species growing on acidic forest soils; and (2) examine how leaf phenology and other traits that distinguish evergreen and deciduous tree species influence foliar Mn accumulation rates and sensitivity to excess Mn. For the first objective, leaf samples of seedlings from five acidic, non-glaciated field sites on Pennsylvania's Allegheny Plateau were collected and analyzed for leaf element concentrations. In a second study, we examined growth and photosynthetic responses of seedlings exposed to excess Mn in sand culture. In field samples, Mn in deciduous foliage hyperaccumulated to concentrations more than twice as high as those found in evergreen needles. Among species, sugar maple was the most sensitive to excess Mn based on growth and photosynthetic measurements. Photosynthesis in red maple and red oak was also sensitive to excess Mn, whereas white oak, black cherry, white ash and the three evergreen species were tolerant of excess Mn. Among the nine species, relative rates of photosynthesis were negatively correlated with foliar Mn concentrations, suggesting that photosynthetic sensitivity to Mn is a function of its rate of accumulation in seedling foliage.

  8. Past and Future Climate Change Impacts on Mountain Forests on the Olympic Peninsula (Washington, USA)

    NASA Astrophysics Data System (ADS)

    Schwörer, C.; Fisher, D. M.; Gavin, D. G.; Temperli, C.; Bartlein, P. J.

    2015-12-01

    Mountain forest composition and distribution is strongly affected by temperature and is expected to shift to higher elevations with climate change. However, warmer winters will also lead to an upward shift of the snowline and a decrease in snowpack at lower and intermediate elevations. In the mountain ranges of Western North America, snowpack plays an important role in providing additional moisture during the dry summer months. It is therefore unclear if the projected climate change will lead to a rise of subalpine forest due to a longer growing season or a contraction due to drought stress. Since forest succession processes take place over decades and centuries we use LandClim, a dynamic vegetation model, to assess the impact of climate change on mountain forests on the Olympic Peninsula (Washington, USA). As a reality check we first simulate vegetation dynamics since the last Ice Age and compare model output with paleobotanical data from five natural archives that span the topographic and climatic gradients on the Peninsula. LandClim produces realistic present-day species compositions with respect to elevation and precipitation gradients. Moreover, the simulations of forest dynamics for the last 16,000 years generally agree with the pollen and macrofossil data. We then simulated mountain forests under future climate projections. As a result, our model indicates drastic changes in species composition with a replacement of mountain hemlock (Tsuga mertensiana) by more drought-resistant species such as subalpine fir (Abies lasiocarpa). On the drier, eastern side of the Peninsula, the model even suggests a lowering of timberline due to insufficient moisture availability in shallow alpine soils. Our results have important implications for ecosystem managers and stress the urgency of climate change mitigation.

  9. Wood colors and their coloring matters: a review.

    PubMed

    Yazaki, Yoshikazu

    2015-03-01

    A number of colored specialty woods, such as ebony, rosewood, mahogany and amboyna, and commercially important woods, such as morus, logwood, Brazilwood, Japanese yellowwood, blackwood, kwila, red beech and myrtle beech, exhibit a wide range of colors from black, violet, dark red, reddish brown, to pale yellow. These colors are not only due to colored pigments contained in extractives from those woods but also to insoluble polymers. Wood and bark from many species of both hardwood and softwood trees contain many types of flavonoid compounds. Research on flavonoids has been conducted mainly from two points of view. The first is chemotaxonomy with flavonoid compounds as taxonomic markers, and the second relates to the utilization of woods for pulp and paper and the use of tannins from bark for wood adhesives. Most chemotaxonomic studies have been conducted on flavonoids in the extracts from softwoods such as Podocarpus, Pinus, Pseudotsuga, Larix, Taxus, Libocedrus, Tsuja, Taxodium, Sequoia, Cedrus, Tsuga, Abies and Picea. Hardwood chemotaxonomic studies include those on Prunus and Eucalyptus species. Studies on flavonoids in pulp and paper production were conducted on Eucalyptus woods in Australia and woods from Douglas fir in the USA and larch in Japan. Flavonoids as tannin resources from black wattle tannin and quebracho tannin have been used commercially as wood adhesives. Flavonoids in the bark from radiata pine and southern pine, from western and eastern hemlock, southern red oak and Quercus dentata are also discussed. In addition, the distribution of flavonoids among tree species is described, as is the first isolation of rare procyanidin glycosides in nature.

  10. Understory vegetation in old and young Douglas-fir forests of western Oregon

    USGS Publications Warehouse

    Bailey, J.D.; Mayrsohn, C.; Doescher, P.S.; St., Pierre; Tappeiner, J.C.

    1998-01-01

    We studied understory composition in thinned and unthinned Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)/western hemlock (Tsuga heterophylIa (Raf.) Sarg.) stands on 28 sites in western Oregon. These stands had regenerated naturally after timber harvest, 40-70 years before thinning. Commercial thinning had occurred 10-24 years previously, with 8-60% of the volume removed from below with the intent to homogenize spacing among trees. Undisturbed old-growth Douglas-fir stands were present for comparison on 18 of these sites. Total herbaceous cover was greater in thinned 1125% cover) stands than in unthinned (13% cover) or old-growth (15% cover) stands. Species richness was also greater in thinned (137) than in unthinned (114) and old-growth (91) stands (P=0.05). Part of the increased richness was caused by the presence of exotic species in thinned stands, but there were also more native grass and nitrogen-fixing species in thinned stands than in unthinned or oldgrowth stands. Groups of species differed among stand-types. For example, the frequency of tall cordate-leaved species was greater in old-growth stands (P=O.009), but their relative cover was different only between old-growth and unthinned stands (P=0.08). Both the cover and frequency of grasses and sedges in thinned stands were greater than in unthinned or old-growth stands (P<0.002). Ordination of shrub cover showed differences among old-growth and unthinned stands compared to thinned stands, mainly because of the amount of Gaultheria shallon Pursh and Polystichum munitum (Kaulf.) Presl in heavily thinned stands. Ordination of herbaceous community data showed that there were much stronger differences among sites than among stand-types. The lack of difference among stand-types demonstrates the resiliency of herbaceous communities to disturbance associated with past and current forest management.

  11. Effects of forest die-off on hydrologic processes in southern Appalachian forests

    NASA Astrophysics Data System (ADS)

    Vose, J.; Ford, C. R.

    2011-12-01

    Forests in the southern Appalachian region of the eastern U.S. have been impacted by numerous disturbances over the past century. Many of these disturbances have resulted in non-random species losses. For example, in the early 1900s, American chestnut (Castenea dentata) was decimated by the chestnut blight. Severe droughts in the 1980s and 1990s resulted in significant southern pine beetle (Dendroctonus frontalis, SPB) outbreaks; and, most of the native pines (Pinus rigida) were killed. These same droughts resulted in a pulse of mortality of older red oaks and extensive SPB infestation of white pine (Pinus strobus) plantations. In the 2000s, the introduction of the hemlock woolly adelgid (HWA) resulted in widespread mortality of eastern hemlock (Tsuga canadensis). Linking hydrologic responses to partial or complete changes in forest conditions due to die-off is especially challenging in the eastern U.S. because high vegetation diversity and substantial differences in tree-level water use makes it difficult to generalize or predict responses. Gauged watersheds and sapflow monitoring across multiple tree species at the Coweeta Hydrologic Laboratory in western NC provides a unique opportunity to quantify the impacts of large-scale forest die-off on hydrologic processes. Here, we provide three examples of our efforts to quantify and predict impacts. First, we analyzed long-term streamflow data from WS17, a 53 year old white pine plantation, where approximately 15% of the watershed was killed by SPB in the late 1990s. Second, we examined the effects of losing an individual species (i.e., loss of eastern hemlock from HWA) using sapflow, long-term permanent plot data, and models to scale from the individual tree to the watershed. Third, sapflow data from 11 forest canopy species were used to evaluate the potential impacts of losses of individual species on stand transpiration. Annual streamflow responses are exponentially related to decreases in forest cover (e.g., from

  12. Late-Quaternary paleovegetation, paleoclimate and fire disturbance records from subalpine sites on Vancouver Island, British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Fitton, R. J.; Brown, K. J.; Hebda, R. J.

    2003-04-01

    Analyses of pollen, macrofossils and charcoal from subalpine lakes provide insight into past climatic changes as well as local factors affecting the sites, especially since steep precipitation and temperature gradients typify mountainous regions. Lake and bog cores collected from three sites on southern and central Vancouver Island (Porphyry and Walker lakes and Harris Lake Ridge Bog) were analysed for pollen, macrofossils and charcoal and the resulting data were used to reveal post-glacial changes in vegetation, climate and fire disturbance. The paleovegetation, paleoclimate, and fire disturbance records from Porphyry and Walker Lakes parallel those from low elevations during the post-glacial interval, suggesting that these sites responded strongly to regional forcing and were somewhat less sensitive to local forcing. Of notable interest is the upward migration of lowland taxa to these lakes during the warm dry early-Holocene. A change to cooler and moister conditions in the mid- and late-Holocene is subsequently characterised by downslope movement of species ranges and the establishment of modern subalpine communities. In contrast, Harris Lake Ridge Bog from central Vancouver Island has a more complicated history that exhibits strong local and regional influences. This site is less similar to lowland records despite a relatively similar ecotonal position as the other two sites. In the early-Holocene upslope movement of low elevation species is less obvious than at Porphyry and Walker lakes. In the mid- and late-Holocene forest composition changed around Harris Lake Ridge Bog as conditions cooled and moistened and taxa better suited to nutrient poor soils, such as Tsuga mertensiana and T. heterophylla expanded. At the same time, there is evidence to suggest that local switches between forest and heather communities were initiated by fire. Consequently, records from subalpine wetlands may provide more potential for detailed reconstruction of local in

  13. Phenology of belowground carbon allocation in a mid-latitude forest

    NASA Astrophysics Data System (ADS)

    Abramoff, R. Z.; Klosterman, S.; Finzi, A. C.

    2012-12-01

    Annual forest productivity and carbon storage are affected by the amount and timing of carbon allocated belowground. Despite clear relationships between some climate factors (e.g. temperature) and NPP, there are still large gaps in our understanding of the partitioning between above and belowground C allocation. It is generally assumed that above and belowground phenology is synchronous, but a number of recent studies show that there is wide variability. Some phenological studies suggest that root production peaks are offset from leaf out and shoot elongation. Related belowground processes such as root respiration and nonstructural carbohydrate accumulation may also be offset from root or shoot production as a result of tradeoffs in C allocation. Due to uncertainties in the seasonal pattern and magnitude of allocation to roots, we have collected measurements of root phenology for three temperate tree species at Harvard Forest in Petersham, MA: eastern hemlock (Tsuga canadensis), red oak (Quercus rubra), and white ash (Fraxinus americana). Bi-weekly to monthly measurements of root production, root respiration, and root nonstructural carbohydrate content are used to determine when roots are receiving C from aboveground and patterns of C use. Minirhizotron and soil core data suggest that fine root biomass does not accumulate in a unimodal peak. In T.canadensis stands, fine root production peaks in late May, coinciding with green up and shoot elongation. In Q.rubra stands, fine root production begins in early June, about 3 weeks after leaf out and continues throughout the season in oscillating peaks. Average turnover times for Q.rubra and T.canadensis were 3.76 years and 6.83 years respectively. Standing root biomass for all stands fluctuates seasonally but with high spatial variability, with live fine root biomass averaging 210 ± 75.2 gC m-2 in F.americana stands, 554 ± 241 gC m-2 in Q.rubra, and 449 ± 172 gC m-2 in T.canadensis. Root respiration for all stands

  14. Mid-Pliocene to Early Quaternary Evolution of the Beringian Arctic from Deep Drilling at Lake El'gygytgyn, Chukotka: initial results (Invited)

    NASA Astrophysics Data System (ADS)

    Brigham-Grette, J.; Melles, M.; Minyuk, P.; Andreev, A.; Snyder, J.; Wennrich, V.; Lake El'Gygytgyn Scientific Party

    2010-12-01

    One of the primary objectives for deep drilling at Lake El’gygytgyn (67°30' N, 172°05' E), formed 3.6 Ma ago by a meteorite impact event, was to recover lacustrine sediments that would provide the first high resolution Pliocene-Pleistocene paleoclimate record from the terrestrial Arctic. While discontinuous, spatially diverse Pliocene marine records are known from the arctic borderlands at the outcrop scale, the Lake El’gygytgyn record is critically important for balancing the inherent marine bias we currently have in understanding the climate variability of a world warmer than today. Moreover, this continuous land record contributes to our knowledge of the terminal Pliocene transition, be it steps, jolts or plunges, into the early Quaternary. The Pliocene portion of the lake record recovered extends from 130 m to 315 m depth below lake floor with nearly twice the sedimentation rate of Quaternary interval, presumably due to enhanced hydrologic systematics. The lower most, initial 15 m of the lake sequence directly after the meteorite impact appear to be sterile perhaps due to the intense heat generated by the impact that would have taken thousands of years to dissipate. The remaining portion of the Pliocene sequence is characterized by sequences of lacustrine mud overlain by coarser facies. Palynologically studied portions of the core are mostly dominated by tree pollen, providing us with a compositional idea of changes in Pliocene El’gygtgyn forests of pine (Pinus), larch (Larix) spruce (Picea), fir (Abies), alder (Alnus), and, hemlock (Tsuga), not just scrubs. However, sediments paleomagnetically dated between 3.11 and 3.04 Ma ago show dramatic decrease in tree pollen contents, while pollen of Artemisia and spores of Selaginella rupestris and coprophiluous fungi became common elements in the record. Such changes point to treeless environments that can be described as early tundra-steppe. We present here a very preliminary compilation of the collective

  15. Inferring long-term carbon sequestration from tree rings at Harvard Forest: A calibration approach using tree ring widths and geochemistry / flux tower data

    NASA Astrophysics Data System (ADS)

    Belmecheri, S.; Maxwell, S.; Davis, K. J.; Alan, T. H.

    2012-12-01

    Improving the prediction skill of terrestrial carbon cycle models is important for reducing the uncertainties in global carbon cycle and climate projections. Additional evaluation and calibration of carbon models is required, using both observations and long-term proxy-derived data. Centennial-length data could be obtained from tree-rings archives that provide long continuous series of past forest growth changes with accurate annual resolution. Here we present results from a study conducted at Harvard Forest (Petersham, Massachusetts). The study examines the potential relationship between δ13C in dominant trees and GPP and/or NEE measured by the Harvard Forest flux tower (1992-2010). We have analyzed the δ13C composition of late wood-cellulose over the last 18 years from eastern hemlock (Tsuga canadensis) and northern red oak (Quercus rubra) trees growing in the flux tower footprint. δ13C values, corrected for the declining trend of atmospheric δ13C, show a decreasing trend from 1992 to 2010 and therefore a significant increase in discrimination (Δ). The intra-cellular CO2 (Ci) calculated from Δ shows a significant increase for both tree species and follows the same rate of atmospheric CO2 (Ca) increase (Ci/Ca increases). Interestingly, the net Ci and Δ increase observed for both species did not result in an increase of the iWUE. Ci/Ca is strongly related to the growing season Palmer Drought Severity Index (PDSI) for both species thus indicating a significant relationship between soil moisture conditions and stomatal conductance. The Ci trend is interpreted as a result of higher CO2 assimilation in response to increasing soil moisture allowing a longer stomata opening and therefore stimulating tree growth. This interpretation is consistent with the observed increase in GPP and the strengthening of the carbon sink (more negative NEE). Additionally, the decadal trends of basal area increment (BAI) calculated from tree-ring widths exhibit a positive trend over

  16. Impacts of a changing winter precipitation regime on the Great Snowforest of British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Knudsvig, H.; Dery, S. J.; Coxson, D.

    2012-12-01

    Rising air temperatures have profoundly impacted British Columbia (BC) mountain ecosystems, including its Interior Wetbelt. This region supports the sole Interior Temperate Rainforest (ITR), or perhaps more appropriately "snowforest", of North America. This snowforest encompasses about 30,500 km2 and contains Western redcedar (Thuja plicata) and western hemlock (Tsuga heteropylla) in excess of 1500 years old. This region is projected to be one of the more vulnerable biogeoclimatic zones in BC due to forest operations and climate change. Loss of snow as a storage medium has the potential to negatively affect the forest. A decrease in snow water equivalent (SWE) has the potential to decrease soil moisture values; impacts of decreased water availability in this region have the possibility to affect soil moisture storage, vegetative species composition, flora and fauna interdependence, and pathogen outbreaks. Given the projected climate change in high latitude and altitude areas, this project analyzes the contemporary and potential future climate of BC's Interior Wetbelt and explores the possible environmental and ecohydrological impacts of climate change on the snowforest. Models project an increase in air temperature and precipitation but a decrease in snowfall in this region. Analyses of the snow depth, SWE, and temperature from the Upper Fraser River Basin automated snow pillow sites of the BC River Forecast Centre (RFC) were conducted; snow depth, SWE, and temperature were also measured at the field site via automated weather stations and bi-monthly snow surveys. Surveys recorded depth and SWE after observed peak accumulation and continued until snowpack was depleted in 80% of the field site. To determine the influence of precipitation on the soil moisture levels in the ITR, soil moisture and water table levels were measured for the 2011-12 water year in addition to meteorological conditions; snow, spring water, and near surface ground water samples were collected

  17. A Cultural Resource Inventory of the Left Bank of Lake Oahe: Burleigh and Emmons Counties, North Dakota. Volume 1

    DTIC Science & Technology

    1986-11-01

    vegetative cover. Such forbs as iris (Iris missouriensis), giant goldenrod (Solida 3131 Heli jantea), Jerusalem artichoke (Helianthus...big bluestem and such forbs as Jerusalem artichoke , ground cherry (Physalis heterophylla) and fragrant giant hyssop (Agastache foeniculacium

  18. A/C(i) curve analysis across a range of woody plant species: influence of regression analysis parameters and mesophyll conductance.

    PubMed

    Manter, Daniel K; Kerrigan, Julia

    2004-12-01

    The analysis and interpretation of A/C(i) curves (net CO(2) assimilation rate, A, versus calculated substomatal CO(2) concentration, C(i)) is dependent upon a number of underlying assumptions. The influence of the C(i) value at which the A/C(i) curve switches between the Rubisco- and electron transport-limited portions of the curve was examined on A/C(i) curve parameter estimates, as well as the effect of mesophyll CO(2) conductance (g(m)) values on estimates of the maximum rate of Rubisco-mediated carboxylation (V(cmax)). Based on an analysis using 19 woody species from the Pacific Northwest, significant variation occurred in the C(i) value where the Rubisco- and electron transport-limited portions of the curve intersect (C(i_t)), ranging from 20 Pa to 152 Pa and averaging c. 71 Pa and 37 Pa for conifer and broadleaf species, respectively. Significant effects on estimated A/C(i) parameters (e.g. V(cmax)) may arise when preliminary estimates of C(i_t), necessary for the multiple regression analyses, are set either too high or too low. However, when the appropriate threshold is used, a significant relationship between A/C(i) and chlorophyll fluorescence estimates of carboxylation is achieved. The use of the V(cmax) parameter to describe accurately the Rubisco activity from the A/C(i) curve analysis is also dependent upon the assumption that C(i) is approximately equal to chloroplast CO(2) concentrations (C(c)). If leaf mesophyll conductance is low, C(c) will be much lower than C(i) and will result in an underestimation of V(cmax) from A/C(i) curves. A large range of mesophyll conductance (g(m)) values was observed across the 19 species (0.005+/-0.002 to 0.189+/-0.011 mol m(-2) s(-1) for Tsuga heterophylla and Quercus garryana, respectively) and, on average, g(m) was 1.9 times lower for the conifer species (0.058+/-0.017 mol m(-2) s(-1) for conifers versus 0.112+/-0.020 mol m(-2) s(-1) for broadleaves). When this mesophyll limitation was accounted for in V

  19. Implications of high amplitude atmospheric CO2 fluctuations on past millennium climate change

    NASA Astrophysics Data System (ADS)

    van Hoof, Thomas; Kouwenberg, Lenny; Wagner-Cremer, Friederike; Visscher, Henk

    2010-05-01

    . Tellus, v 47B, p. 264-272 Kouwenberg L.L.R., F. Wagner, W.M. Kürschner and H. Visscher 2005. Atmospheric CO2 fluctuations during the last Millennium reconstructed by stomatal frequency analysis of Tsuga heterophylla needles. Geology, v. 33, no.1, pp. 33-36 van Hoof T.B., K.A. Kaspers, F. Wagner, R.S.W. van de Wal, W.M. Kürschner and H. Visscher 2005. Atmospheric CO2 during the 13th century AD: reconciliation of data from ice core measurements and stomatal frequency analysis. Tellus B, v. 57, pp. 351-355 van Hoof T.B., F. Wagner-Cremer, W.M. K Kürschner and H. Visscher 2008. A role for atmospheric CO2 in preindustrial climate forcing. Proceedings of the National Academy of Sciences of the USA, v. 105, no. 41, pp. 15815-15818 Wagner F., L.L.R. Kouwenberg, T.B. van Hoof and H. Visscher 2004. Reproducibility of Holocene atmospheric CO2 records based on stomatal frequency. Quartenary Science Reviews. V. 23, pp. 1947-1954

  20. DoD Qualification Program Overview

    DTIC Science & Technology

    2011-08-01

    4 RAtiDALLINDUSTRIES LLC 4565 HEMLOCK RD CHERRY TREE , PA 157247223 USA 4 12-456- 1321 Click on the appropriate link to see m ore. Test Re f<>r...080-93-2 Cage Code: 4K7C9 NOTES: Company Nam e: RANDALL INDUSTRIES LLC Address: 4565 HEMLOCK RD CHERRY TREE . PA 157247223 USA Phone: 4 12-456...Cage Code: 4K7C9 Company Name: RANDALL INDUSTRIES LLC Address: 4565 HEMLOCK RD CHERRY TREE . PA 157247223 USA .., . . - . -- . -- . Qualified

  1. Differential response by hardwood and deciduous stands in New England forests to climate change and insect-induced mortality

    NASA Astrophysics Data System (ADS)

    Munger, J. William; Wofsy, Steven C.; Orwig, David A.; Williams, Chris

    2016-04-01

    Forests in the northeastern United States include large areas dominated by mosaics of oak/maple and hemlock stands. Often the hardwood dominated stands include a significant cohort of hemlock saplings. However, long-term survival of hemlock in this region is threatened by Hemlock Wooly Adelgid (HWA), an invasive insect that is fatal to eastern hemlock. The northern limit of HWA is affected in part by winter minimum temperature and warmer winters are enabling northward expansion of HWA infestation. At the Harvard Forest in central Massachusetts, two long-term eddy flux towers are measuring carbon exchange in a >100 year old hardwood stand since 1992 (EMS- Ha1) and in a 100-200 year old hemlock stand (Ha2) since 2004. The flux measurements are complemented by vegetation dynamics plots. Carbon exchange at the two sites has distinctly different seasonality. The hardwood site has a shorter carbon uptake period, but higher peak fluxes, while the hemlock stand has a long carbon uptake period extending from spring thaw until early winter freeze. Some contribution from the evergreen hemlock in the understory is evident before canopy greenup at the EMS tower and spring and fall carbon uptake rates have been increasing and contribute in part to a trend towards larger annual carbon uptake at this site. Carbon uptake by hemlock increases with warmer temperatures in the spring and fall transition. Adelgids have reached the hemlock stand near Ha2 and have been widely distributed in the canopy since spring of 2012. The hemlock canopy in that stand is thinning and net carbon uptake and evapotranspiration have been decreasing since 2012. Adelgids have also been observed in scattered stands near the Ha1 tower, but as of 2015 the trees are still healthy. Because hemlocks stands have different seasonality and provide a distinct soil and sub-canopy light environment, their mortality and replacement by hardwood species will have significant impacts on forest dynamics, carbon balance, and

  2. Root phenology at Harvard Forest and beyond

    NASA Astrophysics Data System (ADS)

    Abramoff, R. Z.; Finzi, A.

    2013-12-01

    Roots are hidden from view and heterogeneously distributed making them difficult to study in situ. As a result, the causes and timing of root production are not well understood. Researchers have long assumed that above and belowground phenology is synchronous; for example, most parameterizations of belowground carbon allocation in terrestrial biosphere models are based on allometry and represent a fixed fraction of net C uptake. However, using results from metaanalysis as well as empirical data from oak and hemlock stands at Harvard Forest, we show that synchronous root and shoot growth is the exception rather than the rule. We collected root and shoot phenology measurements from studies across four biomes (boreal, temperate, Mediterranean, and subtropical). General patterns of root phenology varied widely with 1-5 production peaks in a growing season. Surprisingly, in 9 out of the 15 studies, the first root production peak was not the largest peak. In the majority of cases maximum shoot production occurred before root production (Offset>0 in 32 out of 47 plant sample means). The number of days offset between maximum root and shoot growth was negatively correlated with median annual temperature and therefore differs significantly across biomes (ANOVA, F3,43=9.47, p<0.0001). This decline in offset with increasing temperature may reflect greater year-round coupling between air and soil temperature in warm biomes. Growth form (woody or herbaceous) also influenced the relative timing of root and shoot growth. Woody plants had a larger range of days between root and shoot growth peaks as well as a greater number of growth peaks. To explore the range of phenological relationships within woody plants in the temperate biome, we focused on above and belowground phenology in two common northeastern tree species, Quercus rubra and Tsuga canadensis. Greenness index, rate of stem growth, root production and nonstructural carbohydrate content were measured beginning in April

  3. 78 FR 18789 - Establishment of the San Juan Islands National Monument

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-28

    ... hundred years old, include a majestic assemblage of trees, such as Douglas fir, red cedar, western hemlock... stream of wildlife watchers. Native, terrestrial mammals include black- tail deer, river otter,...

  4. 3 CFR 8947 - Proclamation 8947 of March 25, 2013. Establishment of the San Juan Islands National Monument

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... hundred years old, include a majestic assemblage of trees, such as Douglas fir, red cedar, western hemlock... stream of wildlife watchers. Native, terrestrial mammals include black-tail deer, river otter,...

  5. Modeling ecosystem disturbance over regional scales with the Ecosystem Demography model

    NASA Astrophysics Data System (ADS)

    Albani, M.; Moorcroft, P. R.; Medvigy, D.

    2004-12-01

    The Ecosystem Demography (ED) model is a mechanistic individual-based terrestrial ecosystem model that is capable of explicitly incorporating ecosystem disturbance and recovery in regional and continental scale simulations. The ED model is a momentum approximation of a traditional `gap model', a stochastic individual model of forest dynamics. As such, ED models both the age and the size structures of the terrestrial ecosystems it simulates. The age structure directly accounts for the distribution of ages since last disturbance in each simulation grid cell, and captures the disturbance impact on the ecosystem's carbon stocks. The size structure is used to model the impact of different kinds of disturbance on ecosystem dynamics and the recovery processes following disturbance. We present a set of ED simulations of the carbon dynamics of New England for the period 1700-2100 that account for both natural and anthropogenic ecosystem disturbance. We simulate tree-fall, land-use change, forest harvesting, and the impact of the Hemlock Wooly Adelgid, an introduced pathogen of eastern hemlock. While all these disturbances involve tree mortality, their simulated impact on the carbon dynamics is substantially different depending on the timing, frequency, and selectivity of the disturbance. In particular the temporal patterns of net ecosystem productivity during ecosystem recovery from Hemlock Wooly Adelgid infestation is not only influenced by the amount of hemlock present, but also by the ecological role that hemlock played in that specific ecosystem, and by the species that replace it after removal.

  6. Lower Mississippi River Environmental Program. Report 2. A Physical Description of Main Stem Levee Borrow Pits along the Lower Mississippi River

    DTIC Science & Technology

    1988-02-01

    Paspalum boscianum Bull paspalum Paspalum dilatatum Dallis grass Paspalum distichum Knotgrass Paspalum ...notatum Bahia grass Paspalum urvillei Vasey grass Passiflora incarnata Maypop Phoradendron flavescens Mistletoe Physalis heterophylla Ground cherry...mixed of Johnson grass and Bermuda grass pasture, while the river side exhibits typical marsh vegetation and bottomland hardwood characteristics

  7. Comparison of ultrastructure, pollen tube growth pattern and starch content in developing and abortive ovaries during the progamic phase in hazel

    PubMed Central

    Liu, Jianfeng; Zhang, Huidi; Cheng, Yunqing; Wang, Ju; Zhao, Yixin; Geng, Wanting

    2014-01-01

    HIGHLIGHTS In an abortive ovary of hazel, an integument seldom differentiated and a mature embryo sac never developed.In an abortive ovary of hazel, pollen tube growth was arrested at the style base about 40 days after blooming. Thus, fertilization of the ovule was precluded.Ovary abortion in the four hybrid cultivars was indicated to be associated with insufficient resource availability to support fruit set by all flowers, whereas ovary abortion in C. heterophylla was at least partly determined by pollen availability. In Northeast China, a high frequency of ovary abortion contributes to serious losses in yield of hazelnut. The development of pistillate inflorescences and fruit clusters of four large-fruited hybrid hazel cultivars and the small-fruited Corylus heterophylla were used to study ovary abortion and its possible causes during the progamic phase in hazel. The average number of pistillate (ANP) flowers per inflorescence and average number of fruit (ANF) per cluster of four hybrid hazel cultivars were 7.6–8.5 and 2.4–3.0 respectively; in C. heterophylla, its ANP and ANF was 5.8–6.2 and 3.5, respectively. The total drop varied from 50 to 67%. Ovary abortion in hazel initiated from about 30 days after blooming. The percentage of abortive ovaries (PAO) in the four hybrid hazel cultivars ranged from 63 to 72%, and was significantly higher than that of C. heterophylla (29–42%). Only the abortive ovary ratio of C. heterophylla was significantly reduced after artificial pollination. Fruit number per cluster was positively and negatively correlated with yield and nut mass, respectively. In abortive ovaries, the diameter remained less than 2 mm during the entire fruit development, an integument seldom differentiated and a mature embryo sac never developed. In addition, pollen tube growth was arrested at the style base about 40 days after blooming. Thus, fertilization of the ovule was precluded. Compared with abortive ovary, starch content in developing ovary

  8. What killed Socrates? Toxicological considerations and questions.

    PubMed

    Dayan, A D

    2009-01-01

    The death of Socrates in 399 BCE, as reported by Plato in the Phaedo, is usually attributed to poisoning with common hemlock. His progressive centripetal paralysis is characteristic of that poison. Socrates is said to have had a prominent loss of sensation extending centrally from his legs, which is not a feature of hemlock poisoning, and he seems not to have had the unpleasant taste or common gastrointestinal effects of that poison. It is suggested that Plato gave a modified account of the death of Socrates for political and other reasons by describing a more "noble" death.

  9. A field test of the effect of acidic rain on ion balance in a woodland salamander

    SciTech Connect

    Frisbie, M.P.; Wyman, R.L. )

    1994-06-01

    Earlier laboratory studies demonstrated that red-backed salamanders, Plethodon cinereus, are susceptible to osmotic disruption by low pH substrates. In natural systems, however, acidic input from precipitation may be mediated by soils before it impacts salamanders. We tested the effect of acidic rain on sodium balance in salamanders by confining individuals in enclosure in two forest types (hemlock, beech) for 34 d. Enclosures received artificial rain of either pH 3 or 5 every 3-4 d. Soils inside enclosures in the hemlock forest were more acidic than those in the beech forest at the outset. At termination, [H[sup +

  10. Crooked Calf Syndrome: Managing Lupines on Rangelands of the Channel Scablands of East-Central Washington State

    Technology Transfer Automated Retrieval System (TEKTRAN)

    “Crooked calf syndrome”, the contracture-type skeletal defects and cleft palate caused by velvet lupine (Lupinus leucophyllus) on the channel Scablands of east-central Washington State are the same as those defects induced by Conium maculatum (poison-hemlock) and Nicotiana spp. (wild tobacco) in rum...

  11. Comparative analysis of carbon, water, and energy exchanges in co-located mid-latitude forests at various stages of development

    NASA Astrophysics Data System (ADS)

    Williams, C. A.; Munger, J. W.; Hadley, J.; Fitzjarrald, D. R.

    2010-12-01

    Biosphere-atmosphere exchanges of mass and energy vary with forest type, stand age, and following disturbance, but the degree, character, and persistence of these variations remain poorly understood. This work explores such gradients by synthesizing across a local network of flux tower sites within Harvard Forest (central Massachusetts). We examine how CO2, H2O, and energy exchanges compare among mature and intermediate aged deciduous forests, a mature hemlock forest, and a newly instrumented site in the early stages of secondary succession following a recent clearcut. We find markedly lower growing season evapotranspiration in the hemlock stand compared to adjacent deciduous forests, lower still in the revegetating clearcut. Daytime net ecosystem carbon exchange follows a similar pattern, with highest uptake in the deciduous forests, intermediate in the hemlock site, and lowest in the clearcut. This is true despite sizeable midday uptake in the clearcut during the second growing season post-harvest. Large nighttime CO2 emissions from the clearcut indicate high respiration rates of the early succession vegetation as well as vigorous decomposition of the abundant woody debris and litter left onsite after harvest. Surface albedo and corresponding net radiation are both surprisingly consistent across these adjacent cover types. Implications for water resources and carbon balance of New England landscapes will be discussed, particularly within the contexts of human and natural disturbances, such as harvesting and Hemlock Wooly Adelgid infestations.

  12. Oviposition traps to survey eggs of Lambdina fiscellaria (Lepidoptera: Geometridae).

    PubMed

    Hébert, Christian; Jobin, Luc; Auger, Michel; Dupont, Alain

    2003-06-01

    Outbreaks of the hemlock looper, Lambdina fiscellaria (Gueneé), are characterized by rapid increase and patchy distribution over widespread areas, which make it difficult to detect impending outbreaks. This is a major problem with this insect. Population forecasting is based on tedious and expensive egg surveys in which eggs are extracted from 1-m branches; careful observation is needed to avoid counting old unhatched eggs of previous year populations. The efficacy of artificial substrates as oviposition traps to sample hemlock looper eggs was tested as a means of improving outbreak detection and population forecasting. A white polyurethane foam substrate (1,095 lb/ft3) used with the Luminoc insect trap, a portable light trap, was highly efficient in sampling eggs of the hemlock looper. Foam strips placed on tree trunks at breast height were less efficient but easier and less expensive to use for the establishment of extensive survey networks. Estimates based on oviposition traps were highly correlated with those obtained from the 1-m branch extraction method. The oviposition trap is a standard, inexpensive, easy, and robust method that can be used by nonspecialists. This technique makes it possible to sample higher numbers of plots in widespread monitoring networks, which is crucial for improving the management of hemlock looper populations.

  13. Gods behaving badly.

    PubMed

    Retsas, Spyros

    2015-02-01

    This paper addresses the myths surrounding the birth and death of Asclepios, the popular healing God of the Greeks and his place among other deities of the Greek Pantheon. The enigmatic invocation of Asclepios by Socrates, the Athenian philosopher condemned to take the hemlock, in his final moments is also discussed.

  14. Otherness through Elves: Into Elfland and Beyond

    ERIC Educational Resources Information Center

    Yamazaki, Akiko

    2008-01-01

    This article examines three novels which use stories of elves--especially the ballad "Tam Lin"--as pre-texts, and contemplates how they explore the issue of Otherness. The three novels are "The Sterkarm Handshake" by Susan Price, "Cold Tom" by Sally Prue, and "Fire and Hemlock" by Diana Wynne Jones. Although the novels seem to be about elves as…

  15. Operation Alaskan Road

    DTIC Science & Technology

    2008-03-01

    equipment and personnel. Equipment Maintenance and Fueling Operations. Hemlock Bay con- sisted of a K-span building that housed the maintenance...large trees from growing, although stunted shore pine, cottonwood, some species of willow, and black spruce can be found. Stepping on muskeg is

  16. Haida Food Gathering and Preparation.

    ERIC Educational Resources Information Center

    Cogo, Robert

    Students are introduced to the Haida language as well as to traditional Haida foods in this booklet, one in a series of curriculum materials on Southeast Alaska Natives. Ten selections written in simple language describe a Haida barbecue, Indian bread, sea cucumbers, black sea weed, the edible pulp sap of Hemlock, Indian ice cream made from soap…

  17. 29 CFR 1915.72 - Ladders.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) Portable metal ladders shall be of strength equivalent to that of wood ladders. Manufactured portable metal... be made from West Coast hemlock, Eastern spruce, Sitka spruce, or wood of equivalent strength. Material shall be seasoned, straight-grained wood, and free from shakes, checks, decay or other...

  18. 29 CFR 1915.72 - Ladders.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) Portable metal ladders shall be of strength equivalent to that of wood ladders. Manufactured portable metal... be made from West Coast hemlock, Eastern spruce, Sitka spruce, or wood of equivalent strength. Material shall be seasoned, straight-grained wood, and free from shakes, checks, decay or other...

  19. 29 CFR 1915.72 - Ladders.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) Portable metal ladders shall be of strength equivalent to that of wood ladders. Manufactured portable metal... be made from West Coast hemlock, Eastern spruce, Sitka spruce, or wood of equivalent strength. Material shall be seasoned, straight-grained wood, and free from shakes, checks, decay or other...

  20. 29 CFR 1915.72 - Ladders.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) Portable metal ladders shall be of strength equivalent to that of wood ladders. Manufactured portable metal... be made from West Coast hemlock, Eastern spruce, Sitka spruce, or wood of equivalent strength. Material shall be seasoned, straight-grained wood, and free from shakes, checks, decay or other...

  1. 29 CFR 1915.72 - Ladders.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Portable metal ladders shall be of strength equivalent to that of wood ladders. Manufactured portable metal... be made from West Coast hemlock, Eastern spruce, Sitka spruce, or wood of equivalent strength. Material shall be seasoned, straight-grained wood, and free from shakes, checks, decay or other...

  2. PHOTOGRAPHIC COPY REDUCTION OF CAD DRAWING (FROM COLLECTION OF GIFFORD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PHOTOGRAPHIC COPY REDUCTION OF CAD DRAWING (FROM COLLECTION OF GIFFORD PINCHOT NATIONAL FOREST). HEMLOCK DAM (TROUT CREEK) SITE PLAN. 1995 FISH LADDER “ATTRACTION FLOW” MODIFICATIONS - Trout Creek Dam, River Mile 1.8 on Trout Creek, Carson, Skamania County, WA

  3. Changes in Landscape Greenness: Anthropogenic or Natural: Proof of Concept, Selected Study Areas

    EPA Science Inventory

    We selected four National Forest areas that span east to west of USA to conduct the study over the 25-year period from 1989 through 2013: GWJ (Virginia), Chatt-O (Georgia), Kisatchie (Louisiana), Hemlock Restoration (California). The Normalized Difference Vegetation Index (NDV...

  4. Structural characterization of rubber from jackfruit and euphorbia as a model of natural rubber.

    PubMed

    Mekkriengkrai, Dararat; Ute, Koiichi; Swiezewska, Ewa; Chojnacki, Tadeusz; Tanaka, Yasuyuki; Sakdapipanich, Jitladda T

    2004-01-01

    A structural study of low molecular weight rubbers from Jackfruit (Artocarpus heterophyllus) and Painted spurge (Euphorbia heterophylla) was carried out as model compounds of natural rubber from Hevea brasiliensis. The rubber content of latex from Jackfruit was 0.4-0.7%, which is very low compared with that of 30-35% in the latex from Hevea tree. The rubber from Jackfruit latex was low molecular weight with narrow unimodal molecular weight distribution (MWD), whereas that obtained from E. heterophylla showed very broad MWD. The 1H and 13C NMR analyses showed that Jackfruit rubber consists of a dimethylallyl group and two trans-isoprene units connected to a long sequence of cis-isoprene units. The alpha-terminal group of Jackfruit rubber was presumed to be composed of a phosphate group based on the presence of 1H NMR signal at 4.08 ppm corresponding to the terminal =CH-CH2OP group.

  5. A Long Term View of Forest Response to Environmental Change: 25 Years of Studying Harvard Forest

    NASA Astrophysics Data System (ADS)

    Munger, J. W.; Wofsy, S. C.; Lindaas, J.; David, F.; David, O.

    2014-12-01

    Forests influence the budgets of greenhouse gases, and understanding how they will respond to environmental change is critical to accurately predicting future GHG trends. The time scale for climate change is long and forest growth is slow, thus very long measurement periods are required to observe meaningful forest response. We established an eddy flux tower within a mixed forest stand dominated by red oak and red maple at the Harvard Forest LTER site in 1989 where CO2, H2O and energy fluxes together with meteorological observations have been measured continuously. An array of plots for biometric measurements was established in 1993. Flux measurement at an adjacent hemlock stand began in 2000. Records of land use and disturbance and vegetation plot data extend back to 1907. The combined suite of measurements merges observations of instantaneous ecosystem responses to environmental forcing with details of vegetation dynamics and forest growth that represent the emergent properties relevant to long-term ecosystem change. Both the deciduous stand and hemlock stand are accumulating biomass. Each has added over 20 Mg-C ha-1 as woody biomass in trees >10cm dbh since 1990, even though the hemlock stand is older. Net carbon exchange shows enhanced uptake in early spring and late fall months in response to warmer temperatures and likely an increase in evergreen foliage at the deciduous site. Net carbon uptake efficiency at the deciduous stand has increased over time as well as indicated by peak NEE under optimum light conditions. The trend is only partly explained by variation in mean leaf area index and cannot be directly attributed to climate response. The combination of longer growing season and increased uptake efficiency yields a general trend of increasing annual NEE (Fig. 1). However, significant excursions in the trend highlight the sensitivity of forest carbon stocks. The pulse of high annual carbon uptake (peak 6 Mg-C ha-1y-1 in 2008) from 2000-2008 is only

  6. Diagenesis of conifer needles in a coastal marine environment

    NASA Astrophysics Data System (ADS)

    Hedges, John I.; Weliky, K.

    1989-10-01

    Physically intact fir, hemlock and cedar needles were isolated from different horizons of a sediment core from a coastal marine bay (Dabob Bay, Washington State, U.S.A.) and from nearby trees and forest litter. Green fir, hemlock and cedar needles were all characterized by glucose-rich aldose mixtures (~30% of tissue carbon), the production of vanillyl and cinnamyl CuO-derived phenols (~8% of tissue carbon) and the presence of both pinitol and myo-inositol (1-2% of tissue carbon). Needles from forest litter were enriched in lignin phenols and non-glucose aldoses and depleted in glucose and cyclitols. The sediment core contained an average of 10 mg/1 of physically intact fir, hemlock and cedar needles, which occurred in similar relative abundances and accounted for less than 1% of the total nonwoody gymnosperm tissue. Compared to the green and litter counterparts, all sedimentary needles were greatly depleted in cyclitols, glucose and p-coumaric acid and enriched in vanillyl phenol precursors. The degree of elevation of vanillyl phenol yield from the degraded needles was used to estimate minimal carbon losses from the samples, which ranged from near 40% for needle litter to almost 70% for the deepest (~100 years old) sedimentary fir/hemlock samples. Although downcore increases in carbon loss and refractory organic components indicated in situ diagenesis, the bulk of overall degradation occurred either on land or during the first 10-20 years after deposition. Atomic C/N ratios of degraded needles were lower than for green counterparts, but nitrogen was lost overall. These relative changes indicate the following stability series: vanillyl phenols > N > ferulic acid, p-hydroxy phenols, most aldoses and bulk tissue > glucose and p-coumaric acid > cyclitols (near 100% loss). Vanillic acid to vanillin ratios, (Ad/Al)v, of the green fir and hemlock needles were unusually high (0.36-0.38) and decreased downcore. Diagenesis also decreased the cinnamyl/vanillyl phenol ratio

  7. Radar modeling of a boreal forest

    NASA Technical Reports Server (NTRS)

    Chauhan, Narinder S.; Lang, Roger H.; Ranson, K. J.

    1991-01-01

    Microwave modeling, ground truth, and SAR data are used to investigate the characteristics of forest stands. A mixed coniferous forest stand has been modeled at P, L, and C bands. Extensive measurements of ground truth and canopy geometry parameters were performed in a 200-m-square hemlock-dominated forest plot. About 10 percent of the trees were sampled to determine a distribution of diameter at breast height (DBH). Hemlock trees in the forest are modeled by characterizing tree trunks, branches, and needles as randomly oriented lossy dielectric cylinders whose area and orientation distributions are prescribed. The distorted Born approximation is used to compute the backscatter at P, L, and C bands. The theoretical results are found to be lower than the calibrated ground-truth data. The experiment and model results agree quite closely, however, when the ratios of VV to HH and HV to HH are compared.

  8. Distribution Patterns of Some Criconematinae in Different Forest Associations

    PubMed Central

    Hoffmann, John K.; Norton, D. C.

    1976-01-01

    A total of 243 samples from Hemlock-Hardwood, Boreal Forest, and Alpine Tundra associations of New York, Vermont, New Hampshire, and Maine were analyzed for species of Bakernema, Criconema, and Criconemoides and for selected edaphic factors. The Hemlock-Hardwood formation contained 13 species of these genera, but the Boreal Forest and Alpine Tundra contained only Criconema menzeli and Criconemoides sphagni. Criconemoides axeste, C. rusticum, and C. xenoplax were associated primarily with mineral soils that have high pH, low moisture after drainage, and organic matter content of less than 15%. Criconemoides sphagni was associated with organic soils that had low pH, high moisture after drainage, and organic matter content greater than 15%. PMID:19308192

  9. Associations between regional moisture gradient, tree species dominance, and downed wood abundance

    NASA Astrophysics Data System (ADS)

    Johnson, A. C.; Mills, J.

    2007-12-01

    Downed wood functions as a source of nurse logs, physical structure in streams, food, and carbon. Because downed wood is important in upland and aquatic habitats, an understanding of wood recruitment along a continuum from wet to dry landscapes is critical for both preservation of biodiversity and restoration of natural ecosystem structure and function. We assessed downed wood in public and private forests of Washington and Oregon by using a subset of the Forest Inventory and Analysis (FIA) database including 15,842 sampled conditions. Multivariate regression trees, ANOVA, and t-tests were used to discern environmental conditions most closely associated with abundance of woody debris. Of the 16 parameters included in the analysis, rainfall, forest ownership, number of damaged standing trees, and forest elevation were most indicative of woody debris abundance. The Hemlock/spruce Group, including hemlock, spruce, cedar, and white pine, most associated with wetter soils, had significantly more downed wood than 12 other forest groups. The Ponderosa Pine Group, indicative of drier sites with higher fire frequencies, included ponderosa pine, sugar pine, and incense cedar, and had significantly less downed wood volume. Overall, the amount of woody debris in either the Spruce/hemlock Group or the Ponderosa Pine Group did not change significantly as tree age increased from 5 to 350 years. Plots within the Hemlock/spruce with greater standing tree volume also had significantly greater downed wood volume. In contrast, greater downed wood volume was not associated with greater standing tree volume in the Ponderosa Pine Group. Knowledge of linkages among environmental variables and stand characteristics are useful in development of regional forest models aimed at understanding the effects of climate change and disturbance on forest succession.

  10. Reconnaissance Study for Cape Vincent Harbor, New York.

    DTIC Science & Technology

    1981-04-01

    breakwater is of the timber-crib type, with a concrete superstruc- ture. Illustration No. 1(c), page 4, presents a clear and detailed descrip- tion of a...typical cross section of the breakwater. This includes both the timber crib and the concrete superstructure. The timber crib consists of hemlock blocks...while the superstructure contains concrete blocks as well as filling stone. Illustration 1 (a): Portion q Cape Vincent Villa geA Ferry Route to Wolfe I

  11. Blue Marsh Lake Project Water Quality Data Report (RCS DAEN-CWE-15).

    DTIC Science & Technology

    1980-12-01

    fields devoted principally to agricultural pursuits. Poll htion control in the W atershed is problematic, due to septic tank overflows, 1-ick of sewae...that the alkaline conditions are caused by carbonate material that is picked up as the streams travel through limestone beds and from run- off on...tree species are red oak and white oak. Other major components include black oak, chestnut oak, several hickory species, beech, tulip , hemlock

  12. Diatom Records of Holocene Environmental and Climatic Change in Southeastern British Columbia

    NASA Astrophysics Data System (ADS)

    Westover, K. S.; Gavin, D. G.; Fritz, S. C.; Hu, F.; Roschen, L. A.

    2004-12-01

    The sediments of three lakes, spanning a latitudinal gradient and situated within the Interior Cedar-Hemlock biogeoclimatic zone of southeast British Columbia, have been analyzed for independent records of Holocene climate and vegetation history in order to evaluate the role of climate as a control on range expansion of western hemlock and western redcedar. Holocene climate reconstructions are based on multiple proxies, including the diatom and biogenic silica stratigraphies presented here. To our knowledge, these sites provide the first continuous Holocene paleoecological and paleoclimatic records from the region between the Interior Plateau and the Rocky Mountains. Stratigraphic variability in the diatom sedimentary records reflects lake response to changes in water balance, catchment development, and atmospheric inputs of silica (i.e. volcanic ash). At Eleanor Lake, the diatom record shows significant assemblage shifts at ˜7500, 6300, and 3700 cal yr BP. Increased abundance of planktonic and tychoplanktonic diatoms and an increase in the abundance of chrysophyte cysts relative to diatoms at 6300 cal yr BP is consistent with an increase in effective moisture at this time. At Mirror Lake, in the south, an assemblage dominated by small benthic species is replaced by a predominantly planktonic assemblage at 6900 cal yr BP, suggesting an earlier increase in lake level. After 6000 cal yr BP, planktonic diatoms further increase in dominance. These dates are consistent with reconstructions of Holocene climate in south-central British Columbia, which suggest a shift to moister conditions ca. 7000 to 6000 cal yr BP. The pollen record indicates the expansion of western hemlock and western redcedar near Mirror Lake at 3550 cal yr BP and 3250 cal yr BP respectively. At Eleanor Lake, hemlock expansion is dated at 4350 cal yr BP. The data indicate a difference of 1950 to > 3000 years between the lacustrine record of increased effective moisture and the vegetation response and

  13. Sacramento River, Chico Landing to Red Bluff, California Bank Protection Project

    DTIC Science & Technology

    1975-01-01

    than on the river channel proper. 10 2.25. The Sacramento River is an essential system for most of the anadromous fishery resource in California...that are free of impoundments and generally inaccessible except by trail, with watersheds or shorelines essentially primitive and waters unpolluted... Lippia nodi flora) Southern California Milk thistle Common-Nationwide X (Silybum marianum) Poi son hemlock Common-Nat i onw i de X

  14. Sequence of pumiceous tephra layers and the late quaternary environmental record near mount st. Helens.

    PubMed

    Heusser, C J; Heusser, L E

    1980-11-28

    Tephra in lake beds within 40 kilometers of Mount St. Helens was deposited an average of once every 2,700 years over the past 35,000 years, for a total of 13 layers. Times of deposition span the period of the Fraser Glaciation and intervals before and after it, and include the series of climates prevailing when vegetation west of the Cascade Range shifted between a park-tundra type and the modern western hemlock forest.

  15. Growth, condition factor, and bioenergetics modeling link warmer stream temperatures below a small dam to reduced performance of juvenile steelhead

    USGS Publications Warehouse

    Sauter, S.T.; Connolly, P.J.

    2010-01-01

    We investigated the growth and feeding performance of juvenile steelhead Oncorhynchus mykiss using field measures and bioenergetics modeling. Juvenile steelhead populations were sampled from mid-June through August 2004 at study sites upstream and downstream of Hemlock Dam. The growth and diet of juvenile steelhead were determined for a warm (summer) and subsequent (late summer) transitional period at each study site. Empirical data on the growth and diet of juvenile steelhead and mean daily temperatures were used in a bioenergetics model to estimate the proportion of maximum consumption achieved by juvenile steelhead by site and period. Modeled estimates of feeding performance were better for juvenile steelhead at the upstream compared to the downstream site during both periods. The median condition factor of juvenile steelhead did not change over the summer at the upstream site, but showed a significant decline over time at the downstream site. A negative trend in median condition factor at the downstream site supported bioenergetics modeling results that suggested the warmer stream temperatures had a negative impact on juvenile steelhead. Bioenergetics modeling predicted a lower feeding performance for juvenile steelhead rearing downstream compared to upstream of Hemlock Dam although food availability appeared to be limited at both study sites during the warm period. Warmer water temperatures, greater diel variation, and change in diel pattern likely led to the reduced feeding performance and reduced growth, which could have affected the overall survival of juvenile steelhead downstream of Hemlock Dam. ?? 2010 by the Northwest Scientific Association.

  16. Differential selection on pollen and pistil traits in relation to pollen competition in the context of a sexual conflict over timing of stigma receptivity

    PubMed Central

    Lankinen, Åsa; Strandh, Maria

    2016-01-01

    Sexual conflict and its evolutionary consequences are understudied in plants, but the theory of sexual conflict may help explain how selection generates and maintains variability. Here, we investigated selection on pollen and pistil traits when pollen arrives sequentially to partially receptive pistils in relation to pollen competition and a sexual conflict over timing of stigma receptivity in the mixed-mating annual Collinsia heterophylla (Plantaginaceae). In this species the conflict is generated by early fertilizing pollen that reduces seed production, which is counteracted by delaying receptivity in the recipient. We performed sequential two-donor pollinations at early floral developmental stages involving two pollen deposition schedules (with or without a time lag of 1 day), using only outcross or self and outcross pollen. We investigated pollen and pistil traits in relation to siring success (male fitness) and seed production (female fitness). In contrast to previous findings in receptive pistils in C. heterophylla and in other species, last arriving pollen donors showed highest siring success in partially receptive pistils. The last male advantage was weaker when self pollen was the first arriving donor. Two measures of germination rate (early and late) and pollen tube growth rate of first arriving donors were important for siring success in crosses with a time lag, while only late germination rate had an effect in contemporary crosses. Curiously, late stigma receptivity was negatively related to seed production in our contemporary crosses, which was opposite to expectation. Our results in combination with previous studies suggest that pollen and pistil traits in C. heterophylla are differentially advantageous depending on stage of floral development and varying pollen deposition schedules. Variation in success of these traits over floral development time may result from sexually antagonistic selection. PMID:27562796

  17. Geology of the Lake Mary quadrangle, Iron County, Michigan

    USGS Publications Warehouse

    Bayley, Richard W.

    1959-01-01

    The Lake Mary quadrangle is in eastern Iron County, in the west part of the Upper Peninsula of Michigan. The quadrangle is underlain by Lower and Middle Precambrian rocks, formerly designated Archean and Algonkian rocks, and is extensively covered by Pleistocene glacial deposits. A few Upper Precambrian (Keweenawan) diabase dikes and two remnants of sandstone and dolomite of early Paleozoic age are also found in the area. The major structural feature is the Holmes Lake anticline, the axis of which strikes northwest through the northeast part of the quadrangle. Most of the quadrangle, therefore, is underlain by rock of the west limb of the anticline. To the northwest along the fold axis, the Holmes Lake anticline is separated from the Amasa oval by a saddle of transverse folds in the vicinity of Michigamme Mountain in the Kiernan quadrangle. The Lower Precambrian rocks are represented by the Dickinson group and by porphyritic red granite whose relation to the Dickinson group is uncertain, but which may be older. The rocks of the Dickinson group are chiefly green to black metavolcanic schist and red felsite, some of the latter metarhyolite. The dark schist is commonly magnetic. The Dickinson group underlies the core area of the Holmes Lake anticline, which is flanked by steeply dipping Middle Precambrian formations of the Animikie series. A major unconformity separates the Lower Precambrian rocks from the overlying Middle Precambrian rocks. In ascending order the formations of the Middle Precambrian are the Randville dolomite, the Hemlock formation, which includes the Mansfield iron-bearing slate member, and the Michigamme slate. An unconformity occurs between the Hemlock formation and Michigamme slate. The post-Hemlock unconformity is thought to be represented in the Lake Mary quadrangle by the absence of iron-formation of the Amasa formation, which is known to lie between the Hemlock and the Michigamme to the northwest of the Lake Mary quadrangle in the Crystal

  18. Munkoyo beverage, a traditional Zambian fermented maize gruel using Rhynchosia root as amylase source.

    PubMed

    Zulu, R M; Dillon, V M; Owens, J D

    1997-03-03

    A typical munkoyo beverage was made by fermenting Rhynchosia heterophylla root extract-cooked maize meal mixture with Lactobacillus confusus LZI and Saccharomyces cerevisiae YZ20. The fermented munkoyo beverage had a pH of 3.3, lactic acid content of 60 mmol/l, ethanol 320-410 mmol/l and a characteristic 'munkoyo' aroma. L. confusus, used alone, produced a beverage with a faint munkoyo flavour note whilst beverage produced with S. cerevisiae alone seemed not to have a typical munkoyo note. R. heterophylla root extract converted 75% of the starch in sterile cooked maize meat to maltose (80% of total sugars), maltotriose (17%) and glucose (3%) in I h at 45 degrees C. During fermentation by the mixed culture or the yeast alone most of the maltose was utilised but little or none of the maltotriose. The ratio of yeast to lactic acid bacteria in the starter culture affected the rate of production of ethanol but had no effect on the growth or acid production by the bacterium. To obtain a munkoyo beverage with the desired low alcohol concentration (< 100 mmol/l), the ratio of yeast concentration (cfu/ml) to Lactobacillus concentration in the starter culture should be 1:1000 or less and the beverage should be fermented for 24 h only.

  19. Heteroploid reticulate evolution and taxonomic status of an endemic species with bicentric geographical distribution.

    PubMed

    Uwe Nierbauer, Kai; Paule, Juraj; Zizka, Georg

    2017-01-24

    Reticulate evolution is considered to be among the main mechanisms of plant evolution, often leading to the establishment of new species. However, complex evolutionary scenarios result in a challenging definition of evolutionary and taxonomic units. In the present study, we aimed to examine the evolutionary origin and revise the species status of Campanula baumgartenii, a rare endemic species from the polyploid complex Campanula section Heterophylla. Morphometry, flow cytometric ploidy estimation, AFLPs, as well as chloroplast and nuclear DNA sequence markers were used to assess the morphological and genetic differentiation among C. baumgartenii, C. rotundifolia and other closely related taxa. Tetra- and hexaploid C. baumgartenii is morphologically and molecularly (AFLP) differentiated from sympatric C. rotundifolia. Contrasting signals from nuclear (ITS) and chloroplast (trnL-rpl32) markers suggest a hybrid origin of C. baumgartenii with C. rotundifolia and a taxon related to the alpine C. scheuchzeri as ancestors. Additionally, hexaploid C. baumgartenii currently hybridizes with co-occurring tetraploid C. rotundifolia resulting in pentaploid hybrids, for which C. baumgartenii serves as both seed and pollen donor. Based on the molecular and morphological differentiation, we propose to keep C. baumgartenii as a separate species. This study exemplifies that detailed population genetic studies can provide a solid basis for taxonomic delimitation within Campanula section Heterophylla as well as for sound identification of conservation targets.

  20. A study of weeds as potential inoculum sources for a tomato-infecting begomovirus in central Brazil.

    PubMed

    Barreto, S S; Hallwass, M; Aquino, O M; Inoue-Nagata, A K

    2013-05-01

    Tomato severe rugose virus (ToSRV) is the most important begomovirus species in Brazilian tomato production. Many weeds are associated with tomato, and some are hosts of begomoviruses. Only one species of weed, Nicandra physaloides, has been found to be infected with ToSRV. In this study, four weed species were investigated for their capacity to be infected by ToSRV and serve as a potential source of inoculum for tomato. Begomoviruses from naturally infected Crotalaria spp., Euphorbia heterophylla, N. physaloides, and Sida spp. were successfully transferred to tomato plants by biolistic inoculation. ToSRV was the major virus transferred to tomato. In contrast, other begomoviruses were transferred to weeds, such as Sida micrantha mosaic virus and Euphorbia yellow mosaic virus. Furthermore, a new strain of Sida micrantha mosaic virus is reported. We also confirmed that Crotalaria spp., E. heterophylla, and Sida spp. are infected with ToSRV but at low viral titers and in mixed infections with weed-infecting begomoviruses. Thus, it was demonstrated that weeds are potential sources of ToSRV for tomato in central Brazil.

  1. Holocene climate of New England

    NASA Astrophysics Data System (ADS)

    Davis, Margaret B.; Spear, Ray W.; Shane, Linda C. K.

    1980-09-01

    Stratigraphic studies of pollen and macrofossils from six sites at different elevations in the White Mountains of New Hampshire demonstrate changes in the distributions of four coniferous tree species during the Holocene. Two species presently confined to low elevations extended farther up the mountain slopes during the early Holocene: white pine grew 350 m above its present limit beginning 9000 yr B.P., while hemlock grew 300-400 m above its present limit soon after the species immigrated to the region 7000 yr. B.P. Hemlock disappeared from the highest sites about 5000 yr B.P., but both species persisted at sites 50-350 m above their present limits until the Little Ice Age began a few centuries ago. The history of the two main high-elevation conifers is more difficult to interpret. Spruce and fir first occur near their present upper limits 9000 or 10,000 yr B.P. Fir persisted in abundance at elevations similar to those where it occurs today throughout the Holocene, while spruce became infrequent at all elevations from the beginning of the Holocene until 2000 yr B.P. These facts suggest a more complex series of changes than a mere upward shift of the modern environmental gradient. Nevertheless, we conclude that the minimum climatic change which would explain the upward extensions of hemlock and white pine is a rise in temperature, perhaps as much as 2°C. The interval of maximum warmth started 9000 yr B.P. and lasted at least until 5000 yr B.P., correlative with the Prairie Period in Minnesota.

  2. Potentiality for obtaining poria disease signatures in the Oregon Cascades from orbital altitudes

    NASA Technical Reports Server (NTRS)

    Wear, J. F.

    1972-01-01

    A prime photographic signature indicator of an important forest disease was identified in valuable Douglas-fir stands of the Pacific Northwest. The disease signature was verified by a multidisciplinary team of scientists to be the direct result of the Poria weirii root-rot syndrome in the Douglas-fir and hemlock stands of the high Cascades in Oregon. It is readily discernible on small-scale suborbital photography and has good potential for detection from earth-orbiting satellites or remote sensing platforms.

  3. Consume users guide. Forest Service general technical report

    SciTech Connect

    Ottmar, R.D.; Burns, M.F.; Hall, J.N.; Hanson, A.D.

    1993-01-01

    CONSUME is a user-friendly computer program designed for resource managers with some working knowledge of IBM-PC applications. The software predicts the amount of fuel consumption on logged units based on weather data, the amount and fuel moisture of fuels, and a number of other factors. Using these predictions, the resource manager can accurately determine when and where to conduct a prescribed burn to achieve desired objectives, while reducing impacts on other resources. CONSUME can be used for most broadcast and underburns on forested lands in the western states if the woody fuels are relatively homogeneous and composed of Douglas-fir, hemlock, alder, lodgepole pine, or mixed conifer species.

  4. AmeriFlux US-UMB Univ. of Mich. Biological Station

    DOE Data Explorer

    Curtis, Peter [Ohio State University; Gough, Christopher [Virginia Commonwealth University

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-UMB Univ. of Mich. Biological Station. Site Description - The UMBS site is located within a protected forest owned by the University of Michigan. Arboreal composition of the forest consists of mid-aged northern hardwoods, conifer understory, aspen, and old growth hemlock. Logging of local white pines began in 1879. In successive years, several other species were harvested. Logging was discontinued in 1980 when the land became protected under the private ownership of the University of Michigan. Patchy low- to high-intensity wildfires occurred yearly from 1880 - 1920, essentially burning the entire region.

  5. Fiber 3.0: An ecological growth model for northeastern forest types. Forest Service general technical report (Final)

    SciTech Connect

    Solomon, D.S.; Herman, D.A.; Leak, W.B.

    1995-05-22

    Fiber, a stand projection growth model, simulates the growth and structural development of stands in the Northeast. The internal structure of the model is specified and constructed by the ecological type classifications of sugar maple--ash, beech--red maple, oad--white pine, spruce--fir, hemlock--spruce, and cedar--black spruce. Guidelines are provided on operational procedures for the major commercial species growing on these different ecologic land classifications for a range of even-aged and uneven-aged silvicultural treatments and harvesting schedules.

  6. Soil drainage and vegetation controls of nitrogen transformation rates in forest soils, southern Quebec

    NASA Astrophysics Data System (ADS)

    Ullah, Sami; Moore, Tim R.

    2009-03-01

    We investigated the influence of soil drainage class and tree species on nitrogen (N) mineralization and nitrification rates in two forest catenas in southern Quebec. Monthly net N mineralization and nitrification rates were determined along transects running from well-drained to poorly drained soils for 2 years through in situ incubation of homogenized soils. Potential N transformation rates in soils under American beech, sugar maple, and eastern hemlock trees were determined through incubation of homogenized soils in the laboratory under two different moisture regimes (50 and 100% water by volume) mimicking well-drained and poorly drained soil conditions in the two watersheds. Field-based N mineralization rates averaged 38 ± 6 mg m-2 d-1 in well-drained soils, while those in the poorly drained soils averaged 17 ± 5 mg N m-2 d-1. Similarly, net nitrification rates in well-drained soils (18 ± 4 mg N m-2 d-1) were 3 times greater than those in poorly drained soils (6 ± 3 mg N m-2 d-1). Laboratory-based potential N mineralization rates in soils ranked sugar maple > American beech > eastern hemlock under both well-drained (incubated at 50% water by volume) and poorly drained soil conditions (incubated at 100% water by volume). Potential nitrification rates ranked sugar maple > American beech > eastern hemlock under well-drained soil conditions, while under poorly drained conditions, American beech > sugar maple ≥ eastern hemlock. Nitrification enzyme activity determined through a soil slurry method correlated significantly with field-based nitrification rates. Differences in soil volumetric water contents, leaf litter N input, and soil C:N ratios, as surrogates of soil drainage and floristic heterogeneity, respectively, correlated significantly with field-based N mineralization and nitrification rates. Field-based N mineralization and nitrification rates were higher in summer than in early spring and autumn. Soil drainage class and tree species exert marked

  7. Biogenic and thermogenic origins of natural gas in Cook Inlet basin, Alaska.

    USGS Publications Warehouse

    Claypool, G.E.; Threlkeld, C.N.; Magoon, L.B.

    1980-01-01

    Two types of natural gas occurences are present. The major reserves (1.8 x 1011m3) occur in shallow (less than 2.300 m), nonassociated dry gas fields that contain methane with del13C in the range of -63 to -56 per mil. These gas fields are in sandstones interbedded with coals, the gas fields are interpreted as biogenic in origin. Lesser reserves of natural gas are associated with oil in the deeper Hemlock Conglomerate at the base of the Tertiary section; associated gas contains methane with del13C of about -46 per mil. These gases are thermogenic in origin.- from Authors

  8. Operational experience at a `dog-hair` site. Forest Service research note

    SciTech Connect

    Ricketts, S.R.; Miller, R.E.

    1995-04-01

    The authors installed plots in a nine-year-old Douglas-fir plantation established after clearcutting a grossly overstocked stand. One plot sampled the slash-burned portion. In the nonburned portion, two plots were in areas thinned three years earlier by machete combined with pulling small seedlings, and four were in areas thinned by chainsaw. Stumps with sprouts averaged 5,665 per acre in saw-thinned plots and only 250 per acre in plots thinned by machete and pulling. Most seedlings and sprouts were western hemlock. Machete cutting and pulling proved more effective than chainsaws for reducing stem density. Slash burning destroyed most new seedlings.

  9. AmeriFlux US-Ha1 Harvard Forest EMS Tower (HFR1)

    DOE Data Explorer

    Munger, J. William [Harvard University

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Ha1 Harvard Forest EMS Tower (HFR1). Site Description - The Harvard Forest tower is on land owned by Harvard University. The site is designated as an LTER site. Most of the surrounding area was cleared for agrigulture during European settlement in 1600-1700. The site has been regrowing since before 1900 (based on tree ring chronologies) and is now predominantly red oak and red maple, with patches of mature hemlock stand and individual white pine. Overstory trees were uprooted by hurricane in 1938. Climate measurements have been made at Harvard Forest since 1964.

  10. Toxicity of pyrolysis gases from wood

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Huttlinger, N. V.; Oneill, B. A.; Kourtides, D. A.; Parker, J. A.

    1977-01-01

    The toxicity of the pyrolysis gases from nine wood samples was investigated. The samples of hardwoods were aspen poplar, beech, yellow birch, and red oak. The samples of softwoods were western red cedar, Douglas fir, western hemlock, eastern white pine, and southern yellow pine. There was no significant difference between the wood samples under rising temperature conditions, which are intended to simulate a developing fire, or under fixed temperature conditions, which are intended to simulate a fully developed fire. This test method is used to determine whether a material is significantly more toxic than wood under the preflashover conditions of a developing fire.

  11. Pliocene terrace gravels of the ancestral Yukon River near Circle, Alaska: Palynology, paleobotany, paleoenvironmental reconstruction and regional correlation

    USGS Publications Warehouse

    Ager, T.A.; Matthews, J.V.; Yeend, W.

    1994-01-01

    Gravels deposited by the ancestral Yukon River are preserved in terrace remnants on the margins of the Yukon River valley near the village of Circle in east-central Alaska. Plant fossils recovered from sandy silt lenses within these gravels include cones and needles of Picea and Larix and a variety of seeds. Seed types include several taxa which no longer grow in Alaska, such as Epipremnum, Prunus and Weigela. Pollen types recovered from these deposits represent tree and shrub taxa that grow in interior Alaska today, such as Picea, Larix, Betula and Alnus, as well as several taxa that no longer grow in interior Alaska today, such as Pinus, Tsuga, Abies and Corylus. Pollen of herb taxa identified include Gramineae, Cyperaceae, Caryophyllaceae, Compositae, Polemonium and Epilobium. The fossil flora from the gravels near Circle are similar and probably age-equivalent to the flora recovered from the Nenana Gravel in the Alaska Range 250 km to the south. Palynological and tectonic evidence summarized in this paper now suggests that the Nenana Gravel was deposited during the early and middle Pliocene. The presence of plant fossils of Tsuga, Abies, Pinus, Weigela and Prunus suggests that the mean annual temperature (MAT) of eastern interior Alaska during the early and middle Pliocene was perhaps 7-9??C warmer and less continental than today's MAT of -6.4??C. ?? 1994.

  12. High-level expression, purification and production of the fungal immunomodulatory protein-gts in baculovirus-infected insect larva.

    PubMed

    Wu, Tzong-Yuan; Chen, Hsin-An; Li, Feng-Yin; Lin, Ching-Ting; Wu, Chi-Ming; Hsieh, Feng-Chia; Tzen, Jason Tze-Cheng; Hsieh, Sheng-Kuo; Ko, Jiunn-Liang; Jinn, Tzyy-Rong

    2013-02-01

    Fip-gts, a fungal immunomodulatory protein (Fip) isolated from Ganoderma tsugae (gts), has been reported to possess therapeutic effects in the treatment of cancer and autoimmune disease. To cost-effectively produce Fip-gts and bypass the bottleneck involved in its time-consuming purification from G. tsugae, in this study, we incorporated the SP(bbx) secretion signal into recombinant baculovirus for expressing glycosylated and bioactive rFip-gts in baculovirus-infected insect cells and Trichoplusia ni larva. This is the first study to employ the aerosol infecting T. ni larva with recombinant baculovirus for economical and high-level production of foreign proteins. In this study, one purification could yield 10 mg of rFip-gts protein merely from ∼100 infected T. ni larvae by aerosol inoculation, corresponding to 5 L (5 × 10⁹ cells) of the infected Sf21 culture. In addition, the rFip-gts purified from T. ni larvae could induce the expression of interleukin-2 in murine splenocytes with an immunoresponsive level similar to that induced by LZ-8 (a known potent immunomodulatory protein purified from Ling zhi, Ganoderma lucidum). Thus, our results demonstrated that the larva-based baculovirus expression system can successfully express rFip-gts with the assembling capability required for maintaining immunomodulatory and anticancer activity. Our approach will open a new avenue for the production of rFip-gts and facilitate the immunoregulatory activity of rFip-gts available in the future.

  13. Late-glacial and Holocene Vegetation and Climate Variability, Including Major Droughts, in the Sky Lakes Region of Southeastern New York State

    NASA Technical Reports Server (NTRS)

    Menking, Kirsten M.; Peteet, Dorothy M.; Anderson, Roger Y.

    2012-01-01

    Sediment cores from Lakes Minnewaska and Mohonk in the Shawangunk Mountains of southeastern New York were analyzed for pollen, plantmacrofossils, macroscopic charcoal, organic carbon content, carbon isotopic composition, carbon/nitrogen ratio, and lithologic changes to determine the vegetation and landscape history of the greater Catskill Mountain region since deglaciation. Pollen stratigraphy generally matches the New England pollen zones identified by Deevey (1939) and Davis (1969), with boreal genera (Picea, Abies) present during the late Pleistocene yielding to a mixed Pinus, Quercus and Tsuga forest in the early Holocene. Lake Minnewaska sediments record the Younger Dryas and possibly the 8.2 cal kyr BP climatic events in pollen and sediment chemistry along with an 1400 cal yr interval of wet conditions (increasing Tsuga and declining Quercus) centered about 6400 cal yr BP. BothMinnewaska andMohonk reveal a protracted drought interval in themiddle Holocene, 5700-4100 cal yr BP, during which Pinus rigida colonized the watershed, lake levels fell, and frequent fires led to enhanced hillslope erosion. Together, the records show at least three wet-dry cycles throughout the Holocene and both similarities and differences to climate records in New England and central New York. Drought intervals raise concerns for water resources in the New York City metropolitan area and may reflect a combination of enhanced La Niña, negative phase NAO, and positive phase PNA climatic patterns and/or northward shifts of storm tracks.

  14. Flavanol binding of nuclei from tree species.

    PubMed

    Feucht, W; Treutter, D; Polster, J

    2004-01-01

    Light microscopy was used to examine the nuclei of five tree species with respect to the presence of flavanols. Flavanols develop a blue colouration in the presence of a special p-dimethylaminocinnamaldehyde (DMACA) reagent that enables those nuclei loaded with flavanols to be recognized. Staining of the nuclei was most pronounced in both Tsuga canadensis and Taxus baccata, variable in Metasequoia glyptostroboides, faint in Coffea arabica and minimal in Prunus avium. HPLC analysis showed that the five species contained substantial amounts of different flavanols such as catechin, epicatechin and proanthocyanidins. Quantitatively, total flavanols were quite different among the species. The nuclei themselves, as studied in Tsuga seed wings, were found to contain mainly catechin, much lower amounts of epicatechin and traces of proanthocyanidins. Blue-coloured nuclei located centrally in small cells were often found to maximally occupy up to 90% of a cell's radius, and the surrounding small rim of cytoplasm was visibly free of flavanols. A survey of 34 gymnosperm and angiosperm species indicated that the first group has much higher nuclear binding capacities for flavanols than the second group.

  15. Community Structure and Survival of Tertiary Relict Thuja sutchuenensis (Cupressaceae) in the Subtropical Daba Mountains, Southwestern China.

    PubMed

    Tang, Cindy Q; Yang, Yongchuan; Ohsawa, Masahiko; Momohara, Arata; Yi, Si-Rong; Robertson, Kevin; Song, Kun; Zhang, Shi-Qiang; He, Long-Yuan

    2015-01-01

    A rare coniferous Tertiary relict tree species, Thuja sutchuenensis Franch, has survived in the Daba Mountains of southwestern China. It was almost eliminated by logging during the past century. We measured size and age structures and interpreted regeneration dynamics of stands of the species in a variety of topographic contexts and community associations. Forest communities containing T. sutchuenensis were of three types: (1) the Thuja community dominated by T. sutchuenensis, growing on cliffs; (2) the Thuja-Quercus-Cyclobalanopsis community dominated by T. sutchuenensis, Quercus engleriana and Cyclobalanopsis oxyodon, along with Fagus engleriana and Carpinus fargesiana, on steep slopes; (3) the Thuja-Tsuga-Quercus community dominated by T. sutchuenensis, Tsuga chinensis, and Quercus spinosa, on crest ridges. The established seedlings/saplings were found in limestone crevices, on scarred cliff-faces, cliff-edges, fallen logs, canopy gaps and forest margins. The radial growth rate was 0.5-1.1 mm per year. Its growth forms were distorted. It had strong sprouting ability after disturbances. The T. sutchuenensis population thrives on cliffs where there is little competition from other species because of harsh conditions and rockslide disturbances. It is shade-intolerant but stress-tolerant. Its regeneration has depended on natural disturbances.

  16. Community Structure and Survival of Tertiary Relict Thuja sutchuenensis (Cupressaceae) in the Subtropical Daba Mountains, Southwestern China

    PubMed Central

    Tang, Cindy Q.; Yang, Yongchuan; Ohsawa, Masahiko; Momohara, Arata; Yi, Si-Rong; Robertson, Kevin; Song, Kun; Zhang, Shi-Qiang; He, Long-Yuan

    2015-01-01

    A rare coniferous Tertiary relict tree species, Thuja sutchuenensis Franch, has survived in the Daba Mountains of southwestern China. It was almost eliminated by logging during the past century. We measured size and age structures and interpreted regeneration dynamics of stands of the species in a variety of topographic contexts and community associations. Forest communities containing T. sutchuenensis were of three types: (1) the Thuja community dominated by T. sutchuenensis, growing on cliffs; (2) the Thuja-Quercus-Cyclobalanopsis community dominated by T. sutchuenensis, Quercus engleriana and Cyclobalanopsis oxyodon, along with Fagus engleriana and Carpinus fargesiana, on steep slopes; (3) the Thuja-Tsuga-Quercus community dominated by T. sutchuenensis, Tsuga chinensis, and Quercus spinosa, on crest ridges. The established seedlings/saplings were found in limestone crevices, on scarred cliff-faces, cliff-edges, fallen logs, canopy gaps and forest margins. The radial growth rate was 0.5-1.1 mm per year. Its growth forms were distorted. It had strong sprouting ability after disturbances. The T. sutchuenensis population thrives on cliffs where there is little competition from other species because of harsh conditions and rockslide disturbances. It is shade-intolerant but stress-tolerant. Its regeneration has depended on natural disturbances. PMID:25928845

  17. Pollen record from Colle Curti and Cesi: Early and Middle Pleistocene mammal sites in the Umbro-Marchean Apennine Mountains (central Italy)

    NASA Astrophysics Data System (ADS)

    Bertini, Adele

    2000-12-01

    The palynological record from the Colle Curti and Cesi continental deposits has been examined in order to identify the main palaeofloristic and vegetational changes between 0.99 and 0.6-0.7 Ma. These data show a progressive increase in aridity, as well as a progressive decrease in temperature, which are associated with the transition in dominance from the 41 to 100 ka cyclicity in the Milankovitch orbital record during the Middle Pleistocene. The disappearance of Tsuga, recorded during the lower part of the Brunhes Chron, also has been related to a shift in global aridity. During the successive open vegetational phases (glacials), Chenopodiaceae and Artemisia progressively increase, whereas Cyperaceae decrease. Forest phases (interglacials) are successively dominated by Tsuga, Abies with Picea and, finally, Pinus; but all lack significant expansion of broad-leaved deciduous taxa. Palynological and sedimentological data, in addition to taphonomic interpretations, demonstrate the occurrence of several hiatuses in the lower parts of the interglacials. These hiatuses are considered to represent the palaeoenvironmental response to climatic changes affecting local sedimentological and geomorphological conditions.

  18. Entomopathogenic Fungi Associated with Exotic Invasive Insect Pests in Northeastern Forests of the USA.

    PubMed

    Gouli, Vladimir; Gouli, Svetlana; Marcelino, José A P; Skinner, Margaret; Parker, Bruce L

    2013-11-04

    Mycopathogens of economically important exotic invasive insects in forests of northeastern USA have been the subject of research at the Entomology Research Laboratory, University of Vermont, for the last 20 years. Elongate hemlock scale, European fruit lecanium, hemlock woolly adelgid and pear thrips were analyzed for the presence of mycopathogens, in order to consider the potential for managing these pests with biological control. Fungal cultures isolated from insects with signs of fungal infection were identified based on morphological characters and DNA profiling. Mycopathogens recovered from infected insects were subdivided into three groups, i.e., specialized entomopathogenic; facultative entomopathogens; ubiquitous opportunistic contaminants. Epizootics were caused by fungi in the specialized group with the exception of M. microspora, P. marquandii and I. farinosa. Inoculation of insects in laboratory and field conditions with B. bassiana, L. muscarium and Myriangium sp. caused insect mortality of 45 to 95%. Although pest populations in the field seemed severely compromised after treatment, the remnant populations re-established themselves after the winter. Although capable of inducing high mortality, a single localized aerial application of a soil-dwelling fungus does not maintain long-time suppression of pests. However, it can halt their range expansion and maintain populations below the economic threshold level without the use of expensive insecticides which have a negative impact on the environment.

  19. Interannual variability in aboveground tree growth in Stehekin River watershed, North Cascade Range, Washington

    USGS Publications Warehouse

    Hessl, Amy E.; Peterson, D.L.

    2004-01-01

    Many forests in the Pacific Northwest region of North America are both highly productive and sensitive to climate. The combination of productivity and sensitivity makes forests vulnerable to changes in future climate and most likely to feed back to the regional carbon cycle. We reconstructed basal area increment (BAI) for 20 yr using tree-ring increments and diameter to identify species-specific responses of 14 forested vegetation types in the Stehekin River watershed in the North Cascade Range, to interannual climatic variability. Mean basal area increment (MBAI) for the 20-yr period is low when the standard error is low, but as MBAI increases, the standard error (SE) is more variable. Growth at sites with both low SE and MBAI may be related to climatic variables, however, some forest types dominated by Douglas-fir and mountain hemlock are both productive and responsive to climatic variability. Many forests in the Pacific Northwest are dominated by Douglas-fir, a commercially important timber species, and as a result, may play a major role in the regional carbon balance. Douglas-fir and mountain hemlock forests in the eastern portion of the North Cascades should be carefully monitored and managed in the context of both changing climatic conditions and regional carbon budgets.

  20. Poisonous plants: effects on embryo and fetal development.

    PubMed

    Panter, Kip E; Welch, Kevin D; Gardner, Dale R; Green, Benedict T

    2013-12-01

    Poisonous plant research in the United States began over 100 years ago as a result of livestock losses from toxic plants as settlers migrated westward with their flocks, herds, and families. Major losses were soon associated with poisonous plants, such as locoweeds, selenium accumulating plants, poison-hemlock, larkspurs, Veratrum, lupines, death camas, water hemlock, and others. Identification of plants associated with poisoning, chemistry of the plants, physiological effects, pathology, diagnosis, and prognosis, why animals eat the plants, and grazing management to mitigate losses became the overarching mission of the current Poisonous Plant Research Laboratory. Additionally, spin-off benefits resulting from the animal research have provided novel compounds, new techniques, and animal models to study human health conditions (biomedical research). The Poisonous Plant Research Laboratory has become an international leader of poisonous plant research as evidenced by the recent completion of the ninth International Symposium on Poisonous Plant Research held July 2013 in Hohhot, Inner Mongolia, China. In this article, we review plants that negatively impact embryo/fetal and neonatal growth and development, with emphasis on those plants that cause birth defects. Although this article focuses on the general aspects of selected groups of plants and their effects on the developing offspring, a companion paper in this volume reviews current understanding of the physiological, biochemical, and molecular mechanisms of toxicoses and teratogenesis.

  1. Boreal peatland margins as repository sites of long-term natural disturbances of balsam fir/spruce forests

    NASA Astrophysics Data System (ADS)

    Lavoie, Martin; Filion, Louise; Robert, Élisabeth C.

    2009-05-01

    A multidisciplinary, high-resolution paleoecological study (Lepidoptera and plant remains, macroscopic charcoal, pollen) was conducted on a 4000-yr peat monolith extracted from the margin of an ombrotrophic peatland on Anticosti Island (Gulf of St. Lawrence, eastern Canada) to reconstruct the long-term natural disturbances (insect outbreaks, forest fires) of a balsam fir/spruce forest. We hypothesized that an activity of insect defoliators (spruce budworm, hemlock looper) was the main disturbance factor of conifer forests during the Late Holocene. The earliest remains of spruce budworm and hemlock looper were found ca. 3220 and 2350 cal yr BP, respectively. Peaks of insect head capsules occurred from ca. 1640 to ca. 625 cal yr BP. Low balsam fir pollen concentrations during this period suggest a lengthy episode (˜ 1000 yr) of high insect activity, resulting in extensive fir dieback and mortality. The long-term dynamics of the pristine balsam fir/spruce forests were mainly governed by the activity of insect defoliators. The limited extent and possibly the low occurrence of forest fires in the maritime environment of Anticosti Island allowed the development of mature coniferous stands propitious for insect infestations. Insect head capsules appeared to be a useful and effective tool for establishing insect presence and activity during the Holocene.

  2. Fire History and Tree Recruitment in an Uncut New England Forest

    NASA Astrophysics Data System (ADS)

    Mann, Daniel H.; Engstrom, F. Brett; Bubier, Jill L.

    1994-09-01

    Fire and forest histories in a hemlock-pine forest in Vermont have been reconstructed by dating fire scars and reconstructing the age distributions of living and dead trees. The ages of living red pines, white pines, and hemlocks show that most of the present forest germinated after a series of spatially overlapping fires between A.D. 1790 and 1850. The ages of cross-dated, dead red pines indicate that this was the third major recruitment interval for pines in this forest since ca. A.D. 1450. We interpret the fire scar and tree age data as recording ca. 50-yr intervals of increased fire frequency recurring every 100-200 yr in response to accumulating fuel loads that coincide with summer drought. The historical records of fires and tree ages, together with the present fuel load, suggest that the next interval of stand-regenerating fires is now overdue. Our success in cross-dating the remnants of dead red pines as old as the 15th century A.D. holds promise for extending reconstructions of fire, forest, and climate history in other parts of this tree's range.

  3. Distribution of Selected Plant Parasitic Nematodes Relative to Vegetation and Edaphic Factors

    PubMed Central

    Norton, D. C.; Hoffmann, J. K.

    1974-01-01

    The occurrence of selected plant-parasitic nematodes in the hemlock-hardwood-white pine, boreal forest, tundra, and oak-hickory associations in some northern states was compared. Helicotylenchus platyurus and Xiphinema americanum were not found in the boreal forest and tundra, and occurred infrequently in the hemlock-hardwood-white pine areas. They were found frequently, however, in the oak-hickory forest of Iowa. It is questioned that vegetational differences among the areas account directly for the major differences in nematode occurrence. Presence and absence of nematodes and their numbers in the oak-hickory association were clustered by similarity coefficients by sites and correlated with soil pH, percentage organic matter, percentage sand-silt-clay, and field capacity. Of the soil factors measured, pH gave the strongest correlations with nematode numbers. Xiphinema chambersi was found only in soils with a pH between 4.5 and 6.4 while the largest numbers of H. platyurus, H. pseudorobustus, and X. americanum occurred in soil above pH 6.0. PMID:19319372

  4. Entomopathogenic Fungi Associated with Exotic Invasive Insect Pests in Northeastern Forests of the USA

    PubMed Central

    Gouli, Vladimir; Gouli, Svetlana; Marcelino, José A. P.; Skinner, Margaret; Parker, Bruce L.

    2013-01-01

    Mycopathogens of economically important exotic invasive insects in forests of northeastern USA have been the subject of research at the Entomology Research Laboratory, University of Vermont, for the last 20 years. Elongate hemlock scale, European fruit lecanium, hemlock woolly adelgid and pear thrips were analyzed for the presence of mycopathogens, in order to consider the potential for managing these pests with biological control. Fungal cultures isolated from insects with signs of fungal infection were identified based on morphological characters and DNA profiling. Mycopathogens recovered from infected insects were subdivided into three groups, i.e., specialized entomopathogenic; facultative entomopathogens; ubiquitous opportunistic contaminants. Epizootics were caused by fungi in the specialized group with the exception of M. microspora, P. marquandii and I. farinosa. Inoculation of insects in laboratory and field conditions with B. bassiana, L. muscarium and Myriangium sp. caused insect mortality of 45 to 95%. Although pest populations in the field seemed severely compromised after treatment, the remnant populations re-established themselves after the winter. Although capable of inducing high mortality, a single localized aerial application of a soil-dwelling fungus does not maintain long-time suppression of pests. However, it can halt their range expansion and maintain populations below the economic threshold level without the use of expensive insecticides which have a negative impact on the environment. PMID:26462527

  5. Vegetation Response to Transient Drought Events in the Upper Midwest

    NASA Astrophysics Data System (ADS)

    Minckley, T.; Booth, R.; Jackson, S.

    2006-12-01

    Two paleohydrological proxies from bog sediments, water level based on testate amoebae assemblages and peat humification, indicate both prolonged and transient drought events over the past 3500 years. High- resolution pollen data for the periods 3000-2200 and 1400-500 cal yr BP from Minden Bog (46.6106N, 82.8347W), Michigan were examined to assess how regional vegetation composition was affected by drought events. Between 3000-2200 cal yr BP, four intervals of multi-decadal drought and one prolonged drought episode were identified. Four of the five dominant arboreal pollen taxa (Betula, Fagus, Quercus and Pinus) do not appear to response to these particular events. In contrast, Tsuga percentages rise at the onset of a prolonged drought ca. 2850 cal yr BP, but decrease rapidly for the duration of this event. Between 1400-500 cal yr BP, five transient droughts and one prolonged dry period were identified. Betula, Pinus, and Tsuga generally increased and Fagus decreased during this period. These trends are punctuated by stepwise changes in pollen percentages associated with the onset and persistence of drought, particularly with the drought starting ca. 1000 cal yr BP. These data suggest that pollen-assemblage responses to climate variation occur across a broad range of scales, involving processes at landscape, community, population, and individual levels. At centennial timescales regional forest composition changes in response to climate variation via demographic processes and altered disturbance regimes. These responses can be rapid if the forcing is large enough. Transient drought events of lower magnitude (e.g., decadal/multidecadal) are accompanied by pollen responses, but these may be linked to changes in pollen productivity at the scale of individual trees across the landscape rather than demographic changes. Tree species differ in their physiological and reproductive responses to drought stress, with some reducing allocations to pollen productivity and others

  6. Spasmolytic activity of some plants used by the Otomi Indians of Quéretaro (México) for the treatment of gastrointestinal disorders.

    PubMed

    Rojas, A; Bah, M; Rojas, J I; Serrano, V; Pacheco, S

    1999-11-01

    The present study was performed to investigate the effect of chloroform-methanol (1:1) extracts derived from Baccharis heterophylla H. B. K (Asteraceae), Desmodium grahami Gray (Leguminosae), Dyssodia pinnata var. pinnata Rob. (Asteraceae), Gentiana spathacea H. B. K. (Gentianaceae), Loeselia mexicana Brand. (Polemoniaceae), Selaginella pallescens Spring. (Selaginellaceae) and Zornia diphylla Pers. (Fabaceae) on the spontaneous contractions of isolated rat ileum. The concentration-response curves and IC50 values were obtained and the respective relaxant potencies were compared with that of the CHCl3-MeOH (1:1) extract of Datura lanosa. The data showed that all the extracts produce a concentration-dependent inhibition of spontaneous ileum contractions. In addition, the antimicrobial activity of the extracts against pathogenic enterobacteria was tested. The pharmacological actions shown by the extracts of the selected species tend to support ethnomedical use of the plants for the treatment of gastrointestinal disorders.

  7. Wall Analyses of Lophocolea Seta Cells (Bryophyta) Before and After Elongation 1

    PubMed Central

    Thomas, Robert J.

    1977-01-01

    Lophocolea heterophylla (Schrad.) Dum. (a leafy liverwort) produces sporophytes with seta cells that elongate 50-fold in 3 to 4 days. Wall components of these cells have been characterized by microscopic histochemistry, colorimetry, and gas chromatography of neutral sugars. Seta cell walls are qualitatively similar to primary cell walls of higher plants. The pectic fraction, however, responds differently to standard histochemical staining and extraction. Quantitatively, mannose, fucose, and rhamnose are in higher percentage, and arabinose and xylose are lower than typically found in vascular plants. Hexuronic acids increase on a percentage basis during elongation; pentoses decrease slightly, while hexose levels remain about the same. Increase in total wall carbohydrate after 2,400% elongation of setae was 1.8-fold. Images PMID:16659846

  8. Corroborating molecular species discovery: Four new pine-feeding species of Chionaspis (Hemiptera, Diaspididae)

    PubMed Central

    Vea, Isabelle M.; Gwiazdowski, Rodger A.; Normark, Benjamin B.

    2013-01-01

    Abstract The genus Chionaspis (Hemiptera, Diaspididae) includes two North American species of armored scale insects feeding on Pinaceae: Chionaspis heterophyllae Cooley, and Chionaspis pinifoliae (Fitch). Despite the economic impact of conifer-feeding Chionaspis on horticulture, the species diversity in this group has only recently been systematically investigated using samples from across the group’s geographic and host range. This paper provides morphological recognition characters for four new species that were recently hypothesized to exist on the basis of molecular evidence. The new species, here described, are Chionaspis brachycephalon Vea sp. n., Chionaspis caudata Vea sp. n., Chionaspis sonorae Vea sp. n. and Chionaspis torreyanae Vea sp. n.  One of the new species, Chionaspis caudata Vea, has a gland spine at the apex of the pygidium, between the median lobes, unlike any other species of Chionaspis. An identification key to the species of Chionaspis feeding on pine in North America is provided. PMID:23717184

  9. Correct names for some of the closest relatives of Carica papaya: A review of the Mexican/Guatemalan genera Jarilla and Horovitzia

    PubMed Central

    Carvalho, Fernanda Antunes; Renner, Susanne S.

    2013-01-01

    Abstract Using molecular data, we recently showed that Carica papaya L. is sister to a Mexican/Guatemalan clade of two genera, Jarilla Rusby with three species and Horovitzia V.M. Badillo with one. These species are herbs or thin-stemmed trees and may be of interest for future genomics-enabled papaya breeding. Here we clarify the correct names of Jarilla heterophylla (Cerv. ex La Llave) Rusby and Jarilla caudata (Brandegee) Standl., which were confused in a recent systematic treatment of Jarilla (McVaugh 2001). We designate epitypes for both, provide weblinks to type specimens, a key to the species of Jarilla and Horovitzia, and notes on their habitats and distribution. PMID:24399895

  10. Identification of Begomoviruses Infecting Crops and Weeds in Belize

    PubMed Central

    McLaughlin, Pamela D.; McLaughlin, Wayne A.; Maxwell, Douglas P.; Roye, Marcia E.

    2010-01-01

    Plants including pepper, red kidney bean, squash, string bean and tomato, as well as weeds with viral symptoms were collected from five districts in Belize over a three year period with the aim of determining the diversity of the begomoviruses present. Sixty five percent of the samples screened via DNA hybridization produced signals indicative of begomovirus infection. Subsequent PCR amplifications and nucleotide sequence analyses revealed the presence of four begomoviruses in Belize. Pepper golden mosaic virus and Tomato mottle virus-[Flo] were found associated with tomato and sweet pepper and the former was also isolated from hot pepper. Merremia mosaic virus was found infecting hot pepper, sweet pepper and the weed species Euphorbia heterophylla. Euphorbia mosaic virus-[Yucatan Peninsula] was found in hot pepper and Euphorbia. This is the first report of the identification of begomoviruses in Belize. PMID:20596296

  11. Structural, biochemical, and physiological characterization of C4 photosynthesis in species having two vastly different types of kranz anatomy in genus Suaeda (Chenopodiaceae).

    PubMed

    Voznesenskaya, E V; Chuong, S D X; Koteyeva, N K; Franceschi, V R; Freitag, H; Edwards, G E

    2007-11-01

    C (4) species of family Chenopodiaceae, subfamily Suaedoideae have two types of Kranz anatomy in genus Suaeda, sections Salsina and Schoberia, both of which have an outer (palisade mesophyll) and an inner (Kranz) layer of chlorenchyma cells in usually semi-terete leaves. Features of Salsina (S. AEGYPTIACA, S. arcuata, S. taxifolia) and Schoberia type (S. acuminata, S. Eltonica, S. cochlearifoliA) were compared to C (3) type S. Heterophylla. In Salsina type, two layers of chlorenchyma at the leaf periphery surround water-storage tissue in which the vascular bundles are embedded. In leaves of the Schoberia type, enlarged water-storage hypodermal cells surround two layers of chlorenchyma tissue, with the latter surrounding the vascular bundles. The chloroplasts in Kranz cells are located in the centripetal position in Salsina type and in the centrifugal position in the Schoberia type. Western blots on C (4) acid decarboxylases show that both Kranz forms are NAD-malic enzyme (NAD-ME) type C (4) species. Transmission electron microscopy shows that mesophyll cells have chloroplasts with reduced grana, while Kranz cells have chloroplasts with well-developed grana and large, specialized mitochondria, characteristic of NAD-ME type C (4) chenopods. In both C (4) types, phosphoenolpyruvate carboxylase is localized in the palisade mesophyll, and Rubisco and mitochondrial NAD-ME are localized in Kranz cells, where starch is mainly stored. The C (3) species S. heterophylla has Brezia type isolateral leaf structure, with several layers of Rubisco-containing chlorenchyma. Photosynthetic response curves to varying CO (2) and light in the Schoberia Type and Salsina type species were similar, and typical of C (4) plants. The results indicate that two structural forms of Kranz anatomy evolved in parallel in species of subfamily Suaedoideae having NAD-ME type C (4) photosynthesis.

  12. Human-ecosystem interactions in relation to Holocene environmental change in Port Joli Harbour, southwestern Nova Scotia, Canada

    NASA Astrophysics Data System (ADS)

    Neil, Karen; Gajewski, Konrad; Betts, Matthew

    2014-03-01

    A high-resolution pollen record from Path Lake in Port Joli Harbour, Nova Scotia, Canada, provides a paleo-ecological perspective on Holocene climate and vegetation variability within the context of local archaeological research. Pollen assemblages in the early Holocene reflect a post-glacial forest dominated by Pinus, Tsuga, Betula and Quercus. During this time, a lower frequency of radiocarbon dated cultural material suggests lower human settlement intensity. Shallow water aquatic (Isoetes) and wetland (Alnus, Sphagnum) taxa increased after 3400 cal yr BP in response to a transition towards wetter climatic conditions. Culturally significant periods, where settlement intensity increased in the Maritimes and Maine, coincide with maximum values of reconstructed total annual precipitation, suggesting that environmental conditions may have influenced prehistoric human activity. European settlement, after 350 cal yr BP, was marked by a rise in Ambrosia. The impact of anthropogenic fire disturbances on the landscape was evidenced by peak charcoal accumulations after European settlement.

  13. Naturally occurring insect growth regulators. II. Screening of insect and plant extracts as insect juvenile hormone mimics.

    PubMed

    Jacobson, M; Redfern, R E; Mills, G D

    1975-01-01

    Ethereal extracts prepared from the larvae, pupae, or eggs of 10 species of insects and from various parts of 343 species of higher plants were screened for juvenilizing effects against Tenebrio molitor and Oncopeltus fasciatus. Activity in both species was shown by an extract of the larvae of the stable fly, Stomoxys calcitrans, whereas an extract of the pupae was active in O. fasiatus only. Extracts of two plant species (Echinacea angustifolia roots and Chamaecyparis lawsoniana seeds) showed high juvenilizing activity in T. MOLITOR, AND EXtracts of five plant species (Clethra alnifolia stems, leaves, and fruits, Sassafras albidum roots and root bark, Eucalyptus camaldulensis stems and bark, Pinus rigida twigs and leaves, and Iris douglasiana roots, stems, and fruits) were highly active in O. fasciatus an extract of Tsuga canadensis leaves showed lower activity in this insect. Extracts of 16 species of plants showed high insecticidal activity (mortality) in O. fasciatus but lacked juvenilizing properties in both species of test insects.

  14. Mapped plant macrofossil and pollen records of late Quaternary vegetation change in eastern North America

    SciTech Connect

    Jackson, S.T.; Overpeck, J.T.; Webb, T. III ||

    1995-06-01

    We compiled a plant macrofossil database for 12 eastern North American tree and shrub taxa (Picea sp., P. glauca, P. mariana, Larix laricina, Abies balsamea, Tsuga canadensis, Pinus strobus, P. banksiana, P. resinosa, Betula papyrifera, B. alleghaniensis, B. Series Humiles) at 264 late Quaternary sites. Presence/absence maps for these taxa at 18,000, 15,000, 12,000, 9000, 6000, 3000, and 0 {sup 14}C yr B.P. show changes in geographic ranges of these species in response to climatic change. Comparison of the macrofossil maps with isopoll maps for corresponding taxa corroborates inferences from the pollen data, and reveals species-level patterns not apparent in the pollen maps.

  15. Modern pollen deposition in Long Island Sound

    USGS Publications Warehouse

    Beuning, Kristina R.M.; Fransen, Lindsey; Nakityo, Berna; Mecray, Ellen L.; Bucholtz ten Brink, Marilyn R.

    2000-01-01

    Palynological analyses of 20 surface sediment samples collected from Long Island Sound show a pollen assemblage dominated by Carya, Betula, Pinus, Quercus, Tsuga, and Ambrosia, as is consistent with the regional vegetation. No trends in relative abundance of these pollen types occur either from west to east or associated with modern riverine inputs throughout the basin. Despite the large-scale, long-term removal of fine-grained sediment from winnowed portions of the eastern Sound, the composition of the pollen and spore component of the sedimentary matrix conforms to a basin-wide homogeneous signal. These results strongly support the use of select regional palynological boundaries as chronostratigraphic tools to provide a framework for interpretation of the late glacial and Holocene history of the Long Island Sound basin sediments.

  16. Inhibition of methane consumption in forest soils by monoterpenes

    SciTech Connect

    Amaral, J.A.; Knowles, R.

    1998-04-01

    Selected monoterpenes were tested for their ability to inhibit atmospheric methane consumption by three forest soils from different vegetation types and by the cultured methanotrophic strain, Methylosinus trichosporium OB3b. Subsurface soil from coniferous (Pinus banksiana), deciduous (Populus tremuloides), and mixed hardwood (Tsuga canadensis and Prunus pensylvanica) stands was used under field-moist and slurry conditions. Most of the hydrocarbon monoterpenes tested significantly inhibited methane consumption by soils at environmentally relevant levels, with ({minus})-{alpha}-pinene being the most effective. With the exception of {beta}-myrcene, monoterpenes also strongly inhibited methane oxidation by Methylosinus trichosporium OB3b. Carbon dioxide production was stimulated in all of the soils by the monoterpenes tested. In one case, methane production was stimulated by ({minus})-{alpha}-pinene in an intact, aerobic core. Oxide and alcohol monoterpenoids stimulated methane production. Thus, monoterpenes appear to be potentially important regulators of methane consumption and carbon metabolism in forest soils.

  17. AMS radiocarbon dating of wood trunks in the pumiceous deposits of the Kikai-Akahoya eruption in Yakushima Island, SW Japan

    NASA Astrophysics Data System (ADS)

    Okuno, Mitsuru; Nakamura, Toshio; Geshi, Nobuo; Kimura, Katsuhiko; Saito-Kokubu, Yoko; Kobayashi, Tetsuo

    2013-01-01

    Radiocarbon dating using accelerator mass spectrometry (AMS) was performed on numerous wood trunks from pumiceous deposits along the Nagata, Isso and Miyanoura rivers on the northern side of Yakushima Island, 60 km south of Kyushu Island. The obtained 14C dates were around 6.5 ka BP, which, in combination with the geological characteristics of the pumiceous deposits indicates that these specimens were buried during the Kikai-Akahoya (K-Ah) eruption from the Kikai caldera. However, the fact that they are not charred suggests that the origin of these deposits are not pyroclastic flows. Fourteen taxa (Pinus subgen. Diploxylon, Tsuga, Cryptomeria, Chamaecyparis, Myrica, Castanea, Castanopsis, Quercus subgen. Cyclobalanopsis, Trochodendron, Phellodendron, Lagerstroemia, Rhododendron, Myrsine and Symplocos) were identified through anatomical characteristics. This is the first discovery of forest species on the Yakushima Island before the devastating eruption.

  18. Late Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and San Joaquin Ridge, Mono County, Sierra Nevada, CA, USA

    NASA Astrophysics Data System (ADS)

    Millar, Constance I.; King, John C.; Westfall, Robert D.; Alden, Harry A.; Delany, Diane L.

    2006-09-01

    Deadwood tree stems scattered above treeline on tephra-covered slopes of Whitewing Mtn (3051 m) and San Joaquin Ridge (3122 m) show evidence of being killed in an eruption from adjacent Glass Creek Vent, Inyo Craters. Using tree-ring methods, we dated deadwood to AD 815-1350 and infer from death dates that the eruption occurred in late summer AD 1350. Based on wood anatomy, we identified deadwood species as Pinus albicaulis, P. monticola, P. lambertiana, P. contorta, P. jeffreyi, and Tsuga mertensiana. Only P. albicaulis grows at these elevations currently; P. lambertiana is not locally native. Using contemporary distributions of the species, we modeled paleoclimate during the time of sympatry to be significantly warmer (+3.2°C annual minimum temperature) and slightly drier (-24 mm annual precipitation) than present, resembling values projected for California in the next 70-100 yr.

  19. Monitoring Forest Change and Ice Storm Disturbance to Forest Structure Using Echidna° Ground-Based Lidar

    NASA Astrophysics Data System (ADS)

    Yao, T.; Strahler, A. H.; Schaaf, C.; Yang, X.; zhao, F.; Woodcock, C. E.; Jupp, D. L.; Culvenor, D.; Lovell, J.; Newnham, G.; Li, X.; Wang, J.

    2011-12-01

    The ground-based, upward-scanning, near-infrared (1064 nm), full-waveform lidar, the Echidna° Validation Instrument (EVI), built by CSIRO Australia, is used to monitor forest change over a 2- or 3-year time period through changes in retrievals of mean stem diameter, stem density, basal area, above-ground standing biomass, leaf area index, foliage profile, and canopy height. The changes were validated by comparison with direct field measurements, or in the case of canopy height, with data from the Laser Vegetation Imaging Sensor (LVIS). Site-level EVI-retrieved values of mean DBH, stem count density, basal area and above-ground biomass matched the field measurements well, with R2 values of 0.84, 0.97, 0.96 and 0.98 respectively. Furthermore, the changes in EVI retrievals had the same trend as the change in field measurements over these 2-3 year periods. Based on five scans within each 1-ha plot, we focused on detecting forest change over a 2- or 3-year period at three New England forest stands: a second-growth conifer stand thinned as a shelterwood, an aging hemlock plantation, and a young second-growth hardwood stand. The first stand provided the opportunity to look for change in a stand containing many co-dominant and intermediate trees recently released by removal of selected over-story trees, while the other two stands suffered significant damage in an ice storm during the change period. At the shelterwood conifer site at Howland Experimental Forest, mean DBH, aboveground biomass, and leaf area index (LAI) all increased between 2007 and 2009. An ice storm struck the Harvard Forest in December, 2008, providing the opportunity to detect damage between 2007 and 2009 or 2010 with EVI scans at two sites : hemlock and hardwood. Retrieved leaf area index (LAI) was 13 percent lower in the hemlock site in 2009 and 10 percent lower in the hardwood site in 2010 as compared to 2007. The decrease of LAI quantifies a loss of biomass from the canopy, and broken tops were both

  20. Responses of Tree Seedlings to a Changing Atmosphere: Effects of Carbon Dioxide, Nitrogen Dioxide, and Ozone

    NASA Astrophysics Data System (ADS)

    Eller, A. S.; Sparks, J. P.

    2008-12-01

    Human activities have caused changes in the chemical composition of the atmosphere: the concentrations of carbon dioxide (CO2), nitrogen dioxide (NO2), and ozone (O3) have increased and are expected to continue increasing in the future. These gases have the potential to alter plant physiological processes, change growth rates, C:N, and carbon storage potential. The responses of tree seedlings to these changes will have a profound impact on the species composition and carbon storage potential of forests in the future. Others have found CO2 tends to increase plant growth and O3 to decrease it. NO2, if assimilated by plants, can be a source of nutrient nitrogen, but is also an oxidant with the potential to damage cell membranes and decrease growth. The objectives of this study were to determine the single and combined effects of CO2, NO2, and O3 on sugar maple, eastern hemlock, and two clones of trembling aspen. The trees were fumigated for two growing seasons with elevated (40ppb) or ambient NO2, elevated (560ppm) or ambient CO2, elevated (100 ppb 5 days/week) or ambient O3, and with or without additional soil nitrate (30 kg ha-1 yr-1) to simulate ecosystems with and without nitrogen limitation. We found that elevated CO2 increased total biomass of both maples and hemlocks. Further, the CO2 growth effect was most striking when combined with elevated O2; elevated CO2 eliminated the growth decrease induced by O3 especially when nitrogen was limited. Elevated NO2 had no effect on maple seedlings, but, similar to CO2, eliminated the decrease in growth under O3 on hemlock seedlings. The two aspen clones differed in their resistance to ozone. The non-resistant clone exhibited growth responses similar to maple. However, the resistant clone did not exhibit a growth response under any gas treatment regardless of soil nitrogen status. The variation in responses among species, within clones of the same species, and between fumigations was large in this study and suggests

  1. Greenhouse Gas Exchange and Biogeochemistry of Fertilized Canadian Plantation Forests

    NASA Astrophysics Data System (ADS)

    Basiliko, N.; Grayston, S. J.; Roy, R.; Mohn, W. W.; Yolova, V.; Prescott, C.

    2005-12-01

    Canada's ratification of the Kyoto Protocol in 2002 has raised questions of the role of ecosystem management as a tool to temporarily reduce the net greenhouse gas burden of the forestry industry and potentially generate emission offset credits. We examined growing season methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) fluxes, soil nutrient chemistry, and microbial biomass and CH4-oxidizing bacterial communities in 20-year-old sub-boreal lodgepole pine and maritime hemlock plantations under control conditions and simulated operational fertilization with N (200kg urea-N per ha, applied twice) and N, P, K, and micronutrients. CH4 uptake was significantly greater in the lodgepole pine site than in the hemlock site (152-221 and 57-81 micrograms CH4 consumed per square meter per hour), and there were no significant differences among treatments at either site. Among sites, treatments, and sampling times, CH4 uptake correlated positively with NH4 concentrations and negatively with extractable organic N:P quotients, indicating that this process may potentially be limited by nutrient availability to the CH4-oxidizing bacteria. N2O efflux was measured sporadically at a few flux collars, but was not significantly different from zero at any site, treatment, or time. Soil respiration (CO2 efflux) rates were faster in the hemlock than lodgepole pine site (243-409 and 100-266 milligrams CO2 per square meter per hour), and significant treatment differences were observed at individual times, though with fertilized plots exhibiting both faster and slower rates than controls. Soil respiration correlated significantly with microbial biomass C and N and NO3. Within each site, soil respiration, but not CH4 uptake, was positively correlated with soil temperature. New experiments examining the short-term effects of fertilization on greenhouse gas exchanges are underway, and both short and long-term effects will be evaluated in relation to changes in C storage in plant biomass

  2. The diagenetic behavior of cutin acids in buried conifer needles and sediments from a coastal marine environment

    NASA Astrophysics Data System (ADS)

    Goñi, Miguel A.; Hedges, John I.

    1990-11-01

    Whole green, litter, and sedimentary fir, hemlock, and cedar needles and bulk sediments collected from the Dabob Bay region in Washington state were analyzed for their cutin-derived CuO reaction products. All samples yielded dihydroxyhexadecanoic acid isomers (x,ω-C 16), 16-hydroxyhexa-decanoic acid (ω-C 16), 14-hydroxytetradecanoic acid (ω-C 14), and 18-hydroxyoctadec-9-enoic acid (ω-C 18: 1) as the major cutin acids. Fir/hemlock needle mixtures were characterized by a high abundance of the 9,16-dihydroxyhexadecanoic acid positional isomer, while cedar needles produced primarily the 10,16-dihydroxy counterpart. Cutin acids accounted for ~3% of tissue C in green needles, ~4% in needle litter, 0.5-1.5% in sedimentary needles, and about 0.1% of the organic carbon (OC) in bulk sediments. Approximately 80% of the original cutin acids in fresh green needles were lost from the deepest (~100 years old) sedimentary tissues. Cutin was more reactive than lignin and polysaccharides, but more stable than the cyclitol components of the same needles. Comparative diagenetic losses of the individual cutin acids were not uniform and suggest that additional hydroxy groups and the presence of C double bonds both increase overall reactivity. The relative stability series derived for all the molecular constituents measured is: total vanillyl phenols > total P- hydroxy phenols, ferulic acid, most aldoses, bulk organic matter > mannose, ω-C 14, ω-C 16 ⩾ ω-C 18:1 > glucose, p- coumaric acid, x, ω-C 16 > all cyclitols. Diagenetically induced changes in the various cutin parameters used to characterize nonwoody vascular plant tissues were not large enough to confuse degraded conifer tissues with other cutin sources. Based on these trends, the finely disseminated cutin-bearing tissues in Dabob Bay sediments appear to be comprised approximately of equal amounts of highly degraded fir/hemlock and cedar needle fragments. According to this estimate, nonwoody vascular plant debris

  3. Palynology of latest Neogene (Middle Miocene to late Pliocene) strata in the Delmarva Peninsula of Maryland and Virginia

    USGS Publications Warehouse

    Sirkin, L.; Owens, J.P.

    1998-01-01

    Palynology of Miocene and Pliocene formations in the Delmarva Peninsula of Maryland and Virginia reveals a significant representation of exotic pollen interspersed in pollen assemblages that are otherwise comparable to those from the modern vegetation of the Mid-Alantic coastal plain region. The late Tertiary arboreal pollen (AP) assemblages are dominated by oak, hickory, pine, birch and alder with minor amounts of mid- and southern coastal tree taxa, as well as minor spruce and hemlock and a trace of fir. Nonarboreal pollen (NAP) include grass, sedge, composite and aquatic taxa. Exotic pollen in these assemblages represent plants now foreign to this region. They may be placed in three categories. First, there are extinct forms, such as Labrapollis, Plicatopollis, and Multiporopollenites, that can be traced from the Cretaceous or Early Tertiary into the Late Tertiary. The second group includes forms, such as Podocarpus, Engelhardtia, Pterocarya, Ephedra, Eucommia, Ulmus-Zelkova, Glyptostrobus, Palmae, and Cyathea, that are not found in this region today and not found in early Pleistocene sediments in the eastern United States. Many of these taxa are subtropical or greatly restricted in geographic range. A third group of exotics, mainly Cyrilla, Planera, Gordonia, Jussiaea, and Sapotacaea, including Minusops, are generally found south of the study area or have their northern limit here at this time. The lack of the extinct or distant exotics in early to mid-Pleistocene sediments in the mid-Atlantic coastal plain and the last appearance of Pterocarya, as the last exotic taxon in the early Pleistocene of western Europe, support the stratigraphic assignment of the Pliocene units. The number of exotic taxa diminish markedly between the Miocene pollen assemblages and those of the Late Pliocene. Climatic fluctuations characterize the Late Tertiary environments. The Miocene, for example, incorporates a warming trend between the upper, middle Miocene and the Manokin beds

  4. Sensitivity analysis for solar plates

    NASA Technical Reports Server (NTRS)

    Aster, R. W.

    1986-01-01

    Economic evaluation methods and analyses of emerging photovoltaic (PV) technology since 1976 was prepared. This type of analysis was applied to the silicon research portion of the PV Program in order to determine the importance of this research effort in relationship to the successful development of commercial PV systems. All four generic types of PV that use silicon were addressed: crystal ingots grown either by the Czochralski method or an ingot casting method; ribbons pulled directly from molten silicon; an amorphous silicon thin film; and use of high concentration lenses. Three technologies were analyzed: the Union Carbide fluidized bed reactor process, the Hemlock process, and the Union Carbide Komatsu process. The major components of each process were assessed in terms of the costs of capital equipment, labor, materials, and utilities. These assessments were encoded as the probabilities assigned by experts for achieving various cost values or production rates.

  5. Economics of polysilicon processes

    NASA Astrophysics Data System (ADS)

    Yaws, C. L.; Li, K. Y.; Chou, S. M.

    1986-02-01

    Techniques are being developed to provide lower cost polysilicon material for solar cells. Existing technology which normally provides semiconductor industry polysilicon material is undergoing changes and also being used to provide polysilicon material for solar cells. Economics of new and existing technologies are presented for producing polysilicon. The economics are primarily based on the preliminary process design of a plant producing 1,000 metric tons/year of silicon. The polysilicon processes include: Siemen's process (hydrogen reduction of trichlorosilane); Union Carbide process (silane decomposition); and Hemlock Semiconductor process (hydrogen reduction of dichlorosilane). The economics include cost estimates of capital investment and product cost to produce polysilicon via the technology. Sensitivity analysis results are also presented to disclose the effect of major paramentes such as utilities, labor, raw materials and capital investment.

  6. Sensitivity analysis for solar plates

    NASA Astrophysics Data System (ADS)

    Aster, R. W.

    1986-02-01

    Economic evaluation methods and analyses of emerging photovoltaic (PV) technology since 1976 was prepared. This type of analysis was applied to the silicon research portion of the PV Program in order to determine the importance of this research effort in relationship to the successful development of commercial PV systems. All four generic types of PV that use silicon were addressed: crystal ingots grown either by the Czochralski method or an ingot casting method; ribbons pulled directly from molten silicon; an amorphous silicon thin film; and use of high concentration lenses. Three technologies were analyzed: the Union Carbide fluidized bed reactor process, the Hemlock process, and the Union Carbide Komatsu process. The major components of each process were assessed in terms of the costs of capital equipment, labor, materials, and utilities. These assessments were encoded as the probabilities assigned by experts for achieving various cost values or production rates.

  7. Alkaloid-Containing Plants Poisonous to Cattle and Horses in Europe

    PubMed Central

    Cortinovis, Cristina; Caloni, Francesca

    2015-01-01

    Alkaloids, nitrogen-containing secondary plant metabolites, are of major interest to veterinary toxicology because of their occurrence in plant species commonly involved in animal poisoning. Based on epidemiological data, the poisoning of cattle and horses by alkaloid-containing plants is a relatively common occurrence in Europe. Poisoning may occur when the plants contaminate hay or silage or when forage alternatives are unavailable. Cattle and horses are particularly at risk of poisoning by Colchicum autumnale (meadow saffron), Conium maculatum (poison hemlock), Datura stramonium (jimson weed), Equisetum palustre (marsh horsetail), Senecio spp. (ragwort and groundsel) and Taxus baccata (European yew). This review of poisonous alkaloid-containing plants describes the distribution of these plants, conditions under which poisoning occurs, active toxic principles involved and subsequent clinical signs observed. PMID:26670251

  8. Silicon production process evaluations

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Chemical engineering analysis of the HSC process (Hemlock Semiconductor Corporation) for producing silicon from dichlorosilane in a 1,000 MT/yr plant was continued. Progress and status for the chemical engineering analysis of the HSC process are reported for the primary process design engineering activities: base case conditions (85%), reaction chemistry (85%), process flow diagram (60%), material balance (60%), energy balance (30%), property data (30%), equipment design (20%) and major equipment list (10%). Engineering design of the initial distillation column (D-01, stripper column) in the process was initiated. The function of the distillation column is to remove volatile gases (such as hydrogen and nitrogen) which are dissolved in liquid chlorosilanes. Initial specifications and results for the distillation column design are reported including the variation of tray requirements (equilibrium stages) with reflux ratio for the distillation.

  9. Pioneer exotic tree search for the douglas-fir region. Forest Service general technical report

    SciTech Connect

    Silen, R.R.; Olson, D.L.

    1992-03-01

    After three-quarters of a century of introduction of 152 conifer and broadleaf species, no promising candidate exotic was found for the Douglas-fir region. Growth curves spanning 50 years or longer are figured for many species. Firs, pines, larches, spruces, hemlocks, and cedars orginating in northwestern North America had superior growth rates to those from other forest regions. The probable basis for these differences is discussed. The record highlights a general failure of introduced hardwoods, the slow decline of most introduced conifers, the long time needed to express failures, dramatic effects of climatic extremes or introduced pests, failure of native species of continental origin at Wind River, striking similarities of growth rate for the species originating in each country, and many important contrasts between results from early reports and long-term conclusions.

  10. Primary deforestation and regrowth on limestone slopes on Vancouver Island, British Columbia

    SciTech Connect

    Harding, K.A.; Ford, D.C. . Dept. of Geography)

    1992-01-01

    Limestones, well bedded and steeply dipping, are common in northern Vancouver Island. They have been glaciated and host a high density of postglacial karren (dissolution pits, grooves and troughs linked to underlying caves). There is rich, mature forest cover of western hemlock, silver fir and red cedar that is rooted in the karren or in overlying glacial deposits. Logging commenced around 1900 AD, intensifying after 1960 with clear cutting and (often) burning of slash. Impacts were investigated quantitatively by comparing sixteen limestone sites with eight on adjoining volcanic rocks. Some sites on each retained original forest, other were cleared. It was found that soil losses following logging are significantly greater on the limestones because of wash into karren (the epikarst zone). Regrowth is retarded on the limestones also; one site cleared in 1911 had regained approximately 17% of its original volume of timber 75 years later.

  11. Downed dead woody fuel and biomass in the Northern Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Brown, J. K.; See, T. E.

    1981-07-01

    Weights and volumes of downed woody material in diameter classes of one-fourth to 1, 1 to 3, and greater than 3 inches and forest floor duff depths were summarized from extensive inventories in nothern Idaho and Montana. Biomass loadings are shown by cover types and habitat types within National Forests. Total downed woody biomass ranged from 5 tons per acre in ponderosa pine to 33 tons per acre in cedar-hemlock. Loadings generally increased with increased productivity, but varied greatly with stand age. Fuels tended to become predictably high in overmature stands but unpredictable in young, immature, and mature stands. Forest fuel succession is discussed in relation to tree mortality, fuel buildup, and depletion.

  12. Model for Calculating Photosynthetic Photon Flux Densities in Forest Openings on Slopes.

    NASA Astrophysics Data System (ADS)

    Chen, Jing M.; Black, T. Andrew; Price, David T.; Carter, Reid E.

    1993-10-01

    A model has been developed to calculate the spatial distribution of the photosynthetic photon flux density (PPFD) in elliptical forest openings of given slopes and orientations. The PPFD is separated into direct and diffuse components. The direct component is calculated according to the opening and radiation geometries, and pathlength of the solar beam through the forest canopy. The diffuse component is obtained from the sky, tree, and landscape view factors. In this model, the distribution of foliage area with height and the effect of foliage clumping on both direct and diffuse radiation transmission are considered.The model has been verified using measurements for six quantum sensors (LI-COR Inc.) located at different positions in a small clear-cut (0.37 ha) in a 90-year-old western hemlock-Douglas fir forest.

  13. A review of the silicon material task

    NASA Technical Reports Server (NTRS)

    Lutwack, R.

    1984-01-01

    The Silicon Material Task of the Flat-Plate Solar Array Project was assigned the objective of developing the technology for low-cost processes for producing polysilicon suitable for terrestrial solar-cell applications. The Task program comprised sections for process developments for semiconductor-grade and solar-cell-grade products. To provide information for deciding upon process designs, extensive investigations of the effects of impurities on material properties and the performance of cells were conducted. The silane process of the Union Carbide Corporation was carried through several stages of technical and engineering development; a pilot plant was the culmination of this effort. The work to establish silane fluidized-bed technology for a low-cost process is continuing. The advantages of the use of dichlorosilane is a siemens-type were shown by Hemlock Semiconductor Corporation. The development of other processes is described.

  14. Harvesting Overstocked Stands of Small Diameter Trees. Report No. 5: Energy Value of Whole-Trees and Crowns.

    SciTech Connect

    Howard, James O.

    1987-07-01

    The objective of the study was to determine the higher heating value of whole-tree chips and crown materials for species being harvested in the doghair stands on the Quilcene Ranger district, Olympic National Forest. Values, in terms of Btu's per oven dry pound, were derived for the three major species occurring in these stands: western hemlock, Douglas-fir, and western redcedar. Hogfuel derived from these stands comes from whole-tree chipping and crown materials created during the delimbing/debarking process. Since hogfuel may be created separately from these two sources it is important that their energy values are known. Separation of species is not done during whole-tree chipping, thus a composite value of hogfuel from this source was determined. 6 refs., 1 tab.

  15. AmeriFlux US-Syv Sylvania Wilderness Area

    SciTech Connect

    Desai, Ankur

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Syv Sylvania Wilderness Area. Site Description - Old growth forest consisting primarily of sugar maple and eastern hemlock. Note that a small lake to the north and data analyses suggest that wind direction screening is appropriate (see Desai, A.R., Bolstad, P.V., Cook, B.D., Davis, K.J., and Carey, E.V., 2005. Comparing net ecosystem exchange of carbon dioxide between an old-growth and mature forest in the upper midwest, USA. Ag. For. Met. 128(1-2): 33-55 (doi: 10.1016/j.agrformet.2004). Site was chosen to represent an end member representative of the upland forests in the WLEF tall tower flux footprint. (Note, however, that old growth forests are not found within the WLEF tall tower flux footprint.)

  16. Evaluating the Contribution of Climate Forcing and Forest Dynamics to Accelerating Carbon Sequestration by Forest Ecosystems in the Northeastern U.S.: Final Report

    SciTech Connect

    Munger, J. William; Foster, David R.; Richardson, Andrew D.

    2014-10-01

    This report summarizes work to improve quantitative understanding of the terrestrial ecosystem processes that control carbon sequestration in unmanaged forests It builds upon the comprehensive long-term observations of CO2 fluxes, climate and forest structure and function at the Harvard Forest in Petersham, MA. This record includes the longest CO2 flux time series in the world. The site is a keystone for the AmeriFlux network. Project Description The project synthesizes observations made at the Harvard Forest HFEMS and Hemlock towers, which represent the dominant mixed deciduous and coniferous forest types in the northeastern United States. The 20+ year record of carbon uptake at Harvard Forest and the associated comprehensive meteorological and biometric data, comprise one of the best data sets to challenge ecosystem models on time scales spanning hourly, daily, monthly, interannual and multi-decadal intervals, as needed to understand ecosystem change and climate feedbacks.

  17. Economics of polysilicon processes

    NASA Technical Reports Server (NTRS)

    Yaws, C. L.; Li, K. Y.; Chou, S. M.

    1986-01-01

    Techniques are being developed to provide lower cost polysilicon material for solar cells. Existing technology which normally provides semiconductor industry polysilicon material is undergoing changes and also being used to provide polysilicon material for solar cells. Economics of new and existing technologies are presented for producing polysilicon. The economics are primarily based on the preliminary process design of a plant producing 1,000 metric tons/year of silicon. The polysilicon processes include: Siemen's process (hydrogen reduction of trichlorosilane); Union Carbide process (silane decomposition); and Hemlock Semiconductor process (hydrogen reduction of dichlorosilane). The economics include cost estimates of capital investment and product cost to produce polysilicon via the technology. Sensitivity analysis results are also presented to disclose the effect of major paramentes such as utilities, labor, raw materials and capital investment.

  18. Evaluating Paleoecological Patterns Using Paleoenvironmental Proxies: The Promise and the Peril

    NASA Astrophysics Data System (ADS)

    Jackson, S. T.; Booth, R. K.

    2007-12-01

    For the past seven years we have been studying the vegetational history of the western Great Lakes region in the context of mid- to late Holocene climate change and variability. Our work has included diverse archives and proxies for both paleoecological and paleoclimatic inference. The former consist of pollen, plant-macrofossil, and charcoal records from sediments of small lakes and peatlands. Paleoclimate inferences have been based on lake-level records, peatland-inception dates, dune and lakeshore dynamics, and paleohydrological reconstructions from ombrotrophic and kettle peatlands. Our greatest success has been in pairing lake-based paleoecological records with peatland-based paleohydrological records. Peatland hydrology is sensitive to annual and seasonal moisture variation, and peatland-sediment archives contain diverse proxies including testate-amoeba assemblages, humification, organic biomarkers, stable isotopes, and plant macrofossils. Our work has resolved old controversies while unveiling unforeseen patterns. Examples include: (1) A mid-Holocene decline in hemlock populations, long attributed to a pest/pathogen outbreak, coincided with a rapid, unprecedented drop in peatland water levels. However, the decline shows complex structure in time, both ecologically and climatically. Hemlock's final demise 5000 yr BP was preceded by several centuries of multidecadal hydrological fluctuation accompanied by time- lagged hemlock fluctuations. (2) A late Holocene decline in beech populations, variously attributed to human-set fires and the Little Ice Age, occurred during a series of severe multidecadal droughts. This event is also structured in time and space: in some areas the droughts were dampened and beech increased, and at sites where beech decline and droughts occurred, beech pollen, charcoal concentrations, and water-levels fluctuated dramatically between 1000 and 700 yr BP. (3) Yellow birch populations expanded rapidly across a broad swath of Upper

  19. AmeriFlux US-Wrc Wind River Crane Site

    SciTech Connect

    Bible, Ken; Wharton, Sonia

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Wrc Wind River Crane Site. Site Description - Wind River Field Station flux tower site is located in the T.T. Munger Research Area of the Wind River Ranger District in the Gifford Pinchot National Forest. Protected since 1926, the T.T. Munger Research Natural Area (RNA) is administered by the USDA Forest Service Pacific Northwest Research Station and Gifford Pinchot National Forest. The Douglas-fir/western hemlock dominant stand is approximately 500 years old and represents end points of several ecological gradients including age, biomass, structural complexity, and density of the dominant overstory species. A complete stand replacement fire, approximately 450-500 years ago, resulted in the initial establishment. No significant disturbances have occurred since the fire aside from those confined to small groups of single trees, such as overturn from high wind activity and mechanical damage from winter precipitation.

  20. Cytology of Leidyana canadensis (apicomplexa: eugregarinida) in Lambdina fiscellaria fiscellaria larvae (lepidoptera: geometridae).

    PubMed

    Lucarotti, C J

    2000-02-01

    The eugregarine Leidyana canadensis infects the larval gut of the eastern hemlock looper, Lambdina fiscellaria fiscellaria. Guts of infected larvae were chemically fixed, embedded in epoxy resin, and sectioned for light and electron microscopy to describe the cytology of L. canadensis and its pathology in the larval host. Oocysts of L. canadensis are ingested by larval hemlock looper. Trophozoites emerge from the oocysts, pass through the peritrophic membrane into the ectoperitrophic space, and attach to the epithelium of the midgut by means of an apical epimerite. The epimerite does not actually penetrate the affected epithelial cell; instead, it causes an invagination of the plasma membrane of the cell. The center of the epimerite contains membrane cisternae, and mitochondria line its periphery. Microtubules and mitochondria in the host cell cytoplasm surround the epimerite. At the light microscopic level, there appeared to be septa between the epimerite and the protomerite and between the protomerite and the deutomerite; however, in the electron microscope, no septa were evident. Only differences in the concentrations and nature of the inclusions in the cytoplasms of these three regions were apparent. The deutomerite contains a single nucleus in the central-posterior area. After an undetermined period, the epimerite detaches from the host gut epithelium and is withdrawn into the protomerite, and the trophozoites float freely in the ectoperitrophic space before differentiating into gamonts. Division of the single, large nucleus into numerous small nuclei appears to occur prior to syzygy. Gamonts pair and a cyst wall is laid down around them, forming a gametocyst. Oocysts are extruded from mature gametocysts, in chains, through sporoducts.

  1. Geographic biotype and host-associated local adaptation in a polyphagous species, Lambdina fiscellaria (Lepidoptera: Geometridae) feeding on balsam fir on Anticosti Island, Canada.

    PubMed

    Hébert, C; Berthiaume, R; Bauce, E; Brodeur, J

    2006-12-01

    The debate about mechanisms underlying the evolution of host specialization by herbivorous insects remains open. Natural selection may act locally and lead to different patterns of geographic variation in life history traits of polyphagous herbivores. The hypothesis of genetically-based trade-offs in offspring performance on different hosts has been proposed but this has rarely been demonstrated. Under laboratory conditions, the biological performance of two populations of the hemlock looper Lambdina fiscellaria (Guenée), a highly polyphagous lepidopteran, was compared when reared on three different tree host species: balsam fir, eastern hemlock and sugar maple. One population originated from Anticosti Island, Québec, Canada, where the insect has evolved without having access to two of the three tree species tested, the other being from the mainland where all tree species are present. When reared on balsam fir foliage, which was naturally available to each population, larvae from Anticosti Island underwent four instars compared with five for the mainland population, indicating the existence of geographic biotypes in L. fiscellaria. When reared on the foliage of non-naturally available host trees, larvae from Anticosti Island had a higher incidence of supernumerary instars. This is a unique example where local adaptation to environmental conditions of an insect herbivore is expressed through a differential number of larval instars. Moreover, the Anticosti Island population showed a higher growth related index on the host available to both populations indicating that a fitness trade-off was the evolutionary process underlying the local adaptation of this population on balsam fir.

  2. Twenty years of ecosystem response after clearcutting and slashburning in conifer forests of central British Columbia, Canada

    PubMed Central

    Feller, Michael; Bradfield, Gary

    2017-01-01

    Forests are being clearcut over extensive areas of western North America, but plant community response to harvesting and slashburning under varying climatic conditions in central British Columbia, Canada is still largely unknown. Evaluation of resilience is hampered by the short history of logging, lack of long-term experiments and methodological limitations. To test the effect of clearcut logging, prescribed burning and reforestation on forest resilience, we recorded vascular plant cover repeatedly after treatment between 1981 and 2008 in 16 permanent research installations in three biogeoclimatic zones: Engelmann Spruce-Subalpine Fir, Interior Cedar-Hemlock and Sub-Boreal Spruce. We created a plant-trait dataset for the 181 recorded species to define plant functional types representing groups of plants that behave in similar ways and/or produce similar ecological outcomes. These plant functional types, along with taxonomic analysis of diagnostic and indicator species, were then used to evaluate plant community response to disturbance. Twenty years post-treatment, species diversity increased in all zones and plant abundance was greatest in the Interior Cedar-Hemlock. Cover of understory plant functional types associated with mature conifer forests increased in all zones, constituting a significant proportion (> 40%) of the vegetation community by year 20. Response patterns varied by zone and with time. Understory species diagnostic of mature forests were present in all zones by year 20, but we identified indicator species sensitive to slashburning or requiring more time for recovery, including white-flowered rhododendron (Rhododendron albiflorum) and devil's club (Oplopanax horridus). Overall, loss of compositional or functional diversity following harvest and site remediation was not detected, suggesting that montane and subalpine forests in British Columbia are resilient to this treatment. However, because these forests can be slow to recover from disturbance

  3. The problem of conifer species migration lag in the Pacific Northwest region since the last glaciation

    NASA Astrophysics Data System (ADS)

    Elias, Scott A.

    2013-10-01

    Multiproxy evidence indicates that warmer-than-present summers became established in Eastern Beringia as early as 14,000-13,000 years ago, but the dispersal of spruces, pines, cedars and hemlocks across the Pacific Northwest (PNW) region of southern Alaska did not begin until at least 1500 years afterwards, and took many thousands of years to be completed. There are many potential reasons for this slow spread of PNW conifers towards their modern range limits. The absence of mycorrhizae in the soils of southern Alaska may have slowed conifer establishment. The availability of soil moisture was another limiting factor. With the exception of Pinus contorta, the other PNW conifers become established most readily from seeds that fall on moist, shaded substrates, thus they are not good pioneering species. Competition with alder and birch played an important role, especially along Prince William Sound and the Kenai Peninsula. Alder or alder and birch dominated these regions until the mid- to late Holocene. The other key element for most PNW conifer species is the precipitation regime. The hemlocks, cedars and Sitka spruce are not drought-hardy. So although the PNW temperature regime may have been warm enough in early postglacial times to support the growth of PNW conifers, it was probably too dry for them to successfully become established in new regions. The conflation of these environmental factors limits our present understanding of the problem, but the recent trend of multi-proxy analysis in Quaternary paleoecology will certainly sharpen our reconstructions. Such proxies as conifer needle stomata and insect fossil remains hold significant promise.

  4. Twenty years of ecosystem response after clearcutting and slashburning in conifer forests of central British Columbia, Canada.

    PubMed

    Chandler, Julia R; Haeussler, Sybille; Hamilton, Evelyn H; Feller, Michael; Bradfield, Gary; Simard, Suzanne W

    2017-01-01

    Forests are being clearcut over extensive areas of western North America, but plant community response to harvesting and slashburning under varying climatic conditions in central British Columbia, Canada is still largely unknown. Evaluation of resilience is hampered by the short history of logging, lack of long-term experiments and methodological limitations. To test the effect of clearcut logging, prescribed burning and reforestation on forest resilience, we recorded vascular plant cover repeatedly after treatment between 1981 and 2008 in 16 permanent research installations in three biogeoclimatic zones: Engelmann Spruce-Subalpine Fir, Interior Cedar-Hemlock and Sub-Boreal Spruce. We created a plant-trait dataset for the 181 recorded species to define plant functional types representing groups of plants that behave in similar ways and/or produce similar ecological outcomes. These plant functional types, along with taxonomic analysis of diagnostic and indicator species, were then used to evaluate plant community response to disturbance. Twenty years post-treatment, species diversity increased in all zones and plant abundance was greatest in the Interior Cedar-Hemlock. Cover of understory plant functional types associated with mature conifer forests increased in all zones, constituting a significant proportion (> 40%) of the vegetation community by year 20. Response patterns varied by zone and with time. Understory species diagnostic of mature forests were present in all zones by year 20, but we identified indicator species sensitive to slashburning or requiring more time for recovery, including white-flowered rhododendron (Rhododendron albiflorum) and devil's club (Oplopanax horridus). Overall, loss of compositional or functional diversity following harvest and site remediation was not detected, suggesting that montane and subalpine forests in British Columbia are resilient to this treatment. However, because these forests can be slow to recover from disturbance

  5. Petroleum geology of Cook Inlet basin - an exploration model

    USGS Publications Warehouse

    Magoon, L.B.; Claypool, G.E.

    1981-01-01

    Oil exploration commenced onshore adjacent to lower Cook Inlet on the Iniskin Peninsula in 1900, shifted with considerable success to upper Cook Inlet from 1957 through 1965, then returned to lower Cook Inlet in 1977 with the COST well and Federal OCS sale. Lower Cook Inlet COST No. 1 well, drilled to a total depth of 3,775.6 m, penetrated basinwide unconformities at the tops of Upper Cretaceous, Lower Cretaceous, and Upper Jurassic strata at 797.1, 1,540.8, and 2,112.3 m, respectively. Sandstone of potential reservoir quality is present in the Cretaceous and lower Tertiary rocks. All siltstones and shales analyzed are low (0 to 0.5 wt. %) in oil-prone organic matter, and only coals are high in humic organic matter. At total depth, vitrinite readings reached a maximum ave age reflectance of 0.65. Several indications of hydrocarbons were present. Oil analyses suggest that oils from the major fields of the Cook Inlet region, most of which produce from the Tertiary Hemlock Conglomerate, have a common source. More detailed work on stable carbon isotope ratios and the distribution of gasoline-range and heavy (C12+) hydrocarbons confirms this genetic relation among the major fields. In addition, oils from Jurassic rocks under the Iniskin Peninsula and from the Hemlock Conglomerate at the southwestern tip of the Kenai lowland are members of the same or a very similar oil family. The Middle Jurassic strata of the Iniskin Peninsula are moderately rich in organic carbon (0.5 to 1.5 wt. %) and yield shows of oil and of gas in wells and in surface seeps. Extractable hydrocarbons from this strata are similar in chemi al and isotopic composition to the Cook Inlet oils. Organic matter in Cretaceous and Tertiary rocks is thermally immature in all wells analyzed. Oil reservoirs in the major producing fields are of Tertiary age and unconformably overlie Jurassic rocks; the pre-Tertiary unconformity may be significant in exploration for new oil reserves. The unconformable relation

  6. Characterizing Structure, Microclimate and Decomposition of Peatland, Beachfront, and Newly Logged Forest Edges in Southeastern Alaska

    NASA Astrophysics Data System (ADS)

    Concannon, Julie Ann

    In this study, I examined the forest structure, composition, microclimate, and decomposition of three common edge types in southeastern Alaska including; peatland, beachfront, and new clearcuts adjacent to productive western hemlock-Sitka spruce forests. Sites were located on 4 larger islands of the Alexander Archipelago in southeastern Alaska. The study was focussed on transects extending from the open area, through the forest boundary to 200 m into the forest. Twenty-two edges were examined during 1990 and 1991. Forest structure was unique for each edge type. Peatland -forest edges exhibit feathered transition of short and sparse tree growth to large dense old-growth western hemlock -Sitka spruce forests. Beachfront-forest edges were sealed at the boundary by a multi-layering of shrubs, small trees, mid-canopy trees, and some emergents. The transition to large productive old-growth was abrupt. Clearcut-forest edges were essentially old-growth forests opened up by logging. Average size of trees at the boundary was large but stand size and productivity decreased moving into the forest. Productive western hemlock-Sitka spruce associations were not apparent for a long distance into the forest. Herbaceous cover appeared to be directly linked to light levels along the forest transects. Because structure was so inherently different for each edge type, microclimatic gradients from open area to the forest interior environment varied with edge type. The strongest gradients were observed on sunny and extremely windy days. An edge index value (EIV) was calculated to differentiate edge-affected microclimate from interior environments. Edge type influenced forest microclimate such that; (1) Peatlands affected interior radiation and air temperature range for 120 m into the forest until interior environments were encountered. (2) Beachfront-forests were penetrated by ocean winds for up to 120 m however, other variables such as interior air temperature and relative humidity were

  7. Using Peatland Archives to Assess Climate Forcing of Holocene Vegetational Changes: Case Studies From the Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Jackson, S. T.; Booth, R. K.; Andersen, J.; Hotchkiss, S.; Huang, Y.; Lesser, M.; Minckley, T.; Nichols, J.; Pendall, E.; Reeves, K.; Taylor, M.

    2006-12-01

    A dilemma has long confronted paleoecologists: pollen data are required to assess past vegetational changes, and at the same time pollen data serve as a primary source of paleoclimate inference. Paleoecologists have had to use the same data sets to infer past climate changes and the ecological responses to those changes. The emergence of independent paleoclimate proxies and archives is providing relief from this dilemma. Peatland archives are especially effective at providing independent paleoclimatic records, owing to their sensitivity to climate variation, their subcentennial to subdecadal temporal precision, and the multiplicity of available proxies. Pollen records can be obtained from the same stratigraphic levels as paleoclimate proxies, and peatland records can also be compared with lake-based pollen and macrofossil records at regional scales. Peatland records of mid- to late Holocene climate change and variability, together with pollen and macrofossil records from peatlands and lakes in the Great Lakes region of North America, resolve some long-standing questions and controversies concerning the causation of vegetational changes in the region. We present three case studies where peatlands have played a pivotal role. 1. Hemlock populations plummeted across eastern North America 5400 yr BP. The extent, rapidity, and synchrony of the event suggested that it resulted from a widespread pathogen outbreak, similar to the early 20th Century chestnut blight in the same region. However, some have argued for climate as a primary mechanism. Paleohydrological records from a kettle bog in northeastern Lower Michigan indicate an abrupt decline in water-table depth 5400 yr BP that persisted for the next 2500 years, coincident with the hemlock decline. Pathogens may have played a proximal role, but an abrupt climate shift was the ultimate driver of the hemlock decline. 2. Holocene expansions of yellow birch and beech in their northwestern ranges were episodic, alternating

  8. Late Holocene environmental change at three glacier-fed lakes, southern Alaska

    NASA Astrophysics Data System (ADS)

    Kaufman, D. S.; Anderson, R. S.; Daigle, T. A.; Kathan, K. M.; McKay, N. P.; Michelutti, N. N.; Werner, A.

    2007-12-01

    Lake-sediment cores and glacial geomorphology were used to infer late Holocene paleoenvironmental changes at three glacier-fed lakes across southern Alaska. The lakes form a 730-km-long transect around 60N lat, and they span the transition zone between two centers of opposite surface air-temperature responses attributed to fluctuations in the strength of the Aleutian Low, the primary indicator of winter climate in the North Pacific. Sediment cores from Hallet Lake in the NE Chugach Range display varying concentrations of biogenic silica (BSi), a measure of overall lake production. A transfer function was developed to infer summer temperature from downcore BSi content. The reconstruction shows clear evidence of first millennium AD cooling, warmth from 1300-1500 AD, Little Ice Age (LIA) cooling between 1750 and 1900 AD, and recent warming beginning ca. 1900 AD. During the last 30 yr, summer temperatures were nearly 2C warmer than the reconstructed mean of the past 2 millennia. Goat Lake is near treeline in the Kenai Mountains, and about 1 km from an outlet glacier of the Harding Icefield. Pollen assemblages show increasing abundances of mountain hemlock from 700-1200 AD, which we interpret as an expansion of treeline. The expansion was terminated around 1230 AD when 10 cm of tephra was deposited in the lake. Treeline above the modern and prior to the LIA is further indicated by a 14C age of 1470 ± 85 AD on logs exposed below till at the present glacier terminus. By 1660 AD the outlet glacier thickened by 150 m where it overtopped its drainage divide and spilled meltwater into Goat Lake, which continued until around 1890 AD. Since then, hemlock pollen has increased to levels comparable to the 1200 AD peak, and the outlet glacier has retreated 1.4 km to the location of the 1470 AD logs. At Cascade Lake, sediment traps installed for 2 yr collected 77% less BSi when spring and summer temperatures were lower, suggesting that BSi flux in the lake is related to growing

  9. An integrated approach to demonstrating the ANR pathway of proanthocyanidin biosynthesis in plants.

    PubMed

    Peng, Qing-Zhong; Zhu, Yue; Liu, Zhong; Du, Ci; Li, Ke-Gang; Xie, De-Yu

    2012-09-01

    Proanthocyanidins (PAs) are oligomers or polymers of plant flavan-3-ols and are important to plant adaptation in extreme environmental conditions. The characterization of anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) has demonstrated the different biogenesis of four stereo-configurations of flavan-3-ols. It is important to understand whether ANR and the ANR pathway widely occur in the plant kingdom. Here, we report an integrated approach to demonstrate the ANR pathway in plants. This includes different methods to extract native ANR from different tissues of eight angiosperm plants (Lotus corniculatus, Desmodium uncinatum, Medicago sativa, Hordeum vulgare, Vitis vinifera, Vitis bellula, Parthenocissus heterophylla, and Cerasus serrulata) and one fern plant (Dryopteris pycnopteroides), a general enzymatic analysis approach to demonstrate the ANR activity, high-performance liquid chromatography-based fingerprinting to demonstrate (-)-epicatechin and other flavan-3-ol molecules, and phytochemical analysis of PAs. Results demonstrate that in addition to leaves of M. sativa, tissues of other eight plants contain an active ANR pathway. Particularly, the leaves, flowers and pods of D. uncinatum, which is a model plant to study LAR and the LAR pathways, are demonstrated to express an active ANR pathway. This finding suggests that the ANR pathway involves PA biosynthesis in D. uncinatum. In addition, a sequence BLAST analysis reveals that ANR homologs have been sequenced in plants from both gymnosperms and angiosperms. These data show that the ANR pathway to PA biosynthesis occurs in both seed and seedless vascular plants.

  10. Characteristics of Four Plant Species Used for Soil Bioengineering Techniques in River Bank Stabilization

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Gao, J. R.; Lou, H. P.; Zhang, J. R.; Rauch, H. P.

    2010-05-01

    Use the potential values of soil bioengineering techniques are important for the wide attention river ecological restoration works in Beijing. At first, demand for basic knowledge of the technical and biological properties of plants is essential for development of such techniques. Species for each chosen plant material type should be selected with an emphasis on the following: suitability for anticipated environment conditions, reasonable availability in desired quantity and probability of successful establishment. Account on these criteria, four species which used as live staking and rooted cutting techniques were selected, namely, Salix X aureo-pendula, Salix cheilophila, Vitex negundo var. heterophylla and Amorpha fruticosa L.. And monitoring work was performed on three construction sites of Beijing. Various survival rates and morphological parameters data were collected. Concerning plants hydraulic and hydrological behavior, bending tests were used to analysis the flexibility of each plant species. The results from rate and morphological parameters monitoring show that: Salix cheilophila performed the best. Other three plants behaved satisfactorily in shoots or roots development respectively. In the bending test mornitoring, Salix cheilophila branch had the least broken number. Then were Salix X aureo-pendula and Amorpha fruticosa L.. Vitex negundo var. branch had the highest broken number, but it tolerated the highest amount of stress. All plant species should be considered in the future scientific research and construction works in Beijing. Keywords: River bank stabilization, live staking, rooted cutting

  11. Hydrodynamically mediated macrophyte silica dynamics.

    PubMed

    Schoelynck, J; Bal, K; Puijalon, S; Meire, P; Struyf, E

    2012-11-01

    In most aquatic ecosystems, hydrodynamic conditions are a key abiotic factor determining species distributions and abundance of aquatic plants. Resisting stress and keeping an upright position often relies on investment in tissue reinforcement, which is costly to produce. Silica could provide a more economical alternative. Two laboratory experiments were conducted to measure the response of two submerged species, Egeria densa Planch. and Limnophila heterophylla (Roxb.) Benth., to dissolved silicic acid availability and exposure to hydrodynamic stress. The results were verified with a third species in a field study (Nuphar lutea (L.) Smith). Biogenic silica (BSi) concentration in both stems and leaves increases with increasing dissolved silica availability but also with the presence of hydrodynamic stress. We suggest that the inclusion of extra silica enables the plant to alternatively invest its energy in the production of lignin and cellulose. Although we found no significant effects of hydrodynamic stress on cellulose or lignin concentrations either in the laboratory or in the field, BSi was negatively correlated with cellulose concentration and positively correlated with lignin concentration in samples collected in the field study. This implies that the plant might perform with equal energy efficiency in both standing and running water environments. This could provide submerged species with a tool to respond to abiotic factors, to adapt to new ecological conditions and hence potentially colonise new environments.

  12. Cotterillia bromelicola nov. gen., nov. spec., a gonostomatid ciliate (Ciliophora, Hypotricha) from tank bromeliads (Bromeliaceae) with de novo originating dorsal kineties.

    PubMed

    Foissner, Wilhelm; Stoeck, Thorsten

    2011-01-01

    Cotterillia bromelicola nov. gen., nov. spec. was discovered in the tanks of the Mexican bromeliad Tillandsia heterophylla. Its morphology, ontogenesis, and 18S rDNA were studied with standard methods. Cotterillia has many cirral rows on both sides of the body. Uniquely, and thus used to diagnose the new genus Cotterillia, it has dorsal kineties originating de novo, producing neokinetal waves where the parental dorsal kineties reorganize to "combined rows", consisting of dorsal bristles anteriorly and of cirri posteriorly. Thus, up to four generations of bristles and cirri occur on the dorsal body surface. Cotterillia bromelicola has a gonostomatid body and adoral zone of membranelles, while the dense ciliature and the neokinetal waves resemble kahliellid hypotrichs. However, the de novo origin of anlage 1 and the molecular analyses show convincingly that Cotterillia belongs to the GonostomatidaeSmall and Lynn, 1985, for which an improved diagnosis is provided. Thus, neokinetal waves originated several times independently. The molecular differences between Trachelostyla, Gonostomum, and Cotterillia are small (≤ 5%) compared to their distinct morphologies and ontogeneses, suggesting that the 18S rDNA underestimates generic diversity. Our study emphasizes the need of combined morphological, ontogenetic, and molecular investigations to unravel the complex phylogeny and evolution of hypotrich ciliates.

  13. Glyphosate-resistant weeds of South American cropping systems: an overview.

    PubMed

    Vila-Aiub, Martin M; Vidal, Ribas A; Balbi, Maria C; Gundel, Pedro E; Trucco, Frederico; Ghersa, Claudio M

    2008-04-01

    Herbicide resistance is an evolutionary event resulting from intense herbicide selection over genetically diverse weed populations. In South America, orchard, cereal and legume cropping systems show a strong dependence on glyphosate to control weeds. The goal of this report is to review the current knowledge on cases of evolved glyphosate-resistant weeds in South American agriculture. The first reports of glyphosate resistance include populations of highly diverse taxa (Lolium multiflorum Lam., Conyza bonariensis L., C. canadensis L.). In all instances, resistance evolution followed intense glyphosate use in fruit fields of Chile and Brazil. In fruit orchards from Colombia, Parthenium hysterophorus L. has shown the ability to withstand high glyphosate rates. The recent appearance of glyphosate-resistant Sorghum halepense L. and Euphorbia heterophylla L. in glyphosate-resistant soybean fields of Argentina and Brazil, respectively, is of major concern. The evolution of glyphosate resistance has clearly taken place in those agroecosystems where glyphosate exerts a strong and continuous selection pressure on weeds. The massive adoption of no-till practices together with the utilization of glyphosate-resistant soybean crops are factors encouraging increase in glyphosate use. This phenomenon has been more evident in Argentina and Brazil. The exclusive reliance on glyphosate as the main tool for weed management results in agroecosystems biologically more prone to glyphosate resistance evolution.

  14. In Vitro Screening of Medicinal Plants Used in Mexico as Antidiabetics with Glucosidase and Lipase Inhibitory Activities

    PubMed Central

    Ramírez, Guillermo; Zavala, Miguel; Pérez, Julia; Zamilpa, Alejandro

    2012-01-01

    This work shows the inhibitory effect on glucosidase and lipase enzymes of 23 medicinal plants described as traditional treatments for diabetes in several Mexican sources. Hydroalcoholic extracts of selected plants were evaluated at 1 mg/mL for glucosidase and 0.25 mg/mL for lipase inhibitory activities, respectively. Camellia sinensis, acarbose, and orlistat were used as positive controls. Dose-response curves were done with the most active species. Sixty percent of all tested extracts inhibited more than 25% of α-glucosidase activity. C. sinensis displayed an inhibition of 85% (IC50 = 299 μg/mL), while Ludwigia octovalvis and Iostephane heterophylla showed the highest inhibition (82.7 %, IC50 = 202 μg/mL and 60.6%, CI50 = 509 μg/mL, resp.). With respect to lipase activity, L. octovalvis and Tecoma stans were the most inhibiting treatments (31.4%, IC50 = 288 μg/mL; 27.2%, IC50 = 320 μg/mL), while C. sinensis displayed 45% inhibition (IC50 = 310 μg/mL). These results indicate that a high proportion of plants used in Mexico as treatment for diabetes displays significant inhibition of these digestive enzymes. PMID:23082084

  15. Vegetation mapping of the Mond Protected Area of Bushehr Province (south-west Iran).

    PubMed

    Mehrabian, Ahmadreza; Naqinezhad, Alireza; Mahiny, Abdolrassoul Salman; Mostafavi, Hossein; Liaghati, Homan; Kouchekzadeh, Mohsen

    2009-03-01

    Arid regions of the world occupy up to 35% of the earth's surface, the basis of various definitions of climatic conditions, vegetation types or potential for food production. Due to their high ecological value, monitoring of arid regions is necessary and modern vegetation studies can help in the conservation and management of these areas. The use of remote sensing for mapping of desert vegetation is difficult due to mixing of the spectral reflectance of bright desert soils with the weak spectral response of sparse vegetation. We studied the vegetation types in the semiarid to arid region of Mond Protected Area, south-west Iran, based on unsupervised classification of the Spot XS bands and then produced updated maps. Sixteen map units covering 12 vegetation types were recognized in the area based on both field works and satellite mapping. Halocnemum strobilaceum and Suaeda fruticosa vegetation types were the dominant types and Ephedra foliata, Salicornia europaea-Suaeda heterophylla vegetation types were the smallest. Vegetation coverage decreased sharply with the increase in salinity towards the coastal areas of the Persian Gulf. The highest vegetation coverage belonged to the riparian vegetation along the Mond River, which represents the northern boundary of the protected area. The location of vegetation types was studied on the separate soil and habitat diversity maps of the study area, which helped in final refinements of the vegetation map produced.

  16. Taxonomic significance of trichomes micromorphology in cucurbits.

    PubMed

    Ali, Mohammad Ajmal; Al-Hemaid, Fahad M A

    2011-01-01

    Studies on trichomes micromorphology using Scanning Electron Microscope (SEM) were undertaken in 23 species with one variety under 13 genera of the family Cucurbitaceae (viz., Benincasa hispida (Thunb.) Cogn., Citrullus lanatus (Thunb.) Matsum. & Nakai, Cucumis melo var. agrestis Naudin, Cucumis sativus L., Diplocyclos palmatus (L.) C. Jeffrey, Edgaria dargeelingensis C.B. Clarke, Gynostemma burmanicum King ex Chakr., Gynostemma pentaphyllum (Thunb.) Makino, Gynostemma pubescens (Gagnep.) C.Y. Wu, Hemsleya dipterygia Kuang & A.M. Lu, Lagenaria siceraria (Molina) Standl., Luffa acutangula (L.) Roxb., Luffa cylindrica M. Roem., Luffa echinata Roxb., Melothria heterophylla (Lour.) Cogn., Melothria leucocarpa (Blume) Cogn., Melothria maderspatana (L.) Cogn., Sechium edule (Jacq.) Sw., Thladiantha cordifolia (Blume) Cogn., Trichosanthes cucumerina L., T. cucumerina var. anguina (L.) Haines, Trichosanthes dioica Roxb., Trichosanthes lepiniana (Naudin) Cogn. and T. tricuspidata Lour.). The trichomes in the family Cucurbitaceae vary from unicellular to multicellular, conical to elongated, smooth to ridges, with or without flattened disk at base and cyctolithic appendages, thin to thick walled, curved at apices to blunt. Trichomes micromorphology in the family Cucurbitaceae was found significant taxonomically.

  17. Method for RNA extraction and cDNA library construction from microbes in crop rhizosphere soil.

    PubMed

    Fang, Changxun; Xu, Tiecheng; Ye, Changliang; Huang, Likun; Wang, Qingshui; Lin, Wenxiong

    2014-02-01

    Techniques to analyze the transcriptome of the soil rhizosphere are essential to reveal the interactions and communications between plants and microorganisms in the soil ecosystem. In this study, different volumes of Al₂(SO₄)₃ were added to rhizosphere soil samples to precipitate humic substances, which interfere with most procedures of RNA and DNA analyses. After humic substances were precipitated, cells of soil microorganisms were broken by vortexing with glass beads, and then DNA and RNA were recovered using Tris-HCl buffer with LiCl, SDS, and EDTA. The crude extract was precipitated and dissolved in RNAse-free water, and then separated by agarose gel electrophoresis. We determined the optimum volume of Al₂(SO₄)₃ for treating rhizosphere soil of rice, tobacco, sugarcane, Rehmannia glutinosa, and Pseudostellaria heterophylla. The crude nucleic acids extract from rice soil was treated with DNase I and then RNA was purified using a gel filtration column. The purified RNA was reverse-transcribed into single-strand cDNA and then ligated with an adaptor at each end before amplifying ds cDNA. The ds cDNA was sub-cloned for subsequent gene sequence analysis. We conducted qPCR to amplify 16S ribosomal DNA and observed highly efficient amplification. These results show that the extraction method can be optimized to isolate and obtain high-quality nucleic acids from microbes in different rhizosphere soils, suitable for genomic and post-genomic analyses.

  18. [Niche characteristics of plant populations in Quercus aliena var. acuteserrata stands in Qinling Mountains].

    PubMed

    Zhao, Yonghua; Lei, Ruide; He, Xingyuan; Jia, Xia

    2004-06-01

    Based on the data collected from 31 plots and using Levins, Hurlbert and Pianka formulas, this paper calculated and analyzed the niche breadths and overlaps of 24 tree and 29 shrub populations in Quercus aliena var. acuteserrata stands in Mt. Qinling, Shaanxi. The results showed that the Levins and Hurlbert's niche breadths of Quercus aliena var. acuteserrata , Pinus armandi, Toxicodendron vernicifluum, Populus davidiana and Pinus tabulaeformis in arbor layer were 3.695, 1.695, 1.325, 0.840, 0.702 and 0.036, 0.299, 0.568, 1.721, 2.701 respectively, and those of Corrylus heterophylla, Lespedeza formosa and Smilax vaginata in shrub layer were 1.833, 1.466, 0.984 and 0.111, 0.300, 0.594, respectively. In general, the niche overlaps between the species with bigger niche breadth and other species were higher, and those of the species having similar environmental requirements were also higher.

  19. Pollen analysis of natural honeys from the central region of Shanxi, North China.

    PubMed

    Song, Xiao-Yan; Yao, Yi-Feng; Yang, Wu-De

    2012-01-01

    Based on qualitative and quantitative melissopalynological analyses, 19 Chinese honeys were classified by botanical origin to determine their floral sources. The honey samples were collected during 2010-2011 from the central region of Shanxi Province, North China. A diverse spectrum of 61 pollen types from 37 families was identified. Fourteen samples were classified as unifloral, whereas the remaining samples were multifloral. Bee-favoured families (occurring in more than 50% of the samples) included Caprifoliaceae (found in 10 samples), Laminaceae (10), Brassicaceae (12), Rosaceae (12), Moraceae (13), Rhamnaceae (15), Asteraceae (17), and Fabaceae (19). In the unifloral honeys, the predominant pollen types were Ziziphus jujuba (in 5 samples), Robinia pseudoacacia (3), Vitex negundo var. heterophylla (2), Sophora japonica (1), Ailanthus altissima (1), Asteraceae type (1), and Fabaceae type (1). The absolute pollen count (i.e., the number of pollen grains per 10 g honey sample) suggested that 13 samples belonged to Group I (<20,000 pollen grains), 4 to Group II (20,000-100,000), and 2 to Group III (100,000-500,000). The dominance of unifloral honeys without toxic pollen grains and the low value of the HDE/P ratio (i.e., honey dew elements/pollen grains from nectariferous plants) indicated that the honey samples are of good quality and suitable for human consumption.

  20. Invasion possibility and potential effects of Rhus typhina on Beijing municipality.

    PubMed

    Wang, Guangmei; Jiang, Gaoming; Yu, Shunli; Li, Yinghao; Liu, Hui

    2008-05-01

    Rhus typhina, an alien species introduced from North America, was identified as a main afforestation species in Beijing municipality. However, its invasiveness is still at odds. To clarify this problem, we applied the North American Screening System and the Australian Screening System to preliminarily predict its invasion possibility. Both screening systems gave the same recommendation to "reject". The geographical distribution was surveyed, with the population features of R. typhina against the native plant communities being assessed. With anthropogenic assistance, R. typhina has been scattered on almost all habitats from downtown to mountains, including roadsides, farmlands and protected areas. As a clonal shrub, R. typhina possessed a high spreading rate, varying from 6.3 m/3 years at sterile habitats to 6.7 m/3 years at fertile ones. Significantly lower species richness, individual density and diversity were observed in the R. typhina community than those of the native Vitex negundo Linn.var. heterophylla (Franch.) Rehd. community at both sterile and fertile habitats. Continual wide plantation of R. typhina may further foster its population expansion, which helps the species to overcome spatial isolation. The fact that each root fragment can develop into a new individual makes R. typhina very difficult to be eradicated once established. From a biological point of view, we believe that R. typhina is a plant invader in Beijing. We therefore suggest the government should remove the name of R. typhina from the main tree species list in afforesting Beijing.

  1. [Effects of relative abundance of Quercus mongolica acorns on five tree species seed dispersal in Xiaoxing' an Mountains, Northeast China].

    PubMed

    Yu, Fei; Shi, Xiao-Xiao; Yi, Xian-Feng; Wang, De-Xiang

    2013-06-01

    An investigation was conducted in a forest farm in the Xiaoxing' an Mountains in autumn, 2009 and 2010 to study the effects of Quercus mongolica acorn quantity and rodent density on the seed dispersal of five tree species (Juglans mandshurica, Pinus koraiensis, Corylus mandshurica, Corylus heterophylla, and Q. mongolica). In the farm, there was an annual change in rodent density. The total capture rate of small rodents in 2009 (31.0%) was significantly higher than that in 2010 (16.7%). The acorn quantity and relative seed abundance (per capita rodent) of Quercus mongolica in 2009 (6.2 +/- 2.1 acorns x m(-2) and 20.0, respectively) were significantly lower than those in 2010 (26.7 +/- 10.2 acorns x m(-2) and 160.0, respectively). In 2009, all the seeds of the five tree species except J. mandshurica were dispersed or eaten in situ, among which, the acorns of Q. mongolica were scatter-hoarded most, and their average dispersal distance was the furthest. In 2010, the seeds of J. mandshurica were scatter-hoarded most, and their average dispersal distance was the furthest. The relative seed abundance of Q. mongolica could be the key factor determining the seed dispersal of the other tree species in the study area.

  2. Comparisons between conventional, ultrasound-assisted and microwave-assisted methods for extraction of anthraquinones from Heterophyllaea pustulata Hook f. (Rubiaceae).

    PubMed

    Barrera Vázquez, M F; Comini, L R; Martini, R E; Núñez Montoya, S C; Bottini, S; Cabrera, J L

    2014-03-01

    This work reports a comparative study about extraction methods used to obtain anthraquinones (AQs) from stems and leaves of Heterophyllae pustulata Hook (Rubiáceae). One of the conventional procedures used to extract these metabolites from a vegetable matrix is by successive Soxhlet extractions with solvents of increasing polarity: starting with hexane to eliminate chlorophylls and fatty components, following by benzene and finally ethyl acetate. However, this technique shows a low extraction yield of total AQs, and consumes large quantities of solvent and time. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) have been investigated as alternative methods to extract these compounds, using the same sequence of solvents. It was found that UAE increases the extraction yield of total AQs and reduces the time and amount of solvent used. Nevertheless, the combination UAE with benzene, plus MAE with ethyl acetate at a constant power of 900 W showed the best results. A higher yield of total AQs was obtained in less time and using the same amount of solvent that UAE. The optimal conditions for this latter procedure were UAE with benzene at 50 °C during 60 min, followed by MAE at 900 W during 15 min using ethyl acetate as extraction solvent.

  3. Delayed tree mortality in the Atchafalaya Basin of Southern Louisiana following Hurricane Andrew

    USGS Publications Warehouse

    Keeland, B.D.; Gorham, L.E.

    2009-01-01

    Hurricanes can damage trees in forested wetlands, and the potential for mortality related to these storms exists due to the effects of tree damage over time. In August 1992, Hurricane Andrew passed through the forested wetlands of southern Louisiana with winds in excess of 225 kph. Although more than 78 of the basal area was destroyed in some areas, most trees greater than 2.5 cm dbh were alive and resprouting prolifically the following year (98.8). Survival of most tree species was similarly high two years after the hurricane, but mortality rates of some species increased dramatically. For example, Populus heterophylla (swamp cottonwood) mortality increased from 7.8 to 59.2 (n 76) and Salix interior (sandbar willow) mortality increased from 4.5 to 57.1 (n 21). Stem sprouts on many up-rooted hardwood trees of other species were still alive in 1998, 6 years after the hurricane. Due to the understory tree species composition, regeneration, and high levels of resprouting, there was little change in species composition or perhaps a slight shift toward more shade and flood tolerant species six years following the hurricane event. Triadica sebifera (Chinese tallow) was found on some of the sites heavily disturbed by Hurricane Andrew, and may proliferate at the expense of native tree species. ?? 2009 The Society of Wetland Scientists.

  4. Acute toxicity and mutagenic activity of Mexican plants used in traditional medicine.

    PubMed

    Déciga-Campos, Myrna; Rivero-Cruz, Isabel; Arriaga-Alba, Myriam; Castañeda-Corral, Gabriela; Angeles-López, Guadalupe E; Navarrete, Andrés; Mata, Rachel

    2007-03-21

    The present work was undertaken to determine safety parameters of selected Mexican medicinal plants chosen on the basis of their frequency of medicinal use and commercial importance. The medicinal herbs included Amphipteryngium adstringens, Hintonia standleyana, Hintonia latiflora, Piper sanctum, Haemathoxylon brasiletto, Iostephane heterophylla, Valeriana procera, Arracacia tolucensis, Brickellia veronicaefolia, Scaphyglottis livida, Exostema caribaeum, Hippocratea excelsa, Ligusticum porteri, Poliomintha longiflora and Gnaphalium sp. In the acute toxicity studies in mice performed according to the Lorke procedure, Exostema caribaeum, Hippocratea excelsa, Ligusticum porteri and Poliomintha longiflora were the most toxic with LD(50) values between 1085 and 2mg/kg. The Ames test revealed that Gnaphalium sp. and Valeriana procera extracts induced mutations of S. typhimurium TA98 with or without the S9 microsomal fraction, and TA100 in the presence of the enzymatic fraction, respectively. The tincture of Valeriana procera, however, was non-mutagenic. Finally, in the Artemia salina lethality test Brickellia veronicaefolia, Arracacia tolucensis, Poliomintha longiflora and Piper sanctum caused significant mortality of the crustacean larvae with LC(50) in the range of 37-227 microg/mL.

  5. Begomoviruses infecting weeds in Cuba: increased host range and a novel virus infecting Sida rhombifolia.

    PubMed

    Fiallo-Olivé, Elvira; Navas-Castillo, Jesús; Moriones, Enrique; Martínez-Zubiaur, Yamila

    2012-01-01

    As a result of surveys conducted during the last few years to search for wild reservoirs of begomoviruses in Cuba, we detected a novel bipartite begomovirus, sida yellow mottle virus (SiYMoV), infecting Sida rhombifolia plants. The complete genome sequence was obtained, showing that DNA-A was 2622 nucleotides (nt) in length and that it was most closely related (87.6% nucleotide identity) to DNA-A of an isolate of sida golden mosaic virus (SiGMV) that infects snap beans (Phaseolus vulgaris) in Florida. The DNA-B sequence was 2600 nt in length and shared the highest nucleotide identity (75.1%) with corchorus yellow spot virus (CoYSV). Phylogenetic relationship analysis showed that both DNA components of SiYMoV were grouped in the Abutilon clade, along with begomoviruses from Florida and the Caribbean islands. We also present here the complete nucleotide sequence of a novel strain of sida yellow vein virus found infecting Malvastrum coromandelianum and an isolate of euphorbia mosaic virus that was found for the first time infecting Euphorbia heterophylla in Cuba.

  6. Pollen Analysis of Natural Honeys from the Central Region of Shanxi, North China

    PubMed Central

    Song, Xiao-Yan; Yao, Yi-Feng; Yang, Wu-De

    2012-01-01

    Based on qualitative and quantitative melissopalynological analyses, 19 Chinese honeys were classified by botanical origin to determine their floral sources. The honey samples were collected during 2010–2011 from the central region of Shanxi Province, North China. A diverse spectrum of 61 pollen types from 37 families was identified. Fourteen samples were classified as unifloral, whereas the remaining samples were multifloral. Bee-favoured families (occurring in more than 50% of the samples) included Caprifoliaceae (found in 10 samples), Laminaceae (10), Brassicaceae (12), Rosaceae (12), Moraceae (13), Rhamnaceae (15), Asteraceae (17), and Fabaceae (19). In the unifloral honeys, the predominant pollen types were Ziziphus jujuba (in 5 samples), Robinia pseudoacacia (3), Vitex negundo var. heterophylla (2), Sophora japonica (1), Ailanthus altissima (1), Asteraceae type (1), and Fabaceae type (1). The absolute pollen count (i.e., the number of pollen grains per 10 g honey sample) suggested that 13 samples belonged to Group I (<20,000 pollen grains), 4 to Group II (20,000–100,000), and 2 to Group III (100,000–500,000). The dominance of unifloral honeys without toxic pollen grains and the low value of the HDE/P ratio (i.e., honey dew elements/pollen grains from nectariferous plants) indicated that the honey samples are of good quality and suitable for human consumption. PMID:23185358

  7. Eriophyes species (Acari: Eriophyoidea) inhabiting lime trees (Tilia spp.: Tiliaceae)--supplementary description and morphological variability related to host plants and female forms.

    PubMed

    Soika, Grazyna; Kozak, Marcin

    2013-01-01

    Three poorly known species of the subfamily Eriophyinae living on Tilia spp. (Tiliaceae) are illustrated and supplementary descriptions are provided. Two of them, Eriophyes exilis (Nalepa 1892) and Eriophyes nervalis (Nalepa 1918), were recorded both in vein angle galls on leaves of Tilia platyphyllos Scop. and in erinea on leaves of Tilia tomentosa Moench, Tilia americana L. 'Moltkei', Tilia americana var. heterophylla (Vent.) Loudon, Tilia cordata Mill., Tiliajaponica (Miq.) Simonk., Tilia petiolaris DC. and Tilia zamoyskiana Wr6bl. The third species, Eriophyes tiliae Nalepa 1890, was found in nail galls on leaves of T platyphyllos, T americana and T. cordata. All of these Eriophyes species showed noticeable morphological differences between protogyne and deutogyne females in terms of the number of dorsal annuli, location of setae d, length of setae e and 3a, distance between tubercles 3a and the length and pattern of the prodorsal shield. Based on a comparative morphological analysis of this original data with that published by A. Nalepa, new synonyms for the following species are proposed: Erophyes exilis (Nalepa) = Eriophyes leiosoma Nalepa syn. nov.; Eriophyes nervalis (Nalepa) = Eriophyes tiliaceus Nalepa syn. nov., Eriophyes tiliae Nalepa = Eriophyes rudis Nalepa syn. nov. = Eriophyes tomentosae Nalepa syn. nov. A key to all studied Eriophyes species living on lime trees is included.

  8. Geographical influences on content of 10-hydroxy-trans-2-decenoic acid in royal jelly in China.

    PubMed

    Wei, Wen-Ting; Hu, Yuan-Qiang; Zheng, Huo-Qing; Cao, Lian-Fei; Hu, Fu-Liang; Hepburn, H Randall

    2013-10-01

    The content of 10-hydroxy-trans-2-decenoic acid (10-HDA), a marker compound in royal jelly (RJ), is the most important criterion in grading RJ for commercial trade and varies with its origin. To identify the effect of geographical origin on 10-HDA content in RJ, 138 samples were collected from 19 provinces of China (divided into three groups) produced by either Apis mellifera ligustica Spinola, 1806 or a hybrid of A. m. ligustica and Apis mellifera carnica Pollman, 1879 and analyzed for moisture, sugar, crude protein, ash, acid, and 10-HDA concentration. The results show that RJ from western China has a significantly higher 10-HDA level (2.01 +/- 0.05%) than those from northeastern (1.87 +/- 0.05%) and eastern (1.75 +/- 0.03%) China. RJ secreted by hybrid bees contained more 10-HDA (1.89 +/- 0.03%) than that secreted by A. m. ligustica (1.78 +/- 0.03%). The 10-HDA content of RJ produced during flowering of rape (Brassica campestris L.), lime (Tilia amurensis Ruprecht), and vitex (Vitex negundo L. variety heterophylla (Franch.) Rehder) was 1.92, 1.80, and 1.68%, respectively. The results would be helpful during the process of price determination of RJ by providing some basis of geographical, bee strain, and botanical information for commercial trade.

  9. Kootenai River White Sturgeon Investigations; White Sturgeon Spawning and Recruitment Evaluation, 2003-2004 Annual Report.

    SciTech Connect

    Rust, Pete; Wakkinen, Virginia

    2005-06-01

    The objective of this research was to determine the environmental requirements for successful spawning and recruitment of the Kootenai River white sturgeon Acipenser transmontanus population. Annual tasks include monitoring and evaluating the various life stages of Kootenai River white sturgeon. Sampling for adult Kootenai River white sturgeon in 2003 began in March and continued through April. Eighty-one adult white sturgeon were captured with 3,576 hours of angling and set-lining effort in the Kootenai River. Discharge from Libby Dam and river stage at Bonners Ferry in 2003 peaked in May and early June. Flows remained above 500 m{sup 3}/s throughout June, decreased rapidly through mid July, and increased back to near 500 m{sup 3}/s after mid July and through mid August. By late August, flows had decreased to below 400 m{sup 3}/s. We monitored the movements of 24 adult sturgeon in Kootenay Lake, British Columbia (BC) and the Kootenai River from March 15, 2003 to August 31, 2003. Some of the fish were radio or sonic tagged in previous years. Twelve adult white sturgeon were moved upstream to the Hemlock Bar reach (rkm 260.0) and released as part of the Set and Jet Program. Transmitters were attached to seven of these fish, and their movements were monitored from the time of release until they moved downstream of Bonners Ferry. Eight additional radio-tagged white sturgeon adults were located in the traditional spawning reach (rkm 228-240) during May and June. Sampling with artificial substrate mats began May 21, 2003 and ended June 30, 2003. We sampled 717 mat d (a mat d is one 24 h set) during white sturgeon spawning. Three white sturgeon eggs were collected near Shortys Island on June 3, 2003, and five eggs were collected from the Hemlock Bar reach on June 5, 2003. Prejuvenile sampling began June 17, 2003 and continued until July 31, 2003. Sampling occurred primarily at Ambush Rock (rkm 244.0) in an attempt to document any recruitment that might have occurred from

  10. Vegetation and Water Level Changes for the Northeast U.S. During the "8.2 ka Event"

    NASA Astrophysics Data System (ADS)

    Newby, P. E.; Donnelly, J. P.; Shuman, B.; MacDonald, D.

    2006-12-01

    Cool conditions, known as the "8.2 ka event", occurred between 8400 and 7900 cal yr B.P. in Greenland, Europe and elsewhere in the North Atlantic. The impact of this brief cool interval on local forests is recorded in radiocarbon-dated, high-resolution pollen stratigraphies for New Long Pond (41^{0}50'N, 70^{0}42'W) and Davis Pond (42^{0}30'N, 73^{0}19'W), Massachusetts. The vegetation response to the event is recorded differently for regions with contrasting soil types. At New Long Pond, the sandy outwash derived soils are associated with changes in jack/red, white and pitch pine populations, whereas the dominant changes in vegetation for the clay-rich, proglacial lake derived soils around Davis Pond are among oak, hemlock, and beech. At both sites, pollen evidence for the "8.2 ka event" may be easily overlooked within the more dominant regional pattern for the Northeast, which shows a shift from dry to moist conditions in conjunction with changes from predominantly white pine to oak with more mesic plant taxa between 9000 and 8000 cal yr B.P. At New Long Pond, the "8.2 ka event" is brief, preceded by a low-stand in water-level during the early Holocene and dominated by white pine pollen. After 9000 cal yr B.P., pitch pine with beech, maple, hop/hornbeam, elm and ash pollen indicate a mixed mesophytic forest. A radiocarbon-dated decrease in loss-on-ignition values at 8400 cal yr B.P., likely related to a drawdown in lake level, distinguishes the "8.2 event" and helps highlight subtle shifts in vegetation that favor colder and drier conditions than before the event. Following this brief episode, the pollen data indicate a return to warm and moist conditions until about 5600 years ago. At Davis Pond, increased oak and decreased hemlock pollen abundances, followed by an increase in beech pollen abundance is evident and show what may be the dominant regional pollen signature for the "8.2 ka event" in the Northest. This pattern is also recorded at nearby Berry and

  11. The Effect of Lidar Point Density on LAI Estimation

    NASA Astrophysics Data System (ADS)

    Cawse-Nicholson, K.; van Aardt, J. A.; Romanczyk, P.; Kelbe, D.; Bandyopadhyay, M.; Yao, W.; Krause, K.; Kampe, T. U.

    2013-12-01

    Leaf Area Index (LAI) is an important measure of forest health, biomass and carbon exchange, and is most commonly defined as the ratio of the leaf area to ground area. LAI is understood over large spatial scales and describes leaf properties over an entire forest, thus airborne imagery is ideal for capturing such data. Spectral metrics such as the normalized difference vegetation index (NDVI) have been used in the past for LAI estimation, but these metrics may saturate for high LAI values. Light detection and ranging (lidar) is an active remote sensing technology that emits light (most often at the wavelength 1064nm) and uses the return time to calculate the distance to intercepted objects. This yields information on three-dimensional structure and shape, which has been shown in recent studies to yield more accurate LAI estimates than NDVI. However, although lidar is a promising alternative for LAI estimation, minimum acquisition parameters (e.g. point density) required for accurate LAI retrieval are not yet well known. The objective of this study was to determine the minimum number of points per square meter that are required to describe the LAI measurements taken in-field. As part of a larger data collect, discrete lidar data were acquired by Kucera International Inc. over the Hemlock-Canadice State Forest, NY, USA in September 2012. The Leica ALS60 obtained point density of 12 points per square meter and effective ground sampling distance (GSD) of 0.15m. Up to three returns with intensities were recorded per pulse. As part of the same experiment, an AccuPAR LP-80 was used to collect LAI estimates at 25 sites on the ground. Sites were spaced approximately 80m apart and nine measurements were made in a grid pattern within a 20 x 20m site. Dominant species include Hemlock, Beech, Sugar Maple and Oak. This study has the benefit of very high-density data, which will enable a detailed map of intra-forest LAI. Understanding LAI at fine scales may be particularly useful

  12. Forest fuel reduction alters fire severity and long-term carbon storage in three Pacific Northwest ecosystems.

    PubMed

    Mitchell, Stephen R; Harmon, Mark E; O'Connell, Kari E B

    2009-04-01

    Two forest management objectives being debated in the context of federally managed landscapes in the U.S. Pacific Northwest involve a perceived trade-off between fire restoration and carbon sequestration. The former strategy would reduce fuel (and therefore C) that has accumulated through a century of fire suppression and exclusion which has led to extreme fire risk in some areas. The latter strategy would manage forests for enhanced C sequestration as a method of reducing atmospheric CO2 and associated threats from global climate change. We explored the trade-off between these two strategies by employing a forest ecosystem simulation model, STANDCARB, to examine the effects of fuel reduction on fire severity and the resulting long-term C dynamics among three Pacific Northwest ecosystems: the east Cascades ponderosa pine forests, the west Cascades western hemlock-Douglas-fir forests, and the Coast Range western hemlock-Sitka spruce forests. Our simulations indicate that fuel reduction treatments in these ecosystems consistently reduced fire severity. However, reducing the fraction by which C is lost in a wildfire requires the removal of a much greater amount of C, since most of the C stored in forest biomass (stem wood, branches, coarse woody debris) remains unconsumed even by high-severity wildfires. For this reason, all of the fuel reduction treatments simulated for the west Cascades and Coast Range ecosystems as well as most of the treatments simulated for the east Cascades resulted in a reduced mean stand C storage. One suggested method of compensating for such losses in C storage is to utilize C harvested in fuel reduction treatments as biofuels. Our analysis indicates that this will not be an effective strategy in the west Cascades and Coast Range over the next 100 years. We suggest that forest management plans aimed solely at ameliorating increases in atmospheric CO2 should forgo fuel reduction treatments in these ecosystems, with the possible exception of

  13. Detection of long-term trends in carbon accumulation by forests in Northeastern U. S. and determination of causal factors: Final report

    SciTech Connect

    J. William Munger; Steven C. Wofsy; David R. Foster

    2012-01-31

    The overall project goal was to quantify the trends and variability for Net ecosystem exchange of CO{sub 2}, H{sub 2}O, and energy by northeastern forests, with particular attention to the role of succession, differences in species composition, legacies of past land use, and disturbances. Measurements included flux measurements and observations of biomass accumulation using ecosystem modeling as a framework for data interpretation. Continuation of the long-term record at the Environmental Measurement Site (EMS) Tower was a priority. The final quality-assured CO{sub 2}-flux data now extend through 2010. Data through 2011 are collected but not yet finalized. Biomass observations on the plot array centered on the tower are extended to 2011. Two additional towers in a hemlock stand (HEM) and a younger deciduous stand (LPH) complement the EMS tower by focusing on stands with different species composition or age distribution and disturbance history, but comparable climate and soil type. Over the period since 1993 the forest has added 24.4 Mg-C ha{sup -1} in the living trees. Annual net carbon uptake had been increasing from about 2 Mg-C ha{sup -1}y{sup -1} in the early 1990s to nearly 6 Mg-C ha{sup -1}y{sup -1} by 2008, but declined in 2009-2010. We attribute the increasing carbon uptake to a combination of warmer temperatures, increased photosynthetic efficiency, and increased influence by subcanopy hemlocks that are active in the early spring and late autumn when temperatures are above freezing but the deciduous canopy is bare. Not all of the increased carbon accumulation was found in woody biomass. Results from a study using data to optimize parameters in an ecosystem process model indicate that significant changes in model parameters for photosynthetic capacity and shifts in allocation to slow cycling soil organic matter are necessary for the model to match the observed trends. The emerging working hypothesis is that the pattern of increasing carbon uptake over the

  14. Measuring forest structure and biomass using EchidnaRTM ground-based lidar

    NASA Astrophysics Data System (ADS)

    Yao, Tian

    Forest canopy structural parameters and above-ground biomass, retrieved by a ground-based, upward-scanning, near-infrared (1064 nm), full-waveform lidar, the EchidnaRTM Validation Instrument (EVI), matched ground measurements with R2 values of 0.92 to 0.99 at six hardwood and conifer forest sites within New England in 2007 and at eight conifer forest sites in the Sierra National Forest in California in 2008. Retrieved parameters included mean diameter at breast height (DBH), stem count density, basal area, and above-ground biomass, based on five scans within each 1-ha plot. Canopy heights derived from the EVI-retrieved foliage profile closely matched those derived from the airborne Laser Vegetation Imaging Sensor (LVIS). Topographic slope can induce errors in parameter retrievals because the horizontal plane of the instrument scan, which is used to identify, measure, and count tree trunks, will intersect trunks below breast height in the uphill direction and above breast height in the downhill direction. I tested three methods of slope correction on the Sierra sites. Without correction, single-scan correlations of structural parameters with field measurements ranged from 0.53-0.86; after correction, from 0.78-0.91, 0.80-0.93 and 0,85-0.93 for the three methods respectively. These results document the importance of the slope correction in EVI structural retrievals. Three sites scanned in 2007 provided the opportunity to detect change in comparison to 2009 or 2010 scans. At a shelterwood conifer site at Howland Experimental Forest, mean DBH, above-ground biomass, and leaf area index (LAI) all increased between 2007 and 2009. An ice storm struck the Harvard Forest in December, 2008, providing the opportunity to detect damage between 2007 and 2009 or 2010 EVI scans at two sites there: hemlock and hardwood. Retrieved leaf area index (LAI) was 13 percent lower in the hemlock site in 2009 and 10 percent lower in the hardwood site in 2010. Broken tops were visible in the

  15. Fuel deposition rates of montane and subalpine conifers in the central Sierra Nevada, California, USA

    USGS Publications Warehouse

    van Wagtendonk, J.W.; Moore, P.E.

    2010-01-01

    Fire managers and researchers need information on fuel deposition rates to estimate future changes in fuel bed characteristics, determine when forests transition to another fire behavior fuel model, estimate future changes in fuel bed characteristics, and parameterize and validate ecosystem process models. This information is lacking for many ecosystems including the Sierra Nevada in California, USA. We investigated fuel deposition rates and stand characteristics of seven montane and four subalpine conifers in the Sierra Nevada. We collected foliage, miscellaneous bark and crown fragments, cones, and woody fuel classes from four replicate plots each in four stem diameter size classes for each species, for a total of 176 sampling sites. We used these data to develop predictive equations for each fuel class and diameter size class of each species based on stem and crown characteristics. There were consistent species and diameter class differences in the annual amount of foliage and fragments deposited. Foliage deposition rates ranged from just over 50 g m-2 year-1 in small diameter mountain hemlock stands to ???300 g m-2 year-1 for the three largest diameter classes of giant sequoia. The deposition rate for most woody fuel classes increased from the smallest diameter class stands to the largest diameter class stands. Woody fuel deposition rates varied among species as well. The rates for the smallest woody fuels ranged from 0.8 g m-2 year-1 for small diameter stands of Jeffrey pine to 126.9 g m-2 year-1 for very large diameter stands of mountain hemlock. Crown height and live crown ratio were the best predictors of fuel deposition rates for most fuel classes and species. Both characteristics reflect the amount of crown biomass including foliage and woody fuels. Relationships established in this study allow predictions of fuel loads to be made on a stand basis for each of these species under current and possible future conditions. These predictions can be used to

  16. Paleoecology of late-glacial terrestrial deposits with in situ conifers from the submerged continental shelf of western canada

    NASA Astrophysics Data System (ADS)

    Lacourse, Terri; Mathewes, Rolf W.; Fedje, Daryl W.

    2003-09-01

    Extensive portions of the continental shelf off the coast of British Columbia were subaerially exposed during Late Wisconsinan deglaciation due to lowering of relative sea level by as much as 150 m. Paleoecological analyses were conducted at two sites on the emergent continental shelf where terrestrial surfaces with in situ conifers are preserved. The woody plant remains confirm that, during the latest period of subaerial exposure, terrestrial vegetation was established on the continental shelf. Microscopic identification of fossil wood, and analyses of pollen and plant macrofossils from the associated paleosols and overlying shallow pond sediments indicate that productive Pinus contorta-dominated communities with abundant Alnus crispa and ferns grew on the shelf adjacent to and on the Queen Charlotte Islands around 12,200 14C yr B.P. Dwarf shrubs including Salix and Empetrum, and herbaceous plants such as Heracleum lanatum and Hippuris vulgaris, were also important components of the shelf vegetation. Near northern Vancouver Island, mixed coniferous forests dominated by Pinus contorta with Picea, Tsuga spp., Alnus spp., and ferns occupied the shelf at 10,500 14C yr B.P.

  17. A 12,000-year history of vegetation and climate for Cape Cod, Massachusetts

    NASA Astrophysics Data System (ADS)

    Winkler, Marjorie Green

    1985-05-01

    Pollen and charcoal analysis of radiocarbon-dated sediment cores from Duck Pond in the Cape Cod National Seashore provide a continuous 12,000-yr vegetation and climate history of outer Cape Cod. A Picea-Hudsonia parkland and then a Picea-Pinus banksiana-Alnus crispa boreal forest association grew near the site between 12,000 and 10,000 yr B.P. This vegetation was replaced by a northern conifer forest of Pinus strobus-P. banksiana, and, subsequently, by a more mesophytic forest ( Pinus strobus, Tsuga, Quercus, Fagus, Acer, Ulmus, Fraxinus, Ostrya) as the climate became warmer and wetter by 9500 yr B.P. By 9000 yr B.P. a Pinus rigida-Quercus association dominated the landscape. High charcoal frequencies from this and subsequent levels suggest that the pine barrens association developed during a warmer and drier climate that lasted from 9000 to about 5000 yr B.P. Increased percentages of Pinus strobus pollen indicate a return to moister and cooler conditions by about 3500 yr B.P. A doubled sedimentation rate, increased charcoal, and increased herb pollen suggest land disturbance near the pond before European settlement. These results suggest a rapid warming in the northeast in the early Holocene and support a hypothesis of a rapid sea level rise at that time. Comparison of the pollen results from Duck Pond with those from Rogers Lake, Connecticut, illustrates the importance of edaphic factors in determining the disturbance frequency and vegetation history of an area.

  18. Climate and vegetation history from a 14,000-year peatland record, Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Jones, Miriam C.; Peteet, Dorothy M.; Kurdyla, Dorothy; Guilderson, Thomas

    2009-09-01

    Analysis of pollen, spores, macrofossils, and lithology of an AMS 14C-dated core from a subarctic fen on the Kenai Peninsula, Alaska reveals changes in vegetation and climate beginning 14,200 cal yr BP. Betula expansion and contraction of herb tundra vegetation characterize the Younger Dryas on the Kenai, suggesting increased winter snowfall concurrent with cool, sunny summers. Remarkable Polypodiaceae (fern) abundance between 11,500 and 8500 cal yr BP implies a significant change in climate. Enhanced peat preservation and the occurrence of wet meadow species suggest high moisture from 11,500 to 10,700 cal yr BP, in contrast to drier conditions in southeastern Alaska; this pattern may indicate an intensification and repositioning of the Aleutian Low (AL). Drier conditions on the Kenai Peninsula from 10,700 to 8500 cal yr BP may signify a weaker AL, but elevated fern abundance may have been sustained by high seasonality with substantial snowfall and enhanced glacial melt. Decreased insolation-induced seasonality resulted in climatic cooling after 8500 cal yr BP, with increased humidity from 8000 to 5000 cal yr BP. A dry interval punctuated by volcanic activity occurred between 5000 and 3500 cal yr BP, followed by cool, moist climate, coincident with Neoglaciation. Tsuga mertensiana expanded after ~ 1500 cal yr BP in response to the shift to cooler conditions.

  19. Cytogenetic and molecular characterization of the Abies alba genome and its relationship with other members of the Pinaceae.

    PubMed

    Puizina, J; Sviben, T; Krajacić-Sokol, I; Zoldos-Pećnik, V; Siljak-Yakovlev, S; Papes, D; Besendorfer, V

    2008-03-01

    Genome size, karyotype structure, heterochromatin distribution, position and number of ribosomal genes, as well as the ITS2 sequence of the internal transcribed spacer (ITS) were analysed in silver fir (Abies alba Mill.). The analysis also included characterization of the Arabidopsis-type of telomeric repeats in silver fir and in related species. The results were compared with results from other species of the Pinaceae, to evaluate phylogeny and chromosomal and molecular evolution in the Pinaceae. Integrated chromosomal data provided insights into chromosome and karyotype evolution in the Pinaceae. The evolutionary trend for GC-rich heterochromatic blocks seems to involve loss of blocks that are not associated with rDNA. Similarly, numerous large blocks of interstitial plant telomeric repeats that are typical for all analysed species of the genus Pinus were not observed in the evolutionarily younger genera, such as Abies, Picea and Larix. On the contrary, the majority of telomeric sequences in these three genera appeared confined to the chromosome ends. We confirmed the current position of Abies and Tsuga in subfamily Abietoideae and the position of Pinus in the subfamily Pinoideae based on ITS2 sequences. Pseudotsuga is placed together with Larix into the subfamily Laricoideae. We conclude that the current position of the genus Picea in the subfamily Abietoideae should be reconsidered and, possibly, the genus Picea should be reclassified as a separate subfamily, Piceoideae, as recently proposed.

  20. Paleofire reconstruction for high-elevation forests in the Sierra Nevada, California, with implications for wildfire synchrony and climate variability in the late Holocene

    NASA Astrophysics Data System (ADS)

    Hallett, Douglas J.; Anderson, R. Scott

    2010-03-01

    Here, we present two high-resolution records of macroscopic charcoal from high-elevation lake sites in the Sierra Nevada, California, and evaluate the synchroneity of fire response for east- and west-side subalpine forests during the past 9200 yr. Charcoal influx was low between 11,200 and 8000 cal yr BP when vegetation consisted of sparse Pinus-dominated forest and montane chaparral shrubs. High charcoal influx after ˜ 8000 cal yr BP marks the arrival of Tsuga mertensiana and Abies magnifica, and a higher-than-present treeline that persisted into the mid-Holocene. Coeval decreases in fire episode frequency coincide with neoglacial advances and lower treeline in the Sierra Nevada after 3800 cal yr BP. Independent fire response occurs between 9200 and 5000 cal yr BP, and significant synchrony at 100- to 1000-yr timescales emerges between 5000 cal yr BP and the present, especially during the last 2500 yr. Indistinguishable fire-return interval distributions and synchronous fires show that climatic control of fire became increasingly important during the late Holocene. Fires after 1200 cal yr BP are often synchronous and corroborate with inferred droughts. Holocene fire activity in the high Sierra Nevada is driven by changes in climate linked to insolation and appears to be sensitive to the dynamics of the El Niño-Southern Oscillation.

  1. Macrofossil and Leaf Wax Biomarkers Reveal Vegetational and Climate History of Tamarack Pond, Black Rock Forest, Southeastern New York

    NASA Astrophysics Data System (ADS)

    Alt, M.; Peteet, D. M.; Nichols, J. E.

    2014-12-01

    Tamarack Pond (41.39500°N 74.02505°W) is located at an elevation of 1305 ft, within the variable topography (Fig. 3) of Black Rock Forest, a 3830-acre oak (Quercus) dominated forest located in the Hudson Highlands Physiographic Province in southeastern New York State. A 7.2 m core retrieved in 4 m of water with a modified Livingstone piston corer was subsampled at 2 and 4-cm intervals from the base of the core through the early Holocene. The basal date of 16, 200 cal. yr BP on Dryas integrifolia leaves in inorganic clays demonstrates the pond formation in a landscape of sparse tundra with Salix, Daphnia, and craneflies. Subsequent inorganic layers record Dryas, Salix, Alnus, Polytrichum juniperum, Sphagnum, and bryozoan statoblasts. A dramatic shift to 25% organic matter in the pond records Picea needles and the first record of charcoal. Continued increases in LOI in the pond are correlative with the presence of Abies balsamea and Betula papyrifera appears as the boreal forest develops and tundra disappears. A return to colder conditions is suggested with a slight decline in LOI as Betula glandulosa and Larix laricina are present along with the boreal mixture, and a large increase in Daphnia ephippia. A return to warmer conditions ensues with the decline of the boreal conifers and the presence of Tsuga canadensis. Leaf wax data will be presented along with the macrofossil results.

  2. A unique Middle Pleistocene beech (Fagus)-rich deciduous broad-leaved forest in the Yangtze Delta Plain, East China: Its climatic and stratigraphic implication

    NASA Astrophysics Data System (ADS)

    Shu, Jun-wu; Wang, Wei-ming

    2012-08-01

    Pollen analysis of Middle Pleistocene sediments from the Yangtze Delta Plain provides a paleoecological reconstruction and has implications for stratigraphic correlation in East China. The pollen assemblage is characterized by high values of Fagus (16.8% on average), which is unusual because Fagus is generally present only sporadically in other lowland Quaternary pollen records from the region. In addition to Fagus, the assemblage has a rich diversity of broad-leaved deciduous trees, including Quercus, Ulmus, Carpinus/Ostrya, Juglans, Betula, and Liquidambar, as well as conifers, including Pinus, Picea, Abies, Larix, and Tsuga. Thus, the pollen flora suggests a broad-leaved deciduous forest mixed with abundant conifers, which developed under cooler and more humid conditions than present. The stable pollen sequence throughout the studied section suggests a stable environment. Beech forests also characterize the Middle Pleistocene of Taiwan and Japan, and thus may be a stratigraphic indicator of the Middle Pleistocene in East Asia. The Yangtze Delta Plain may have been an important refugium for the last survival of Fagus in the lowlands.

  3. Age class, longevity and growth rate relationships: protracted growth increases in old trees in the eastern United States.

    PubMed

    Johnson, Sarah E; Abrams, Marc D

    2009-11-01

    This study uses data from the International Tree-Ring Data Bank website and tree cores collected in the field to explore growth rate (basal area increment, BAI) relationships across age classes (from young to old) for eight tree species in the eastern US. These species represent a variety of ecological traits and include those in the genera Populus, Quercus, Pinus, Tsuga and Nyssa. We found that most trees in all age classes and species exhibit an increasing BAI throughout their lives. This is particularly unusual for trees in the older age classes that we expected to have declining growth in the later years, as predicted by physiological growth models. There exists an inverse relationship between growth rate and increasing age class. The oldest trees within each species have consistently slow growth throughout their lives, implying an inverse relationship between growth rate and longevity. Younger trees (< 60 years of age) within each species are consistently growing faster than the older trees when they are of the same age resulting from a higher proportion of fast-growing trees in these young age classes. Slow, but increasing, BAI in the oldest trees in recent decades is a continuation of their growth pattern established in previous centuries. The fact that they have not shown a decreasing growth rate in their old age contradicts physiological growth models and may be related to the stimulatory effects of global change phenomenon (climate and land-use history).

  4. Global diversity of the Ganoderma lucidum complex (Ganodermataceae, Polyporales) inferred from morphology and multilocus phylogeny.

    PubMed

    Zhou, Li-Wei; Cao, Yun; Wu, Sheng-Hua; Vlasák, Josef; Li, De-Wei; Li, Meng-Jie; Dai, Yu-Cheng

    2015-06-01

    Species of the Ganoderma lucidum complex are used in many types of health products. However, the taxonomy of this complex has long been chaotic, thus limiting its uses. In the present study, 32 collections of the complex from Asia, Europe and North America were analyzed from both morphological and molecular phylogenetic perspectives. The combined dataset, including an outgroup, comprised 33 ITS, 24 tef1α, 24 rpb1 and 21 rpb2 sequences, of which 19 ITS, 20 tef1α, 20 rpb1 and 17 rpb2 sequences were newly generated. A total of 13 species of the complex were recovered in the multilocus phylogeny. These 13 species were not strongly supported as a single monophyletic lineage, and were further grouped into three lineages that cannot be defined by their geographic distributions. Clade A comprised Ganoderma curtisii, Ganoderma flexipes, Ganoderma lingzhi, Ganoderma multipileum, Ganoderma resinaceum, Ganoderma sessile, Ganoderma sichuanense and Ganoderma tropicum, Clade B comprised G. lucidum, Ganoderma oregonense and Ganoderma tsugae, and Clade C comprised Ganoderma boninense and Ganoderma zonatum. A dichotomous key to the 13 species is provided, and their key morphological characters from context, pores, cuticle cells and basidiospores are presented in a table. The taxonomic positions of these species are briefly discussed. Noteworthy, the epitypification of G. sichuanense is rejected.

  5. Does canopy position affect wood specific gravity in temperate forest trees?

    PubMed

    Woodcock, D W; Shier, A D

    2003-04-01

    The radial increases in wood specific gravity known in many tree species have been interpreted as providing mechanical support in response to the stresses associated with wind loading. This interpretation leads to the hypothesis that individuals reaching the canopy should (1) be more likely to have radial increases in specific gravity and (2) exhibit greater increases than individuals in the subcanopy. Wood specific gravity was determined for three species of forest trees (Acer rubrum, Fagus grandifolia and Tsuga canadensis) growing in central Massachusetts, USA. Acer rubrum shows radial increases in specific gravity, but these increases are not more pronounced in canopy trees; the other two species show a pattern of radial decreases. The degree of radial increase or decrease is influenced by tree height and diameter. Of the dominant tree species for which we have data, A. rubrum, Betula papyrifera and Pinus strobus show radial increases in specific gravity, whereas F. grandifolia, T. canadensis and Quercus rubra show decreases. The occurrence of radial increases in B. papyrifera and P. strobus, which are often canopy emergents, suggests that it is overall adaptive strategy that is important rather than position (canopy vs. subcanopy) of any individual tree. It is suggested that radial increases in specific gravity are associated with early-successional status or characteristics and decreases with late-successional status or persistence in mature forest.

  6. Does Canopy Position Affect Wood Specific Gravity in Temperate Forest Trees?

    PubMed Central

    WOODCOCK, D. W.; SHIER, A. D.

    2003-01-01

    The radial increases in wood specific gravity known in many tree species have been interpreted as providing mechanical support in response to the stresses associated with wind loading. This interpretation leads to the hypothesis that individuals reaching the canopy should (1) be more likely to have radial increases in specific gravity and (2) exhibit greater increases than individuals in the subcanopy. Wood specific gravity was determined for three species of forest trees (Acer rubrum, Fagus grandifolia and Tsuga canadensis) growing in central Massachusetts, USA. Acer rubrum shows radial increases in specific gravity, but these increases are not more pronounced in canopy trees; the other two species show a pattern of radial decreases. The degree of radial increase or decrease is influenced by tree height and diameter. Of the dominant tree species for which we have data, A. rubrum, Betula papyrifera and Pinus strobus show radial increases in specific gravity, whereas F. grandifolia, T. canadensis and Quercus rubra show decreases. The occurrence of radial increases in B. papyrifera and P. strobus, which are often canopy emergents, suggests that it is overall adaptive strategy that is important rather than position (canopy vs. subcanopy) of any individual tree. It is suggested that radial increases in specific gravity are associated with early‐successional status or characteristics and decreases with late‐successional status or persistence in mature forest. PMID:12646497

  7. Molecular and pathogenic variation within Melampsora on Salix in western North America reveals numerous cryptic species.

    PubMed

    Bennett, Chandalin; Aime, M Catherine; Newcombe, George

    2011-01-01

    In North America Melampsora rusts that parasitize willows (Salix species) have never been adequately studied and mostly have been referred to a collective species, Melampsora epitea (Kunze & Schm.) Thüm, of European origin. Even taxa that are nominally distinct from M. epitea, such as M. abieti-caprearum and M. paradoxa, currently are considered to be "races" of M. epitea. Within the range of our field surveys and collections in the Pacific Northwest and the Southwest only two species of Melampsora thus were expected: M. epitea (including its races) and M. ribesii-purpureae. In this study of Melampsora on 19 species of Salix in the western United States 14 phylogenetic species, or phylotypes, were apparent from nuclear rDNA sequencing of 140 collections or isolates. Our collections of the races of M. epitea, M. abieti-caprearum and M. epitea f. sp. tsugae belonged to one phylotype, termed lineage 'N'. Assuming that M. ribesii-purpureae represents one other phylotype, 12 phylotypes still are unaccounted for by current taxonomy. Moreover Eurasian M. ribesii-purpureae was not closely related to any of the phylotypes reported here. Even more problematic was the resistance of Eurasian species of Salix, including the type host of M. epitea, S. alba, to North American Melampsora, including phylotype 'N', in both the field and in inoculation experiments. These results suggest the need for the description of many new species of Melampsora on Salix in western North America. Additional analyses presented here might guide further research in this direction.

  8. The transmission of gas pressure to xylem fluid pressure when plants are inside a pressure bomb.

    PubMed

    Wei, C; Tyree, M T; Bennink, J P

    2000-02-01

    In earlier work tobacco leaves were placed in a Scholander-Hammel pressure bomb and the end of the petiole sealed with a pressure transducer in order to measure pressure transmission from the compressed gas (Pg) in the bomb to the xylem fluid (Px). Pressure bomb theory would predict a 1:1 relationship for Pg:Px when tobacco leaves start at a balance pressure of zero. Failure to observe the expected 1:1 relationship has cast doubt on the pressure-bomb technique in the measurement of the xylem pressure of plants. The experimental and theoretical relationship between Px and Pg was investigated in Tsuga canadensis (L) branches and Nicotiana rustica (L) leaves in this paper. It is concluded that the non 1:1 outcome was due to the compression of air bubbles in embolized xylem vessels, evaporation of water from the tissue, and the expansion of the sealed stem segment (or petiole) protruding beyond the seal of the pressure bomb. The expected 1:1 relationship could be obtained when xylem embolism was eliminated and stem expansion prevented. It is argued that the non 1:1 relationship in the positive pressure range does not invalidate the Scholander pressure bomb method of measuring xylem pressure in plants because Px never reaches positive values during the determination of the balance pressure.

  9. Parenchyma cell respiration and survival in secondary xylem: does metabolic activity decline with cell age?

    PubMed

    Spicer, R; Holbrook, N M

    2007-08-01

    Sapwood respiration often declines towards the sapwood/heartwood boundary, but it is not known if parenchyma metabolic activity declines with cell age. We measured sapwood respiration in five temperate species (sapwood age range of 5-64 years) and expressed respiration on a live cell basis by quantifying living parenchyma. We found no effect of parenchyma age on respiration in two conifers (Pinus strobus, Tsuga canadensis), both of which had significant amounts of dead parenchyma in the sapwood. In angiosperms (Acer rubrum, Fraxinus americana, Quercus rubra), both bulk tissue and live cell respiration were reduced by about one-half in the oldest relative to the youngest sapwood, and all sapwood parenchyma remained alive. Conifers and angiosperms had similar bulk tissue respiration despite a smaller proportion of parenchyma in conifers (5% versus 15-25% in angiosperms), such that conifer parenchyma respired at rates about three times those of angiosperms. The fact that 5-year-old parenchyma cells respired at the same rate as 25-year-old cells in conifers suggests that there is no inherent or intrinsic decline in respiration as a result of cellular ageing. In contrast, it is not known whether differences observed in cellular respiration rates of angiosperms are a function of age per se, or whether active regulation of metabolic rate or positional effects (e.g. proximity to resources and/or hormones) could be the cause of reduced respiration in older sapwood.

  10. An Appraisal of the Classic Forest Succession Paradigm with the Shade Tolerance Index

    PubMed Central

    Lienard, Jean; Florescu, Ionut; Strigul, Nikolay

    2015-01-01

    In this paper we revisit the classic theory of forest succession that relates shade tolerance and species replacement and assess its validity to understand patch-mosaic patterns of forested ecosystems of the USA. We introduce a macroscopic parameter called the “shade tolerance index” and compare it to the classic continuum index in southern Wisconsin forests. We exemplify shade tolerance driven succession in White Pine-Eastern Hemlock forests using computer simulations and analyzing approximated chronosequence data from the USDA FIA forest inventory. We describe this parameter across the last 50 years in the ecoregions of mainland USA, and demonstrate that it does not correlate with the usual macroscopic characteristics of stand age, biomass, basal area, and biodiversity measures. We characterize the dynamics of shade tolerance index using transition matrices and delimit geographical areas based on the relevance of shade tolerance to explain forest succession. We conclude that shade tolerance driven succession is linked to climatic variables and can be considered as a primary driving factor of forest dynamics mostly in central-north and northeastern areas in the USA. Overall, the shade tolerance index constitutes a new quantitative approach that can be used to understand and predict succession of forested ecosystems and biogeographic patterns. PMID:25658092

  11. Quantifiable long-term monitoring on parks and nature preserves

    USGS Publications Warehouse

    Beck, Scott; Moorman, Christopher; DePerno, Christopher S.; Simons, Theodore R.

    2013-01-01

    Herpetofauna have declined globally, and monitoring is a useful approach to document local and long-term changes. However, monitoring efforts often fail to account for detectability or follow standardized protocols. We performed a case study at Hemlock Bluffs Nature Preserve in Cary, NC to model occupancy of focal species and demonstrate a replicable long-term protocol useful to parks and nature preserves. From March 2010 to 2011, we documented occupancy of Ambystoma opacum(Marbled Salamander), Plethodon cinereus (Red-backed Salamander), Carphophis amoenus (Eastern Worm Snake), and Diadophis punctatus (Ringneck Snake) at coverboard sites and estimated breeding female Ambystoma maculatum (Spotted Salamander) abundance via dependent double-observer egg-mass counts in ephemeral pools. Temperature influenced detection of both Marbled and Red-backed Salamanders. Based on egg-mass data, we estimated Spotted Salamander abundance to be between 21 and 44 breeding females. We detected 43 of 53 previously documented herpetofauna species. Our approach demonstrates a monitoring protocol that accounts for factors that influence species detection and is replicable by parks or nature preserves with limited resources.

  12. Changes in winter conditions impact forest management in north temperate forests.

    PubMed

    Rittenhouse, Chadwick D; Rissman, Adena R

    2015-02-01

    Climate change may impact forest management activities with important implications for forest ecosystems. However, most climate change research on forests has focused on climate-driven shifts in species ranges, forest carbon, and hydrology. To examine how climate change may alter timber harvesting and forest operations in north temperate forests, we asked: 1) How have winter conditions changed over the past 60 years? 2) Have changes in winter weather altered timber harvest patterns on public forestlands? 3) What are the implications of changes in winter weather conditions for timber harvest operations in the context of the economic, ecological, and social goals of forest management? Using meteorological information from Climate Data Online and Autoregressive Integrated Moving Average (ARIMA) models we document substantial changes in winter conditions in Wisconsin, including a two- to three-week shortening of frozen ground conditions from 1948 to 2012. Increases in minimum and mean soil temperatures were spatially heterogeneous. Analysis of timber harvest records identified a shift toward greater harvest of jack pine and red pine and less harvest of aspen, black spruce, hemlock, red maple, and white spruce in years with less frozen ground or snow duration. Interviews suggested that frozen ground is a mediating condition that enables low-impact timber harvesting. Climate change may alter frozen ground conditions with complex implications for forest management.

  13. Measurement of biogenic hydrocarbon emissions from vegetation in the Lower Fraser Valley, British Columbia

    NASA Astrophysics Data System (ADS)

    Drewitt, G. B.; Curren, K.; Steyn, D. G.; Gillespie, T. J.; Niki, H.

    Biogenic volatile organic compounds (VOCs) participate in many chemical reactions in the atmosphere and in some cases, adversely affect air quality through increased production of photochemical ozone near urban sources of nitrogen oxides. In order to implement an effective control strategy, the relative role of these biogenic hydrocarbon emissions in producing ground-level ozone must be known. During the summers of 1995 and 1996, a field study was undertaken to determine fluxes of biogenic VOCs from both natural and agricultural surfaces in the Lower Fraser Valley located in southwestern British Columbia. Emissions from agricultural surfaces were measured using a flux gradient approach while emissions from the dominant tree species in the region were measured with a branch enclosure system. Results show very little biogenic VOC production from many agricultural crops such as pasture, Potatoes or Blueberries. Cranberries showed very high emissions during the summer of 1994 but failed to show similar results during the summer of 1995. Emissions of isoprene and monoterpenes from native tree species such as Western Red Cedar, Douglas Fir and Coastal Hemlock were quite low. Cottonwood trees on the other hand had fairly low emissions of monoterpenes but extremely high emissions of isoprene. Measurements provided here will be useful for improving our database of hydrocarbon emissions rates from vegetation for future emission inventories and model testing.

  14. Vegetation and disturbance history of two forest stands in northern New York using paleoecological data from small forest hollows

    SciTech Connect

    Kearsley, J.B.; Jackson, S.T.

    1995-06-01

    Pollen, macrofossils and charcoal from two small hollows (<0.05 ha) were analyzed to reconstruct the vegetational history of an outwash plain in the central Adirondack upland of New York. The basins are located 700 meters apart in contrasting modern vegetation at 461 in elevation. Dave`s Lost Hollow (DLH) is in a hemlock-dominated old-growth forest with yellow birch, red spruce and red maple, and Valhalla Hollow (VH) is surrounded by second-growth forest of white pine, balsam fir, paper birch and red maple. The record from DLH spans the entire Holocene, while VH provides data for the late Holocene. Modem pollen-vegetation data from 26 closed-canopy sites in the area provide evidence for the fine-scale sensing properties of closed- canopy pollen assemblages. We found abundant jack pine needles during the early Holocene at DLH. In contrast, data from the High Peaks, 30 km to the east, show white pine as the dominant pine species during that time period. DLH provides an early Holocene record for yellow birch in the region, whereas yellow birch was not present in the High Peaks until 6,000 yrs. B.P.

  15. Glacial geology, glacial recession, proglacial lakes, and postglacial environments, Fishers Island, New York

    SciTech Connect

    Sirkin, L. ); Funk, R.E. . Anthropological Survey)

    1993-03-01

    The Fishers Island Moraine, a complex of three parallel ice margin depositional trends, forms the west-central segment of a major recessional moraine of the Connecticut-Rhode Island Lobe of the late Wisconsinan glacier. As such, the moraine links the Orient Point Moraine of eastern Long Island and the Charlestown Moraine of western Rhode Island and marks a prominent recessional ice margin. The moraine is correlative with the Roanoke Point Moraine of the Connecticut Lobe of northeastern Long Island. Pollen stratigraphy of >13,180 ka bog sediments begins early in the spruce (A) pollen zone with evidence of a cold, late-glacial climate. The pine (B) pollen zone, beginning prior to 11,145 ka, and the oak (C) pollen zone, dating from about 9,000 ka with hickory and hemlock subzones, are well represented. However, after about 2,000 ka, the stratigraphic record in the bog sections is missing in most cases due to peat harvesting. Pollen spectra from several archeological sites fall within the late oak pollen zone, well within the land clearing interval with evidence of hardwood forests and locally holly and cedar. Evidence of cultigens in the pollen record is sparse. Marine deposits over fresh water bog and proglacial lake sediments show that some coastal bogs were drowned by sea level rise.

  16. Rapid Vegetational Change in Coastal North America: The Response to Climate Since the LGM

    NASA Technical Reports Server (NTRS)

    Peteet, Dorothy; Kneller, Margaret

    1999-01-01

    The late-glacial interval provided rapid shifts in climate which are mirrored by dramatic vegetational changes in North America. Through a transect of lake and mire sites from Connecticut to Virginia on the east coast and Kodiak Island on the western coast, we trace the warming following the LGM with the response of forests and tundra. A brief cold reversal in Virginia is seen from 12,260 to 12,200. The subsequent longer and extreme Younger Dryas event is marked in the southern New England - New Jersey region by dramatic boreal and deciduous forest changes. In the southeastern US, forests also change rapidly, with hemlock forest expansion suggesting increased moisture. In Kodiak Island, the warm, moist tundra of the Bolling/Allerod is replaced by colder, windswept Empetrum-dominated tundra during the Younger Dryas. The Pleistocene/Holocene shift in vegetation is remarkably pronounced in eastern North America as well as the Alaskan coastline. Response time of vegetation to climate change appears to be on the order of decades throughout these coastal locations, probably because of the proximity of sites to important ecotonal boundaries, and the magnitude of the events. Even in Virginia's Holocene record, a cold reversal inferred from increases in spruce and fir is noted at 7500 C14 yr BP. This response of the forests to a short-lived cooling shows the sensitivity of the biosphere to a rapid climate shifts.

  17. Impact of vegetation cover and stand age on scaling carbon fluxes in the upper Midwest: a multiple eddy flux site study

    NASA Astrophysics Data System (ADS)

    Desai, A. R.; Normeets, A.; Bolstad, P. V.; Chen, J.; Cook, B. D.; Curtis, P. S.; Davis, K. J.; Euskirchen, E.; Gough, C.; Martin, J.; Ricciuto, D. M.; Schmid, H. P.; Tang, J.; Su, H.; Vogel, C.; Wang, W.

    2004-12-01

    Eight permanent and three roving eddy flux towers were used to observe the exchange of carbon dioxide between the ecosystem and atmosphere at fourteen different sites in northern Wisconsin and Michigan (USA) during the growing seasons (May-Sept) of 2002 and 2003. These towers were part of the Chequamegon Ecosystem-Atmosphere Study (ChEAS), the University of Michigan Biological Station (UMBS), and the Michigan Technical University. The sites spanned a range of vegetation types typical of the region (northern hardwood, hemlock-hardwood, mixed forest, red pine, jack pine, pine barrens and shrub wetland). The hardwood and red pine sites also spanned a range of forest stand age (young, intermediate, mature and old). All sites experienced roughly similar climate; thus, comparisons among the sites allow for an examination of the impact of heterogeneous vegetation cover and stand age across a regional landscape. Carbon fluxes at different sites generally reacted similarly in response to variability in climate. Results suggest that both cover type and stand age are important variables for modeling and predicting fluxes in this region. These results have implications for developing methods of scaling carbon dioxide fluxes from sites to regions. These results will be contrasted to a flux decomposition at the WLEF tall tower.

  18. Silicon production process evaluations

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Chemical engineering analysis was continued for the HSC process (Hemlock Semiconductor Corporation) in which solar cell silicon is produced in a 1,000 MT/yr plant. Progress and status are reported for the primary engineering activities involved in the preliminary process engineering design of the plant base case conditions (96%), reaction chemistry (96%), process flow diagram (85%), material balance (85%), energy balance (60%), property data (60%), equipment design (40%), major equipment list (30%) and labor requirements (10%). Engineering design of the second distillation column (D-02, TCS column) in the process was completed. The design is based on a 97% recovery of the light key (TCS, trichlorosilane) in the distillate and a 97% recovery of the heavy key (TET, silicon tetrachloride) in the bottoms. At a reflux ratio of 2, the specified recovery of TCS and TET is achieved with 20 trays (equilibrium stages, N=20). Respective feed tray locations are 9, 12 and 15 (NF sub 1 = 9, NF sub 2 = 12,, and NF sub 3 = 15). A total condenser is used for the distillation which is conducted at a pressure of 90 psia.

  19. Intraspecific variation in sapling mortality and growth predicts geographic variation in forest composition

    SciTech Connect

    Kobe, R.K.

    1996-05-01

    With a view toward understanding variation in species composition among different forest communities, I examined species-specific growth and mortality of juvenile tree (2.3-78 mm diameter at 10cm above the ground) at three contrasting sites. Two sites differing in soil mineralogy and elevation (schists/gneiss uplands vs. calcareous bedrock valley) were situated in northwestern Connecticut, USA. To examine variation over a more extensive geographic scale, I located the third site in central-western Michigan, USA. Among the three sites, the deciduous species (American beech, white ash, and sugar maple) showed little intraspecific variation in models of relative radial growth at the Michigan site could be explained by sapling growth models originally calibrated for the Connecticut sites. in contrast to the deciduous species, the evergreen species (white pine and eastern hemlock) exhibited between the two Connecticut sites. Intraspecific species, mortality processes exhibited more variation among the sites than did growth. I found significant site differences in mortality as a function of recent growth for both sugar maple and white ash on the calcareous soils in comparison to the schist/gneiss soils in Connecticut site were similar, and both differed from the Connecticut calcareous site. 65 refs., 13 figs., 6 tabs.

  20. Mortality rates associated with crown health for eastern forest tree species.

    PubMed

    Morin, Randall S; Randolph, KaDonna C; Steinman, Jim

    2015-03-01

    The condition of tree crowns is an important indicator of tree and forest health. Crown conditions have been evaluated during inventories of the US Forest Service Forest Inventory and Analysis (FIA) program since 1999. In this study, remeasured data from 55,013 trees on 2616 FIA plots in the eastern USA were used to assess the probability of survival among various tree species using the suite of FIA crown condition variables. Logistic regression procedures were employed to develop models for predicting tree survival. Results of the regression analyses indicated that crown dieback was the most important crown condition variable for predicting tree survival for all species combined and for many of the 15 individual species in the study. The logistic models were generally successful in representing recent tree mortality responses to multiyear infestations of beech bark disease and hemlock woolly adelgid. Although our models are only applicable to trees growing in a forest setting, the utility of models that predict impending tree mortality goes beyond forest inventory or traditional forestry growth and yield models and includes any application where managers need to assess tree health or predict tree mortality including urban forest, recreation, wildlife, and pest management.

  1. Fetal muscle-type nicotinic acetylcholine receptor activation in TE-671 cells and inhibition of fetal movement in a day 40 pregnant goat model by optical isomers of the piperidine alkaloid coniine.

    PubMed

    Green, Benedict T; Lee, Stephen T; Welch, Kevin D; Pfister, James A; Panter, Kip E

    2013-01-01

    Coniine is an optically active toxic piperidine alkaloid and nicotinic acetylcholine receptor (nAChR) agonist found in poison hemlock (Conium maculatum L.). Coniine teratogenicity is hypothesized to be attributable to the binding, activation, and prolonged desensitization of fetal muscle-type nAChR, which results in the complete inhibition of fetal movement. However, pharmacological evidence of coniine actions at fetal muscle-type nAChR is lacking. The present study compared (-)-coniine, (+)-coniine, and nicotine for the ability to inhibit fetal movement in a day 40 pregnant goat model and in TE-671 cells that express fetal muscle-type nAChR. Furthermore, α-conotoxins (CTx) EI and GI were used to antagonize the actions of (+)- and (-)-coniine in TE-671 cells. (-)-Coniine was more effective at eliciting electrical changes in TE-671 cells and inhibiting fetal movement than was (+)-coniine, suggesting stereoselectivity by the receptor. The pyridine alkaloid nicotine did not inhibit fetal movement in a day 40 pregnant goat model, suggesting agonist specificity for the inhibition of fetal movement. Low concentrations of both CTxs potentiated the TE-671 cell response and higher concentrations of CTx EI, and GI antagonized the actions of both coniine enantiomers demonstrating concentration-dependent coagonism and selective antagonism. These results provide pharmacological evidence that the piperidine alkaloid coniine is acting at fetal muscle-type nAChR in a concentration-dependent manner.

  2. Maps showing mines, quarries, prospects, and exposures in the Cheat Mountain Roadless Area, Randolph County, West Virginia

    USGS Publications Warehouse

    Behum, Paul T.; Hammack, Richard W.

    1981-01-01

    Physiographically, the Cheat Mountain Roadless Area is in the Allegheny Mountain section of the Appalachian Plateaus province and is situated at the eastern edge of the Appalachian coal region. Cheat Mountain, a northeast-trending ridge, is bordered on the west by the right fork of Files Creek and on the east by Shavers Fork and its tributaries. Most of the area occupies an elevated plateau capped by resistant sandstone and conglomerate. Altitudes range form 2,320 ft on Lime Kiln Run to more than 3,900 ft on Cheat Mountain. The topography ranges from relatively flat in the uplands to very steep in the canyons along tributaries of Shavers Fork. The area is heavily forested with vegetation varying from mixed hardwoods on the western slope of Cheat Mountain to thickets of conifers in the uplands. Hemlocks are sparsely interspersed and red spruce, the dominant tree at higher elevations prior to logging in the mid 1920's, is again reforesting upland areas. Rhododendron and laurel flourish in moist protected areas along drainage courses and in coves.

  3. An appraisal of the classic forest succession paradigm with the shade tolerance index.

    PubMed

    Lienard, Jean; Florescu, Ionut; Strigul, Nikolay

    2015-01-01

    In this paper we revisit the classic theory of forest succession that relates shade tolerance and species replacement and assess its validity to understand patch-mosaic patterns of forested ecosystems of the USA. We introduce a macroscopic parameter called the "shade tolerance index" and compare it to the classic continuum index in southern Wisconsin forests. We exemplify shade tolerance driven succession in White Pine-Eastern Hemlock forests using computer simulations and analyzing approximated chronosequence data from the USDA FIA forest inventory. We describe this parameter across the last 50 years in the ecoregions of mainland USA, and demonstrate that it does not correlate with the usual macroscopic characteristics of stand age, biomass, basal area, and biodiversity measures. We characterize the dynamics of shade tolerance index using transition matrices and delimit geographical areas based on the relevance of shade tolerance to explain forest succession. We conclude that shade tolerance driven succession is linked to climatic variables and can be considered as a primary driving factor of forest dynamics mostly in central-north and northeastern areas in the USA. Overall, the shade tolerance index constitutes a new quantitative approach that can be used to understand and predict succession of forested ecosystems and biogeographic patterns.

  4. Simultaneous prediction of density and moisture content of wood by terahertz time domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Inagaki, Tetsuya; Ahmed, Belal; Hartley, Ian D.; Tsuchikawa, Satoru; Reid, Matthew

    2014-11-01

    In this study, demonstration of simultaneous prediction of solid wood density and moisture content, both of which are critical in manufacturing operations, of 4 species (Aspen, Birch, Hemlock and Maple) was accomplished using terahertz time-domain spectroscopy (THz-TDS). THz measurements of wood at various moisture contents were taken for two orientations of the THz field (parallel and perpendicular) with respect to the visible grain. The real and imaginary parts of the dielectric function averaged over the frequency range of 0.1 to 0.2 THz had strong correlation with density and moisture content of the wood. We extend a model that has been applied previously to oven-dry wood to include the effects of moisture below the fiber saturation point by combining two effective medium models, which allows the dielectric function of water, air and oven-dry cell wall material to be modeled to give an effective dielectric function for the wood. A strong correlation between measured and predicted values for density and moisture content were observed.

  5. Effects of mycorrhizas and pH on nitrogen and potassium fluxes in Pacific Northwest coniferous roots

    SciTech Connect

    Rygiewicz, P.T.

    1983-01-01

    This dissertation research studied mechanisms by which mycorrhizal tree roots take up ammonium and nitrate over a range of solution pH. Using mycorrhizal and nonmycorrhizal Douglas-fir, Sitka spruce and western hemlock seedlings, fluxes of N, H/sup +/, OH/sup -/, K/sup +/ and Ca/sup + +/ were measured. As pH increased, ammonium uptake rates increased and mycorrhizas significantly increased uptake for all three tree species. Surprisingly, nitrate uptake rates also increased with increasing pH, although not as dramatically as for ammonium. Even though mycorrhizas increased nitrate uptake rates, the effect was observed only to a small extent for Douglas-fir. Ammonium rates were substantially greater than nitrate rates for all coniferous seedlings. Calcium fluxes increased with increasing pH and ranged from efflux at low pH to uptake at high pH. Potassium was consistently released and these dynamic fluxes were the largest measured. Bicarbonate was also released during ammonium uptake and in significantly greater amounts by mycorrhizal roots. Total cation fluxes were much faster than anion fluxes and may have resulted in increased organic acid synthesis. This relative importance of cation flux was particularly significant for these coniferous seedlings, because cation fluxes were tenfold greater than comparable fluxes reported for agricultural species. In conclusion, this research suggests that ectomycorrhizas can significantly improve nutrient acquisition and have particular importance for nitrogen, the major nutrient limitation in Pacific Northwest forests.

  6. Forest decline from air pollution

    SciTech Connect

    Hileman, B.

    1984-01-01

    Scientists in West Germany and the USA are involved in intensive efforts to ascertain the cause or causes of the declines in their forests. Ongoing research was discussed at an October 1983 symposium on air pollution and forest productivity, held in Washington, D.C., and sponsored by the Izaak Walton League of America and Pennsylvania State University. The dieback of spruce in the Northeast is relatively well-known. It was revealed at the symposium, however, that forests in other areas of the U.S. may be showing signs of stress and damage and that species other than spruce are affected. Samuel B. McLaughlin of Oak Ridge National Laboratory (ORNL) pointed out that red spruce, shortleaf pine, hickory, yellow birch, pitch pine, hemlock, and Fraser fir are declining in East Tennessee. He noted that these decline together with those in New England suggest that decreased productivity in several tree species has been occurring over a broad scale during the past two decades. One commonly held view is that acid deposition is causing the decline of forests in both Europe and the U.S. At the symposium, a number of different opinions about possible causes were expressed, ranging from drought to ozone to combinations of pollutants, including acid deposition, ozone and trace metals. Possible causes that were not subjects of active inquiry were disease and insects. Most researchers in the field believe there is little evidence that one of these is the primary damaging agent.

  7. Late glacial and early Holocene Landscapes in northern New England and adjacent areas of Canada

    NASA Astrophysics Data System (ADS)

    Davis, R. B.; Jacobson, G. L.

    1985-05-01

    The landscapes of northern New England and adjacent areas of Canada changed greatly between 14,000 and 9000 yr B.P.: deglaciation occurred, sea levels and shorelines shifted, and a vegetational transition from tundra to closed forest took place. Data from 51 14C-dated sites from a range of elevations were used to map ice and sea positions, physiognomic vegetational zones, and the spread of individual tree taxa in the region. A continuum of tundra-woodland-forest passed northeastward and northward without major hesitation or reversal. An increased rate of progression from 11,000 to 10,000 yr B.P. suggests a more rapid warming than in the prior 2000-3000 yr. Elevational gradients controlled the patterns of deglaciation and vegetational change. The earliest spread of tree taxa was via the lowlands of southern Vermont and New Hampshire, and along a coastal corridor in Maine. Only after 12,000 yr B.P. did the taxa spread northward through the rest of the area. Different tree species entered the southern part of the area at different times and continued their spread at different