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1

Within-crown Foliar Plasticity of Western Hemlock, Tsuga heterophylla, in Relation to Stand Age  

E-print Network

positions showed morphological and anatomical responses normally associated with `sun leaves'. As a measure stands. In the youngest stand, UO needles had higher maximal rates of photosynthesis than LI needles, ontogeny, photosynthesis, stand development, sun±shade, Tsuga heterophylla (Raf.) Sarg., western hemlock

Richardson, Andrew D.

2

Growth and Infestation by Hemlock Woolly Adelgid of Two Exotic Hemlock Species in a New England Forest  

Microsoft Academic Search

The hemlock woolly adelgid (HWA, Adelges tsugae Annand) an invasive exotic insect, may extirpate eastern hemlock (Tsuga canadensis (L.) Carrière) trees from native forests, but other hemlock species could be planted to occupy their ecological niche. This study tests two of the most likely replacement species candidates: western hemlock (T. heterophylla (Raf.) Sargent) and Chinese hemlock (T. chinensis (Franchet) Pritzel).

Alexander M. Evans

2008-01-01

3

Response of macroarthropod assemblages to the loss of hemlock (Tsuga canadensis), a foundation species  

E-print Network

Response of macroarthropod assemblages to the loss of hemlock (Tsuga canadensis), a foundation species TARA E. SACKETT,1,4, SYDNE RECORD,2 SHARON BEWICK,3 BENJAMIN BAISER,2 NATHAN J. SANDERS,1, Tennessee 37996 USA Abstract. In eastern North American forests, eastern hemlock (Tsuga canadensis

Sanders, Nathan J.

4

Development of a Rain Down Technique to Artificially Infest Hemlocks with the Hemlock Woolly Adelgid, Adelges tsugae  

PubMed Central

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 m2 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 m2 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 m2 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 m2 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 an operational tree-breeding program where screening large numbers of hemlock seedlings for resistance to A. tsugae is required. PMID:25199530

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

2014-01-01

5

Development of a Rain Down Technique to Artificially Infest Hemlocks with the Hemlock Woolly Adelgid, Adelges tsugae.  

PubMed

Abstract 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 an operational tree-breeding program where screening large numbers of hemlock seedlings for resistance to A. tsugae is required. PMID:25199530

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

2014-08-01

6

Variation in Plant Defense against Invasive Herbivores: Evidence for a Hypersensitive Response in Eastern Hemlocks ( Tsuga canadensis )  

Microsoft Academic Search

Herbivores can trigger a wide array of morphological and chemical changes in their host plants. Feeding by some insects induces\\u000a a defensive hypersensitive response, a defense mechanism consisting of elevated H2O2 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;

Laura Radville; Arielle Chaves; Evan L. Preisser

2011-01-01

7

Effects of Different Sources of Fertilizer Nitrogen on Growth and Nutrition of Western Hemlock Seedlings.  

National Technical Information Service (NTIS)

Twelve different nitrogen (N) fertilizer treatments were tested on potted western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings. Fertilizers affected soil N and pH, and growth and foliar chemical composition of seedlings. Urea plus N-Serve and sulfu...

M. A. Radwan, D. S. DeBell

1980-01-01

8

Fungi Associated with the Hemlock Woolly Adelgid, Adelges tsugae, and Assessment of Entomopathogenic Isolates for Management  

PubMed Central

Fungi associated with the hemlock wooly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), were collected throughout the eastern USA and southern China. Twenty fungal genera were identified, as were 79 entomopathogenic isolates, including: Lecanicillium lecanii (Zimmermann) (Hypocreales: Insertae sedis), Isaria farinosa (Holm: Fries.) (Cordycipitaceae), Beauveria bassiana (Balasamo) (Hyphomycetes), and Fusarium spp (Nectriaceae). The remaining fungal genera associated with insect cadavers were similar for both the USA and China collections, although the abundance of Acremonium (Hypocreaceae) was greater in China. The entomopathogenic isolates were assayed for efficacy against Myzus persicae (Sulzer) (Homoptera: Aphididae) and yielded mortality ranging from 3 to 92%. Ten isolates demonstrating the highest efficacy were further assessed for efficacy against field-collected A. tsugae under laboratory conditions. Overall, two B. bassiana, one L. lecanii, and a strain of Metarhizium anisopliae (Metchnikoff) (Hypocreales: Clavicipitaceae), demonstrated significantly higher efficacy against A. tsugae than the others. Isolates were further evaluated for conidial production, germination rate and colony growth at four temperatures representative of field conditions. All isolates were determined to be mesophiles with optimal temperature between 25–30° C. In general, conidial production increased with temperature, though two I. farinosa produced significantly more conidia at cooler temperatures. When efficacy values were compared with conidial production and temperature tolerances, Agricultural Research Service Collection of Entomopathogenic Fungi (ARSEF) 1080, 5170, and 5798 had characteristics comparable to the industrial B. bassiana strain GHA. PMID:20672977

Reid, W.R.; Parker, B.L.; Gouli, S.Y.; Skinner, M.; Gouli, V.V.; Teillon, H.B.

2010-01-01

9

Fungi associated with the hemlock woolly adelgid, Adelges tsugae, and assessment of entomopathogenic isolates for management.  

PubMed

Fungi associated with the hemlock wooly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), were collected throughout the eastern USA and southern China. Twenty fungal genera were identified, as were 79 entomopathogenic isolates, including: Lecanicillium lecanii (Zimmermann) (Hypocreales: Insertae sedis), Isaria farinosa (Holm: Fries.) (Cordycipitaceae), Beauveria bassiana (Balasamo) (Hyphomycetes), and Fusarium spp (Nectriaceae). The remaining fungal genera associated with insect cadavers were similar for both the USA and China collections, although the abundance of Acremonium (Hypocreaceae) was greater in China. The entomopathogenic isolates were assayed for efficacy against Myzus persicae (Sulzer) (Homoptera: Aphididae) and yielded mortality ranging from 3 to 92%. Ten isolates demonstrating the highest efficacy were further assessed for efficacy against field-collected A. tsugae under laboratory conditions. Overall, two B. bassiana, one L. lecanii, and a strain of Metarhizium anisopliae (Metchnikoff) (Hypocreales: Clavicipitaceae), demonstrated significantly higher efficacy against A. tsugae than the others. Isolates were further evaluated for conidial production, germination rate and colony growth at four temperatures representative of field conditions. All isolates were determined to be mesophiles with optimal temperature between 25-30 degrees C. In general, conidial production increased with temperature, though two I. farinosa produced significantly more conidia at cooler temperatures. When efficacy values were compared with conidial production and temperature tolerances, Agricultural Research Service Collection of Entomopathogenic Fungi (ARSEF) 1080, 5170, and 5798 had characteristics comparable to the industrial B. bassiana strain GHA. PMID:20672977

Reid, W R; Parker, B L; Gouli, S Y; Skinner, M; Gouli, V V; Teillon, H B

2010-01-01

10

BORRELIA BURGDORFERI INFECTION IN WHITE-FOOTED MICE (PEROMYSCUS LEUCOPUS) IN HEMLOCK (TSUGA CANADENSIS) HABITAT IN WESTERN PENNSYLVANIA  

Microsoft Academic Search

White-footed mice (Peromyscus leucopus) were captured and their tissues sampled from 27 sites in seven counties of western Pennsylvania in 1990 for isolation and identification of Borrelia burgdorferi. Two hundred sixty mice were captured from which there were 27 isolations. Significantly more mice were captured and significantly more isolations made from hemlock (Tsuga canadensis) habitat than from deciduous species forest.

Rexford D. Lord; Jan G. Humphreys; Veronica R. Lord; Robert G. McLean; Curtis L. Garland

11

Genetic considerations in cloning western hemlock  

Microsoft Academic Search

Using clones to regenerate a species new to clonal reforestation presents the forest manager with many problems. A number of interrelated and interdependent research and development activities are needed to answer these technical questions. Network diagramming was used for scheduling research activities and for indicating interdependencies among activities. The resultant diagram, although developed specifically for western hemlock (Tsuga heterophylla (Raf.)

G. S. Jr

1983-01-01

12

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

PubMed

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. PMID:21573865

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

2011-06-01

13

Changes in Stomatal Frequency and Size During Elongation of Tsuga heterophylla Needles  

PubMed Central

• Background and Aims The inverse relationship between the number of stomata and atmospheric CO2 levels observed in different plant species is increasingly used for reconstructions of past CO2 concentrations. To validate this relationship, the potential influence of other environmental conditions and ontogenetical development stage on stomatal densities must be investigated as well. Quantitative data on the changes in stomatal density of conifers in relation to leaf development is reported. • Methods Stomatal frequency and epidermal cells of Tsuga heterophylla needles during different stages of budburst were measured using computerized image analysis systems on light microscope slides. • Key Results Stomata first appear in the apical region and subsequently spread basipetally towards the needle base during development. The number of stomatal rows on a needle does not change during ontogeny, but stomatal density decreases nonlinearly with increasing needle area, until about 50 % of the final needle area. The total number of stomata on the needle increases during the entire developmental period, indicating that stomatal and epidermal cell formation continues until the needle has matured completely. • Conclusions Epidermal characteristics in developing conifer needles appear to be fundamentally different from angiosperm dicot leaves, where in general leaf expansion in the final stages is due to cell expansion rather than cell formation. The lack of further change in either stomatal density or stomatal density per millimetre needle length (the stomatal characteristic most sensitive to CO2 in conifers) in the final stages of leaf growth indicates that in conifers the stage of leaf maturation would not influence CO2 reconstructions based on stomatal density. PMID:15321836

KOUWENBERG, LENNY L. R.; KÜRSCHNER, WOLFRAM M.; VISSCHER, HENK

2004-01-01

14

Spatial and population characteristics of dwarf mistletoe infected trees in an old-growth Douglas-fir – western hemlock forest  

Microsoft Academic Search

We investigated the distribution and severity of trees infected with western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosendahl) G.N. Jones subsp. tsugense) in an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) - western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest. With the use of Hawksworth six-class dwarf mistletoe rating system, infection status was assessed for 3516 hemlock and true firs ?5 cm diameter

David C. Shaw; Jiquan Chen; Elizabeth A. Freeman; David M. Braun

2005-01-01

15

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

USGS Publications Warehouse

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.

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

1999-01-01

16

Behavior and Daily Activity Patterns of Specialist and Generalist Predators of the Hemlock Woolly Adelgid, Adelges tsugae  

PubMed Central

The behavior and daily activity patterns of two specialist predators, Laricobius nigrinus Fender (Coleoptera: Derodontidae) and Sasajiscymnus tsugae, Sasaji and McClure (Coleoptera: Coccinellidae), and a generalist predator, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), of hemlock woolly adelgid, Adelges tsugae (Hemiptera: Adelgidae), were examined using digital video recording in the laboratory. The two specialists are part of a biological control program for A. tsugae, and it is not known if competitive interactions with previously established generalist predators will negatively impact their effectiveness. The behavior and daily activity patterns of adult females of each species were documented in single- and paired-predator assays under simulated spring and summer conditions. Behavior varied qualitatively and quantitatively by species, and did not appear to be highly coordinated temporally or spatially. All species exhibited continuous activity patterns that were punctuated by longer periods of rest. Extensive and intensive searching behavior occurred in all species, with intensive searching being highly variable. Specialist predators appeared to be more selective of feeding and oviposition sites, and rested at more concealed locations than the generalist species. In spring conditions, L. nigrinus had greater activity and a more even behavior distribution than S. tsugae or H. axyridis, which were skewed towards resting. In summer, the latter two species showed increased activity at higher temperatures. Conspecifics significantly altered the time allocated to specific behaviors for L. nigrinus and H. axyridis, resulting in reduced predator effectiveness by reducing time and energy expenditure on activities that directly impact the adelgids. In contrast, S. tsugae conspecifics and all heterospecific combinations showed non-interference. The activity of each species varied with time of day; L. nigrinus was more active at night, while S. tsugae and H. axyridis were more active during the day. All predator groupings maintained a high degree of spatial separation relative to assay size. The use of multiple-predator species combinations that include the specialist predators, is recommended over single-species for biological control of A. tsugae, as temporal and spatial patterns were not highly coordinated. Low-density releases may reduce the potential negative effects of intraspecific competition. PMID:20345314

Flowers, R.W.; Salom, S.M.; Kok, L.T.; Mullins, D.E.

2007-01-01

17

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

PubMed

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. PMID:18419918

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

2008-04-01

18

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

PubMed

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. PMID:22251687

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

2011-08-01

19

Abundance and attributes of wildlife trees and coarse woody debris at three silvicultural systems study areas in the Interior Cedar-Hemlock Zone, British Columbia  

Microsoft Academic Search

Unmanaged cedar (Thuja plicata)-hemlock (Tsuga heterophylla) forests of the northern Interior Wetbelt of British Columbia support standing and dead trees with a variety of structural features that provide habitat for wildlife. We describe the pre-harvest abundance and characteristics of wildlife trees (standing trees with special characteristics that provide habitat for wildlife) and coarse woody debris (CWD) at three silvicultural systems

Susan K. Stevenson; Michael J. Jull; Bruce J. Rogers

2006-01-01

20

Journal of the Torrey Botanical Society 132(4), 2005, pp. 602612 Disjunct eastern hemlock (Tsuga canadensis) stands at its  

E-print Network

lived trees in eastern North America. Individuals may live for over 800 yrs and can grow to 40 m and stream valleys. Large tracts of old-growth east- ern hemlock can still be found in northern On- 1 of the manuscript. Maps were prepared by the Carto- graphic Research Laboratory at the University of Al- abama. 3

Hart, Justin

21

Assessing the Potential Impacts to Riparian Ecosystems Resulting from Hemlock Mortality in Great Smoky Mountains National Park  

Microsoft Academic Search

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\\u000a physical, chemical, and biological alterations to stream environments. To assess the influence of riparian

Scott W. Roberts; Roger Tankersley Jr; Kenneth H. Orvis

2009-01-01

22

Avian response to removal of a forest dominant: consequences of hemlock woolly adelgid infestations  

Microsoft Academic Search

Aim This study examines changes in avian community composition associated with the decline and loss of eastern hemlock (Tsuga canadensis (L.) Carr.) resulting from chronic hemlock woolly adelgid (HWA; Adelges tsugae Annand) infestations. Location The study was conducted in a 4900-km2 study region extending from Long Island Sound northward to the southern border of Massachusetts and including the Connecticut River

Morgan W. Tingley; David A. Orwig; Rebecca Field; Glenn Motzkin

2002-01-01

23

Multi-year ecosystem response to hemlock woolly adelgid infestation in southern New England forests  

Microsoft Academic Search

The introduced hemlock woolly adelgid (HWA) (Adelges tsugae Annand) has generated widespread tree decline and substantial mortality of eastern hemlock (Tsuga canadensis (L.) Carriere) throughout the eastern United States. To as- sess the magnitude of ecosystem response to this disturbance, we conducted a multi-year study of forests with and without damage from HWA. Infested forests had significantly higher HWA-induced foliar

David A. Orwig; Richard C. Cobb; Anthony W. D’Amato; Matthew L. Kizlinski; David R. Foster

2008-01-01

24

Allozyme Variation in Hemlock Woolly Adelgid (Hemiptera: Adelgidae) From the United States and China  

Microsoft Academic Search

The hemlock woolly adelgid,Adelgestsugae Annand (Hemiptera: Adelgidae), is a major introduced pest of eastern hemlock, Tsuga canadensis (L.) Carriere. Hemlock woolly adelgid in the United States is anholocyclic and an obligate parthenogen, because no suitable primary host (on which sexual reproduction occurs in Asia) is reported for this adelgid in the United States. Allozyme analyses were conducted to assess the

V. Sánchez; M. A. Keena

2009-01-01

25

Tsuga canadensis in Ohio: Synecological and phytogeographical relationships  

Microsoft Academic Search

Summary Tsuga canadensis is the dominant in four topo-edaphic associations and one edaphic association in Ohio. WhileTsuga may occur withPinus strobus and a variety of deciduous trees (e.g.,Fagus grandifolia, Acer saccharum) in these communities, only hemlock is persistently reproducing. As compared with the contiguous mesophytic deciduous forest, these associations have a depauperate understory, a possible consequence of the shallow and

R. Alan Black; Richard N. Mack

1976-01-01

26

Hemlock woolly adelgid (hemiptera: adelgidae) induces twig volatiles of eastern hemlock in a forest setting.  

PubMed

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. PMID:25259691

Pezet, Joshua; Elkinton, Joseph S

2014-10-01

27

Hemlock Tsuga canadensis Yellow Birch Betula alleghaniensis  

E-print Network

(includes N. Pin Oak Q. ellipsoidalis) Bur Oak Quercus macrocarpa White Oak Quercus alba Prairie Water Red Pine Pinus resinosa White Pine Pinus strobus Red Oak Quercus rubra Black Oak Quercus velutina

Mladenoff, David

28

Avian response to removal of a forest dominant: consequences of hemlock woolly  

E-print Network

associated with the decline and loss of eastern hemlock [Tsuga canadensis (L.) Carr.] resulting from chronic (Sitta carolinensis), red-eyed vireo (Vireo olivaceus), hooded warbler (Wilsonia citrina), and several

Tingley, Morgan W.

29

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

PubMed

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. PMID:23900803

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

2013-08-01

30

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

PubMed

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. PMID:24665708

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

2014-02-01

31

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

PubMed

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. PMID:21939217

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

2011-10-28

32

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

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. PMID:18244947

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

2008-04-01

33

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

PubMed

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 forests of differing ages that have similar stature. PMID:11830411

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

2002-02-01

34

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

PubMed

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. PMID:18595846

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

2008-09-01

35

Gradients in Epiphyte Biomass in Three Pseudotsuga-Tsuga Forests of Different Ages in Western Oregon and Washington  

Microsoft Academic Search

Epiphyte biomass on branches and trunks was estimated for 42 individual felled trees, distributed among three Pseudotsuga menziesii-Tsuga heterophylla stands aged 95, 145, and 400+ years, in the western Cascade Range of Oregon and Washington, then extrapolated to the whole stands by regression techniques. Epiphytes were sorted into four groups defined by ecological roles rather than taxonomy: cyanolichens, alectorioid lichens,

Bruce McCune

1993-01-01

36

Possible Use of Field Insectaries to Rear Hemlock Woolly Adelgid Predators  

Microsoft Academic Search

Suppression of the hemlock woolly adelgid (HWA), Adelges tsugae Annand (Homoptera: Adelgidae), in the Eastern United States has focussed on several predators as biological control agents. Three have been released and large numbers of each species will be needed for additional releases. Current rearing programs of predators of the HWA in the laboratory require an abundance of prey that may

L. T. Kok; S. M. Salom

37

Ecosystem Response to Hemlock Woolly Adelgid (Adelges tsugae) Induced Tsuga canadensis Mortality  

E-print Network

Species Dutch elm disease Approximately 7, 000 exotic species are established in US Less than 600 species harm or harm to human health. Invasive species are now the second highest threat to the conservation Biodiversity Ecosystem EconomiesBiodiversity Function Economies Aesthetics Human Health Chesnut blight Invasive

Gray, Matthew

38

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

Federal Register 2010, 2011, 2012, 2013

...Authority for Subzone Status, Hemlock Semiconductor Corporation, (Polysilicon), Hemlock...polysilicon manufacturing facility of Hemlock Semiconductor Corporation, located in Hemlock...polysilicon at the facility of Hemlock Semiconductor Corporation, located in...

2013-04-10

39

Density-dependent survival and fecundity of hemlock woolly adelgid (hemiptera: adelgidae).  

PubMed

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. PMID:25203223

Sussky, Elizabeth M; Elkinton, Joseph S

2014-10-01

40

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

PubMed

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. PMID:25230456

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

41

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

PubMed

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. PMID:22220637

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

2011-01-01

42

Influence of streamside vegetation on inputs of terrestrial invertebrates to salmonid food webs  

E-print Network

(Alnus rubra) and conifer (mix of western hemlock (Tsuga heterophylla) and Sitka spruce (Picea sitchensis sous des couvertures d'aulnes rouges (Alnus rubra) récoltent toujours une plus grande biomasse de TI

Wagner, Diane

43

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

PubMed Central

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

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

2012-01-01

44

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

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. PMID:24498740

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

2013-12-01

45

Height growth and vertical development of an old-growth Pseudotsuga - Tsuga forest in southwestern Washington State, U.S.A  

Microsoft Academic Search

A detailed analysis of diameter-height relationships was applied to an old-growth Pseudotsuga menziesii (Mirb.) Franco var. menziesii - Tsuga heterophylla (Raf.) Sarg. forest in southwestern Washington State, U.S.A., to pre- dict future development of vertical stratification among tree species. Differences among species in relative abundance and size structure resulted in diameter-height regressions of varying certainty and stability. Damage and shading

Hiroaki Ishii; Joel H. Reynolds; E. David Ford; David C. Shaw

2000-01-01

46

Nuclei of Tsuga canadensis: Role of Flavanols in Chromatin Organization  

PubMed Central

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

Feucht, Walter; Schmid, Markus; Treutter, Dieter

2011-01-01

47

Hemlock: murder before the Lord.  

PubMed

Two healthy young men were killed by a plume of hemlock (Conium maculatum) emitted when contaminated incense was vaporized during religious rites about the middle of the thirteenth century BC. PMID:7830518

Davies, M L; Davies, T A

1994-10-01

48

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

Microsoft Academic Search

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

Najat Bhiry; Louise Filion

1996-01-01

49

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

USGS Publications Warehouse

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.

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

2002-01-01

50

Antioxidant properties of polysaccharides from Ganoderma tsugae  

Microsoft Academic Search

Ganoderma tsugae Murrill (Ganodermataceae) were available in the form of mature and baby Ling chih, mycelia and fermentation filtrate. From these four forms, hot water extracted and hot alkali extracted polysaccharides were prepared and their antioxidant properties were studied. Polysaccharides showed good antioxidant activity as evidenced by their particularly low EC50 values (<0.1mg\\/ml). At 20mg\\/ml, both extracted polysaccharides from mycelia

Yu-Hsiu Tseng; Joan-Hwa Yang; Jeng-Leun Mau

2008-01-01

51

Poison hemlock (Conium maculatum L.).  

PubMed

One of the most poisonous species amongst higher plants is Conium maculatum. It is a very common nitrophile weed species, belonging to the Apiaceae (formerly Umbelliferae) family. It contains some piperidine alkaloids (coniine, N-methyl-coniine, conhydrine, pseudoconhydrine, gamma-coniceine), which are formed by the cyclisation of an eight-carbon chain derived from four acetate units. gamma-Coniceine is the precursor of the other hemlock alkaloids. All vegetative organs, flowers and fruits contain alkaloids. The concentrations (both absolute and relative) of the different alkaloids depend on plant varieties, on ecological conditions and on the age of the plant. The characteristic biological effects of the plants are summarised on cattle, sheep, goat, swine, rabbit, elk, birds and insects and the symptoms of the human toxicosis (some cases of poisonings) are discussed according to the literature data. The general symptoms of hemlock poisoning are effects on nervous system (stimulation followed by paralysis of motor nerve endings and CNS stimulation and later depression), vomiting, trembling, problems in movement, slow and weak later rapid pulse, rapid respiration, salivation, urination, nausea, convulsions, coma and death. PMID:15234067

Vetter, J

2004-09-01

52

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

Federal Register 2010, 2011, 2012, 2013

...Flint, Michigan; Application for Subzone; Hemlock Semiconductor Corporation (Polysilicon); Hemlock, MI An application...status for the polysilicon manufacturing facility of Hemlock Semiconductor Corporation (HSC), located in Hemlock, Michigan....

2011-10-12

53

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)

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.

Bhiry, Najat; Filion, Louise

1996-11-01

54

The importance of mature conifers to red crossbills in southeast Alaska  

Microsoft Academic Search

Red crossbills (Loxia curvirostra) in southeast Alaska feed mostly on seeds in the cones of western hemlock (Tsuga heterophylla) and Sitka spruce (Picea sitchensis). During a year of poor cone production, red crossbills did not forage in young stands. Within mature stands, crossbills tended to forage preferentially on trees with large cone crops. These favored trees were also the larger

William C Holimon; Craig W Benkman; Mary F Willson

1998-01-01

55

DEMOGRAPHY OF THE PRINCE OF WALES FLYING SQUIRREL, AN ENDEMIC OF SOUTHEASTERN ALASKA TEMPERATE RAIN FOREST  

Microsoft Academic Search

We studied the Prince of Wales flying squirrel ( Glaucomys sabrinus griseifrons ) in tem- perate rain forest of southeastern Alaska to provide the 1st quantitative estimates of de- mography from southeastern Alaska and test predictions of the hypothesis that Sitka spruce (Picea sitchensis)-western hemlock (Tsuga heterophylla) forest is primary habitat for G. sabrinus in southeastern Alaska. We expected that

WINSTON P. S MITH; JEFFREY V. N ICHOLS

2003-01-01

56

Factors influencing fungal degradation of lignin in a representative lignocellulosic, thermomechanical pulp  

Microsoft Academic Search

This research examined culture parameters influencing the rate of degradation of lignin in lignocellulosic substrates by the Basidiomycete Phanerochaete chryosoprorium. Thermomechanical pulps prepared from western hemlock (Tsuga heterophylla) and red alder (Alnus rubra) were chosen as model substrates. Degradation of lignin in shallow, liquid-phase, stationary cultures was 10 times as rapid as in agitated cultures. Lignin degradation was at least

H. H. Yang; M. J. Effland; T. K. Kirk

1980-01-01

57

Antioxidant and radical scavenging properties of extracts from Ganoderma tsugae  

Microsoft Academic Search

The antioxidant activities and scavenging effects on free radicals of extracts from Ganoderma were investigated. The methanolic extracts of Ganoderma tsugae (MEGT) showed the strongest antioxidant activity of five species of Ganoderma tested. MEGT exhibited substantial antioxidant activity in the linoleic acid and rat liver microsome peroxidation systems. The antioxidant activity of MEGT was stronger than ?-tocopherol. MEGT had a

Gow-Chin Yen; Jun-Yi Wu

1999-01-01

58

Antioxidant properties of hot water extracts from Ganoderma tsugae Murrill  

Microsoft Academic Search

Ganoderma tsugae Murrill (Ganodermataceae) were available in the form of mature and baby Ling chih, mycelia and fermentation filtrate. From these four forms, hot water extracts were prepared and their antioxidant properties were studied. Hot water extracts from mature and baby Ling chih showed high antioxidant activities (78.5% and 78.2%) at 20mg\\/ml, and had EC50 values of 7.25 and 5.89mgextract\\/ml,

Jeng-Leun Mau; Shu-Yao Tsai; Yu-Hsiu Tseng; Shih-Jeng Huang

2005-01-01

59

MAPPING HEMLOCKS VIA TREE-BASED CLASSIFICATION OF SATELLITE IMAGERY AND ENVIRONMENTAL DATA  

Microsoft Academic Search

Within the last few years, the hemlock woolly adelgid (HWA) has made significant inroads into the southern Appalachians. Since the region's native hemlock species are not resistant, timely application of control measures is critical to minimizing hemlock mortality. Unfortu- nately, hemlock stands in the region are incompletely mapped, and general characteristics of their distribution present serious mapping challenges. One approach

Frank H. Koch; Heather M. Cheshire; Hugh A. Devine

60

The phytotoxic effect of exogenous ethanol on Euphorbia heterophylla L.  

PubMed

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. PMID:19640725

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

2009-01-01

61

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

Federal Register 2010, 2011, 2012, 2013

...Authority for Subzone Status, Hemlock Semiconductor, L.L.C., (Polysilicon), Clarksville...polysilicon manufacturing facility of Hemlock Semiconductor, L.L.C., located in Clarksville...polysilicon at the facility of Hemlock Semiconductor, L.L.C., located in...

2013-04-09

62

The triterpenoids of Ganoderma tsugae prevent stress-induced myocardial injury in mice.  

PubMed

Ganoderma mushrooms (Lingzhi in Chinese) have well-documented health benefits. Ganoderma tsugae (G. tsugae), one of the ganoderma species, has been commercially cultivated as a dietary supplement. Because G. tsugae has high antioxidant activity and because oxidative stress is often associated with cardiac injury, we hypothesized that G. tsugae protects against cardiac injury by alleviating oxidative stress. We tested the hypothesis using a work-overload-induced myocardial injury model created by challenging mice with isoproterenol (ISO). Remarkably, oral G. tsugae protected the mice from ISO-induced myocardial injury. Moreover, the triterpenoid fraction of G. tsugae, composed of a mixture of nine structurally related ganoderic acids (GAs), provided cardioprotection by inhibiting the ISO-induced expression of Fas/Fas ligand, oxidative stress, and apoptosis. The antioxidant activity of GAs was tested in cultured cardio-myoblast H9c2 cells against the insult of H?O?. GAs dissipated the cellular reactive oxygen species imposed by H?O? and prevented cell death. Our findings uncovered the cardioprotective activity of G. tsugae and identified GAs as the bioactive components against cardiac insults. PMID:23610080

Kuok, Qian-Yu; Yeh, Chen-Yu; Su, Bor-Chyuan; Hsu, Pei-Ling; Ni, Hao; Liu, Ming-Yie; Mo, Fan-E

2013-10-01

63

Decomposing the mid-Holocene Tsuga decline in eastern North America.  

PubMed

The mid-Holocene decline of Tsuga canadensis (hereafter Tsuga) populations across eastern North America is widely perceived as a synchronous event, driven by pests/pathogens, rapid climate change, or both. Pattern identification and causal attribution are hampered by low stratigraphic density of pollen-sampling and radiometric dates at most sites, and by absence of highly resolved, paired pollen and paleoclimate records from single sediment cores, where chronological order of climatic and vegetational changes can be assessed. We present an intensely sampled (contiguous 1-cm intervals) record of pollen and water table depth (inferred from testate amoebae) from a single core spanning the Tsuga decline at Irwin Smith Bog in Lower Michigan, with high-precision chronology. We also present an intensively sampled pollen record from Tower Lake in Upper Michigan. Both sites show high-magnitude fluctuations in Tsuga pollen percentages during the pre-decline maximum. The terminal decline is dated at both sites ca. 5000 cal yr BP, some 400 years later than estimates from other sites and data compilations. The terminal Tsuga decline was evidently heterochronous across its range. A transient decline ca. 5350 cal yr BP at both sites may correspond to the terminal decline at other sites in eastern North America. At Irwin Smith Bog, the terminal Tsuga decline preceded an abrupt and persistent decline in water table depths by approximately 200 years, suggesting the decline was not directly driven by abrupt climate change. The Tsuga decline may best be viewed as comprising at least three phases: a long-duration pre-decline maximum with high-magnitude and high-frequency fluctuations, followed by a terminal decline at individual sites, followed in turn by two millennia of persistently low Tsuga populations. These phases may not be causally linked, and may represent dynamics taking place at multiple temporal and spatial scales. Further progress toward understanding the phenomenon requires an expanded network of high-resolution pollen and paleoclimate chronologies. PMID:22928413

Booth, Robert K; Brewer, Simon; Blaauw, Maarten; Minckley, Thomas A; Jackson, Stephen T

2012-08-01

64

Toxicoses in livestock from the hemlocks (Conium and Cicuta spp.).  

PubMed

The hemlocks, Conium maculatum (poison-hemlock) and Cicuta spp. (waterhemlock), are poisonous plants that cause sizeable losss to the livestock industry. Clinical signs of poisonhemlock toxicosis are similar in all species of livestock and include muscular weakness, incordination, trembling, initial central nervous system stimulation, depression and death from respiratory paralysis. Poison-hemlock also causes skeletal defects in the offspring of cattle, pigs and sheep and cleft palate in pigs when ingested during specific periods of gestation. The primary toxicants in poison-hemlock are coniine and gamma-coniceine. Coniine predominates in mature plants and seed, whereas gamma-coniceine predominates in early growth of the plant. Waterhemlock is the most violently toxic poisonous plant known. The toxicant is cicutoxin, which acts on the central nervous system, causing violent convulsions and death. Clinical signs of poisoning appear within 15 min after ingestion of a lethal dose and include excessive salivation, nervousness, tremors, muscular weakness and convulsive seizures interspersed by intermittent periods of relaxation and a final paralytic seizure resulting in anoxia and death. Elevated activities of lactic dehydrogenase, aspartate aminotransferase and creatine kinase in blood are observed, indicative of muscular damage. Toxicoses from poisonhemlock and waterhemlock generally occur in early spring when both plants emerge before other, more palatable plants begin to grow. All parts of the poison-hemlock plant are toxic. The root or tubers of waterhemlock are toxic; however, experimental evidence concerning the toxicity of other plant parts is inconclusive. PMID:3049497

Panter, K E; Keeler, R F; Baker, D C

1988-09-01

65

Hemlock alkaloids from Socrates to poison aloes.  

PubMed

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. PMID:15955542

Reynolds, Tom

2005-06-01

66

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 ...

67

Estimated persistence of northern flying squirrel populations in temperate rain forest fragments of Southeast Alaska  

Microsoft Academic Search

Habitat reserves are a common strategy used to ensure viability of wildlife populations and communities. The efficacy of reserves, however, is rarely empirically evaluated. We examined the likelihood that small (650 ha), isolated habitat reserves composed of old-growth Sitka spruce (Picea sitchensis)–western hemlock (Tsuga heterophylla) rain forest (upland-OG) and mixed-conifer peatlands (peatland-MC) would sustain populations of northern flying squirrels (Glaucomys

Winston P. Smith; David K. Person

2007-01-01

68

Patterns o F sP read o F hemlock W oolly a delgid in c arolina hemlock P o P ulations  

Microsoft Academic Search

Census and mapping of individuals was carried out in four populations of Carolina hemlock to uncover patterns of spread of hemlock woolly adelgid. Spatial cluster analysis was used to distinguish among three patterns of adelgid transmission: random spread, spread in a wavelike pattern, and spread from multiple foci. The finding of clusters in all populations refuted the random spread hypothesis.

Jordan Baker

69

Short Paper Analysis of hemlock pollen size in Holocene lake sediments from New England  

E-print Network

. Day a , W. Wyatt Oswald a,b, , Elaine D. Doughty b , David R. Foster b a Emerson College, 120 Boylston that Tsuga persisted in scattered, low-density populations during the middle Holocene, as it has remained), its abundance is low until ~4000­3000 cal yr BP, and then Tsuga recovers to nearly pre-decline levels

Oswald, Wyatt

70

[A research on fast-propagation of Pseudostellaria heterophylla].  

PubMed

The result of fast-propagation of Pseudostellaria heterophylla by tissue culture showed that the best explant was stem tip. It also showed the suitable inducement mediums were MS + 6-BA 2.0 mg/L + NAA 0.2 mg/L or MS + 6-BA 4.0 mg/L + NAA 0.4 mg/L for the clustered bud, MS + 2,4-D 4.0 mg/L + Kt 0.5 mg/L or MS + 2,4-D 3.0 mg/L + Kt 0.5 mg/L for the callus growth and 1/2 MS + NAA 0.3 mg/L for the root growth. PMID:12795214

Tan, Xianhe; Chao, Jianguo; Zhang, Yu; Zhang, Ying

2003-02-01

71

Structure and antitumor activities of the water-soluble polysaccharides from Ganoderma tsugae mycelium  

Microsoft Academic Search

Six water-soluble polysaccharides coded as GTM1 to GTM6 were extracted sequentially from the mycelium of Ganoderma tsugae with 0.2M sodium phosphate buffer solution at 25, 40, and 80°C, water at 120°C, 0.5M sodium hydroxide at 25 and 65°C. The chemical structures were determined by using IR, EA, GC and 13C NMR. The weight-average molecular mass (Mw) was characterized by size

Yanfei Peng; Lina Zhang; Fanbo Zeng; John F. Kennedy

2005-01-01

72

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

PubMed

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) living biomass is increasingly dominated by very large trees whose dead trunks have longer residence time in the CWD pool, and (b) infrequent major disturbances, thought to be important in the dynamics of these forests, have not occurred during the study period but would be expected to produce major, episodic pulses in CWD input. Few fragments of old-growth cool-temperate forests remain, but such forests can constitute a very large carbon pool on a per-area basis. The carbon sink/source status of these forests remains unclear. While aboveground living biomass at this study site shows no strong aggrading or declining trend over the last half-century, this remains a modest span in the innate time-scale of late-successional forest. The effects of rare disturbances, long-term shifts in composition and size structure, and changes in soil carbon and CWD pools may all influence long-term carbon status. PMID:25289184

Woods, Kerry D

2014-01-01

73

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

PubMed Central

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 m3/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) living biomass is increasingly dominated by very large trees whose dead trunks have longer residence time in the CWD pool, and (b) infrequent major disturbances, thought to be important in the dynamics of these forests, have not occurred during the study period but would be expected to produce major, episodic pulses in CWD input. Few fragments of old-growth cool-temperate forests remain, but such forests can constitute a very large carbon pool on a per-area basis. The carbon sink/source status of these forests remains unclear. While aboveground living biomass at this study site shows no strong aggrading or declining trend over the last half-century, this remains a modest span in the innate time-scale of late-successional forest. The effects of rare disturbances, long-term shifts in composition and size structure, and changes in soil carbon and CWD pools may all influence long-term carbon status. PMID:25289184

2014-01-01

74

Proceedings of the Sudden Oak Death Fifth Science Symposium Susceptibility of Larch, Hemlock, Sitka Spruce, and  

E-print Network

on Japanese larch (Larix kaempferi (Lam.) Carrière) in the United Kingdom (Forestry Commission 2012, Webber et. laricina (Du Roi) K. Koch), and western larch (L. occidentalis Nutt.); western and eastern hemlock (T

Standiford, Richard B.

75

Inclination distributions and size measurements of hemlock and red spruce needles  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

76

Conium maculatum (poison hemlock) toxicosis in a flock of range turkeys.  

PubMed

Five 20-week-old tom turkeys from a flock of range turkeys were presented for examination; the flock had a history of salivation, tremors, paralysis, and increased mortality. Necropsy revealed numerous seeds identified as seeds from Conium maculatum (poison hemlock) within the crop, proventriculus, and gizzard. Histopathologic alterations were limited to catarrhal enteritis. Clinical signs of Conium maculatum toxicosis abated after the turkeys were removed from their range, which was infested with poison hemlock. PMID:3619833

Frank, A A; Reed, W M

1987-01-01

77

Three sesquiterpenes from the roots and stems of Aristolochia heterophylla hemsl with novel skeletons  

Microsoft Academic Search

Three novel skeleton sesquiterpenes, namely, madolin-F (1), -G (2a), and -H (3), were isolated and characterised from the fresh roots and stems of Aristolochia heterophylla. Madolin-F belongs to a novel skeleton, normaaliane type. Madolin-G and -H were constructed from three- and eleven-membered rings and named madolin type.

Yu-Yi Chan; Yann-Lii Leu; Tain-Shung Wu

1998-01-01

78

Phytochemistry of Plants Associated with a 400YearOld Stand of Hemlock at Clear Lake Reserve, Ontario  

Microsoft Academic Search

Several species of higher plants and mushrooms have been surveyed growing under the canopy of old stands of hemlock surrounding Clear Lake near Minden, Ontario. Some of the hemlock seedlings growing on fallen trunks together with debris in which they were growing were brought to a greenhouse in pots, and some of them were transferred into sandy soil. The conditions

A. M. Zobell; K. Glowniak; J. E. Lynch; S. Dudka; A. Alliota

79

The impact of hemlock looper ( Lambdina fiscellaria fiscellaria (Guen.)) on balsam fir and spruce in New Brunswick, Canada  

Microsoft Academic Search

In 1989, the first recorded outbreak of hemlock looper (Lambdina fiscellaria fiscellaria (Guen.)) occurred in New Brunswick, Canada. Data were collected from ten plots established in an area infested from 1992–1994, to assess impacts of hemlock looper. Ocular and branch sample assessments of current defoliation and ocular assessments of total defoliation (all age classes of foliage) were conducted for balsam

David A MacLean; Paul Ebert

1999-01-01

80

Molecular and biological characterization of a new Brazilian begomovirus, euphorbia yellow mosaic virus (EuYMV), infecting Euphorbia heterophylla plants  

Microsoft Academic Search

To date, no begomovirus has been fully characterized from Euphorbia heterophylla, a widely distributed weed, in Brazil. Here, we show the occurrence of a new begomovirus on E. heterophylla plants showing bright yellow mosaic. The bipartite viral genome was cloned from 10 samples, and all clones are almost identical\\u000a to each other (95.6-98.8% nucleotide sequence identity). The DNA-A sequences shared

Fernanda R. Fernandes; Leonardo C. Albuquerque; Cristiane L. de Oliveira; Andréa R. R. Cruz; Wesley B. da Rocha; Talita G. Pereira; Fernanda Y. B. Naito; Natália de M. Dias; Tatsuya Nagata; Josias C. Faria; Francisco M. Zerbini; Francisco J. L. Aragão; Alice K. Inoue-Nagata

81

Water hemlock (Cicuta douglasii) toxicoses in sheep: pathologic description and prevention of lesions and death.  

PubMed

Water hemlock causes numerous livestock losses in North America every year. Description of pathologic and serum biochemical changes has been lacking in the literature. Tubers of western water hemlock (Cicuta douglasii) induced excessive salivation, tremors, grand mal seizures, skeletal and cardiac myodegeneration, and death in sheep given 1.2-2.7 g fresh tuber/kg body weight by gavage. Seizures were intermittent with periods of relaxation until death occurred from anoxia during seizure activity. In sheep given 1.5-2.5 times the lethal dose of water hemlock by gavage, intravenous administration of sodium pentobarbital at the onset of the first seizure prevented further seizure activity and skeletal and cardiac myodegeneration and resulted in rapid and complete recovery. PMID:8953535

Panter, K E; Baker, D C; Kechele, P O

1996-10-01

82

Proteomic analysis of the effect of triterpenes from Patrinia heterophylla on leukemia K562 cells.  

PubMed

For centuries, Patrinia heterophylla had been used in China to treat many diseases including tumor. Triterpenes has been identified as the major active constituents in Patrinia heterophylla. To elucidate the antitumor mechanism of triterpenes from Patrinia heterophylla1 (TPH), a proteomic analysis is carried out with TPH treatment in K562 cells. The total proteins extracted from TPH treated K562 cells are analyzed by two dimensional gel electrophoresis (2-DE) and compared with those untreated K562 cells. Mass spectrometry is applied to identify the differentially expressed proteins. Twenty-three differentially expressed significant proteins are discovered. Eight proteins are later identified by mass spectrometry (MALDI-TOF-MS) and Mascot software. Among them, four proteins are up-regulated (Aldolase A, Glyceraldehyde-3-phosphate dehydrogenase, Flavin reductase and Hemoglobin subunit) and four proteins were down-regulated (Heat-shock protein 90 ?Alpha? (HSP90-?Alpha?), Eukaryotic translation initiation factor 5A, Moesin, tublin) by TPH treatment in K562 cells. The identified proteins are associated with energy metabolism, oxidative stress, apoptosis, signal transduction, differential induction, and protein biosynthesis. These findings might provide valuable insights into the antitumor mechanism of TPH in K562 cells. PMID:23064283

Wei, Dong-Feng; Wei, Yan-Xia; Cheng, Wei-Dong; Yan, Ming-Fei; Su, Gang; Hu, Yan; Ma, Ya-Qiong; Han, Chao; Lu, Yan; Hui-Ming, Cao; Bao, Ying-Cun

2012-12-18

83

Transcriptome Sequencing and Identification of Cold Tolerance Genes in Hardy Corylus Species (C. heterophylla Fisch) Floral Buds  

PubMed Central

Background The genus Corylus is an important woody species in Northeast China. Its products, hazelnuts, constitute one of the most important raw materials for the pastry and chocolate industry. However, limited genetic research has focused on Corylus because of the lack of genomic resources. The advent of high-throughput sequencing technologies provides a turning point for Corylus research. In the present study, we performed de novo transcriptome sequencing for the first time to produce a comprehensive database for the Corylus heterophylla Fisch floral buds. Results The C. heterophylla Fisch floral buds transcriptome was sequenced using the Illumina paired-end sequencing technology. We produced 28,930,890 raw reads and assembled them into 82,684 contigs. A total of 40,941 unigenes were identified, among which 30,549 were annotated in the NCBI Non-redundant (Nr) protein database and 18,581 were annotated in the Swiss-Prot database. Of these annotated unigenes, 25,311 and 10,514 unigenes were assigned to gene ontology (GO) categories and clusters of orthologous groups (COG), respectively. We could map 17,207 unigenes onto 128 pathways using the Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG) database. Additionally, based on the transcriptome, we constructed a candidate cold tolerance gene set of C. heterophylla Fisch floral buds. The expression patterns of selected genes during four stages of cold acclimation suggested that these genes might be involved in different cold responsive stages in C. heterophylla Fisch floral buds. Conclusion The transcriptome of C. heterophylla Fisch floral buds was deep sequenced, de novo assembled, and annotated, providing abundant data to better understand the C. heterophylla Fisch floral buds transcriptome. Candidate genes potentially involved in cold tolerance were identified, providing a material basis for future molecular mechanism analysis of C. heterophylla Fisch floral buds tolerant to cold stress. PMID:25268521

Liu, Qingzhong; Guo, Wei; Zhao, Tiantian; Ma, Qinghua; Wang, Guixi

2014-01-01

84

Modeling insecticide protection versus forest management approaches to reducing balsam fir sawfly and hemlock looper damage  

Microsoft Academic Search

A decision support system (DSS) for improved management decision making and to reduce impacts of forest insect outbreaks was developed and implemented for two defoliators, hemlock looper (Lambdina fiscellaria fiscellaria Guen.) and balsam fir sawfly (Neodiprion abietis Harris), in District 15, a 336,805ha forest managed by Corner Brook Pulp and Paper Ltd. in western Newfoundland, Canada. Over the past 15years,

Javed Iqbal; Chris R. Hennigar; David A. MacLean

85

SHORT-TERM EFFECTS OF PRESCRIBED FIRE IN GRAND FIR-WHITE PINE-WESTERN HEMLOCK  

E-print Network

SHORT-TERM EFFECTS OF PRESCRIBED FIRE IN GRAND FIR-WHITE PINE-WESTERN HEMLOCK SLASH FUELS Elizabeth our knowledge about fue effects and our skills in prescribing and meeting objectives through, using aplanar intersect method (Brown 1974). On asubsetof18 units, consumption oflargewoody materialwas

Fried, Jeremy S.

86

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

PubMed

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. PMID:16053550

Pontius, Jennifer; Hallett, Richard; Martin, Mary

2005-06-01

87

THE ECONOMIC IMPACTS OF HEMLOCK WOOLLY ADELGID ON RESIDENTIAL LANDSCAPE VALUES: SPARTA, NEW JERSEY CASE STUDY  

Microsoft Academic Search

In this paper, we provide preliminary estimates of the impacts of the hemlock woolly adelgid on residential property values in Sparta, New Jersey, using the hedonic property value method. The literature on the aesthetic perceptions of forest landscapes is briefly reviewed to provide guidance in formulating economic hypotheses based on the assumption of an informative relationship between forest aesthetics and

Thomas P. Holmes; Elizabeth A. Murphy; Denise D. Royle

88

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

PubMed

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 characteristics lacking in New England second-growth stands by integrating structural legacies of disturbance (e.g., downed CWD) and resultant tree-size distribution patterns. This silvicultural approach would emulate the often episodic nature of CWD recruitment within old-growth forests. PMID:18686580

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

2008-07-01

89

Congenital skeletal malformations induced by maternal ingestion of Conium maculatum (poison hemlock) in newborn pigs.  

PubMed

Skeletal malformations were induced in newborn pigs from gilts fed Conium maculatum seed or plant during gestation days 43 through 53 and 51 through 61. The teratogenic effects in groups dosed during gestation days 43 through 53 were more severe than those in groups dosed during the later period, with many newborn pigs showing arthrogryposis and twisted and malaligned bones in the limbs and with 1 pig showing scoliosis and deformity of the thoracic cage. The pigs born to gilts given C maculatum during gestation days 51 through 61 had excessive flexure primarily in the carpal joints, without scoliosis or bone malalignment in the limbs. The teratogenicity of poison hemlock depends on the alkaloid concentration and content. Based on the data presented, we speculate that gamma-coniceine is the teratogenic alkaloid in the poison hemlock fed to the gilts. PMID:4062008

Panter, K E; Keeler, R F; Buck, W B

1985-10-01

90

Radio ultrasound observations of the fetotoxic effects in sheep from ingestion of Conium maculatum (poison-hemlock).  

PubMed

Fetal movement in pregnant ewes gavaged with Conium maculatum (poison-hemlock) was reduced significantly, but temporarily. Fetal movement was observed by radio ultrasound at 45, 54 and 60 days of gestation in control ewes and on days 45, 54, and 60 of gestation immediately before and 1 hour following poison-hemlock feeding in treated ewes. Fetal movement was significantly reduced (P less than 0.01) 1 hour after poison-hemlock administration, but returned to normal within 18 hours post treatment. At parturition seven of eleven lambs born to seven treated ewes had varying degrees of front limb abnormalities. Modest to moderate flexure of the carpal joints, some lateral deviation in the front limbs at the pastern joint and kinked tails were observed. These malformations were transient and resolved spontaneously by 8 weeks after lambing. PMID:3047418

Panter, K E; Bunch, T D; Keeler, R F; Sisson, D V

1988-01-01

91

Subulatin, an antioxidic caffeic acid derivative isolated from the in vitro cultured liverworts, Jungermannia subulata, Lophocolea heterophylla, and Scapania parvitexta.  

PubMed

The new caffeic acid derivative, subulatin (1), was isolated from in vitro cultured liverworts, Jungermannia subulata, Lophocolea heterophylla, and Scapania parvitexta. The structure of 1 involved two caffeic acids, D-glucose, and 2-carboxy-6-(1,2-dihydroxy-ethyl)-4,5-dihydroxy-5,6-dihydro-4H-pyran. The connectivity of those and the absolute stereochemistry of 1 were elucidated on the basis of spectroscopic evidence. The antioxidative activity of 1 was comparable to that of alpha-tocopherol. (2'R)-Phaselic acid (2a) and (-)-9,2''-epiphylloyl-L-malic acid (4) were also isolated from J. subulata and L. heterophylla, respectively. A chiral HPLC analysis of the p-bromobenzoyl-malic acids derived from 2a showed that 2a from J. subulata was unusual (+)-trans-caffeoyl-D-malic acid. PMID:11999396

Tazaki, Hiroyuki; Ito, Mayumi; Miyoshi, Masako; Kawabata, Jun; Fukushi, Eri; Fujita, Takashi; Motouri, Mutsumi; Furuki, Tatsuo; Nabeta, Kensuke

2002-02-01

92

Maternal and fetal toxicity of poison hemlock (Conium maculatum) in sheep.  

PubMed

Poison hemlock (Conium maculatum) was toxic to pregnant ewes and their fetuses when fed during gestation days 30 through 60. Maternal effects included trembling, muscular weakness in the neck initially, then progressing to the limbs, ataxia, frequent urination and defecation, and death. Convulsive seizures were not observed. Fetotoxic effects included excessive flexure of the carpal joints with lateral deviation in the front limbs and kinked tails. At term, 7 of 11 lambs had varying degrees of the limb abnormalities, but all lambs appeared clinically normal at 8 weeks after parturition. PMID:3348538

Panter, K E; Bunch, T D; Keeler, R F

1988-02-01

93

Hemlock Alkaloids in Aloes. Occurrence and Distribution of gamma-Coniceine.  

PubMed

The hemlock alkaloid gamma-coniceine was identified in a number of ALOE species, namely A. GILLILANDII, Reynolds A. BALLYI Reynolds, A. RUSPOLIANA Baker, A. IBITIENSIS Perrier and A. DELTOIDEODONTA Baker. Coniine was identified in A. VIGUIERI Perrier. The levels of gamma-coniceine are higher than those found in CONIUM MACULATUM L. Some species also contained trace amounts of conhydrinone and pseudoconhydrin. Three of the species are Madagascan endemics, one is restricted to Arabia, while the rest are remote from each other in East Africa. Some of the species are loosely related but there is no overall taxonomic affinity between them. PMID:17340347

Dring, J V; Nash, R J; Roberts, M F; Reynolds, T

1984-10-01

94

Fungal pathogens of Euphorbia heterophylla and E. hirta in Brazil and their potential as weed biocontrol agents  

Microsoft Academic Search

A two-year survey of the fungi associated with two important congeneric pantropical weeds, Euphorbia heterophylla and E. hirta, was conducted in part of their native range in southern Brazil. Sampling was concentrated mainly in Rio de Janeiro State\\u000a and ten species were identified as pathogens of these weeds. Two taxa, Botrytis ricini and Uromyces euphorbiae, were common to both weed

Robert W. Barreto; Harry C. Evans

1998-01-01

95

Effect of a supplementation of Euphorbia heterophylla on nutritional meat quality of Guinea pig (Cavia porcellus L.).  

PubMed

The aim of the present work was to study the effect of dietary supplementation of Euphorbia heterophylla on the quality of the Guinea pig meat. Forty guinea pigs were divided into two groups fed ad libitum during 46 days a Panicum maximum diet (Panicum diet) or a mixed diet (75% Panicum maximum+25% Euphorbia heterophylla) (Paneuphorbia diet) to compare their effects on performances and on the composition of guinea pig tissues and carcass. Daily weight gain, liver weight, carcass yield, and the lipid content of both the carcass and the perirenal fat were significantly increased by the Paneuphorbia diet. Feeding Paneuphorbia diet increased (P<0.05) the n-3 PUFA content in perirenal fat, muscle, liver and in the carcass and decreased (P<0.05) the n-6/n-3 ratios in all these tissues and the carcass. In conclusion, this study shows that Euphorbia heterophylla is a source of n-3 fatty acids which can improve significantly the n-3 PUFA content of Guinea pig meat and carcass. PMID:23305832

Kouakou, N'Goran David Vincent; Grongnet, Jean-François; Assidjo, Nogbou Emmanuel; Thys, Eric; Marnet, Pierre-Guy; Catheline, Daniel; Legrand, Philippe; Kouba, Maryline

2013-04-01

96

Occurrence and dominance of six Pacific Northwest conifer species Todd A. Schroeder, Andreas Hamann, Tongli Wang & Nicholas C. Coops  

E-print Network

conifer species (Pseudotsuga menziesii, Tsuga heterophylla, Pinus contorta, Thuja plicata, Larix occidentalis, and Picea glauca) using forest inventory data collected across the United States and Canada

Hamann, Andreas

97

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

PubMed

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. PMID:22370410

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

2012-01-01

98

Ecosystem Function in Appalachian Headwater Streams during an Active Invasion by the Hemlock Woolly Adelgid  

PubMed Central

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. PMID:23613803

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

2013-01-01

99

Forested Communities of the Upper Montane in the Central and Southern  

E-print Network

), lodgepole pine (Pinus contorta), mountain hemlock (Tsuga mertensiana), western white pine (Pinus monticola magnifica), white fir (Abies concolor), sugar pine (Pinus lambertiana), Jeffrey pine (Pinus Jeffreyii

Standiford, Richard B.

100

108 Raupp et al.: Mites on Hemlocks Following Applications of Imidacloprid Systemic insecticides have gained widespread use in the  

E-print Network

crops in which imidacloprid applications have been implicated in increased mite populations in bedding108 Raupp et al.: Mites on Hemlocks Following Applications of Imidacloprid Systemic insecticides beetles (Sclar and Cranshaw 1996), lace bugs (Gill et al. 1999), aphids (Sclar and Cranshaw 1996), scales

Eubanks, Micky

101

EFFECTS OF AMMONIUM AND NITRATE ON NUTRIENT UPTAKE AND ACTIVITY OF NITROGEN ASSIMILATING ENZYMES IN WESTERN HEMLOCK  

EPA Science Inventory

Western hemlock seedlings were grown in nutrient solutions with ammonium, nitrate or ammonium plus nitrate as nitrogen sources. he objectives were to examine (1) possible selectivity for ammonium or nitrate as an N source, (2) the maintenance of charge balance during ammonium and...

102

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

PubMed Central

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 mode in this mixed-mated species. Extrapolating the findings to unpredictable global drought cycles, it is suggested that in addition to reducing yield, water stress may influence the evolutionary trajectory of plant mating system. PMID:23884393

Jorgensen, Rachael; Arathi, H. S.

2013-01-01

103

Comparative toxicity of coniine, an alkaloid of Conium maculatum (poison hemlock), in chickens, quails, and turkeys.  

PubMed

Coniine, an alkaloid of Conium maculatum (poison hemlock), was administered by gavage to immature chickens, quails, and turkeys at 0, 25, 50, and 100 mg/kg body weight. At 25 mg coniine/kg body weight, clinical signs were observed only in quails (2/10) and consisted of excitement, depression, hypermetria, seizures, opisthotonos, and flaccid paralysis. Chickens (9/10) and quails (8/10) dosed at 50 mg/kg body weight were affected, and several birds of each species died (2/10 and 5/10, respectively). Turkeys (7/10) were affected only when dosed at 100 mg/kg body weight, and quails (6/10), turkeys (4/10), and chickens (10/10) died at this dose. There were no gross or microscopic lesions. Coniine was detected in skeletal muscle and liver of birds dying after ingestion and was present in some survivors 7 days post-treatment. PMID:2369382

Frank, A A; Reed, W M

1990-01-01

104

Biochemical Systematlcsand Ecology,Vol. 18,No. 4, pp. 267-280, 1990. 0305-1978/90 $3.00+ 0.00 Printed in GreatBritain. 1990PergamonPressplc.  

E-print Network

TsugamertensJana Abies amabifis Pinus monticola Abies procera Piceasitchensis II. Mountain hemlock Tusgamertensiana Pinusalblcaulis Pinus monticola Abies lasiocarpa Abies grandis Picea engelmannii Piceabreweriana heterophylla), the shore pine race (mainly on Pinus contorta ssp. contorta) and the mountain hemlock race

Nickrent, Daniel L.

105

Common and Scientific Names Table D1 Common and scientific names as referred to in document.  

E-print Network

Abies lasiocarpa Western hemlock T. heterophylla Western larch Larix occidentalis Western redcedar Thuja Symphoricarpos albus Douglas spirea Spirea douglasii Fools huckleberry Menziesia ferruginea Glandular Labrador

106

Fungal pathogens of Euphorbia heterophylla and E. hirta in Brazil and their potential as weed biocontrol agents.  

PubMed

A two-year survey of the fungi associated with two important congeneric pantropical weeds, Euphorbia heterophylla and E. hirta, was conducted in part of their native range in southern Brazil. Sampling was concentrated mainly in Rio de Janeiro State and ten species were identified as pathogens of these weeds. Two taxa, Botrytis ricini and Uromyces euphorbiae, were common to both weed hosts. Alternaria euphorbiicola, Bipolaris euphorbiae, Melampsora sp., Oidium sp. and Sphaceloma poinsettiae were recorded only from E. heterophylla, whereas Colletotrichum gloeosporioides, Sphaceloma sp. and Sphaerotheca fuliginea were restricted to E. hirta. Botrytis ricini and Colletotrichum gloeosporioides are new records for E. hirta, and Alternaria euphorbiicola and Sphaerotheca fuliginea are new host records for Brazil. Bipolaris euphorbiae, previously identified as Helminthosporium sp., is considered to be the correct name for the causal agent of a major disease of E. heterophyllum in Brazil. The potential of these pathogens as biocontrol agents is discussed and the mycobiota associated with both these weeds worldwide is reviewed. PMID:16284862

Barreto, R W; Evans, H C

1998-01-01

107

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

108

The Paleolimnological Record of the North Atlantic Oscillation: Magnetic Properties and Diatom Counts from Hemlock and Conesus Lakes, Western New York State  

NASA Astrophysics Data System (ADS)

Between 1900 and 1930 CE when the NAO index showed large amplitude positive excursions, but the AO index varied at very small amplitudes, drought conditions frequently prevailed in western New York state according the Palmer Drought Index (PDI). Since 1970, when both the NAO and the AO indices show large and progressively increasing positive excursions, the PDI has been generally positive, indicating moisture surpluses in the region. Magnetic properties, including coercivity of remanence, have been measured and the diatoms have been enumerated in sediments from two gravity cores collected from Hemlock and Conesus Lakes. The sediments date from ~1875 CE in the Hemlock core and ~1923 CE in the Conesus core. Variations in magnetic grain-size are interpreted from the coercivity of remanence, with lower coercivity of remanence associated with large grain size. The primary productivity of lakes is interpreted from the Lake Trophic Status Index (LTSI), which is calculated based on known ecologies of several diatom species. In both lakes we find that larger magnetic grain size is associated with greater productivity in the lakes. In the Hemlock core, through the interval corresponding to 1913-1943 coercivity of remanence values declined to 281-259 Oersteds, from late 19th century values that were >350 Oersteds. The bottom of the Conesus core (1923-1938 CE) has the lowest coercivity of remanance values in the record (309-317 Oersteds). LTSI values in the Hemlock samples increase as remanence of coercivity values decline between 1888 and 1920 CE. This reflects an increase in the abundance of the mesoeutrophic Tabellaria fenestrata during this interval. In the Conesus samples the agreement between coercivity of remanence and LTSI is quite close. The range of variation in both LTSI and magnetic grain size is smaller in Conesus than in Hemlock Lake. The diatom assemblage is also quite different in Conesus, dominated by eutrophic Aulacosiera granulata, which are rare or absent at Hemlock Lake. The Hemlock basin is much steeper than than that of Conesus and its water level fluctuates more extremely because it is the reservoir for the city of Rochester. Hemlock Lake is oligotrophic and its drainage basin is heavily forested and lightly populated. Conesus Lake is eutrophic, its shores lined with cottages and the basin is heavily agricultural. In spite of these differences in both natural conditions and anthropogenic factors, the LTSI and magnetic measurements of the two lakes share variance, ostensibly forced by regional climate change. Initial results suggest that the shared component of variance in these proxy indicators can predict variations in regional drought intensity. Regional drought intensity, in turn, seems associated with an uncoupling of AO and NAO variation.

Chaisson, W. P.; Arnold, M. R.; Cottrell, R. D.

2002-05-01

109

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

PubMed

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 ?-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). PMID:24005009

Nakamura, Atsuhiko; Miyazawa, Mitsuo

2013-01-01

110

Estimating cumulative defoliation of balsam fir from hemlock looper and balsam fir sawfly using aerial defoliation survey in western Newfoundland, Canada  

Microsoft Academic Search

Both hemlock looper (Lambdina fiscellaria fiscellaria (Guen.)) and balsam fir sawfly (Neodiprion abietis (Harris)) undergo periodic outbreaks in eastern Canada and cause significant growth and mortality losses to forests. Tree growth and mortality are closely related to cumulative defoliation estimates, which integrate annual defoliation over multiple years. Our objective was to determine a method to estimate cumulative defoliation of balsam

Javed Iqbal; David A. MacLean

2010-01-01

111

Multiple forms of endo-1,4-beta-glucanases in the endosperm of Euphorbia heterophylla L.  

PubMed

Germinating seeds of Euphorbia heterophylla L. contain endo-1,4-beta-glucanases which degrade carboxymethylcellulose (CMC). The activity decreased approximately 66% in extracts of endosperm containing isopropanol or ethanol. The endoglucanases were isolated from endosperm extracts using ammonium sulphate fractionation followed by Sephacryl S-100-HR chromatography resulting in two main peaks: I and II. Peak I endoglucanase was further purified about 15-fold on DEAE-Sephadex A50 and then by affinity chromatography (CF11-cellulose). Peak II endoglucanases were further purified 10-fold on CM-cellulose chromatography. The results indicated the occurrence of a 66 kDa endoglucanase (fractionated by SDS-PAGE and visualized by activity staining using Congo Red). Several acidic (pI 3.0 to 5.7) and basic (pI 8.5 to 10.0) forms from both peaks which differed in their capacities for degrading CMC or xyloglucans from Copaifera langsdorffii or Hymenaea courbaril were detected. PMID:12885862

Suda, Cecilia N K; Giorgini, Jarbas F

2003-09-01

112

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

PubMed Central

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 coastal areas after the regressions and that may have promoted the geographic structuring of genetic diversity observed today. The recent population expansion for the entire species may be linked with the event of marine regression after the most recent sea transgression at ~5 kya. PMID:23987105

2013-01-01

113

Retention of canopy lichens after partial-cut harvesting in wet-belt interior cedar–hemlock forests, British Columbia, Canada  

Microsoft Academic Search

Old-growth cedar–hemlock forests of the interior wet-belt of British Columbia are rich in abundance and diversity of canopy lichens, but are subject to forest harvesting. If these distinctive canopy lichen communities are to be conserved, it is important to learn how they are affected by forestry practices, including partial-cutting techniques designed to retain old-growth attributes. The retention of canopy lichens

Darwyn S. Coxson; Susan K. Stevenson

2005-01-01

114

Ganoderma tsugae Extract Inhibits Growth of HER2-Overexpressing Cancer Cells via Modulation of HER2/PI3K/Akt Signaling Pathway  

PubMed Central

Ganoderma, also known as Lingzhi or Reishi, has been used for medicinal purposes in Asian countries for centuries. It is a medicinal fungus with a variety of biological properties including immunomodulatory and antitumor activities. In this study, we investigated the molecular mechanisms by which Ganoderma tsugae (GT), one of the most common species of Ganoderma, inhibits the proliferation of HER2-overexpressing cancer cells. Here, we show that a quality assured extract of GT (GTE) inhibited the growth of HER2-overexpressing cancer cells in vitro and in vivo and enhanced the growth-inhibitory effect of antitumor drugs (e.g., taxol and cisplatin) in these cells. We also demonstrate that GTE induced cell cycle arrest by interfering with the HER2/PI3K/Akt signaling pathway. Furthermore, GTE curtailed the expression of the HER2 protein by modulating the transcriptional activity of the HER2 gene and the stability/degradation of the HER2 protein. In conclusion, this study suggests that GTE may be a useful adjuvant therapeutic agent in the treatment of cancer cells that highly express HER2. PMID:23662119

Kuo, Han-Peng; Hsu, Shih-Chung; Li, Jhy-Wei; Tseng, Hsiu-Hsueh; Chuang, Tzu-Chao; Liu, Jah-Yao; Chen, Shih-Jung; Su, Muh-Hwan; Cheng, Yung-Chi; Chou, Wei-Yuan; Kao, Ming-Ching

2013-01-01

115

Ganoderma tsugae Extract Inhibits Growth of HER2-Overexpressing Cancer Cells via Modulation of HER2/PI3K/Akt Signaling Pathway.  

PubMed

Ganoderma, also known as Lingzhi or Reishi, has been used for medicinal purposes in Asian countries for centuries. It is a medicinal fungus with a variety of biological properties including immunomodulatory and antitumor activities. In this study, we investigated the molecular mechanisms by which Ganoderma tsugae (GT), one of the most common species of Ganoderma, inhibits the proliferation of HER2-overexpressing cancer cells. Here, we show that a quality assured extract of GT (GTE) inhibited the growth of HER2-overexpressing cancer cells in vitro and in vivo and enhanced the growth-inhibitory effect of antitumor drugs (e.g., taxol and cisplatin) in these cells. We also demonstrate that GTE induced cell cycle arrest by interfering with the HER2/PI3K/Akt signaling pathway. Furthermore, GTE curtailed the expression of the HER2 protein by modulating the transcriptional activity of the HER2 gene and the stability/degradation of the HER2 protein. In conclusion, this study suggests that GTE may be a useful adjuvant therapeutic agent in the treatment of cancer cells that highly express HER2. PMID:23662119

Kuo, Han-Peng; Hsu, Shih-Chung; Ou, Chien-Chih; Li, Jhy-Wei; Tseng, Hsiu-Hsueh; Chuang, Tzu-Chao; Liu, Jah-Yao; Chen, Shih-Jung; Su, Muh-Hwan; Cheng, Yung-Chi; Chou, Wei-Yuan; Kao, Ming-Ching

2013-01-01

116

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

PubMed

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. PMID:16275285

Miyauchi, Teruhisa; Mori, Mitsunori; Ito, Katsuhiko

2005-11-18

117

Factors influencing fungal degradation of lignin in a representative lignocellulosic, thermomechanical pulp  

SciTech Connect

This research examined culture parameters influencing the rate of degradation of lignin in lignocellulosic substrates by the Basidiomycete Phanerochaete chryosoprorium. Thermomechanical pulps prepared from western hemlock (Tsuga heterophylla) and red alder (Alnus rubra) were chosen as model substrates. Degradation of lignin in shallow, liquid-phase, stationary cultures was 10 times as rapid as in agitated cultures. Lignin degradation was at least 50% more rapid in cultures under 100% O/sub 2/ than in those under air. Addition of 0.12% nutrient N (dry pulp basis ) increased the rate of lignin degradation two- to fivefold; 1.2% added N at first suppressed, then stimulated, lignin degradation. Lignin in the alder pulp was degraded over five times as rapidly as in the hemlock pulp. Addition of glucose (35% of dry pulp) to the pulps containing 0.12% added N completely suppressed polysaccharide depletion during two weeks, but did not infleunce lignin degradation. The maximum rate of lignin degradation was 3%/day over a two-week incubation, or approximately 2.9 mg/mg fungal cell protein/day. The influence of the examined parameters was in complete accord with those found earlier for synthetic /sup 14/C-lignin metabolism by P. chrysosporium.

Yang, H.H.; Effland, M.J.; Kirk, T.K.

1980-01-01

118

Distribution of 15N Tracers Applied to the Canopy of a Mature Spruce-Hemlock Stand: Implications for Carbon Sequestration  

NASA Astrophysics Data System (ADS)

Fertilization, through increases in N deposition, can enhance plant growth and thus impact other elemental cycles including that of carbon. However, in many N fertilization experiments chemical amendments are added to soils, making soils and not plants the short term recipient of additional N (years to decades). In 2001, a dissolved fertilizer addition of 18 kg N/ha to a 21 ha plot in a Maine spruce-hemlock forest was initiated to investigate the importance of canopy N processes and impacts on C sequestration. In smaller subplots (0.3 ha), additional N inputs were made with tracer levels of enriched N, as either 15NH4+ or 15NO3-. Ecosystem pools, canopy gaseous N losses, and dissolved N fluxes in the 15N subplots were analyzed to determine ecosystem N retention and estimate the impact on C sequestration. Ecosystem retention of 15NH4+ and 15NO3- was 38% and 70% respectively, much of this (~75%) was recovered in the canopy, yet little N (<5%) was recovered in woody matter with a high C:N ratio. Despite a large canopy N retention potential in this forest, C sequestration into new wood growth was ~4-5 g C m-2 y-1 or about 2% above the current net annual C sequestration for this site after 3 years of fertilization.

Davidson, E.; Dail, D. B.; Hollinger, D. Y.; Davidson, E.; Sievering, H.; Scott, N.; Fernandez, I.; Aber, J.; Gaige, E.

2007-12-01

119

J AM E S B O E H M E R , K E I T H D I N AR D O , L I S A G AG N O N , E R I C K E L L S , AN D R E N E E V I E I R A  

E-print Network

or Polygonum cuspidatum). Not found on the property, but very close to the boundary line. · Autumn or Russian Olive (Elaeagnus spp.) · Invasive insects: · Hemlock woolly adelgid (Adelges tsugae) #12;Invasive

Schweik, Charles M.

120

Millersville University's Trees of Distinction  

E-print Network

-06-03 #12;#12: Eastern hemlock (Tsuga canadensis) 2014-04-24 #12;#13: Kentucky coffee tree (Gymnocladus dioica) #12;#14: Flowering dogwood (Cornus florida) 2014-05-22 #12;#15: London plane, Hybrid sycamore

Hardy, Christopher R.

121

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

NASA Astrophysics Data System (ADS)

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 for paleo-atmospheric CO2 reconstructions. High resolution paleo-atmospheric CO2 records for the Holocene based on fossil Be- tula and Tsuga heterophylla leaves will be briefly discussed.

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

122

Upper petal lip colour polymorphism in Collinsia heterophylla (Plantaginaceae): genetic basis within a population and its use as a genetic marker.  

PubMed

Understanding the genetics of a polymorphic trait is important to predict its likely evolution. In Collinsia heterophylla, the upper petal lip colour can be either be white or white with a purple band, while the lower petal lip colour is invariably purple. Because the corolla is only partly polymorphic, the polymorphism can not have evolved due to a mutation where a pigment was lost in the entire plant, which is common in other polymorphic species. In a previous study, high frequency of the purple band was found in populations with darker flowers, indicating possible selection for this trait. In this study, I determined inheritance of the colour polymorphism using two populations (one with only white morph and other with both morphs). I conducted experimental crosses within and between floral morphs to determine whether patterns of segregation in offspring conform to single-gene predictions. Data from F1, F2, F3 and backcross progeny are consistent with a genetic model of one major locus with presence of the band being completely dominant, as indicated in earlier studies using distantly related populations. A novel finding in this study was that the two morphs did not show a difference in seed germination frequency or seedling survival. This trait can thus be valuable as a genetic marker. Even though more thorough ecological data are needed to understand the potential selection pressures on upper petal lip colour in C. heterophylla, its simple inheritance may indicate the possibility of fast evolutionary response to selective forces acting on this trait. PMID:19700859

Lankinen, Asa

2009-08-01

123

Toxicosis in dairy cattle exposed to poison hemlock (Conium maculatum) in hay: isolation of Conium alkaloids in plants, hay, and urine.  

PubMed

Cattle in two herds developed signs of bloating, increased salivation and lacrimation, depression, respiratory distress, ataxia, and death after ingestion of hay that contained large amounts of poison hemlock (Conium maculatum). Twenty of 30 Angus cows and calves were affected in the first herd (2 died). In the second herd, 5 of 30 Holstein heifers were affected (1 died). The Conium alkaloids, coniine and gamma-coniceine, were quantified in the hay, the plants from the responsible hayfield, and the urine of affected animals. PMID:1554771

Galey, F D; Holstege, D M; Fisher, E G

1992-01-01

124

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

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.

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

1986-01-01

125

Ecology, 85(1), 2004, pp. 284289 2004 by the Ecological Society of America  

E-print Network

AS REFUGES FROM FUNGAL PATHOGENS FOR SEEDS OF EASTERN HEMLOCK (TSUGA CANADENSIS) D. L. O'HANLON-MANNERS AND P not significantly improve survival either in logs or in soil, even though survival of control seeds; fungal pathogens; nurse logs; seed mortality; Tsuga Can- adensis. INTRODUCTION Within forested ecosystems

126

Riparian forest composition affects stream litter decomposition despite similar microbial and invertebrate communities.  

PubMed

Cross-boundary flows of energy and nutrients link biodiversity and functioning in adjacent ecosystems. The composition of forest tree species can affect the structure and functioning of stream ecosystems due to physical and chemical attributes, as well as changes in terrestrial resource subsidies. We examined how variation in riparian canopy composition (coniferous, deciduous, mixed) affects adjacent trophic levels (invertebrate and microbial consumers) and decomposition of organic matter in small, coastal rainforest streams in southwestern British Columbia. Breakdown rates of higher-quality red alder (Alnus rubra) litter were faster in streams with a greater percentage of deciduous than coniferous riparian canopy, whereas breakdown rates of lower-quality western hemlock (Tsuga heterophylla) litter were independent of riparian forest composition. When invertebrates were excluded using fine mesh, breakdown rates of both litter species were an order of magnitude less and were not significantly affected by riparian forest composition. Stream invertebrate and microbial communities were similar among riparian forest composition, with most variation attributed to leaf litter species. Invertebrate taxa richness and shredder biomass were higher in A. rubra litter; however, taxa evenness was greatest for T. heterophylla litter and both litter species in coniferous streams. Microbial community diversity (determined from terminal restriction fragment length polymorphisms) was unaffected by riparian forest or litter species. Fungal allele richness was higher than bacterial allele richness, and microbial communities associated with lower-quality T. heterophylla litter had higher diversity (allele uniqueness and richness) than those associated with higher-quality A. rubra litter. Percent variation in breakdown rates was mostly attributed to riparian forest composition in the presence of invertebrates and microbes; however, stream consumer biodiversity at adjacent trophic levels did not explain these patterns. Riparian and stream ecosystems and their biotic communities are linked through exchange and decomposition of detrital resources, and we provide evidence that riparian forest composition affects stream ecosystem catabolism despite similarities in microbial and invertebrate communities. PMID:21560685

Kominoski, John S; Marczak, Laurie B; Richardson, John S

2011-01-01

127

A Comparative Toxicity Assessment of Materials Used in Aquatic Construction  

Microsoft Academic Search

Comparative toxicity testing was performed on selected materials that may be used in aquatic construction projects. The tests\\u000a 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

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

128

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

PubMed Central

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 among successful gametophytic fathers (pollen), and reducing inbreeding depression associated with self–pollination in plants with mix-mating systems. PMID:19202136

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

2009-01-01

129

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

USGS Publications Warehouse

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.

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

2005-01-01

130

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

USGS Publications Warehouse

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.

Jenkins, Kurt J.; Starkey, Edward E.

1996-01-01

131

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)

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.

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

2013-06-01

132

Stomatal behavior of four woody species in relation to leaf-specific hydraulic conductance and threshold water potential.  

PubMed

Midday stomatal closure is mediated by the availability of water in the soil, leaf and atmosphere, but the response to these environmental and internal variables is highly species specific. We tested the hypothesis that species differences in stomatal response to humidity and soil water availability can be explained by two parameters: leaf-specific hydraulic conductance (K(L)) and a threshold leaf water potential (Psi(threshold)). We used a combination of original and published data to estimate characteristic values of K(L) and Psi(threshold) for four common tree species that have distinctly different stomatal behaviors: black cottonwood (Populus trichocarpa Torr. & Gray.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), red alder (Alnus rubra Bong.) and western hemlock (Tsuga heterophylla (Raf.) Sarg.). We used the values to parameterize a simple, nonelastic model that predicts stomatal conductance by linking hydraulic flux to transpirational flux and maintaining Psi(leaf) above Psi(threshold). The model successfully predicted fundamental features of stomatal behavior that have been reported in the literature for these species. We conclude that much of the variation among the species in stomatal response to soil and atmospheric water deficits can be explained by K(L) and Psi(threshold). The relationship between Psi(threshold) and xylem vulnerability to cavitation differed among these species. PMID:12651540

Bond, Barbara J.; Kavanagh, Kathleen L.

1999-07-01

133

SPILOGALE GRACILIS IN UPLAND FORESTS OF WESTERN WASHINGTON AND OREGON  

Microsoft Academic Search

During surveys of upland forests in the Tsuga heterophylla Zone in Washington and Oregon, 1986 to 1996, we caught 192 S. gracilis. In the Oregon Coast Range, more (85%) S. gracilis were caught in oldeilar to Coast Range old growth (P = 0.60) with no differences between seral stages (P = 0.74). No S. gracilis were caught in upland forests

ANDREW B. CAREY; JANET E. KERSHNER

1996-01-01

134

Oecologia (2003) 137:1021 DOI 10.1007/s00442-003-1316-2  

E-print Network

radius), such as Abies amabilis, Pinus monticola, and Tsuga heterophylla. This pattern was not observed autotrophic respi- ration of forests has been reported to range from 12% (sub-alpine Pinus contorta ssp. latifolia, Ryan and Waring 1992 and Australian Pinus radiata D. Don, Ryan et al. 1996) to 42% (temperate

Lachenbruch, Barbara

135

chapter thirty Restoring dry and moist forests ofthe  

E-print Network

agents. In the northern Rocky Mountain moist forests, early-seral Pinus monticola has nearly been forests (Pinus ponderosa, Pseudotsuga menziesii), and an estimated 18% was covered by moist forests (Pinus monticola, Tsuga heterophylla). Frequent surface fires burned over 75% of the area of dry forests; today

Fried, Jeremy S.

136

13 C content of ecosystem respiration is linked to precipitation and vapor pressure deficit  

Microsoft Academic Search

Variation in the carbon isotopic composition of ecosystem respiration (?13CR) was studied for 3 years along a precipitation gradient in western Oregon, USA, using the Keeling plot approach. Study sites included six coniferous forests, dominated by Picea sitchensis, Tsuga heterophylla, Pseudotsuga menziesii, Pinus ponderosa, and Juniperus occidentalis, and ranged in location from the Pacific coast to the eastern side of

David R. Bowling; Nate G. McDowell; Barbara J. Bond; Beverly E. Law; James R. Ehleringer

2002-01-01

137

13 C content of ecosystem respiration is linked to precipitation and vapor pressure deficit  

Microsoft Academic Search

Variation in the carbon isotopic composition of ecosystem respiration (ཉCR) was studied for 3 years along a precipitation gradient in western Oregon, USA, using the Keeling plot approach. Study sites included six coniferous forests, dominated by Picea sitchensis, Tsuga heterophylla, Pseudotsuga menziesii, Pinus ponderosa, and Juniperus occidentalis, and ranged in location from the Pacific coast to the eastern side of

David R. Bowling; Nate G. McDowell; Barbara J. Bond; Beverly E. Law; James R. Ehleringer

2002-01-01

138

Ordination of epiphytic bryophyte communities in a wet-temperate coniferous forest, South-Coastal British Columbia  

Microsoft Academic Search

Three coniferous tree species (Pseudotsuga menziesii, Tsuga heterophylla, and Thuja plicata) at Capilano Canyon, British Columbia, were studied for their epiphytic communities. Quantitative data were obtained for fourteen bryophyte species by sampling at heights of 0.5 m, 1 m and 2 m above ground level. Scapania bolanderi is an abundant and widely distributed species; Dicranum fuscescens, Bazzania denudata, Lepidozia reptans

N. C. Kenkel; G. E. Bradfield

1981-01-01

139

ACID FOG EFFECTS ON CONIFER SEEDLINGS  

EPA Science Inventory

Experiments were performed to assess the effects of acid fog on foliar injury, biomass production, and nutrient leaching in selected conifers. ne-year old seedlings of Pseudotsuga menzieii, Pinus ponderosa, Tsuga heterophylla and Thuja plicata were exposed episodically to fog eve...

140

Development and application of boundary-line release criteria  

Microsoft Academic Search

Identifying releases from suppression represents one of the most fundamental dendroecological procedures for quantifying forest disturbance histories. In this study we evaluate boundary-line release criteria, which incorporates the effects of growth history on release response. In eastern hemlock (Tsuga canadensis L.) the maximum possible value of a pulse in percent-growth change is dependent on growth decline immediately prior to the

Bryan A. Black; Marc D. Abrams

2004-01-01

141

Plant Communities Growing on Boulders in the Allegheny National Forest: Evidence for Boulders as Refugia from Deer and as a Bioassay of Overbrowsing  

Microsoft Academic Search

Deer have been overabundant throughout much of Pennsylvania since at least the 1940's. We compared plant communities in the Allegheny National Forest (ANF) on boulder tops and the forest floor to test the hypothesis that large boulders serve as refugia for plants threatened by deer herbivory. Five of the ten most common woody species (hemlock, Tsuga canadensis L., mountain maple,

Walter P. Carson; Joshua A. Banta; Alejandro A. Royo; Chad Kirschbaum

142

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

Microsoft Academic Search

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

L. J. Puckett

1982-01-01

143

INDIANA BAT, MYOTIS SODALIS, MATERNITY ROOSTS IN THE SOUTHERN UNITED STATES  

Microsoft Academic Search

We characterized Indiana bat (Myotis sodalis) roosting habitat at three maternity colony sites in western North Carolina and eastern Tennessee. Using radio telemetry, we tracked six bats a total of 40 bat days (range 4-9 days\\/ bat). In 1999, we located a primary roost in an eastern hemlock (Tsuga canadensis) snag (109 cm DBH) in the Nantahala National Forest, NC.

Eric R. Britzke; Michael J. Harvey; Susan C. Loeb

2003-01-01

144

DWARF MISTLETOE CONTROL ON THE ROGUE RIVER NATIONAL FOREST IN ORE GO^^  

E-print Network

~nificiavx. shastensis], ponderosa pine part of the Siskiyou Mountains. The center ponderosa), sugar pine (Pinus of the Forest is about 100 miles inland lambertiana), western white pine (Pinus from the Pacific Ocean, so the climate is monticola), and some western hemlock essentially warm and moist in the winter, (Tsuga

Standiford, Richard B.

145

Factors Affecting Infection of Precommercial Thinning Stumps by Heterobasidion annosum in Coastal British Columbia1  

E-print Network

Root Disease in Western North America, April 18-21, 1989, Monterey, California. 2 Forest Pathologist, Forestry Canada, Pacific Forestry Centre, Victoria, B.C. Canada. hemlock [Tsuga). The stump and its roots may be colonized by the fungus, which spreads to adjacent residual trees at root

Standiford, Richard B.

146

Deer impacts on forest ecosystems: a North American perspective  

Microsoft Academic Search

Summary White-tailed deer have increased in abundance and expanded their geographic range in North America over the past century, and now exist at higher densities than they have in the past several hundred years. This is having numerous impacts on the forest ecosystems they inhabit. Regional recruitment failure of eastern hemlock (Tsuga canadensis) and northern white cedar (Thuja occidentalis) trees

T. P. Rooney

2001-01-01

147

Microbial utilization of dissolved organic carbon leached from riparian litterfall  

Microsoft Academic Search

Dissolved organic carbon (DOC) in aquatic systems is abundant and used within stream food webs, but DOC quality is rarely studied. DOC in the leachates from the litter of five tree species (red alder, Alnus rubra; vine maple, Acer circinatum; western red cedar, Thuja plicata; western hemlock, Tsuga hetrophylla; and Douglas-fir, Pseudotsuga menziesii) were assessed for their chemistry and relative

Michael D. McArthur; John S. Richardson

2002-01-01

148

Dendrochronological dates of the Winkelman House, Gloucester, MA Carol B. Griggs  

E-print Network

; species of spruce cannot be discerned from wood alone). One sample with bark is a spruce sample. The tree%. Four samples are hemlock (Tsuga canadensis); and 3 samples are spruce (Picea spp., red, white or black Begins Ends Number of Rings Outer Ring Spruce 1 Basement, N-S sill behind east entrance 1742 1841 1

Manning, Sturt

149

5. Perspective view of the east facade of the mansion ...  

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

5. Perspective view of the east facade of the mansion and the east lawn, from the northeast (less distant view). The view includes manicured hemlock (Tsuga canadensis), an annual flower bed, white pine (Pinus strobus), white birch (Betula species), and Norway spruce (Picea abies). - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

150

49. Perspective view of the east facade of the mansion ...  

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

49. Perspective view of the east facade of the mansion and the east lawn, from the northeast. The view includes manicured hemlock (Tsuga canadensis), an annual flower bed, white pine (Pinus strobus), white birch (Betula species), and Norway spruce (Picea abies). - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

151

50. Perspective view of the south facade of the mansion ...  

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

50. Perspective view of the south facade of the mansion and the south lawn, from the southeast. The view includes foundation and lawn plantings of wingbark euonymous (Euonymous alatus compactus), Japanese yew (Taxus cuspidata nana), manicured hemlock (Tsuga canadensis), and a white pine (Pinus strobus). - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

152

6. Perspective view of the south facade of the mansion ...  

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

6. Perspective view of the south facade of the mansion and the south lawn, from the southeast. (more distant view). The view includes manicured hemlock (Tsuga canadensis), an annual flower bed, white pine (Pinus strobus) and white birch (Betula species). - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

153

7. Perspective view of the south facade of the mansion ...  

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

7. Perspective view of the south facade of the mansion and the south lawn, from the southwest. The view includes foundation and lawn plantings of wingbark euonymus (Euonymus fortunei vegetis), Japanese yew (Taxus cuspidata nana), manicured hemlock (Tsuga canadensis), and white pine (Pinus strobus). - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

154

4. Perspective view of the east facade of the mansion ...  

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

4. Perspective view of the east facade of the mansion and the east lawn, from the northeast (more distant view). The view includes manicured hemlock (Tsuga canadensis), an annual flower bed, white pine (Pinus strobus) and white birch (Betula species). - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

155

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

PubMed

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. PMID:24376579

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

2013-01-01

156

The Importance of Large-Diameter Trees to Forest Structural Heterogeneity  

PubMed Central

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

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

2013-01-01

157

Holocene vegetational history of the Kootenai River Valley, Montana  

NASA Astrophysics Data System (ADS)

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.

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

1983-09-01

158

Successional trends and biomass of mosses on windthrow mounds in the temperate rainforests of Southeast Alaska  

Microsoft Academic Search

We investigated successional trends on windthrow mounds in two old-growth Tsuga heterophylla-Picea sitchensis forests in northern southeast Alaska to determine the influence of windthrow disturbance on the maintenance of plant diversity. We were particularly interested in assessing the value of mosses in detecting long-term effects of disturbance in temperate rainforests. Mosses established a dense carpet on windthrow mounds within the

Jan den Ouden; Paul B. Alaback

1996-01-01

159

Common name Scientific name  

E-print Network

albidum NT 1 sprouts, suckers I I NT Black cherry Prunus serotina NT 1 sprouts F I NT American beech Fagus fire I I NT White pine, eastern Pinus strobus I 1 F I­L NT Virginia (scrub) pine Pinus virginiana NT 1 T Other Softwoods Eastern red cedar Juniperus virginiana NT 1 S S­I I Eastern hemlock Tsuga canadensis T 1

Liskiewicz, Maciej

160

Tree Species Effects on Calcium Cycling: The Role of Calcium Uptake in Deep Soils  

Microsoft Academic Search

Soil acidity and calcium (Ca) availability in the surface soil differ substantially beneath sugar maple (Acer saccharum) and eastern hemlock (Tsuga canadensis) trees in a mixed forest in northwestern Connecticut. We determined the effect of pumping of Ca from deep soil (rooting zone\\u000a below 20-cm mineral soil) to explain the higher available Ca content in the surface soil beneath sugar

Feike A. Dijkstra; Mark M. Smits

2002-01-01

161

HIERARCHICAL COMPARISONS OF BREEDING BIRDS IN OLD GROWTH CONIFER-HARDWOOD FOREST ON THE APPALACHIAN PLATEAU  

Microsoft Academic Search

I compared relative abundances of breeding birds in old-growth forest (2300 years old) to surrounding landscapes using data from the Breeding Bird Census (BBC) and Breeding Bird Atlas (BBA). Eleven study plots (148 ha total) were established in relict, presettlement hemlock-white pine-northern hardwood (Tsuga canadensis-Pinus strobus) forest on the northern Appalachian Plateau, Pennsylvania. Of 56 breeding species recorded in old-growth

J. CHRISTOPHER HANEY

1999-01-01

162

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

163

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)

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 plant activity by this method. The results emphasise the strong influence of plants on the composition and activity of microbial soil communities. This has clear implications for our ability to predict ecosystem response to environmental change, including shifts in land use managements, and we discuss the need of incorporating these effects into current ecosystem models.

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

2009-04-01

164

Dynamic variation in sapwood specific conductivity in six woody species.  

PubMed

Our goals were to quantify how non-embolism-inducing pressure gradients influence trunk sapwood specific conductivity (k(s)) and to compare the impacts of constant and varying pressure gradients on k(s) with KCl and H2O as the perfusion solutions. We studied six woody species (three conifers and three angiosperms) which varied in pit membrane structure, pit size and frequency of axial water transport across pits (long versus short conduits). Both stepwise ("steady") and nonlinear continuous ("non-steady") decreases in the pressure gradient led to decreased k(s) in all species but white oak (Quercus garryana Dougl. ex Hook), a ring-porous and long-vesseled angiosperm. In one diffuse-porous angiosperm (red alder, Alnus rubra Bong.) and two conifers (western red cedar, Thuja plicata Donn. ex D. Don, and Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco), k(s) was 10-30% higher under steady pressure gradients than under non-steady pressure gradients, and a decrease in the pressure gradient from 0.15 to 0.01 MPa m(-1) caused a 20-42% decrease in k(s). In another diffuse-porous angiosperm (maple, Acer macrophyllum Pursh) and in a third coniferous species (western hemlock, Tsuga heterophylla (Raf.) Sarg), there was no difference between k(s) measured under steady and non-steady pressure gradients. With the exception of western red cedar, a conifer with simple pit membranes, the differences in k(s) between low and high pressure gradients tended to be lower in the conifers than in the diffuse-porous angiosperms. In Douglas-fir, western red cedar and the diffuse-porous angiosperms, k(s) was higher when measured with KCl than with H2O. In white oak, there were no differences in k(s) whether measured under steady or non-steady pressure gradients, or when xylem was perfused with KCl or H2O. The species differences in the behavior of k(s) suggest that elasticity of the pit membrane was the main factor causing k(s) to be disproportionate to the pressure gradient and to the different pressure regimes. The results imply that, if nonlinearities in pressure-flux relationships are ignored when modeling tree water relations in vivo, large errors will result in the predictions of tree water status and its impact on stomatal control of transpiration and photosynthesis. PMID:17669729

Domec, Jean-Christophe; Meinzer, Frederick C; Lachenbruch, Barbara; Housset, Johann

2007-10-01

165

Structural and compositional controls on transpiration in 40- and 450-year-old riparian forests in western Oregon, USA.  

PubMed

Large areas of forests in the Pacific Northwest are being transformed to younger forests, yet little is known about the impact this may have on hydrological cycles. Previous work suggests that old trees use less water per unit leaf area or sapwood area than young mature trees of the same species in similar environments. Do old forests, therefore, use less water than young mature forests in similar environments, or are there other structural or compositional components in the forests that compensate for tree-level differences? We investigated the impacts of tree age, species composition and sapwood basal area on stand-level transpiration in adjacent watersheds at the H.J. Andrews Forest in the western Cascades of Oregon, one containing a young, mature (about 40 years since disturbance) conifer forest and the other an old growth (about 450 years since disturbance) forest. Sap flow measurements were used to evaluate the degree to which differences in age and species composition affect water use. Stand sapwood basal area was evaluated based on a vegetation survey for species, basal area and sapwood basal area in the riparian area of two watersheds. A simple scaling exercise derived from estimated differences in water use as a result of differences in age, species composition and stand sapwood area was used to estimate transpiration from late June through October within the entire riparian area of these watersheds. Transpiration was higher in the young stand because of greater sap flux density (sap flow per unit sapwood area) by age class and species, and greater total stand sapwood area. During the measurement period, mean daily sap flux density was 2.30 times higher in young compared with old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. Sap flux density was 1.41 times higher in young red alder (Alnus rubra Bong.) compared with young P. menziesii trees, and was 1.45 times higher in old P. menziesii compared with old western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees. Overall, sapwood basal area was 21% higher in the young stand than in the old stand. In the old forest, T. heterophylla is an important co-dominant, accounting for 58% of total sapwood basal area, whereas P. menziesii is the only dominant conifer in the young stand. Angiosperms accounted for 36% of total sapwood basal area in the young stand, but only 7% in the old stand. For all factors combined, we estimated 3.27 times more water use by vegetation in the riparian area of the young stand over the measurement period. Tree age had the greatest effect on stand differences in water use, followed by differences in sapwood basal area, and finally species composition. The large differences in transpiration provide further evidence that forest management alters site water balance via elevated transpiration in vigorous young stands. PMID:14996653

Moore, Georgianne W; Bond, Barbara J; Jones, Julia A; Phillips, Nathan; Meinzer, Federick C

2004-05-01

166

Modern pollen rain and vegetational history of the Malaspina Glacier district, Alaska  

NASA Astrophysics Data System (ADS)

Seventy surface pollen samples from coastal forest, coastal meadow, muskeg, tree line, and alpine tundra communities form a basis for interpreting fossil pollen assemblages in the Malaspina Glacier district, Alaska. Poflen and macrofossil analyses of three radiocarbon-dated fossil sections from Icy Cape indicate that vegetational changes resulting from plant succession can be distinguished from those of migrational and climatic origin. Vegetation of the early Holocene xerothermic interval (10,000-7600 yr B.P.) was dominated by Alnus communities. Wetter conditions ensued, enabling generative muskeg surfaces to develop and first Picea sitchensis, then Tsuga heterophylla to expand from areas southeastward. Climatic cooling in more recent millennia (3500 yr B.P. to the present) is indicated by the appearance and persistent growth of Tsuga mertensiana and Selaginella selaginoides along this portion of the Gulf of Alaska coastline.

Peteet, Dorothy M.

1986-01-01

167

Aversive responses of white-tailed deer,Odocoileus virginianus, to predator urines.  

PubMed

We tested whether predator odors could reduce winter browsing of woody plants by white-tailed deer (Odocoileus virginianus). Urine from bobcats (Lyra rufus) and coyotes (Canis latrans) significantly reduced browsing of Japanese yews (Taxus cuspidata), and repellency was enhanced when urine was reapplied weekly as a topical spray. Urine of cottontail rabbits (Sylvilagus floridanus) and humans did not reduce damage, suggesting that deer do not respond aversively to odors of nonpredatory mammals or occasional predators with which they lack a long evolutionary association. Bobcat and coyote urine were more effective in tests conducted with eastern hemlock (Tsuga canadensis), which is less palatable to white-tailed deer than Japanese yew. A dichloromethane extract of bobcat urine was as effective as unextracted urine in reducing damage to hemlocks. Testing of the organic components of bobcat urine, particularly the volatile components, may enable identification of the compounds responsible for the repellency we observed. PMID:24258921

Swihart, R K; Pignatello, J J; Mattina, M J

1991-04-01

168

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

PubMed

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 patterns observed consistently in region-wide studies of adelgid-infested hemlock stands. Mechanisms of T. canadensis loss determine rates, magnitudes, and trajectories of ecological changes in hemlock forests. Logging causes abrupt, large changes in vegetation structure whereas girdling (and by inference, A. tsugae) causes sustained, smaller changes. Ecosystem processes depend more on vegetation cover per se than on species composition. We conclude that the loss of this late-successional foundation species will have long-lasting impacts on forest structure but subtle impacts on ecosystem function. PMID:23638378

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

2013-01-01

169

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

PubMed Central

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 patterns observed consistently in region-wide studies of adelgid-infested hemlock stands. Mechanisms of T. canadensis loss determine rates, magnitudes, and trajectories of ecological changes in hemlock forests. Logging causes abrupt, large changes in vegetation structure whereas girdling (and by inference, A. tsugae) causes sustained, smaller changes. Ecosystem processes depend more on vegetation cover per se than on species composition. We conclude that the loss of this late-successional foundation species will have long-lasting impacts on forest structure but subtle impacts on ecosystem function. PMID:23638378

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

2013-01-01

170

Doreen Hemlock, Fort Lauderdale Sun Sentinel, 2004.10.21  

E-print Network

, virtual security in business "Calling security a top priority for business, FedEx Corp. Chief Executive theft and other offenses on the Internet. ¡ ¢ "Governments need to penalize breaches online, from-mail from bank clients, he said. #12;"While it's a federal offense to tamper with U.S. Postal Service mail

Bernstein, Daniel

171

Late Quaternary dynamics of forest vegetation on northern Vancouver Island, British Columbia, Canada  

NASA Astrophysics Data System (ADS)

Pollen analysis of radiocarbon-dated lake sediment from northern Vancouver Island, southwest British Columbia reveals regional changes in forest vegetation over the last 12,200 14C yr (14,900 cal yr). Between at least 12,200 and 11,700 14C yr BP (14,900-13,930 cal yr BP), open woodlands were dominated by Pinus contorta, Alnus crispa, and various ferns. As P. contorta decreased in abundance, Alnus rubra and more shade-tolerant conifers (i.e., Picea and Tsuga mertensiana) increased. Increases in T. mertensiana, P. contorta, and A. crispa pollen accumulation rates (PARs) between 10,600 and 10,400 14C yr BP (11,660-11,480 cal yr BP) reflect a cool and moist climate during the Younger Dryas chronozone. Orbitally induced warming around 10,000 14C yr BP (11,090 cal yr BP) allowed the northward extension of Pseudotsuga menziesii, although Picea, Tsuga heterophylla, and A. rubra dominated early Holocene forests. By 7500 14C yr BP (8215 cal yr BP), shade-tolerant T. heterophylla was the dominant forest tree. Cupressaceae ( Thuja plicata and Chamaecyparis nootkatensis) was present by 7500 14C yr BP but reached its maximum after 3500 14C yr BP (3600 cal yr BP), when a cooler and wetter regional climate facilitated the development of temperate rainforest. The highest rates of vegetation change are associated with Lateglacial climate change and species with rapid growth rates and short life spans.

Lacourse, Terri

2005-01-01

172

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)

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 can be linked to precipitation and temperature anomalies at the stand level and across the region. Regional EVI anomalies are strongly negatively correlated with the annual precipitation and air temperature anomalies once the MODIS pixels are carefully examined with regards to forest age. EVI data from the tower-centered pixel also correlate well with annual NEE at the AmeriFlux site and show promise for scaling sparse flux tower observations, even over old-growth forests. Lastly, permanent plots have been continuously measured in the old-growth stand since 1947 and provide long-term data on tree demographics, recruitment, growth and mortality, and show evidence of decadal variability in response to precipitation and air temperature anomalies, as well as to disturbance (e.g., a Douglas-fir beetle kill in the 1950’s). We take advantage of the overlapping measurement period 1998-2004 and compare ANPP from the forest inventories to the flux tower estimates of NEE and MODIS EVI with focus on the regional environmental drivers.

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

2010-12-01

173

Drought resistance of two Douglas fir species (Pseudo-tsuga menziesii (Mirb.) Franco and Pseudotsuga macro-  

E-print Network

density and water vapor pressure were controlled. Analyzing the data trough A vs Intracellular C02 molar over a wide predawn water potential range in both species, while gs #12;#12;was reduced. At higher soil and Pseudotsuga macro- carpa (Torr.) Mayr.): relative importance of water use efficiency and root growth potential

Paris-Sud XI, Université de

174

Spatial Relationship of Biomass and Species Distribution in an Old-Growth Pseudotsuga Tsuga Forest  

Microsoft Academic Search

Old-growth forests are known for their complex and variable structure and function. In a 12-ha plot (300 m x 400 m) of an old-growth Douglas-fir forest within the T. T. Munger Research Natural Area in southern Washington, we mapped and recorded live\\/dead condition, species, and diameter at breast height to address the following objectives: (1) to quantify the contribution of

Jiquan Chen; Bo Song; Mark Rudnicki; Melinda Moeur; Ken Bible; Malcolm North; Dave C. Shaw; Jerry F. Franklin; Dave M. Braun

2004-01-01

175

Three-dimensional Structure of an Old-growth Pseudotsuga-tsuga  

E-print Network

for Radiation Balance, Microclimate, and Gas Exchange Geoffrey G. Parker,1* Mark E. Harmon,2 Michael A. Lefsky,3 Department of Forest Science, Colorado State University, Fort Collins, Colorado 80523, USA; 4 Landscape aspects of structure, including the topography of the outer surface, and of microclimate, including

Chen, Jiquan

176

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

NASA Astrophysics Data System (ADS)

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.

Graumlich, Lisa J.; Brubaker, Linda B.

1986-03-01

177

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

NASA Astrophysics Data System (ADS)

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 (Adelges tsugae Annand), an introduced aphid-like insect from Japan, threatens hemlock stands throughout the eastern United States. The hemlock woolly adelgid was first reported in forests of the eastern United States in the early 1950s and is currently leading to mortality of eastern hemlock trees from Georgia to Massachusetts. We found that rates of nitrogen inputs to the forest floor were 4-5 times greater, and rates of nitrogen losses via leachate were more than ten times greater, at the Arnold Arboretum compared to Harvard Forest. Our results also show that current management regimes used to control the hemlock woolly adelgid, such as salvage cutting, may be reducing nitrogen losses in urban areas due to rapid regrowth of vegetation and the associated uptake of nitrogen by those plants. In contrast, cutting of trees in rural areas may be leading to proportionately greater losses of nitrogen in those sites, though the total magnitude of nitrogen lost is still smaller than in urban sites. Results of this study suggest that the combination of the hemlock woolly adelgid, atmospheric nitrogen inputs and management practices lead to changes in the nitrogen cycle within eastern hemlock forest ecosystems.

Templer, P. H.

2011-12-01

178

Effects of temperature and photoperiod on the aestivo-hibernal egg diapause of Scymnus camptodromus (Coleoptera: Coccinellidae).  

PubMed

Three sequential studies were conducted on the interacting effects of exposure to low (5°C) temperature for 0, 7, 28, 56, or 84 d followed by incubation at 10, 15, or 20°C on the egg diapause of Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae). This beetle was imported from China as a potential biological control agent for hemlock woolly adelgid, Adelges tsugae (Annand) (Hemiptera: Adelgidae). Very few eggs laid and held at a constant 15 or 20°C showed any indication of development. Only eggs exposed to temperature combinations of 5 and 10°C had >50% hatch. Highest percent hatch and fastest development occurred when eggs were held at 5°C for 56 or 84 d followed by holding at 10°C. A model estimated the lower threshold for postdiapause development to be 2°C. The effect of temperature on egg hatch was similar at photoperiods of 12:12 and 16:8 (L:D) h, suggesting egg development is not governed by photoperiod or light exposure. Collectively these data indicate that S. camptodromus eggs laid in the spring and summer go through an aestivo-hibernal diapause that is maintained by warm temperatures and that development resumes when temperatures drop, in parallel with the development of hemlock woolly adelgid. This concurrent development allows S. camptodromus eggs to hatch while hemlock woolly adelgid is laying eggs. This synchrony between the development of S. camptodromus eggs and the overwintering adelgid suggest this beetle may be a good candidate for the biological control of the hemlock woolly adelgid. PMID:23321116

Keena, Melody A; Trotter, R Talbot; Cheah, Carole; Montgomery, Michael E

2012-12-01

179

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

SciTech Connect

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.

Dunwiddie, P.W.

1986-02-01

180

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

DOEpatents

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.

Lewis, Norman G. (Pullman, WA); Davin, Laurence B. (Pullman, WA); Dinkova-Kostova, Albena T. (Baltimore, MD); Fujita, Masayuki (Kita-gun, JP), Gang; David R. (Ann Arbor, MI), Sarkanen; Simo (Minneapolis, MN), Ford; Joshua D. (Pullman, WA)

2003-10-21

181

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

SciTech Connect

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.

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

1994-07-20

182

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)

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.

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

2012-11-01

183

Response of high-elevation forests in the Olympic Mountains to climatic change  

USGS Publications Warehouse

The gap model ZELIG was used to examine the effects of increased temperature (2A?C) and altered precipitation on high-elevation ecosystems of the Olympic Mountains, Washington, U.S.A. Changes in tree species distribution and abundance, as well as stand biomass, were examined on north and south aspects in the dry northeast (NE) and wet southwest (SW) regions of the Olympics for (i) warmer, (ii) warmer and 20% wetter, and (iii) warmer and 20% drier climatic-change scenarios. Dominant tree species shift upwards 300-600 m in elevation in the SW, with subalpine meadows and Tsuga mertensiana (Bong.) Carr. forests being replaced by Abies amabilis (Dougl.) Forbes forests at higher elevations and A. amabilis forests being replaced by Tsuga heterophylla (Raf.) Sarg. forests at lower elevations. In the NE, drought-tolerant species become dominant approximately 200 m lower than present, with A. lasiocarpa dominating the north aspect and Pinus contorta Dougl. ex Loud. the south aspect. Biomass increases in the SW and generally decreases in the NE, depending on aspect and precipitation regime. This study suggests that species and site-specific responses at mesoscale (e.g., wet vs. dry climatic regime) and microscale (e.g., north vs. south aspect) resolutions must be characterized to quantify the variation in potential effects of climatic change on forest vegetation in mountainous regions.

Zolbrod, A.N.; Peterson, D.L.

1999-01-01

184

Habitat classification: A comparison using avian species and guilds  

NASA Astrophysics Data System (ADS)

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.

Degraaf, Richard M.; Chadwick, Nan L.

1984-11-01

185

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

Federal Register 2010, 2011, 2012, 2013

...Authority; Dow Corning Corporation, Hemlock Semiconductor Corporation and Hemlock Semiconductor, L.L.C.; Extension of Comment Periods...October 12, 2011), at the Hemlock Semiconductor Corporation facility in Hemlock,...

2011-12-09

186

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

Federal Register 2010, 2011, 2012, 2013

...Authority, Dow Corning Corporation, Hemlock Semiconductor Corporation, and Hemlock Semiconductor, L.L.C.; Reopening of Comment Periods...63283, 10/12/2011), at the Hemlock Semiconductor Corporation facility in Hemlock,...

2012-05-23

187

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

Federal Register 2010, 2011, 2012, 2013

...Authority Dow Corning Corporation, Hemlock Semiconductor Corporation, and Hemlock Semiconductor, L.L.C.; Reopening of Rebuttal Periods...63283, 10/12/2011), at the Hemlock Semiconductor Corporation facility in Hemlock,...

2012-04-09

188

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

USGS Publications Warehouse

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.

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

1995-01-01

189

Distribution of Borrelia burgdorferi in host mice in Pennsylvania.  

PubMed Central

Host mice (Peromyscus leucopus and Peromyscus maniculatus) were sampled throughout the state of Pennsylvania to determine the geographical and ecological distribution of the Lyme disease spirochete Borrelia burgdorferi. All 67 counties of the state were sampled. A total of 1,619 mice were captured from a total of 157 sites during the period 1990 to 1993 for an overall capture rate of 29.69%. A total of 112 (6.92%) isolations of B. burgdorferi were made. The distribution of isolations revealed the reason for the correlated distribution of human cases of Lyme disease in the state. Significantly more mice were captured and significantly more isolations were made from hemlock (Tsuga canadensis) habitat than from deciduous species forest. Nevertheless, high isolation rates from counties of the southeastern corner of the state illustrate well that hemlock habitat is not essential. Evidence suggests that in some areas, transmission between mice is occurring in some way other than through ticks as vectors. Host mice proved useful for determining the geographical and ecological distribution of B. burgdorferi. PMID:7814489

Lord, R D; Lord, V R; Humphreys, J G; McLean, R G

1994-01-01

190

Responses of plants to simulated saline drift as affected by species and conditions of exposure.  

PubMed

In exposures to simulated saline drift generated from a 0.6% (w/w) chloride (Cl)-solution, under controlled environmental conditions, the median effective doses for the occurrence of any salt-induced foliar injury (expressed as microgCl cm(-2) deposited in six hours) were: 2.9 for Canada hemlock (Tsuga canadensis [L.] Carr.); 10.3 for white flowering dogwood (Cornus florida L.); 43.5 for potato (Solanum tubersum L. cv Superior); 44.2 for northern red oak (Quercus rubra L.); 65.1 for sweet corn (Zea mays L. cv Golden Cross Bantam); and, 123 for bush bean (Phaseolus vulgaris L. cv Pinto). Response of bean was a function of total deposition and independent of its rate with multiple (one per day) 6-h exposures but not with exposures less than 6 h where toxicity (per mass of Cl) increased with an increase in the rate of deposition. Toxicity of particles increased with an increase in the concentration of Cl in the solution (1.6 or 5.0% w/w) from which they were generated with bush bean but not with hemlock. Post-exposure periods that cycled between 50 and 855% relative humidity (RH) produced a greater incidence of salt-induced foliar injury than did a regime of constant 85% RH. PMID:15092146

McCune, D C; Silberman, D H

1991-01-01

191

A novel toxic alkaloid from poison hemlock (Conium maculatum L., Apiaceae): identification, synthesis and antinociceptive activity.  

PubMed

2-Pentylpiperidine, named conmaculatin, a novel volatile alkaloid related to coniine was identified from the renowned toxic weed Conium maculatum L. (Apiaceae). The structure of conmaculatin was corroborated by synthesis (8 steps starting from cyclohexanol, overall yield 12%). Conmaculatin's strong peripheral and central antinociceptive activity in mice was observed in a narrow dose range (10-20mg/kg). It was found to be lethal in doses higher than 20mg/kg. PMID:22063758

Radulovi?, Niko; Dor?evi?, Nevenka; Deni?, Marija; Pinheiro, Mariana Martins Gomes; Fernandes, Patricia Dias; Boylan, Fabio

2012-02-01

192

Induction of cleft palate in newborn pigs by maternal ingestion of poison hemlock (Conium maculatum).  

PubMed

Cleft palates were induced in newborn pigs of gilts fed Conium maculatum seed or plant during gestation days 30 through 45. Twelve of 23 newborn pigs born to 3 gilts given Utah-grown C maculatum seed and 9 of 12 newborn pigs born to a single gilt given the fresh Utah spring-growth C maculatum plant had cleft palates. The cleft palates ranged from a unilateral cleft, involving only 1 side of the palate, to a full bilateral cleft. Brachygnathia was also observed in some of these newborn pigs with cleft palate. Other malformations were not observed. Chemical analysis of seed and plant samples indicated that gamma-coniceine was the responsible teratogenic alkaloid. A daily dose of plant or seed that provided greater than or equal to 1.07 mg of gamma-coniceine/kg of body weight fed to gilts during the 30th through the 45th day of pregnancy resulted in teratogenic effects. PMID:4026015

Panter, K E; Keeler, R F; Buck, W B

1985-06-01

193

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

Microsoft Academic Search

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

Katharyn D. Lang; Lisa A. Schulte; Glenn R. Guntenspergen

2009-01-01

194

AN INVESTIGATION INTO THE STAINING PROBLEM IN WESTERN HEMLOCK (A TEST CASE)  

Microsoft Academic Search

The mill grader reported that a visual inspection revealed that from 2% to 25% of the pieces had some stains, and the stains ranged in color from brown and gray to even a light orange. With many differing opinions expressed as to the cause of the stains, the mill manager decided to assemble a team to investigate the cause of

Sita Millar

195

Eastern Hemlock Decline and Persistence of Disjunct Populations Near Its Southern Boundary  

E-print Network

that population size influences extinction, which is not always true. A number of plant and animal species (e distribution theory and assumes when extinction forces arise, a species'range should implode and the last of the particular extinction force rather than population density. Extinction factors often move across

Shawkey, Matthew

196

Poison hemlock, Conium maculatum, (Figure 1) is a member of the plant  

E-print Network

contains a few important vegetable crops such as carrots, celery, and parsnip, and herbs such as parsley plant com- munities in riparian woodlands, flood- plains of natural aquatic systems, and grazing areas germinate almost immediately if moisture and temperature c

Ishida, Yuko

197

Seasonal variation of microbial ecology in hemlock soil of Tatachia Mountain, Taiwan  

Microsoft Academic Search

Background and Purpose: Forest soil microorganisms and fauna decompose the organic materials, and thus strongly influence the nutrient cycling of the ecosystem. Soil microorganisms also contribute to soil structure and soil fertility. In Taiwan, the microbial distributions of soils have only been determined in acidic soil, inorganic acidic soil, upland soil, alkaline soil and power plant areas. There are few

Shang-Shyng Yang; Shu-Hsien Tsai; Hsiao-Yun Fan; Chiun-Kai Yang; Wei-Lan Hung; Shine-Tsern Cho

2006-01-01

198

Wood density of young-growth western hemlock: relation to ring age, radial growth, stand density,  

E-print Network

, and site quality Dean S. DeBell, Ryan Singleton, Barbara L. Gartner, and David D. Marshall Abstract: Breast par l'augmentation du taux de croissance. Les différences rési- duelles dans le poids spécifique

Lachenbruch, Barbara

199

Seizures and death on a white river float trip. Report of water hemlock poisoning.  

PubMed

White river rafting is becoming a major summer recreational activity throughout the United States. Many people who are ill prepared physically or emotionally to survive will find themselves isolated and in extremely dangerous situations without access to medical help. In addition to the physical dangers of drowning, there are dangers that exist in the concept of "living off the land" and foraging for food. Cicuta douglasii is found in all of our western states, is extremely toxic and can easily be confused with wild parsnip or carrot. Physicians and poison control centers need to be aware of the common poisonous plants in their area and be prepared to treat cases of poisoning from these plants. PMID:4013278

Landers, D; Seppi, K; Blauer, W

1985-05-01

200

Dendrochronologia 22 (2005) 93106 ORIGINAL ARTICLE  

E-print Network

Pinus albicaulis Engelmann (whitebark pine), Abies lasiocarpa [Hooker] Nuttall (subalpine fir), Tsuga reserved. Keywords: Temperature and snowpack reconstruction; Pinus albicaulis; Abies lasiocarpa; Tsuga

Smith, Dan

201

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

SciTech Connect

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.

Rhodes, T.E.; Davis, R.B. [Univ. of Maine, Orono, ME (United States)

1995-04-01

202

Dendroclimatic estimates of a drought index for northern Virginia  

USGS Publications Warehouse

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.

Puckett, Larry J.

1981-01-01

203

Abrupt climate change as an important agent of ecological change in the Northeast U.S. throughout the past 15,000 years  

NASA Astrophysics Data System (ADS)

We use a series of tests to evaluate two competing hypotheses about the association of climate and vegetation trends in the northeastern United States over the past 15 kyrs. First, that abrupt climate changes on the scale of centuries had little influence on long-term vegetation trends, and second, that abrupt climate changes interacted with slower climate trends to determine the regional sequence of vegetation phases. Our results support the second. Large dissimilarity between temporally close fossil pollen samples indicates large vegetation changes within 500 years across >4° of latitude at ca 13.25-12.75, 12.0-11.5, 10.5, 8.25, and 5.25 ka. The evidence of vegetation change coincides with independent isotopic and sedimentary indicators of rapid shifts in temperature and moisture balance. In several cases, abrupt changes reversed long-term vegetation trends, such as when spruce ( Picea) and pine ( Pinus) pollen percentages rapidly declined to the north and increased to the south at ca 13.25-12.75 and 8.25 ka respectively. Abrupt events accelerated other long-term trends, such as a regional increase in beech ( Fagus) pollen percentages at 8.5-8.0 ka. The regional hemlock ( Tsuga) decline at ca 5.25 ka is unique among the abrupt events, and may have been induced by high climatic variability (i.e., repeated severe droughts from 5.7 to 2.0 ka); autoregressive ecological and evolutionary processes could have maintained low hemlock abundance until ca 2.0 ka. Delayed increases in chestnut ( Castanea) pollen abundance after 5.8 and 2.5 ka also illustrate the potential for multi-century climate variability to influence species' recruitment as well as mortality. Future climate changes will probably also rapidly initiate persistent vegetation change, particularly by acting as broad, regional-scale disturbances.

Shuman, Bryan N.; Newby, Paige; Donnelly, Jeffrey P.

2009-08-01

204

Biochemistry of hemlock (Conium maculatum L.) alkaloids and their acute and chronic toxicity in livestock. A review.  

PubMed

The literature on Conium maculatum biochemistry and toxicology, dispersed in a large number of scientific publications, has been put together in this review. C. maculatum is a weed known almost worldwide by its toxicity to many domestic animals and to human beings. It is an Umbelliferae, characterized by long, hollow stems, reaching up to 2 m height at maturity, producing a large amount of lush foliage during its vegetative growth. Its flowers are white, grouped in umbels formed by numerous umbellules. It produces a large number of seeds that allow the plant to form thick stands in modified soils, sometimes encroaching on cultivated fields, to the extent of impeding the growth of any other vegetation inside the C. maculatum area of growth. Eight piperidinic alkaloids have been identified in this species. Two of them, gamma-coniceine and coniine are generally the most abundant and they account for most of the plant acute and chronic toxicity. These alkaloids are synthesized by the plant from eight acetate units from the metabolic pool, forming a polyketoacid which cyclises through an aminotransferase and forms gamma-coniceine as the parent alkaloid via reduction by a NADPH-dependent reductase. The acute toxicity is observed when animals ingest C. maculatum vegetative and flowering plants and seeds. In a short time the alkaloids produce a neuromuscular blockage conducive to death when the respiratory muscles are affected. The chronic toxicity affects only pregnant animals. When they are poisoned by C. maculatum during the fetuses organ formation period, the offspring is born with malformations, mainly palatoschisis and multiple congenital contractures (MCC; frequently described as arthrogryposis). Acute toxicity, if not lethal, may resolve in the spontaneous recovery of the affected animals provided further exposure to C. maculatum is avoided. It has been observed that poisoned animals tend to return to feed on this plant. Chronic toxicity is irreversible and although MCC can be surgically corrected in some cases, most of the malformed animals are lost. Since no specific antidote is available, prevention is the only way to deal with the production loses caused by this weed. Control with herbicides and grazing with less susceptible animals (such as sheep) have been suggested. C. maculatum alkaloids can be transferred to milk and to fowl muscle tissue through which the former can reach the human food chain. The losses produced by C. maculatum chronic toxicity may be largely underestimated, at least in some regions, because of the difficulty in associate malformations in offspring with the much earlier maternal poisoning. PMID:10340826

López, T A; Cid, M S; Bianchini, M L

1999-06-01

205

Relative Contribution of Hemlock Pollen to the Phosphorus Loading of the Clear Lake Ecosystem Near Minden, Ontario  

Microsoft Academic Search

The forest stand composition within the terrestrial watershed of a small lake on the southern Precambrian Shield was assessed. Total phosphorus inputs from the terrestrial watersheds were obtained for two sub inflows by measuring flow rates and phosphorus concentrations. Direct aerial phosphorus fallout was estimated from nearby sites sampled by the Ontario Ministry of the Environment. Pollen fallout on the

Hugh H. Banks; James E. Nighswander; White Cedar; Balsam Poplar; Sugar Maple; Red Maple; Striped Maple; Red Oak

206

Changes in Canopy Processes Following Whole-Forest Canopy Nitrogen Fertilization of a Mature Spruce-Hemlock Forest  

Microsoft Academic Search

Most experimental additions of nitrogen to forest ecosystems apply the N to the forest floor, bypassing important processes\\u000a taking place in the canopy, including canopy retention of N and\\/or conversion of N from one form to another. To quantify these\\u000a processes, we carried out a large-scale experiment and determined the fate of nitrogen applied directly to a mature coniferous\\u000a forest

E. Gaige; D. B. Dail; D. Y. Hollinger; E. A. Davidson; I. J. Fernandez; H. Sievering; A. White; W. Halteman

2007-01-01

207

Lidar Remote Sensing of the Canopy Structure and Biophysical Properties of Douglas-Fir Western Hemlock Forests  

Microsoft Academic Search

Scanning lidar remote sensing systems have recently become available for use in ecological applications. Unlike conventional microwave and optical sensors, lidar sensors directly measure the distribution of vegetation material along the vertical axis and can be used to provide three-dimensional, or volumetric, characterizations of vegetation structure. Ecological applications of scanning lidar have hitherto used one-dimensional indices to characterize canopy height.

M. A. Lefsky; W. B. Cohen; S. A. Acker; G. G. Parker; T. A. Spies; D. Harding

1999-01-01

208

Seasonal Changes in Chemical Composition and Nutritive Value of Native Forages in a Spruce-Hemlock Forest, Southeastern Alaska.  

National Technical Information Service (NTIS)

Twenty-two forages from Admirality Island, southeastern Alaska, were monitored bimonthly for one year to assess seasonal changes in their chemical composition: neutral detergent fiber, acid detergent fiber, cellulose, lignin/cutin, invitro-dry-matter dige...

T. A. Hanley, J. D. McKendrick

1983-01-01

209

Sedimentologic and palynologic records of the last deglaciation and Holocene from Ballston Lake, New York  

NASA Astrophysics Data System (ADS)

Continuous pollen and sediment records from two ˜8.5-m-long cores document late Pleistocene and Holocene sedimentation and vegetation change in the Ballston Lake basin, eastern New York State. Pebbles at the base of both cores and the geomorphology of the watershed reflect the presence of the Mohawk River in the basin prior to ˜12,900 ± 70 cal yr B.P. Ballston Lake formed at the onset of the Younger Dryas (YD) by an avulsion of the Mohawk River. The transition from clay to gyttja with low magnetic susceptibility (MS), low bulk density, and high organic carbon indicates rapid warming and increased lake productivity beginning 11,020 cal yr B.P. MS measurements reveal that the influx of magnetic particles, associated with pre-Holocene clastic sedimentation, ceased after ˜10,780 cal yr B.P. The pollen record is subdivided into six zones: BL1 (12,920 to 11,020 cal yr B.P.) is dominated by boreal forest pollen; BL2 (11,020 to 10,780 cal yr B.P.) by pine ( Pinus) forest pollen; BL3 (10,780 to 5290 cal yr B.P.) by hemlock ( Tsuga) and mixed hardwood pollen; BL4 (5290 to 2680 cal yr B.P.) by mixed hardwood pollen; BL5a (2680 cal yr B.P. to 1030 cal yr B.P.) by conifer and mixed hardwood pollen; and BL5b (1030 cal B.P. to present) by increasing ragweed ( Ambrosia) pollen. A 62% decrease in spruce ( Picea) pollen in <320 cal years during BL1 reflects rapid warming at the end of the YD. Holocene pollen zones record more subtle climatic shifts than occurred at the end of the YD. One of the largest changes in the Holocene pollen spectra began ˜5300 cal yr B.P., and is characterized by a marked decline in hemlock pollen. This has been noted in other pollen records from the region and may record preferential selection of hemlock by a pathogen or parasites.

Toney, Jaime L.; Rodbell, Donald T.; Miller, Norton G.

2003-09-01

210

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

USGS Publications Warehouse

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.

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

2001-01-01

211

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

USGS Publications Warehouse

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.

Rambo, T.; Muir, Patricia S.

1998-01-01

212

Stem respiratory potential in six softwood and four hardwood tree species in the central cascades of Oregon.  

PubMed

Mature and old growth trees of varying sapwood thickness were compared with regard to stem respiration. An increment core-based, laboratory method under controlled temperature was used to measure tissue-level respiration (termed respiratory potential) of ten different tree species. Bark (dead outer and live inner combined), sapwood, and heartwood thickness measurements were used to predict sapwood volume from stem diameter (including bark) for four of the ten species. These predictions of sapwood volume were used to scale respiratory potential to the main-bole level (excluding all branches). On the core level, species that maintained narrow sapwood (8-16% of bole radius) such as Pseudotusga menziesii, Taxus brevifolia, and Thuja plicata, had sapwood respiratory potentials in the lower bole that were 50% higher (P<0.05) than species with wide sapwood (>16% of bole radius), such as Abies amabilis, Pinus monticola, and Tsuga heterophylla. This pattern was not observed for inner bark respiratory potential, or for sapwood respiratory potential within the crown. On the main-bole level, respiratory potential per unit volume was inversely correlated to the live bole volumetric fraction (inner bark plus sapwood divided by whole bole volume) (Adj. R(2)=0.6). Specifically, tree species with 18-20% of the main bole alive potentially respired 1.3-3 times more per unit live bole volume than species with over 40%, suggesting that the live bole was less metabolically active in tree species that maintained large volumes of sapwood. PMID:12844251

Pruyn, Michele L; Harmon, Mark E; Gartner, B L

2003-09-01

213

Fire and Vegetation History from the Coastal Rain Forest of the Western Oregon Coast Range  

NASA Astrophysics Data System (ADS)

High-resolution charcoal and pollen analyses were used to reconstruct a 4600-yr-long history of fire and vegetation near Taylor Lake in the wettest forests of coastal Oregon. Today, fires in these forests are rare because the season of ignition does not coincide with months of dry fuels. From ca. 4600 to 2700 cal yr B.P. fire episodes occurred at intervals of 140±30 yr while forest vegetation was dominated by disturbance-adapted taxa such as Alnus rubra. From ca. 2700 cal yr B.P. to the present, fire episodes have become less common, occurring at intervals of 240±30 yr, and fire-sensitive forest taxa, such as Tsuga heterophylla and Picea sitchensis, have become more prominent. Fire occurrence during the mid-Holocene was similar to that of the more xeric forests in the eastern Coast Range and suggests that summer drought was widespread. After ca. 2700 cal yr B.P., a decrease in fire episode frequency suggests that cooler conditions and possibly increased summer fog allowed the establishment of present-day Picea sitchensis forests within the watershed. These results provide evidence that fire has been an important disturbance agent in the Coast Range of Oregon, and variations in fire frequency and climate have led to the establishment of present-day forests.

Long, Colin J.; Whitlock, Cathy

214

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

USGS Publications Warehouse

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.

Woodward, Andrea

1998-01-01

215

Detecting long-term hydrological patterns at Crater Lake, Oregon  

USGS Publications Warehouse

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.

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

1999-01-01

216

Ecological boundary detection using Bayesian areal wombling  

PubMed Central

The study of ecological boundaries and their dynamics is of fundamental importance to much of ecology, biogeography, and evolution. Over the past two decades, boundary analysis (of which wombling is a subfield) has received considerable research attention, resulting in multiple approaches for the quantification of ecological boundaries. Nonetheless, few methods have been developed that can simultaneously (1) analyze spatially homogenized data sets (i.e., areal data in the form of polygons rather than point-reference data); (2) account for spatial structure in these data and uncertainty associated with them; and (3) objectively assign probabilities to boundaries once detected. Here we describe the application of a Bayesian hierarchical framework for boundary detection developed in public health, which addresses these issues but which has seen limited application in ecology. As examples, we analyze simulated spread data and the historic pattern of spread of an invasive species, the hemlock woolly adelgid (Adelges tsugae), using county-level summaries of the year of first reported infestation and several covariates potentially important to influencing the observed spread dynamics. Bayesian areal wombling is a promising approach for analyzing ecological boundaries and dynamics related to changes in the distributions of native and invasive species. PMID:21302814

Fitzpatrick, Matthew C.; Preisser, Evan L.; Porter, Adam; Elkinton, Joseph; Waller, Lance A.; Carlin, Bradley P.; Ellison, Aaron M.

2014-01-01

217

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

SciTech Connect

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.

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

218

Role of Nurse Logs in Forest Expansion at Timberline  

NASA Astrophysics Data System (ADS)

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.

Johnson, A. C.; Yeakley, A.

2008-12-01

219

The Heidelberg Basin Drilling Project - Sedimentology and Stratigraphy of the Quaternary succession  

NASA Astrophysics Data System (ADS)

Within the context of the Heidelberg Basin Drilling Project (Gabriel et al. 2008), a detailed sediment succession is presented here based upon deep drillings taken at Heidelberg UniNord and Mannheim Käfertal. Sediment structures, and micromorphological and pollen analyses were conducted and used to reconsider some of the climate transitions within the lower Pleistocene. A new and novel scenario is postulated regarding the preservation of Quaternary sediment packages within the Cenozoic Graben environment of the Heidelberg basin. The palynological evidence comprises the periods of warm climate of the Holsteinian (mainly Abies (fir), some Fagus (beech), Pterocarya & Azolla); the Cromerian (Pinus-Picea-QM (pine-spruce-QM)); the Bavelian (Abies, Tsuga (hemlock fir), QM & phases of increased NAP including Pinus); the Waalian (Abies, Tsuga, QM); and the Tiglian (Fagus & early Pleistocene taxa especially Sciadopytis, downward increasing Tertiary taxa). The sediment package was studied both macroscopically and microscopically. Both techniques provide evidence of fluvial, lacustrine and mass movement sedimentary processes. Some include evidence of periglacial processes (silt droplets within fine grained sands indicative of frozen ground conditions). The periglacial structures are often, not always, accompanied by pollen spectra dominated by pine and NAP. E.g. the Tiglian part of the succession shows periglacial sediment structures at its base and top but not in its middle sections. I.e. it appears not as a series of warm and cold phases but rather as a constant warm period with warm-cold-alternations at its bottom and top. All results illustrate sediment preservation in the Heidelberg basin almost throughout the Quaternary. This may be due to tectonic subsidence, but also to compaction by sediment loading of underlying fine sediments (Oligocene to Quaternary) leading to incomplete but virtually continuous sediment preservation (Tanner et al. 2009). References Gabriel, G., Ellwanger, D., Hoselmann, C. & Weidenfeller, M. (2008): The Heidelberg Basin Drilling Project. - Eiszeitalter u. Gegenwart (Quaternary Science Journal), 57, 3-4, 253-260, Hannover. Tanner, D.C., Martini, N., Buness, H. & Krawczyk, C.M. (2009): The 3D Geometry of the Quaternary and Tertiary strata in the Heidelberg Basin, as defined by reflection seismics. - DGG Tagung, Dresden, 30.9-02.10.09, Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften, 63, 58.

Ellwanger, Dietrich; Gabriel, Gerald; Hahne, Jürgen; Hoselmann, Christian; Menzies, John; Simon, Theo; Weidenfeller, Michael; Wielandt-Schuster, Ulrike

2010-05-01

220

Holocene Paleohydrological Changes in Northern Michigan: Interpretations of Biomarker Distributions and Compound Specific Stable Isotope Analysis from Peatlands  

NASA Astrophysics Data System (ADS)

Sediments of ombrotrophic peatlands are excellent archives for reconstructing past changes in precipitation/evaporation (P/E) balance. Multiproxy analysis of these sediments is critical for better understanding of climatic events experienced by these highly sensitive systems, as each proxy may respond to different climate parameters. In this study, we use distributions of n-alkanes and ?D of Sphagnum biomarkers to interpret paleohydrology from sediments of Irwin Smith Bog, northern Michigan. We then integrate these data with pollen data and testate amoebae-inferred water table depth. Sphagnum moss is the dominant peat former in ombrotrophic bogs, but vascular plants become abundant when water tables are drawn down. Thus, the abundance of Sphagnum relative to vascular plants is indicative of peatland hydrology. The n-alkanes produced by Sphagnum differ from vascular plants in the relative abundance of the different homologues, with the former having excess amounts of shorter chain C23 n-alkane. We use several measures (compound ratios, PCA) to show changes in then-alkane distributions in the sediments, and thus changes in the peatland plant community. Our data provide high- resolution, quantitative paleohydrological records for the study region that are consistent with other records. We also show that the relative abundance of a newly identified Sphagnum biomarker, 2-heptacosanone, can be used to reconstruct changing plant communities. Because ombrotrophic systems lose water by evaporation, drier/warmer conditions cause hydrogen isotopic enrichment of bog water and Sphagnum biomarkers. We measured the ?D of C23 n-alkane and 2-heptacosanone to provide additional paleoclimate information. Our multiproxy approach allows us to better understand the climate changes during key intervals of the Holocene. For example, a sharp decrease in the abundance of Tsuga canadensis (hemlock) pollen has been previously identified in records from many places throughout eastern North America. The cause of this mid-Holocene hemlock decline has been debated, making this interval of particular interest for paleoclimate studies. We will present new molecular and isotopic data to better understand the causation of this abrupt vegetation change.

Nichols, J. E.; Booth, R. K.; Jackson, S. T.; Pendall, E. G.; Huang, Y.

2006-12-01

221

Nitrogen uptake in riparian plant communities across a sharp ecological boundary of salmon density  

PubMed Central

Background Recent studies of anadromous salmon (Oncorhynchus spp.) on the Pacific Coast of North America indicate an important and previously unrecognized role of salmonid nutrients to terrestrial biota. However, the extent of this uptake by primary producers and consumers and the influences on community structure remain poorly described. We examine here the contribution of salmon nutrients to multiple taxa of riparian vegetation (Blechnum spicant, Menziesii ferruginea, Oplopanax horridus, Rubus spectabilis, Vaccinium alaskaense, V. parvifolium, Tsuga heterophylla) and measure foliar ?15N, total %N and plant community structure at two geographically separated watersheds in coastal British Columbia. To reduce potentially confounding effects of precipitation, substrate and other abiotic variables, we made comparisons across a sharp ecological boundary of salmon density that resulted from a waterfall barrier to salmon migration. Results ?15N and %N in foliage, and %cover of soil nitrogen indicators differed across the waterfall barrier to salmon at each watershed. ?15N values were enriched by 1.4‰ to 9.0‰ below the falls depending on species and watershed, providing a relative contribution of marine-derived nitrogen (MDN) to vegetation of 10% to 60%. %N in foliar tissues was slightly higher below the falls, with the majority of variance occurring between vegetation species. Community structure also differed with higher incidence of nitrogen-rich soil indicator species below the waterfalls. Conclusions Measures of ?15N, %N and vegetation cover indicate a consistent difference in the riparian community across a sharp ecological boundary of salmon density. The additional N source that salmon provide to nitrogen-limited habitats appears to have significant impacts on the N budget of riparian vegetation, which may increase primary productivity, and result in community shifts between sites with and without salmon access. This, in turn, may have cascading ecosystem effects in forests adjacent to salmon streams. PMID:12729462

Mathewson, DD; Hocking, MD; Reimchen, TE

2003-01-01

222

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

PubMed

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. PMID:15519989

St Clair, Samuel B; Lynch, Jonathan P

2005-01-01

223

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)

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.

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

2007-12-01

224

Freezing of Xylem Sap Without Cavitation  

PubMed Central

Freezing of stem sections and entire twigs of hemlock (Tsuga canadensis) has been demonstrated to occur without increasing the resistance to the movement of water through the frozen part after rewarming. This was interpreted to mean that freezing did not produce cavitation in the xylem sap even though A) the sap was unquestionably frozen; B) it contained dissolved gases; and C) it was under tension before freezing and after. Freezing stem sections of some other evergreen gymnosperms during the summer again produced no evidence for cavitation of the xylem sap. On the other hand, freezing stem sections of some angiosperms invariably increased the resistance to sap flow leading to wilting and death in a few hours when the sap tension was at normal daytime values at the time of freezing. These results were interpreted to mean that the bordered pits on the tracheids of gymnosperms function to isolate the freezing sap in each tracheid so that the expansion of water upon freezing not only eliminates any existing tension but also develops positive pressure in the sap. Dissolved gases frozen out of solution may then be redissolved under this positive pressure as melting occurs. As the bubbles are reduced in size by this ice pressure developed in an isolated tracheid, further pressure is applied by the surface tension of the water against air. If the bubbles are redissolved or are reduced to sufficient small size by the time the tension returns to the sap as the last ice crystals melt, then the internal pressure from surface tension in any existing small bubbles may exceed the hydrostatic tension of the melted sap and the bubbles cannot expand and will continue to dissolve. PMID:16656485

Hammel, H. T.

1967-01-01

225

Broadening the ecological context of ungulate-ecosystem interactions: the importance of space, seasonality, and nitrogen.  

PubMed

Spatial heterogeneity of soil resources, particularly nitrogen availability, affects herbaceous-layer cover and diversity in temperate forest ecosystems. Current hypotheses predict that ungulate herbivores influence nitrogen availability at the stand scale, but how ungulates affect nitrogen availability at finer spatial scales that are relevant to the herb layer is less understood. We tested the hypothesis that ungulate exclusion reduces the spatial complexity of nitrogen availability at neighborhood scales (1-26 m) apart from mean stand scale effects. This outcome was expected due to a lack of ungulate nitrogenous waste deposition within exclosures and seasonally variable ungulate habitat use. To test this hypothesis we examined spatial patterning of ammonium and nitrate availability, herb-layer cover and diversity, and under-canopy solar radiation using geostatistical models. Our study sites included six stands of eastern hemlock (Tsuga canadensis) forest: three where white-tailed deer (Odocoileus virginianus) were excluded and three that were accessible to deer. Where deer were present, patch sizes of ammonium availability, cover, and diversity were smaller compared to deer exclosures, whereas mean site-level effects were not significant. Within deer exclosures cover and solar radiation were more similar in patch size than were cover and nitrogen availability. Our results suggest that browsing ungulates affect spatial patterns of herb-layer cover and diversity through the excretion of nitrogenous wastes in small, discrete patches. Ungulate-excreted nitrogen deposition and herbivory were concentrated in the dormant season, allowing herb-layer plants a greater opportunity to benefit from nitrogen additions. Therefore, the impact of ungulates on nitrogen cycling in forest ecosystems varies with spatial scale and the seasonal timing of ungulate impacts. In this way, ungulates may function as a seasonally dependent link between fine-scale and landscape-level ecological processes. PMID:23923495

Murray, Bryan D; Webster, Christopher R; Bump, Joseph K

2013-06-01

226

A woodchuck mows down an entire row of new cabbage transplants... A porcupine is destroying a hedge of hemlocks...Flyingsquirrelsarekeepingfamilymembersawake,chatteringandracingthroughthewallsallnight.  

E-print Network

practical solutions to everyday questions Toll free Info Line 1-877-398-4769 M-F · 9 AM - 2 PM #12;Bats entrances between May and August to avoid sealing in nursing pups. The US Centers for Disease Control,makingtheenvironmentlessattractiveto beavers. · Hire a licensed trapper* Birds · To protect fruit and other crops, create barriers: bird

New Hampshire, University of

227

The Paleolimnological Record of the North Atlantic Oscillation: Magnetic Properties and Diatom Counts from Hemlock and Conesus Lakes, Western New York State  

Microsoft Academic Search

Between 1900 and 1930 CE when the NAO index showed large amplitude positive excursions, but the AO index varied at very small amplitudes, drought conditions frequently prevailed in western New York state according the Palmer Drought Index (PDI). Since 1970, when both the NAO and the AO indices show large and progressively increasing positive excursions, the PDI has been generally

W. P. Chaisson; M. R. Arnold; R. D. Cottrell

2002-01-01

228

Effects of silvicultural practices on carbon stores in Douglas-fir ? western hemlock forests in the Pacific Northwest, U.S.A.: results from a simulation model  

Microsoft Academic Search

We used a new model, STANDCARB, to examine effects of various treatments on carbon (C) pools in the Pacific Northwest forest sector. Simulation experiments, with five replicates of each treatment, were used to investigate the effects of initial conditions, tree establishment rates, rotation length, tree utilization level, and slash burning on eco - system and forest products C stores. The

Mark E. Harmon; Barbara Marks

2002-01-01

229

DataONE currently holds a collection of over 125,000 metadata records linked to data sets in 10 environmental and earth science data reposito-  

E-print Network

analysis cover set analysis cover set forest hemlock species forest hemlock species m biomass cm m biomass nitrogen co2 nitrogen co2 biomass primary biomass primary soil n organic soil n organic river marsh island

California at Santa Barbara, University of

230

Fading Forests: the Threat of Exotic Forest Pests to North  

E-print Network

Pennsylvania (1749) White and Black Oaks White Pine ChChestnut Spruce (Eastern Hemlock) Hickory Sugar Maple Linden Pitch Pine Elm Beech White Walnut (Butternut) Chestnut Spruce (Eastern Hemlock) Hickory Sugar

Gray, Matthew

231

Micronesica 41(2):263274, 2011 Survey of invasive plants on Guam and identification of the 20 most  

E-print Network

hirta, Synedrella nodiflora, Mimosa pudica, Leucaena leucocephala, Pennisetum polystachion, Euphorbia paniculatum, Miscanthus floridulus, Euphorbia heterophylla, Chromolaena odorata, Mikania micrantha, Chamaesyce

Reddy, Gadi VP

232

Southeastern Naturalist D.R. Brown and T. Weinkam  

E-print Network

eastern North America. HWA feeds on plant nutrients in leaf bases, causing decline in tree health throughout the range of Hemlock in Kentucky (Clark 2010). In the southern Appalachians, Hemlock mortality exceeded 85% seven years after invasion (Ford et al. 2012). Forest simu- lation models suggest that Hemlock

Brown, David

233

Molecular Structure of pseudo-Conhydrine  

NSDL National Science Digital Library

Hemlock is an herb with a purple-spotted stem and leaves resembling parsley. The leaves are nauseating to eat, and ingestion may be fatal. The chemical poisons in hemlock are alkaloids like coniine and they affect the nervous system. Hemlock is the poison that Socrates was offered to cause his death.

2002-08-27

234

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

NASA Astrophysics Data System (ADS)

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-stand vegetation dynamics than those from lakes. Studies from subalpine sites have application in forestry management, wildlife conservation, and archaeological reconstruction. For example, on Vancouver Island, the Vancouver Island marmot (Marmota vancouverensis) is near extinction and conservation of the species can benefit from understanding habitat dynamic at high elevations.

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

2003-04-01

235

Vegetation Dynamics in the Kenai Lowlands, Alaska during the Late Pleistocene and Holocene  

NASA Astrophysics Data System (ADS)

The use of paleoinformation through ecosystem reconstruction can help us understand the behavior and sensitivity of the boreal forest as climate continues to change. A 2.5-meter sediment core extracted from Swanson Fen, a muskeg in the northern Kenai Lowlands on the Kenai Peninsula, Alaska, provides a sensitive Holocene paleoenvironmental record that lies in an ecotone between interior boreal forest and maritime coastal forest today. The core was sampled at 2-cm intervals and processed for pollen and spores. Five intervals were dated using AMS radiocarbon dating, and the basal macrofossils produced an age of 12,245 ±45 radiocarbon years. The central Kenai Peninsula Lowlands underwent a number of marked vegetational and climatic changes since deglaciation. Four distinct vegetation zones reveal changes starting in the late Pleistocene. The pioneer vegetation includes a dominance of herbaceous ( Artemisia, Apiaceae, Asteroideae)and shrubby ( Betula) species. The second zone (beginning at 9890±45 radiocarbon years) and marking the Holocene boundary, shows a striking increase in Polypodiaceae (ferns) and Picea (spruce) and a decrease in shrubby species such as Betula, indicative of warming. The third zone indicates a decline in Polypodiaceae and a reemergence of Betula species, while the final most recent zone reveals a rapid resurgence in Picea and Tsuga mertensiana (Mountain hemlock) species. While a general warming trend occurred following deglaciation, vegetation patterns suggest extended periods of increased precipitation, for example in the early Holocene, as is evidenced by the plethora of Polypodiaceae. A movement and an intensification of the Aleutian Low could explain these periods of increased precipitation over the Kenai Peninsula. Alternatively, this spike in Polypodiaceae can be explained by increased disturbance. The presence of 10 % Picea pollen at the base of the core suggests that one of the Picea species may have survived the last glaciation in the region. A decrease in Picea pollen and an increase in herbaceous ( Artemisia, Apiaceae, Asteroideae) pollen in the late Quaternary suggest a reversal to cooler conditions before warming resumed at the Holocene boundary, and Picea once again increased. This coincides with the timing of the Younger Dryas in the North Atlantic, and suggests that this phenomenon was felt on the Kenai Peninsula.

Jones, M. C.; Peteet, D. M.

2005-12-01

236

USDA Forest Service Gen. Tech. Rep. PSW-GTR-193. 2004. 69 Fire and Landscapes: Patterns and Processes1  

E-print Network

and temperature, increasing during warm periods dominated by oaks (Quercus spp.) and sagebrush (Artemisia tridentata) and decreasing during cool periods dominated by subalpine species, such as mountain hemlock

Standiford, Richard B.

237

2011 ISRP Retrospective Presented by  

E-print Network

improvements will be almost immediate... Hemlock Dam before removal After removal #12;Some will take decades projects. #12;Lamprey Few results to date. Critical questions to address: �Is dam passage (mainstem and that realistic timeframes can be established Trout Creek above former site of Hemlock Dam #12;PIT

238

Faculty name Faculty lab website (if available)  

E-print Network

of the plant pathogen Sclerotinia homoeocarpa. The student would be required to perform the following duties lab duties. Prior relevant lab experience is preferred, however, coursework in biotechnology and The hemlock woolly adelgid is an invasive insect from Japan that is killing hemlock trees throughout

Wadsworth, Patricia

239

THE REGIONAL INTEGRATION OF PROTECTED AREAS: A STUDY OF CANADA'S NATIONAL PARKS  

E-print Network

tundra (Parks Canada, 2005). More than half of GNP is alpine tundra, rocks, and glaciers (Parks Canada by old growth forests of western red cedar and western hemlock. Engelmann spruce, sub-alpine fir, and mountain hemlock are present on mid to upper slopes. Further upslope, parkland meadows transition to alpine

Smith, Dan

240

Properties of commonly used New Hampshire woods  

E-print Network

Properties of commonly used New Hampshire woods Pine, Hemlock, Spruce, Aspen Dries and splits of hardwoods is best with a small amount of kindling wood (pine, hemlock, spruce or aspen) mixed in. Talk and employer. UNH, USDA and NH Counties cooperating. New Hampshire Firewood How to Purchase Your Wood Supply

New Hampshire, University of

241

Exploring the transitional forest gap dynamics of small-scale  

E-print Network

1 2 3 PercentCanopyClosure(%) Quadrat % Mountain Hemlock % Western Hemlock #12;Coarse Woody Debris Findings Productivity increases in newly formed gaps #12;Key Findings Coarse woody debris increases, Kim House, and Annie Markvoort #12;Introduction Large and Small-scale Disturbances in Glacier National

Smith, Dan

242

Differential Tree Colonization of Old Fields in a Temperate Rain Forest  

E-print Network

fields have been invaded by Picea sitchensis, one of three dominant forest species (with Alnus rubra vegetation. In experiments with transplanted seedlings, cervid herbivory suppressed growth of Tsuga and Alnus

del Moral, Roger

243

The vegetative propagation of Pinus taeda L. (Loblolly pine)  

E-print Network

three exceptions have been noted, involving two species of Tsuga and one of Picea (50, 51, 120). Gardner (37)? working with Pinus strobus L . , P. resinosa Ait., P. taeda L . , and P. sylvestris L. , observed that rooting ability falls sharply during... three exceptions have been noted, involving two species of Tsuga and one of Picea (50, 51, 120). Gardner (37)? working with Pinus strobus L . , P. resinosa Ait., P. taeda L . , and P. sylvestris L. , observed that rooting ability falls sharply during...

Cech, Franklin Charles

2013-10-04

244

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

NASA Astrophysics Data System (ADS)

Stomatal frequency analysis of leaves of land plants preserved in peat and lake deposits can provide a proxy record of pre-industrial atmospheric CO2 concentration complementary to measurements in Antarctic ice cores. Stomatal frequency based CO2 trends from the USA and NW European support the presence of significant CO2 variability during the first half of the last millennium (Kouwenberg et al., 2005; Wagner et al., 2004; van Hoof et al., 2008). The timing of the most significant perturbation in the stomata records (1200 AD) is in agreement with an observed CO2 fluctuation in the D47 Antarctic ice-core record (Barnola et al., 1995; van Hoof et al., 2005). The amplitude of the stomatal frequency based CO2 changes (> 34ppmv) exceeds the maximum amplitude of CO2 variability in the D47 ice core (< 10 ppmv). A modelling experiment taking into account firn-densification based smoothing processes in the D47 ice core proved, however, that the amplitude difference between the stomata record and the D47 ice-core can be explained by natural smoothing processes in the ice (van Hoof et al., 2005). This observation gives credence to the existence of high-amplitude CO2 fluctuations during the last millennium and suggests that high resolution ice core CO2 records should be regarded as a smoothed representation of the atmospheric CO2 signal. In the present study, potential marine and terrestrial sources and sinks associated with the observed atmospheric CO2 perturbation will be discussed. The magnitude of the observed CO2 variability implies that inferred changes in CO2 radiative forcing are of a similar magnitude as variations ascribed to other forcing mechanisms (e.g. solar forcing and volcanism), therefore challenging the IPCC concept of CO2 as an insignificant preindustrial climate forcing factor. References Barnola J.M., M. Anklin, J. Porcheron, D. Raynaud, J. Schwander and B. Stauffer 1995. CO2 evolution during the last millennium as recorded by Antarctic and Greenland ice. 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

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

2010-05-01

245

Root phenology at Harvard Forest and beyond  

NASA Astrophysics Data System (ADS)

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 2012 through August 2013 at the Harvard Forest in Petersham, MA, USA. Greenness and stem growth were highest in late May and early June with one clear maximum growth period. In contrast, root growth was characterized by multiple production peaks. Q. rubra root growth experienced many small flushes around day of year (DOY) 156 (early June) and one large peak on 234 (late August). T. canadensis root growth peaked on DOY 188 (early July), 234.5 (late August) and 287 (mid-October). However, particular phenological patterns varied widely from site to site. Despite large spatial heterogeneity, it appears that Q. rubra experiences greater overall root production as well as more allocation to roots during the growing season. The storage pool of nonstructural carbohydrates experiences a mid-summer drawdown in Q. rubra but not T. canadensis roots. Timing of belowground C allocation to root growth and nonstructural carbohydrate accumulation may be regulated by climate factors as well as endogenous factors such as vessel size, growth form, or tradeoffs in C allocated between plant organs. Plant roots supply substrate to microbial communities and hence their production feeds back to other plant and soil processes that affect ecosystem C fluxes.

Abramoff, R. Z.; Finzi, A.

2013-12-01

246

POPULATION ECOLOGY Population Dynamics of the Colorado Potato Beetle in an  

E-print Network

, recruitment rates were highest on potatoes, Solanum dulcamara and S. rostratum, and lowest on tomatoes, S. nigrum, S. eleaegnifolium, Physalis heterophylla, and Datura stra- monium; three additional species were

247

77 FR 74866 - Notice of Intent To Repatriate Cultural Items: New York State Museum, Albany, NY  

Federal Register 2010, 2011, 2012, 2013

...January 17, 2013. ADDRESSES: Lisa Anderson, NAGPRA Coordinator, New York State...belt in either 1882 or 1885 from Martha Hemlock, a Seneca elder on the Cattaraugus...cultural patrimony should contact Lisa Anderson, NAGPRA Coordinator, New York...

2012-12-18

248

Soil drainage and vegetation controls of nitrogen transformation rates in forest soils, southern Quebec  

E-print Network

> sugar maple ! eastern hemlock. Nitrification enzyme activity determined through a soil slurry method et al., 1997; Gilliam et al., 2001], moisture [Corre et al., 2003], temperature [Devito et al., 1999

Moore, Tim

249

GLOSSARY OF TERMS USED IN THIS TREE ID KEY Needle-shaped: More or less, sharp and pointy.  

E-print Network

Balsam Fir Hemlock Douglas-fir Spruces Douglas-fir Leaf Margin Toothed Leaf Margin Smooth Sugar Maple Red, religion, age, disability, political beliefs, sexual orientation, marital status, or family status. Simple

250

Mapping Host-Species Abundance of Three Major Exotic Forest Pests.  

National Technical Information Service (NTIS)

Periodically over the last century, forests of the Eastern United States have been devastated by invasive pests. We used existing data to predict the geographical extent of future damage from beech bark disease (BBD), hemlock woolly adelgid (HWA), and gyp...

R. S. Morin, A. M. Liebhold, E. R. Luzader, A. J. Lister, K. W. Gottschalk, D. B. Twardus

2002-01-01

251

Chemical and Structural Features of Plants That Contribute to Biomass Recalcitrance  

E-print Network

Norway Spruce Heartwood, Sapwood and Transition Zone Wood.Wood Components During Chlorite Delignification of Black Spruce.Spruce and Western Hemlock: Moisture Content Determination and Second Moments. Wood

DeMartini, Jaclyn Diana

2011-01-01

252

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

Federal Register 2010, 2011, 2012, 2013

...140 and 78 Applications for Subzone Authority Dow Corning Corporation, Hemlock...Semiconductor, L.L.C.; Notice of Public Hearing and Extension of Comment...held on the applications for subzone authority at the Dow Corning Corporation...

2011-12-28

253

A field simulation of the effect of acidic rain on ion balance in a woodland salamander  

Microsoft Academic Search

The natural density of red-backed salamanders, Plethodon cinereus, is 4–5 times greater at the New York study site in hardwood than in hemlock forests. The hypothesis that physico-chemical differences between forest types differentially affect the physiology of P. cinereus was tested. Salamanders were confined in individual enclosures in either a beech or a hemlock forest for 22 d. At the

M. P. Frisbie; R. L. Wyman

1995-01-01

254

Climate Changes Inferred from Pollen Record of Recent 3000 years in Sonluo Lake, Northeastern Taiwan  

NASA Astrophysics Data System (ADS)

Palynological studies can detect the impact of rapid climate changes on terrestrial ecosystems, since vegetation variation in response to climate fluctuation can occur on the order of decades. In this study, we provide a new pollen record from Sonluo Lake and intend to discover the relationship between winter monsoon and climate conditions of northeastern Taiwan during the recent 3000 years. Sonluo Lake, at an elevation of 1300 m AMSL, is an isolated basin located in Shueshan Range, northeastern Taiwan. Annual precipitation is approximately 4,400 mm, and almost occurs evenly through one year. Vegetation surrounding the basin is of the Machilus-Castanopsis vegetation type and lower Quercus vegetation type. Four climatic phases are determined with the aid of palynological studies. During the interval 3000 to 2200 yr BP (Zone IV), abundant pollens of Tsuga and fern spores indicate that the climate conditions were cool and wet than present. Subsequently, the warm climate conditions prevailed between 2200 and 1500 yr BP (Zone III) as suggested by the decline of Tsuga. From 1500 to 700 yr BP (Zone II), the lowest percentage of Tsuga and fern spores indicates a warmest and driest period. Following that, the basin experienced again cool and wet climate conditions since 700 yr BP, evidenced by the return of Tsuga and fern spore. The last climatic phases can be corresponded to the Little Ice Age. The high correlation(R=0.73)between pollen of Tsuga and fern spores indicates that winter monsoon dominant condition in this region.

Wu, Meng-Huan; Liew, Ping-Mei; Lee, Sep; Hsieh, Meng-Long; Huang, Sue-Yue

2010-05-01

255

USDA Forest Service Proceedings RMRS-P-63. 2011. 235 ExtendedAbstract  

E-print Network

's (Pinus albicaulis) notable ecological values, combined with its precarious state, underscore the need activity from mature western white pine (Pinus mon- ticola), or whitebark pine of any age, appear absent (Tsuga mertensiana) and lodgepole pine (Pinus contorta var. murrayana) are common co-dominants. Shasta

256

Molecular Phylogeny of Pinaceae and Pinus  

Microsoft Academic Search

Molecular phylogenetic reconstructions of Pinaceae based on immunological approaches plus nuclear and organellar DNA sequences consistently resolve the generic pairs Larix - Pseudotsuga and Abies - Keteleeria. In most analyses Pseudolarix and Tsuga (including Nothotsuga) form a clade that is sister to the Abies - Keteleeria clade, and Cathaya, Picea, and Pinus make up an unresolved trichotomy. The position of

Aaron Liston; David S. Gernandt; Thomas F. Vining; Christopher S. Campbell; Daniel Piñero

257

Wood and Fiber Science, 36(1), 2004, pp. 107118 2004 by the Society of Wood Science and Technology  

E-print Network

Wood and Fiber Science, 36(1), 2004, pp. 107­118 2004 by the Society of Wood Science and Technology). Soil chemical barriers and termite baits have provided promising techniques to pre- vent attack- #12;108 WOOD AND FIBER SCIENCE, JANUARY 2004, V. 36(1) lock (Tsuga Canadensis) (Su and Tamashiro 1986

258

Changes in O horizon mass, thickness and carbon content following fire in northern hardwood forests  

Microsoft Academic Search

This study examines temporal changes in the thickness, mass, and organic carbon content of the O horizon (forest floor) of eight forested plots in northern Michigan, USA. Each plot had experienced a recent burn (prescribed or accidental); burn dates ranged from 1798 to 1980. The climax forest in this region is mixed Pinus-Acer-Betula-Tsuga, whereas the fire successional species are predominantly

Randall J. Schaetzl

1994-01-01

259

N d'ordre : 298 -2010 Anne 2010 en cotutelle  

E-print Network

the Messinian Salinity Crisis, North Aegean vegetation was mainly characterized by open plant ecosystems nearby by relict thermophilous plants: Liquidambar orientalis, Parrotia persica, Pterocarya fraxinifolia, Zelkova Salinity Crisis), herbs prevailed in the Dardanelles area while mid- (Tsuga) and high-altitude (Abies

Paris-Sud XI, Université de

260

The Holocene 10,4 (2000) pp. 587601 Postglacial vegetation and fire history,  

E-print Network

parkland with scattered Pinus and Abies. After 13 100 cal. BP a relatively closed forest of P. monticola, P and wetter than present. Pinus and Quercus vaccinifolia dominated at both sites during the early Holocene. at both sites and Tsuga mertensi- ana at Crater Lake increased in importance, displacing Pinus and Quercus

Whitlock, Cathy L.

261

The effects of feeding by Oniscus asellus on leaf litter sulfur constituents  

Microsoft Academic Search

Feeding by the isopod, Oniscus asellus, produced changes in the sulfur constituents of leaf litter substrates (Acer negundo, A. saccharum, Fagus grandifolia, Picea rubens, and Tsuga canadensis). Isopod consumption of leaf litter generally accelerated the mineralization of carbon-bonded S and increased the formation of ester sulfate in all substrates. After the isopod egestion of A. negundo leaves, fecal decomposition over

C. R. Morgan; M. J. Mitchell

1987-01-01

262

Ecological Applications, 17(3), 2007, pp. 869881 2007 by the Ecological Society of America  

E-print Network

, Cornus florida (flowering dogwood) has been described as a calcium ``pump'' that draws calcium from greater concentrations of calcium than three other dominant understory species (Tsuga canadensis, Acer increases in the foliar biomass of T. canadensis, a species whose calcium-poor foliage increases soil

Peet, Robert K.

263

Scale-dependent drivers of ungulate patch use along a temporal and spatial gradient of snow  

E-print Network

-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) selection of eastern hem- lock (Tsuga canadensis (L model, habitat selection, white-tailed deer (Odocoileus virginianus), Upper Peninsula of Michigan par le cerf de Virginie (Odocoileus virginianus (Zimmer- mann, 1780)) de parcelles de pruches du

264

Inhibition of Methane Consumption in Forest Soils by Monoterpenes  

Microsoft Academic Search

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 (bulk and intact cores) and slurry conditions. Most of

J. A. Amaral; R. Knowles

1998-01-01

265

[Child poisoning after ingestion of a wild apiaceae: a case report].  

PubMed

Apiaceae family (formerly Umbelliferae) contains several highly toxic species, including Poison Hemlock (Conium maculatum), Water Hemlock (Cicuta virosa) and Hemlock Water Dropwort (Oenanthe crocata) which are the three main poisonous Apiaceae species growing in France. Thinking he was identifying wild carrots, an 11-year-old boy without previous history ingested the root from a wild Apiaceae. One hour later, he was confused, had drowsiness, headache as well as abdominal pain, vomiting and diarrhoea. Upon hospital admission, myosis, ophtalmoplegia and a moderate rhabdomyolysis were noted. The patient recovered after 24 h of symptomatic treatments. In this case, the description of the ingested plant allowed to identify the Apiaceae family but not the species involved. The geographical location (Southern France in a humid area), the clinical features and the aspect of the ingested root, with an orange secretion led to implicate Oenanthe crocata as the origin of this unusual poisoning. PMID:18206356

Durand, M-F; Pommier, P; Chazalette, A; de Haro, L

2008-02-01

266

Phytochemical constituents of some Nigerian medicinal plants  

Microsoft Academic Search

Alkaloids, tannins, saponins, steroid, terpenoid, flavonoids, phlobatannin and cardic glycoside distribution in ten medicinal plants belonging to different families were assessed and compared. The medicinal plants investigated were Cleome nutidosperma, Emilia coccinea, Euphorbia heterophylla, Physalis angulata, Richardia bransitensis, Scopania dulcis, Sida acuta, Spigelia anthelmia, Stachytarpheta cayennensis and Tridax procumbens. All the plants were found to contain alkaloids, tannins and flavonoids

H. O. Edeoga; D. E. Okwu; B. O Mbaebie

267

Preliminary Phytochemical Analysis and Antimicrobial Activity of Some Weeds collected from Marathwada Region  

Microsoft Academic Search

The aqueous and ethanolic extracts of selected weeds such as Portulaca oleracea L. (Portulaceae), Cardiospermum helicacabum L. (Sapindaceae), Euphorbia hirta L. (Euphorbiaceae), Crotalaria retusa L. (Fabaceae) and Euphorbia heterophylla L. (Euphorbiaceae) were screened for phytochemical analysis and antimicrobial activity. The antimicrobial activities were tested against two gram-positive bacteria (Bacillus subtilis, Staphylococus aureus), one gram-negative bacterium (Pseudomonas aeruginosa) and a mould

Dhole JA; Dhole NA; Lone KD; Bodke SS; Rajarshi Shahu

2011-01-01

268

Toxic effects of some plants in the genus Euphorbia on haematological and biochemical parameters of rats  

Microsoft Academic Search

ADEDAPO, A. A., M. O. ABATAN, O. O. OLORUNSOGO: Toxic effects of some plants in the genus Euphorbia on haematological and biochemical parameters of rats. Vet. arhiv 74, 53-62, 2004. ABSTRACT The toxic effects of 5 suspected poisonous plants of the genus Euphorbia (Euphorbia balsamifera Aiton, E. heterophylla L., E. hirta L., E. hyssopifolia L., and E. lateriflora Schum and

Adeolu A. Adedapo; Matthew O. Abatan; Olufunso O. Olorunsogo

2004-01-01

269

Relations of the western Balkan endemic Campanula L. (Campanulaceae) lineages based on comparative floral morphometry  

Microsoft Academic Search

In the north-eastern quadrant of the Mediterranean Region many endemic Campanula (Campanulaceae) taxa and lineages arose, of which the Isophylla group and the Rotundifolia complex (sect. Heterophylla), essentially separated on the basis of their leaf shapes, and some of the endemic western Balkan, Dinaric lineages (i.e. ‘isophylloid’ aggregates Waldsteiniana and Pyramidalis) are members. The aim of this study is to

S. Kova?i?; T. Nikoli?

2006-01-01

270

Leaf Dimorphism in Aquatic Angiosperms: Significance of Turgor Pressure and Cell Expansion  

Microsoft Academic Search

Depending on environmental conditions, the aquatic angiosperm Callitriche heterophylla can develop two different leaf types with distinctive morphological characteristics. Cellular turgor pressure seems to act as the biophysical mechanism responsible for the selection of leaf form in control conditions designed to mimic the natural habitat of this plant. The experimental induction of leaf form involves the ability of various treatments

Paula A. Deschamp; Todd J. Cooke

1983-01-01

271

Observer Name(s) & contact info Date/Time: Friday 16 Sept: to // Saturday 17 Sept: to  

E-print Network

Observer Name(s) & contact info Date/Time: Friday 16 Sept: to // Saturday 17 Sept: to Number) Holly Forest Zone: (HC) Horseshoe Cove Zone: Common Name Scientific Name FH HF HC NB PI OTHER (name site Liverwort Lophcolea heterophylla 14 Star Moss Mnium cuspidatum 15 Veilwort Pallauicinia lycllii 16 White

Columbia University

272

Comparison of ultrastructure, pollen tube growth pattern and starch content in developing and abortive ovaries during the progamic phase in hazel  

PubMed Central

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 of four hybrid hazel cultivars and C. heterophylla were significantly higher. This study suggests that abortive ovary was incapable to finish fertilization process due to the absence of mature embryo sac and arrested pollen tubes, and this is likely associate with insufficient resource availability to support fruit set by all flowers in four hybrid hazel cultivars, whereas ovary abortion in C. heterophylla is at least partly determined by pollen availability. PMID:25339969

Liu, Jianfeng; Zhang, Huidi; Cheng, Yunqing; Wang, Ju; Zhao, Yixin; Geng, Wanting

2014-01-01

273

18 (4): 363-368 (2011) Large herbivore populations can modify plant com-  

E-print Network

). These modifications, in turn, may affect nutrient cycling, soil fertility, and ecosystem productivity (Singer occurred was severely affected by a hemlock looper epidemic in the early 1970s and was specifically and paper birch coincided with a certain range of soil properties (pH, exchangeable cations, soil depth

Laval, Université

274

Indiana's "Most Unwanted" Invasive Plant Pest List FY 2007 The Indiana "Most Unwanted" List, compiled by the Indiana Cooperative Agricultural Pest Survey (CAPS)  

E-print Network

ambrosia beetle Trypodendron domesticum (Linnaeus) E,I,R,NF European poplar shoot borer Gypsonoma aceriana (Fabricius) E,I,MD Granulate ambrosia beetle Xylosandrus crassiusculus (Motschulsky) E,I,R,NF Hemlock woolly,I,NF Mediterranean pine engraver beetle Orthotomicus erosus (Wollaston) E,I,NF Oak ambrosia beetle Platypus

Ginzel, Matthew

275

Responses to Green Leaf Volatiles in Two Biogeoclimatic Zones by Striped Ambrosia Beetle, Trypodendron lineatum  

Microsoft Academic Search

Experiments in the Coastal Western Hemlock (CWH) biogeoclimatic zone on the British Columbia (BC) coast and the Interior Douglas-fir (IDF) biogeoclimatic zone in the BC interior revealed pronounced differences in the effect of six-carbon green leaf volatiles on the response by striped ambrosia beetles, Trypodendron lineutum to multiple funnel traps baited with the aggregation pheromone lineatin. In the IDF zone,

J. H. Borden; L. J. Chong; A. Savoie; I. M. Wilson

1997-01-01

276

Characterization of old \\  

Microsoft Academic Search

Wet boreal forests occur primarily in Atlantic Canada especially in Newfoundland, but examples are also found in Quebec and the northeastern U.S.A. These forests are dominated by balsam fir (Abies balsamea), which is susceptible to fire but flourishes in wetter environments where fire is absent. The major stand disturbances are caused by insects, primarily spruce budworm (Choristoneura fumiferana) and hemlock

Ian D. Thompson; David J. Larson; William A. Montevecchi

2003-01-01

277

Dr. Charles 3'. Brooks, of Chrk TJniversity,  

E-print Network

the ground i n the aoods, A fen yews ago, hovrrovcr, A tree can hold co certe.in nmount of watcr o n ' i and hemlocks, 'dl1 intercept more rain then broad-leaved trecs. noticoablo in winter when the overgreen boughs

278

A field test of the effect of acidic rain on ion balance in a woodland salamander  

Microsoft Academic Search

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

M. P. Frisbie; R. L. Wyman

1994-01-01

279

Clear and Present Danger: Invasive Species Threats toInvasive Species Threats to  

E-print Network

disease Chesnut Blight Invasive/ Exotic Species Dutch elm disease, Chesnut Blight ­ Hemlock woolly adelgid honeybees, biocontrol species) ­ Livestock (Cows, pigs, chickens) · Harmful/ Invasive Exotics ­ Dutch elm and reservoirs for human disease:Human ­ West Nile Virus ­ Malaria ­ Yellow Fever u a Health Invasive/ Exotic

Gray, Matthew

280

Damage and recovery of tree species after two different tornadoes in the same old growth forest: a comparison of infrequent wind disturbances  

Microsoft Academic Search

Catastrophic wind disturbances in natural forests remain poorly studied, and the literature allows few comparisons of damage and recovery in the same forests disturbed by distinct wind events. Thus, it is still uncertain whether published findings are idiosyncratic or representative. Here I describe damage and recovery patterns in a large, primary hemlock–hardwoods forest in Pennsylvania, USA, which was struck by

Chris J. Peterson

2000-01-01

281

Old forest remnants contribute to sustaining biodiversity: The case of the Albert River valley  

Microsoft Academic Search

The Albert River valley hosts the only old-growth stands of western redcedar in the Invermere Timber Supply Area (tsa). This portion of the Interior Cedar Hemlock moist cool (ichmk1) biogeoclimatic variant is spatially disjunct from the rest of the ichmk1 in British Columbia and lies on calcareous soil. Surveys of lichens and vascular plants in the valley bottom of the

Isabelle Houde; Susan Leech; Fred L. Bunnell; Toby Spribille; Curtis Björk

282

Seed abundance versus substrate limitation of seedling recruitment in northern temperate forests of British Columbia  

Microsoft Academic Search

We examine the influence of (i) the spatial distribution and abundance of parent trees (as seed sources) and (ii) the abundance and favourability of seedbed substrates, on seedling recruitment for the major tree species in north - western interior cedar-hemlock forests of British Columbia, under four levels of canopy openness (full canopy, partial canopy, large gap, and clearcut). Substrate distribution

Philip T. LePage; Charles D. Canham; K. Dave Coates; Paula Bartemucci

2000-01-01

283

Ecological Monographs, 79(2), 2009, pp. 265280 2009 by the Ecological Society of America  

E-print Network

rate of invasive species introductions is unprecedented, and the dramatic impacts of exotic invasive, species diversity, and herbivory in determining exotic plant invasion in 10 eastern hemlock forests in Pennsylvania and New Jersey (USA). Use of a maximum-likelihood estimation framework and information theoretics

Battles, John

284

Characterizing Structure, Microclimate and Decomposition of Peatland, Beachfront, and Newly Logged Forest Edges in Southeastern Alaska  

Microsoft Academic Search

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

Julie Ann Concannon

1995-01-01

285

Fire-related landform associations of remnant old-growth trees in the southern Washington  

E-print Network

Fire-related landform associations of remnant old-growth trees in the southern Washington Cascade and divergent landform classes. Frequency analysis was used to test for landform associations. Live remnant western hemlock and western redcedar were strongly associated with convergent landforms and aspects

Vermont, University of

286

his article summarizes our ex-periences and observations dur-  

E-print Network

to intro- duce generations of forestry students to the dramatic effects of land-use changes in southern New generation. Photo by Todd Fuller. #12;in forest health and species composi- tion. So what began as a mixed white pine, eastern hemlock, sugar maple, and red maple. Our project area encompasses the four counties

Schweik, Charles M.

287

A record of Lateglacial and Holocene vegetation and climate change from Woods Lake, Seymour Inlet, coastal British Columbia, Canada  

E-print Network

, coastal British Columbia, Canada Susann Stolze a,, Helen M. Roe b , R. Timothy Patterson c , Thomas vegetation and environmental history recorded in a small coastal lake in the Seymour Inlet area, British in the Coastal Western Hemlock biogeoclimatic zone of British Columbia. Sedimentological and microfossil records

Patterson, Timothy

288

The action of isolated brown-rot cell-free culture filtrate, H 2 O 2 ?Fe ++ , and the combination of both on wood  

Microsoft Academic Search

Transmission electron microscopy observations of hemlock sawdust that had been incubated with concentrated filtrate from Postia placenta showed that wood was degraded despite the absence of weight loss and release of reducing groups. These results are contrary to the prevailing views that enzyme preparation from brown-rot fungi are unable to degrade wood.

L. Murmanis; T. L. Highley; J. G. Palmer

1988-01-01

289

September 29, 2006 Mark Walker  

E-print Network

Dam proposal based on a BPA/USFS cost share agreement, and are requesting that this funding remain. 200707700 - Removal of Hemlock Dam, and No. 200721500 - Adult Steelhead Monitoring in Trout Creek, because expression of genetic and life history diversity. This project is needed to fulfill the restoration

290

Pruning is fun when the pruner is confident and knowledgeable. Plant health is the main consider-  

E-print Network

harder than juniper, spruce, pine, and fir that usually do not form buds on old wood. Light, periodic, spruce, fir, and hemlock; other narrowleaf evergreens include yew, juniper, arborvitae, and false cypress. Pine, spruce, and fir grow only in the spring and early summer and do not need to be pruned each year

New Hampshire, University of

291

Paper birch competitive effects vary with conifer tree species and stand age in interior British Columbia forests: implications for reforestation policy and practice  

Microsoft Academic Search

Paper birch (Betula papyrifera Marsh) is considered the most important competitive threat to commercially valuable conifers in the highly productive interior cedar–hemlock forests of British Columbia. It is routinely removed from conifer plantations at high cost to increase conifer growth rates and meet reforestation policy regulations. Competitive effects of paper birch and other neighbours on conifer growth were measured in

Suzanne W Simard; Donald L Sachs; Alan Vyse; Leandra L Blevins

2004-01-01

292

Voluntary Euthanasia and the Right to Die: A Dialogue with Derek Humphry.  

ERIC Educational Resources Information Center

Presents interview with Derek Humphry, founder of the Hemlock Society (an international right-to-die organization), who shares his personal experiences, as well as his efforts to educate the public and stimulate legal reform. Notes Humphry has dedicated more than a decade to this highly charged universal problem. (Author/ABL)

Sinnett, E. Robert; And Others

1989-01-01

293

Immunomodulating Activities of Ganoderma, a Mushroom with Medicinal Properties  

Microsoft Academic Search

This review highlights the recent research progress in the study of immunomodulating effects of Ganoderma, which belongs to the basidiomycotina class of fungi. The commonly used Ganoderma species include G. lucidum, G. tsugae, G. capense, and G. applanatum. Several major substances with potent immunomodulating action have been isolated from Ganoderma. These include polysaccharides (in particular ?-d-glucan), proteins (e.g., Ling Zhi-8)

Yihuai Gao; Eli Chan; Shufeng Zhou

2004-01-01

294

Habitat classification: A comparison using avian species and guilds  

Microsoft Academic Search

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

Richard M. Degraaf; Nan L. Chadwick

1984-01-01

295

Habitat classification: A comparison using avian species and guilds  

Microsoft Academic Search

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 andP. resinosa), balsam fir (Abies),

Richard M. Degraaf; Nan L. Chadwick

1984-01-01

296

Late Pliocene vegetation and climate of the Lake Baikal region, southern East Siberia, reconstructed from palynological data  

Microsoft Academic Search

Palynomorphs from a palaeomagnetically dated Late Pliocene sediment core (3.6–2.35 Ma) reflect highly variable climatic conditions and repeated expansion of steppe and boreo-alpine vegetation. Mixed coniferous forests (Picea, Tsuga, Pinus) with associated broadleaved taxa (Quercus, Corylus, Ulmus, Tilia) were affected by dry and cold intervals already between 3.48 and 3.39 Ma. Peak records of non-arboreal pollen types and spores, including

Dieter Demske; Barbara Mohr; Hedi Oberhänsli

2002-01-01

297

Diagenesis of conifer needles in a coastal marine environment  

NASA Astrophysics Data System (ADS)

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 (C/V) of the deepest sedimentary fir/hemlock needles to 20% of the original value and almost tripled the carbon-normalized yield of total vanillyl plus cinnamyl phenols (?). The net result of these compositional variations was to make the lignin component of the buried conifer needles resemble lignin in gymnosperm wood, thereby leading to underestimates of needle input and mass.

Hedges, John I.; Weliky, K.

1989-10-01

298

Two Finger Lakes (New York) Through the Twentieth Century: Response of the Diatom Assemblages to Anthropogenic Influences  

NASA Astrophysics Data System (ADS)

Diatoms in sediment cores from two New York Finger Lakes, Conesus Lake and Hemlock Lake, were enumerated. These lakes are only 8 km apart, but Conesus Lake has a shallower, broader basin and a different diatom complement than Hemlock Lake. Cottages almost completely surrounded Conesus Lake by the 1920s, when the oldest core sediment was deposited. All sampled levels of the core yielded a eutrophic Lake Trophic Status Index (LTSI: 8.3 to 11.6). Eutrophic indicators Aulacosiera granulata, and Stephanodiscus niagarae, and mesoeutrophic A. italica are the dominant diatoms in most samples, consistent with reported nutrient enrichment. Sediment from the 1940s has the lowest LTSI (8.3) during a known wet period. The LTSI is also lower in recent sediments (8.5), likely from sewer system installation in the early 1970s, measures to control agricultural runoff, and increased precipitation. Conesus Lake had low turbidity through most of the 1900s, even with high enrichment. The resident macrophytes, walleye and large zooplankton controlled excess algae growth. During the 1970s, walleye declined, and alewife were introduced, resulting in the loss of large zooplankton and increased turbidity. Even with increased turbidity, the most recent sediment has a lower LTSI; eutrophic A. granulata decrease and mesoeutrophic A. italica increase. Diatoms in the Hemlock Lake core sediments reveal a less anthropogenically impacted lake than Conesus Lake. The bottom portion of the Hemlock Lake core ( ~1870) has 58% of oligomesotrophic A. subarctica, associated with a low LTSI (-0.6). By the latter part of the 1800s, the land around the lake was largely owned by the City of Rochester. Existing cottages were demolished, the land was reforested and the lake used as a reservoir. Alternating increases in mesoeutrophic tychoplanktonic A. italica and mesoeutrophic euplanktonic Tabellaria fenestrata, are consistent with increased nutrient concentration and changing water levels, mostly during historical drought periods. Cyclotella comensis (65%), linked to low total phosphorus enrichment and higher water conditions, increase during the most recent twenty years. The lake is now surrounded by forests and considered pristine. The predominant Conesus Lake core diatoms require higher nutrient enrichment than those in the Hemlock Lake core and indicate a continually disturbed watershed. The Hemlock Lake diatoms are very different and indicate less enrichment. While the LTSIs of both lakes change in response to climatic changes, Conesus Lake consistently shows a higher LTSI. Further studies of longer cores from these lakes are planned.

Arnold, M. R.; Chaisson, W. P.

2002-05-01

299

Sensitivity of mosses to sulfur dioxide  

Microsoft Academic Search

Seven North American moss species responded differentially to fumigations with sulfur dioxide ranging from 0.5 to 4.0 ppm. Leucobryum glaucum and Dicranum scoparium were the most sensitive species; Dicranella heterophylla, Polytrichum ohioense and Pottia truncata, the most resistant. The results of fumigations with 0.1 to 4.0 ppm sulfur dioxide for 8 hours on cultured gametophytes of Polytrichum ohioense indicate that

T. H. Nash; E. H. Nash

1974-01-01

300

Studies on pigments, proteins and photosynthetic rates in some mangroves and mangrove associates from Bhitarkanika, Orissa  

Microsoft Academic Search

Pigment contents, proteins and net photosynthesis were investigated in fully developed leaf of 1-year-old seedlings of six mangroves (Bruguiera gymnorrhiza, Rhizophora apiculata) and mangrove associates (Caesalpinia bonduc, Cerbera manghas, Derris heterophylla, Thespesia populnea), collected from Bhitarkanika, located on the east coast of India. Large variations in the photosynthetic rates (PN) among the six species were observed, ranging from 10.16 µmol

A. Das; A. Parida; U. Basak; P. Das

2002-01-01

301

Comparative pollen morphology and ultrastructure of the Callitrichaceae.  

PubMed

The Callitrichaceae are an aquatic family of dicots that include the single, geographically cosmopolitan genus Callitriche. Callitriche contains 40-50 terrestrial, amphibious, and obligately submersed species, and it is the only known genus in the plant kingdom with co-occurring aerial and hydrophilous pollination syndromes. Pollen morphology and ultrastructure were described for 13 Callitriche species using scanning electron and transmission electron microscopy. Representative taxa of each growth form were examined; these included three terrestrial species (C. deflexa, C. peploides, and C. nuttallii), nine amphibious species (C. brutia, C. cophocarpa, C. cophocarpa-stagnalis hybrid, C. cribrosa, C. hamulata, C. heterophylla var. heterophylla, C. lusitanica, C. marginata, and C. trochlearis), and one obligately submersed species (C. truncata). Of the amphibious taxa, C. heterophylla var. heterophylla and C. trochlearis had internal geitonogamy, a type of internal self-fertilization. Pollen from all taxa was spheroidal, small, intectate, and lacked well-defined apertures. Taxa primarily differed with respect to exine thickness, surface ornamentation, and the presence or absence of aperture-like regions. The pollen of terrestrial species, as well as that of C. marginata, had well-developed exines with thick sculptured and basal layers. In general, amphibious taxa produced pollen with distinct, but thinner, exines than that of terrestrial taxa. Pollen of the amphibious taxa with internal geitonogamy had a thicker basal layer than species without internal geitonogamy, whereas the overall exine was reduced in C. hamulata and absent in C. brutia and C. lusitanica. Pollen of the obligately submersed C. truncata also lacked an exine. These palynological data were correlated with growth habits and related pollination biologies, as well as with phylogenetic interpretations of Callitrichaceae. Exine reduction or loss has evolved at least twice in the family, and it is associated with aneuploid reduction in chromosome number. PMID:10675302

Cooper, R L; Osborn, J M; Philbrick, C T

2000-02-01

302

The nucleotide sequences of 5S ribosomal RNAs from four Bryophyta-species.  

PubMed

The nucleotide sequences of cytoplasmic 5S rRNA from four bryophytes, Marchantia polymorpha, Lophocolea heterophylla, Plagiomnium trichomanes and Anthoceros punctatus have been determined. These RNAs are 119 nucleotides long except for the Anthoceros RNA that has 118 nucleotides. Their sequences are highly similar to each other (91-99% identity) and are more related to those from seed plants (78-83% identity) than to those from green algae (61-73% identity). PMID:6571698

Katoh, K; Hori, H; Osawa, S

1983-08-25

303

The nucleotide sequences of 5S ribosomal RNAs from four Bryophyta-species.  

PubMed Central

The nucleotide sequences of cytoplasmic 5S rRNA from four bryophytes, Marchantia polymorpha, Lophocolea heterophylla, Plagiomnium trichomanes and Anthoceros punctatus have been determined. These RNAs are 119 nucleotides long except for the Anthoceros RNA that has 118 nucleotides. Their sequences are highly similar to each other (91-99% identity) and are more related to those from seed plants (78-83% identity) than to those from green algae (61-73% identity). PMID:6571698

Katoh, K; Hori, H; Osawa, S

1983-01-01

304

Forest management and temporal effects on food abundance for a ground-foraging bird ( Catharus guttatus)  

Microsoft Academic Search

While food abundance is known to limit bird populations, few studies have simultaneously examined both temporal and habitat-related variation in food abundance for ground-foraging birds. We surveyed ground-dwelling arthropods throughout the breeding season and in three forest harvest types (clearcut, selection, and shelterwood stands managed for spruce, fir and hemlock) at the Penobscot Experimental Forest (PEF), Bradley, Maine, USA. Pitfall

Jason C. Johnston; Rebecca L. Holberton

2009-01-01

305

Demographics, Attitudes, and Afterlife Beliefs of Right-To-Life and Right-To-Die Organization Members  

Microsoft Academic Search

The present study provides within- and between-group comparisons of pro-and anti-euthanasia groups on demographic, afterlife-belief, related-attitude, and attitude-influence variables, using a questionnaire that was filled out by 785 members of the Hemlock Society and 161 members of the California Pro-Life Council. It was conjectured that afterlife belief is the foundation upon which people structure fundamental issues of life and death,

J. Holden

1993-01-01

306

THE BREEDING BIOLOGY OF BROAD-WINGED  

Microsoft Academic Search

Nesting Red-shouldered (Buteo lineatus; RSH) and Broad-winged Hawks (Buteo platypterus; BWH) were studied in 1978-1980 in Chautauqua County, New York. Both species nested predominantly in upland maple-beech-hemlock associations. Six of 18 BWH nests were in larch (Larix decidua); 7 of 18 RSH nests were in American beech (Fagus grandifolia). BWH nested closer to woodland openings and lower in a tree

SCOTT T. CROGOLL; JAMES W. PARKER

307

Ex Situ Gene Conservation for Conifers in the Pacific Northwest  

NSDL National Science Digital Library

This current report from the US Department of Agriculture Forest Service, Pacific Northwest Research Station evaluates the genetic resource status of several Pacific Northwest timber species. The 60-page report can be viewed using Adobe Acrobat Reader. The report finds that species like ponderosa pine, noble fir, and western hemlock have "extensive genetic resources in ex situ forms," while the resources for red cedar are more limited.

Johnson, G. R.; Lipow, Sara R.; St. Clair, J. B.

2002-01-01

308

SPATIAL INCIDENCE OF BARRED OWL (STRIX VARIA) REPRODUCTION IN OLD-GROWTH FOREST OF THE APPAI ACHIAN PLATEAU  

Microsoft Academic Search

DuBois, PA 15801 U.S.A. ABSTRACT.--Barred Owl (Strix varia) occtwrence and breeding were evaluated in old-growth forest using Poisson and binomial models constructed with seven spatially-explicit parameters derived from territorial density. Reproduction was evidenced by owl chicks heard inside cavity nests or being fed by adults in old- growth deciduous (beech-maple, oak-hickory) and old-growth mixed forest types (hemlock-white pine-decid- uous). Barred

J. CHRISTOPHER HANEY

309

Mulching Effects of Plant Fiber and Plant Fiber-Polyester Mats Combined With Fertilizer on Loblslly Pine Seedlings  

Microsoft Academic Search

In this preliminary study, several ma ttings, com - bined with and without fertilizer application, were tested around newly planted lob loll,^ pine (Pinus taeda L.) seedlings. After 9 months in the field, jute- polvester and jute mats had similar surr,ir~al rates relitive to controls, but hemlock-po1,vester mats had depressed survival when used in combination with fertilizer. All tlypes of

James D. Haywood; John A. Youngquist

310

Displaced murder.  

PubMed

Most suicide attempts appear to be impulsive and motivated by rage against another person. The author believes that publications of pro-suicide groups like EXIT or Hemlock serve a useful purpose for some terminally ill persons, although hospice care is a better approach for most dying patients. Potential suicides who are suffering from emotional stresses rather than terminal illnesses are best deterred by a personalized approach. PMID:11655389

Brand, Stewart

1981-10-01

311

ABOVE GROUND PERFORMANCE OF PRESERVATIVE-TREATEDWESTERN WOOD SPECIES  

Microsoft Academic Search

Abstact: Incised and non-incised Douglas-fir, western hemlock, andponderosa pine L-joints were treated with ammoniacal-based pentachlorophenol, chromated zinc chloride, thiocyanomethylthiobenzothiazole (TCMBT) or TCMTB plus methylenebisthiocyanate or 3 iodo-2-propynyl carbamate with or without chlorpyrifos to retentions between 0.8 and 6.4 kg\\/m 3 and exposed, uncoated, above ground on a test fence located in Corvallis, Oregon. Additionaljoints dipped in solutions of zinc naphthenatewere

Jeffrey J. Morrell

312

Woody fuel dimensions within Great Smoky Mountains National Park. Research/resources management report  

SciTech Connect

Diameters and bulk density were examined for downed wood in major forest types found in Great Smoky Mountains National Park. One-hour fuel (0 - 7 mm) diameters were smallest in spruce-fir and hemlock forests, intermediate in yellow pine forests, and largest in hardwood forests. Diameters for 10 hour (7 - 25 mm) and 100 hour (25 - 76 mm) fuels were not significantly different between forest types. Bulk density decreased with a decrease in bark coverage.

Harmon, M.E.; Hennessy, T.; Silsbee, D.G.

1980-01-01

313

Antifeedant Compounds from Three Species of Apiaceae Active Against the Field Slug, Deroceras reticulatum (Muller)  

Microsoft Academic Search

Extracts of volatiles from foliage of three plants in the Apiaceae, Conium maculatumL. (hemlock), Coriandrum sativum L. (coriander), and Petroselinum crispum Mill. (Nym.) (parsley), previously shown to exhibit antifeedant activity in assays with the field slug, Deroceras reticulatum (Muller) (Limacidae: Pulmonata), were studied further to identify the active components. Coupled gas chromatography–mass spectrometry (GC–MS) and neurophysiological assays using tentacle nerve

Michael A. Birkett; Catherine J. Dodds; Ian F. Henderson; Lucy D. Leake; John A. Pickett; Martin J. Selby; Peter Watson

2004-01-01

314

Macrofossil Record of a Middle Holocene Drop in Relative Sea Level at the St. Lawrence Estuary, Québec  

NASA Astrophysics Data System (ADS)

Macrofossil analysis of a peat layer overlying shallow-water estuarine sediments allows the reconstruction of vegetation changes between 7000 and 6000 14C yr B.P. near Montmagny, Québec. About 7500-7000 14C yr B.P., the study site was brackish and intertidal. Next, a cattail marsh dominated by Typha changed into a terrestrial fire-prone environment that contained xero-mesophilous tree species ( Pinus/ Tsuga) and lasted a few hundred years, until about 6800 14C yr B.P. This rapid change may have resulted from land tilting associated with the northward migration of the postglacial forebulge. An abrupt change from a Pinus/ Tsuga-dominated cover to shrubby vegetation was due to a fire that affected the site 6800 14C yr B.P. Fossil mosses at the site reflect local wetness likely produced by a rise in the water table starting about 6600 14C yr B.P. By 6500-6400 14C yr B.P., seawater returned and freshwater plants were replaced by semihalophilous and halophilous plants. Thinning of annual rings in fossil larch reflects this change from a terrestrial peatland to a treeless coast.

Bhiry, Najat; Garneau, Michelle; Filion, Louise

2000-09-01

315

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)

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.

Menking, Kirsten M.; Peteet, Dorothy M.; Anderson, Roger Y.

2012-01-01

316

Landscape ecosystem classification in the Cherokee National Forest, east Tennessee, U.S.A.  

PubMed

A landscape ecosystem classification is described for the 43 800 ha Foothills section (elevation 305 to 610 m) of the southern unit of the Cherokee National Forest. Vegetative cover, landform, and soils data were obtained from sixty 0.04 ha plots located in stands representing late successional stages. Vegetation data were grouped by dominant cover type utilizing agglomerative, hierarchical clustering and detrended correspondence analysis. Detrended canonical correspondence analysis (DCCA) and stepwise discriminant analysis (SDA) were used to identify patterns in species composition explained by environmental variables.Four community types were identified: (1) Tsuga canadensis-Acer saccharum-Fagus grandifolia-Fraxinus americana, (2) Tsuga canadensis-Rhododendron maximum, (3) Quercus prinus, and (4) Quercus prinus-Quercus coccinea-Acer rubrum. A recently developed "Landform Index" that quantifies slope type and degree of protection by adjacent land masses was identified through DCCA and SDA as the most important predictor of community types. The strength of the correlations between elevation and several soil thickness variables with DCCA axis 1 indicated that vegetation varies along an interpreted moisture gradient. No ecological meaning was attributed to the second axis. PMID:24198013

Yoke, K A; Rennie, J C

1996-01-01

317

Polyploidy and variation in the Campanula rotundifolia complex. Part II. (Taxonomic) I. Revision of the groups Saxicolae, Lanceolatae and Alpicolae in Czechoslovakia and adjacent regions  

Microsoft Academic Search

A survey is given of three natural groups of the subsectionHeterophylla (Witas.)Fed. of the genusCampanula L. Within theSaxicolae four taxa of higher rank have been revealed:c. xylocarpa\\u000a Kovanda (2n=34),C. gentilis\\u000a Kovanda (2n=34),C. moravica (Spitzner)Kovanda subsp.moravica (2n=68), andC. moravica subsp.xylorrhiza (O. Schwarz)Kovanda (2n=102). BothAlpicolae andLanceolatae are represented by a single species: the first byC. cochleariifolia\\u000a Lam. (2n=34), the latter byC. serrata

Miloslav Kovanda

1970-01-01

318

Toxicity of pyrolysis gases from wood  

NASA Technical Reports Server (NTRS)

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.

Hilado, C. J.; Huttlinger, N. V.; Oneill, B. A.; Kourtides, D. A.; Parker, J. A.

1977-01-01

319

An assessment of presentism  

E-print Network

that everything we encounter by way of our senses is a present thing. My desk and my computer presently exist as I am now sitting and typing this sentence. I can speak to my friend, who is now 23 years old, though it cannot be the case now that I am speaking... sentences express irreducibly primitive propositions about the world, such as the following: (1) It was the case that Socrates drank hemlock. (2) Dennis Kucinich will not be elected president. (3) It is now cloudy. What is distinctive about...

McDaniel, Brannon David

2004-09-30

320

A streptomycete antagonist to Phellinus weirii, Fomes annosus, and Phytophthora cinnamomi.  

PubMed

An actinomycete isolated from the rhizoplane of nitrogen-fixing nodules of Ceanothus velutinus was identified as a variety of Streptomyces griseoloalbus. Streptomyces griseoloalbus is a strong antagonist to three destructive root pathogens, Phellinus weirii, Fomes annosus, and Phytophthora cinnamomi, inhibiting all three on several culture media and preventing establishment of F. annosus on hemlock wood disks. The stability and longevity of the antimicrobial substance produced by it, its consistent effect on the pathogens on all substrates, its ability to colonize wood, and its ability to grow at 10 degrees C suggest biological control possibilities for this organism in the Pacific Northwest. PMID:7397603

Rose, S L; Li, C Y; Hutchins, A S

1980-05-01

321

Forest Ecology  

NSDL National Science Digital Library

This tutorial discusses the concept of forest succession, the stages of development which forest plants follow as they grow or re-grow following an event such as a forest fire or insect infestation. Topics include the role of pioneer species, the transition to longer-lived plants such as lodgepole pine, Douglas fir, and subalpine fir, and the transition to climax species such as cedars, hemlocks and spruce. There is also a discussion of the lifespan of climax forests and the wildlife species that inhabit the forest in each stage of succession. A quiz and glossary are provided.

322

Characterization of baculoviruses from the Martignoni collection.  

PubMed

47 samples from the Martignoni baculovirus collection were characterized by PCR amplification of the lef-8 gene. This led to the identification of sequences from viruses that either were not present in the database, or had been identified, but not further characterized. These included an NPV and a GV from Pseudoletia (Mythimna) unipuncta, and NPVs from Coloradia pandora, the oak and hemlock looper (probably Lambdina sp.), Peridroma sp., the pine butterfly (probably Neophasia sp.), Hemileuca sp., Orgyia vetusta, and several Choristoneura sp. A phylogenetic tree was constructed relating these viruses to their closest relatives in the database. PMID:23628143

Rohrmann, George F

2013-09-01

323

Biogenic and thermogenic origins of natural gas in Cook Inlet basin, Alaska.  

USGS Publications Warehouse

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

Claypool, G. E.; Threlkeld, C. N.; Magoon, L. B.

1980-01-01

324

[Mites (Acari) from rubber trees (Hevea brasiliensis Muell. Arg., Euphorbiaceae) and spontaneous euphorbiaceous in rubber trees cultivation].  

PubMed

Quarterly samples were done in 2001 on three rubber tree plantation in the northwest of the state of São Paulo. Three rubber trees of each locality were sampled. Between the rows of rubber tree four species of spontaneous euphorbiaceous were collected: Chamaesyce hirta, C. hyssopifolia, Euphorbia heterophylla and Phyllanthus tenellus. A total of 8.954 mites of 38 species, belonging to 31 genera of 11 families were collected. Tydeidae and Phytoseiidae had the highest diversity of species, 9 and 7, respectively. The most abundant families were Eriophyidae (3.594), Tydeidae (2.825) and Tenuipalpidae (1.027). The most abundant species on the rubber trees were: phytophagous - Calacarus heveae Feres, Tenuipalpus heveae Baker, Lorryia sp.2, Lorryia formosa Cooreman and Lorryia sp.1; predators - Zetzellia quasagistemas Hernandes & Feres, Pronematus sp., Iphiseiodes zuluagai Denmark & Muma and Euseius citrifolius Denmark & Muma. Among the spontaneous euphorbiaceous, predatory mites were abundantly found on C. hirta and E. heterophylla, mainly Pronematus sp. and E. citrifolius, suggesting that these plants could be important in the maintenance of these predators in the rubber tree cultivation areas. However, plants that can shelter predators and at the same time exert strong competition (nutrients, water etc) to rubber trees, can not be recommended for pest management programs. Studies about competition between rubber trees and spontaneous plants need to be conducted for feasible efficient programs of environmental management, aiming at the control of pest mites of rubber tree. PMID:18813750

Bellini, Marcos R; Feres, Reinaldo J F; Buosi, Renato

2008-01-01

325

Poisonous plants: effects on embryo and fetal development.  

PubMed

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. PMID:24339034

Panter, Kip E; Welch, Kevin D; Gardner, Dale R; Green, Benedict T

2013-12-01

326

The northern and southern sections of the western ca. 1880 Ma Circum-Superior Large Igneous Province, North America: The Pickle Crow dyke connection?  

NASA Astrophysics Data System (ADS)

The ca. 1880 Ma Circum-Superior Large Igneous Province (LIP) consists of a number of discontinuous segments known to cover a significant portion of the margin of the Superior Province craton in North America. New geochemical and isotopic data from western segments of this LIP support a common origin for the these segments and suggest that magmatism in the Lake Superior region may have been fed through the ~ 600 km long Pickle Crow dyke from a source north of the Fox River Belt in northeastern Manitoba. The Fox River Belt, Pickle Crow dyke and sections of the Hemlock Formation in the Lake Superior region possess trace element signatures which are similar to those of more recent oceanic plateaux. The Hemlock Formation displays a heterogeneous geochemical signature. This chemical heterogeneity can in part be explained by lithospheric contamination and possibly by source heterogeneity. The tectonomagmatic setting in which these igneous rocks were formed could have involved a mantle plume. Evidence supporting a plume origin includes high MgO volcanic rocks, high calculated degrees of partial melting and geochemical signatures similar to those of oceanic plateaux.

Minifie, Matthew J.; Kerr, Andrew C.; Ernst, Richard E.; Hastie, Alan R.; Ciborowski, T. Jake R.; Desharnais, Guy; Millar, Ian L.

2013-08-01

327

Modern pollen deposition in Long Island Sound  

USGS Publications Warehouse

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.

Beuning, Kristina R.M.; Fransen, Lindsey; Nakityo, Berna; Mecray, Ellen L.; Bucholtz ten Brink, Marilyn R.

2000-01-01

328

Mapped plant macrofossil and pollen records of late Quaternary vegetation change in eastern North America  

SciTech Connect

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.

Jackson, S.T.; Overpeck, J.T.; Webb, T. III [Northern Arizona Univ., Flagstaff, AZ (United States)]|[NOAA/NGDC, Boulder, CO (United States)]|[Brown Univ., Providence, RI (United States)

1995-06-01

329

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)

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.

Millar, Constance I.; King, John C.; Westfall, Robert D.; Alden, Harry A.; Delany, Diane L.

2006-09-01

330

The Pine Bark Adelgid, Pineus strobi, Contains Two Novel Bacteriocyte-Associated Gammaproteobacterial Symbionts  

PubMed Central

Bacterial endosymbionts of the pine bark adelgid, Pineus strobi (Insecta: Hemiptera: Adelgidae), were investigated using transmission electron microscopy, 16S and 23S rRNA-based phylogeny, and fluorescence in situ hybridization. Two morphologically different symbionts affiliated with the Gammaproteobacteria were present in distinct bacteriocytes. One of them (“Candidatus Annandia pinicola”) is most closely related to an endosymbiont of Adelges tsugae, suggesting that they originate from a lineage already present in ancient adelgids before the hosts diversified into the two major clades, Adelges and Pineus. The other P. strobi symbiont (“Candidatus Hartigia pinicola”) represents a novel symbiont lineage in members of the Adelgidae. Our findings lend further support for a complex evolutionary history of the association of adelgids with a phylogenetically diverse set of bacterial symbionts. PMID:24271164

Toenshoff, Elena R.; Szabo, Gitta; Gruber, Daniela

2014-01-01

331

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)

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.

Okuno, Mitsuru; Nakamura, Toshio; Geshi, Nobuo; Kimura, Katsuhiko; Saito-Kokubu, Yoko; Kobayashi, Tetsuo

2013-01-01

332

Inhibition of methane consumption in forest soils by monoterpenes  

SciTech Connect

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.

Amaral, J.A.; Knowles, R. [McGill Univ., Ste. Anne-de-Bellevue, Quebec (Canada). Dept. of Natural Resource Sciences] [McGill Univ., Ste. Anne-de-Bellevue, Quebec (Canada). Dept. of Natural Resource Sciences

1998-04-01

333

Mapped plant-macrofossil and pollen records of late quaternary vegetation change in Eastern North America  

NASA Astrophysics Data System (ADS)

Macrofossil presence/absence maps and isopoll maps in 3000-year intervals show how ranges and abundance maxima for 12 eastern North American tree and shrub taxa ( Picea, P. glauca, P. mariana, Larix laricina, Abies balsamea, Tsuga canadensis, Pinus strobus, P. resinosa, P. banksiana, Betula papyrifera, B. alleghaniensis, B. Series Humiles) have changed from the last glacial maximum to the present. The macrofossil maps corroborate patterns shown by the isopoll maps and provide spatial detail and taxonomic resolution. The macrofossils confirm the inference from pollen data that unglaciated southeastern North America was cooler during the last glacial maximum (18 and 15 ka) than simulated by the COHMAP experiments with the NCAR CCM0 general circulation model. The geographic distribution of macrofossil occurrences during the Late glacial (12 and 9 ka) indicate that migration lag of boreal species did not occur at regional to subcontinental scales, and that pollen assemblages lacking modern analogs resulted from climate gradients lacking modern analogs. Early Holocene (9 and 6 ka) macrofossil maps show rapid northward expansion of tree species ranges into deglaciated regions. The data also show modest contractions of northern range limits of temperate species and expansions of southern range limits of boreal species in response to cooling trends during the late Holocene (3 and 0 ka). Comparison of modern macrofossil maps of nine of these taxa with corresponding range maps confirm that the macrofossils record the geographic ranges accurately. Comparison of the modern macrofossil maps with maps of tree growing-stock volume shows that for some taxa ( Abies, Tsuga) macrofossil occurrences were most frequent in regions of maximum tree abundance. Comparison of modern isopoll maps with the modern range and growing-stock volume maps indicate that, in contrast to the macrofossil data, the pollen data provide poorer resolution of range limits for most taxa, but better indications of abundance maxima and minima within the ranges.

Jackson, Stephen T.; Overpeck, Jonathan T.; Webb-, Thompson; Keattch, Sharen E.; Anderson, Katherine H.

334

Postglacial vegetation, fire, and climate history of the Siskiyou Mountains, Oregon, USA  

NASA Astrophysics Data System (ADS)

The forests of the Siskiyou Mountains are among the most diverse in North America, yet the long-term relationship among climate, diversity, and natural disturbance is not well known. Pollen, plant macrofossils, and high-resolution charcoal data from Bolan Lake, Oregon, were analyzed to reconstruct a 17,000-yr-long environmental history of high-elevation forests in the region. In the late-glacial period, the presence of a subalpine parkland of Artemisia, Poaceae, Pinus, and Tsuga with infrequent fires suggests cool dry conditions. After 14,500 cal yr B.P., a closed forest of Abies, Pseudotsuga, Tsuga, and Alnus rubra with more frequent fires developed which indicates more mesic conditions than before. An open woodland of Pinus, Quercus, and Cupressaceae, with higher fire activity than before, characterized the early Holocene and implies warmer and drier conditions than at present. In the late Holocene, Abies and Picea were more prevalent in the forest, suggesting a return to cool wet conditions, although fire-episode frequency remained relatively high. The modern forest of Abies and Pseudotsuga and the present-day fire regime developed ca. 2100 cal yr B.P. and indicates that conditions had become slightly drier than before. Sub-millennial-scale fluctuations in vegetation and fire activity suggest climatic variations during the Younger Dryas interval and within the early Holocene period. The timing of vegetation changes in the Bolan Lake record is similar to that of other sites in the Pacific Northwest and Klamath region, and indicates that local vegetation communities were responding to regional-scale climate changes. The record implies that climate-driven millennial- to centennial-scale vegetation and fire change should be considered when explaining the high floristic diversity observed at present in the Siskiyou Mountains.

Briles, Christy E.; Whitlock, Cathy; Bartlein, Patrick J.

2005-07-01

335

Correct names for some of the closest relatives of Carica papaya: A review of the Mexican/Guatemalan genera Jarilla and Horovitzia  

PubMed Central

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

Carvalho, Fernanda Antunes; Renner, Susanne S.

2013-01-01

336

Pushed to the limit: consequences of climate change for the Araucariaceae: a relictual rain forest family  

PubMed Central

Background and Aims Under predicted climate change scenarios, increased temperatures are likely to predispose trees to leaf and other tissue damage, resulting in plant death and contraction of already narrow distribution ranges in many relictual species. The effects of predicted upward temperatures may be further exacerbated by changes in rainfall patterns and damage caused by frosts on trees that have been insufficiently cold-hardened. The Araucariaceae is a relictual family and the seven species found in Australia have limited natural distributions characterized by low frost intensity and frequency, and warm summer temperatures. The temperature limits for these species were determined in order to help understand how such species will fare in a changing climate. Methods Experiments were conducted using samples from representative trees of the Araucariaceae species occurring in Australia, Agathis (A. atropurpurea, A. microstachya and A. robusta), Arauacaria (A. bidwilli, A. cunninghamii and A. heterophylla) and Wollemia nobilis. Samples were collected from plants grown in a common garden environment. Lower and higher temperature limits were determined by subjecting detached winter-hardened leaves to temperatures from 0 to –17 °C and summer-exposed leaves to 25 to 63 °C, then measuring the efficiency of photosystem II (Fv/Fm) and visually rating leaf damage. The exotherm, a sharp rise in temperature indicating the point of ice nucleation within the cells of the leaf, was measured on detached leaves of winter-hardened and summer temperature-exposed leaves. Key Results Lower temperature limits (indicated by FT50, the temperature at which PSII efficiency is 50 %, and LT50 the temperature at which 50 % visual leaf damage occurred) were approx. –5·5 to –7·5 °C for A. atropurpurea, A. microstachya and A. heterophylla, approx. –7 to –9 °C for A. robusta, A. bidwillii and A. cunninghamii, and –10·5 to –11 °C for W. nobilis. High temperature damage began at 47·5 °C for W. nobilis, and occurred in the range 48·5–52 °C for A. bidwillii and A. cunninghamii, and in the range 50·5–53·5 °C for A. robusta, A. microstachya and A. heterophylla. Winter-hardened leaves had ice nucleation temperatures of –5·5 °C or lower, with W. nobilis the lowest at –6·8 °C. All species had significantly higher ice nucleation temperatures in summer, with A. atropurpurea and A. heterophylla forming ice in the leaf at temperatures >3 °C higher in summer than in winter. Wollemia nobilis had lower FT50 and LT50 values than its ice nucleation temperature, indicating that the species has a degree of ice tolerance. Conclusions While lower temperature limits in the Australian Araucariaceae are generally unlikely to affect their survival in wild populations during normal winters, unseasonal frosts may have devastating effects on tree survival. Extreme high temperatures are not common in the areas of natural occurrence, but upward temperature shifts, in combination with localized radiant heating, may increase the heat experienced within a canopy by at least 10 °C and impact on tree survival, and may contribute to range contraction. Heat stress may explain why many landscape plantings of W. nobilis have failed in hotter areas of Australia. PMID:21727080

Offord, Catherine A.

2011-01-01

337

Wall Analyses of Lophocolea Seta Cells (Bryophyta) Before and After Elongation 1  

PubMed Central

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

Thomas, Robert J.

1977-01-01

338

Wall analyses of lophocolea seta cells (bryophyta) before and after elongation.  

PubMed

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. PMID:16659846

Thomas, R J

1977-03-01

339

Labeling patterns of chloroplastidic isoprenoids in cultured cells of liverwort Ptychanthus striatus.  

PubMed

Incorporation studies administering 2H- and 13C-labeled mevalonate (MVA) and 13C-labeled glucose to suspension cultured cells of the liverwort, Ptychanthus striatus, were carried out in order to examine the biosynthesis of the phytyl side-chain of chlorophyll a. Administration of 13C- and 2H-labeled MVA provided evidence for the involvement of the MVA pathway in the phytyl side-chain biosynthesis and preferential labeling of the farnesyl diphosphate (FPP)-derived portion. An alternate labeling pattern in the phytyl side-chain was observed which was slightly different to the non-equivalent labeling in other liverworts, such as Heteroscyphus planus and Lophocolea heterophylla and in the hornwort, Anthoceros punctatus. The labeling pattern observed after the administration of 13C-labeled glucose revealed the simultaneous involvement of the non-MVA pathway in the phytol biosynthesis of P. striatus cells. PMID:11440120

Karunagoda, R P; Itoh, D; Katoh, K; Nabeta, K

2001-05-01

340

Congenital skeletal malformations and cleft palate induced in goats by ingestion of Lupinus, Conium and Nicotiana species.  

PubMed

Three piperidine alkaloid containing plants, Conium maculatum (poison-hemlock), Nicotiana glauca (tree tobacco) and Lupinus formosus (lunara lupine), induced multiple congenital contractures (MCC) and palatoschisis in goat kids when their dams were gavaged with the plant during gestation days 30-60. The skeletal abnormalities included fixed extension or flexure of the carpal, tarsal, and fetlock joints, scoliosis, lordosis, torticollis and rib cage abnormalities. Clinical signs of toxicity included those reported in sheep, cattle and pigs--ataxia, incoordination, muscular weakness, prostration and death. One quinolizidine alkaloid containing plant, Lupinus caudatus (tailcup lupine), on the other hand, which is also known to cause MCC in cows, caused only slight signs of toxicity in pregnant goats and no teratogenic effects in their offspring. PMID:2089736

Panter, K E; Keeler, R F; Bunch, T D; Callan, R J

1990-01-01

341

[The attempts at drug therapy of cancer by Anton Störck (1731-1803). History of experimental pharmacology in the old Vienna Medical School].  

PubMed

The essay deals with the development of medical research in Vienna - especially the development of therapeutic drugs. This progress is related to the philosophical, historical, and political background of the enlightened absolutism and the reformatory efforts of van Swieten during the regency of Maria Theresia in Austria. Anton Störck's research on hemlock (Conium maculatum) is used as an example. The method of Störck's research-work is described. Furthermore it is demonstrated to what extent Störck's data, deduced from empirical examinations, are integrated in the official medical system, i.e. Boerhaave's iatromechanic system. Finally the attempt is made to correlate these processes of medical history with the scientific-historical model of Thomas Kuhn. PMID:7043908

Schweppe, K W; Probst, C

1982-03-15

342

Stereoselective potencies and relative toxicities of coniine enantiomers.  

PubMed

Coniine, one of the major toxic alkaloids present in poison hemlock ( Conium maculatum), occurs in two optically active forms. A comparison of the relative potencies of (+)- and (-)-coniine enantiomers has not been previously reported. In this study, we separated the enantiomers of coniine and determined the biological activity of each enantiomer in vitro and in vivo. The relative potencies of these enantiomers on TE-671 cells expressing human fetal nicotinic neuromuscular receptors had the rank order of (-)-coniine > (+/-)-coniine > (+)-coniine. A mouse bioassay was used to determine the relative lethalities of (-)-, (+/-)-, and (+)-coniine in vivo. The LD 50 values of the coniine enantiomers were 7.0, 7.7, and 12.1 mg/kg for the (-)-, (+/-)-, and (+)- forms of coniine, respectively. The results from this study demonstrate that there is a stereoselective difference in the in vitro potencies of the enantiomers of coniine that directly correlates with the relative toxicities of the enantiomers in vivo. PMID:18763813

Lee, Stephen T; Green, Benedict T; Welch, Kevin D; Pfister, James A; Panter, Kip E

2008-10-01

343

A review of the silicon material task  

NASA Technical Reports Server (NTRS)

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.

Lutwack, R.

1984-01-01

344

Primary deforestation and regrowth on limestone slopes on Vancouver Island, British Columbia  

SciTech Connect

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.

Harding, K.A.; Ford, D.C. (McMaster Univ., Hamilton, Ontario (Canada). Dept. of Geography)

1992-01-01

345

Evaluating Paleoecological Patterns Using Paleoenvironmental Proxies: The Promise and the Peril  

NASA Astrophysics Data System (ADS)

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 Michigan and Wisconsin during an extended pluvial period (4000-3000 yr BP) that followed on a drought of extraordinary duration and severity (4200-4000 yr BP). Continued expansion of yellow birch, as well as hemlock and beech, after 3000 yr BP was mediated by edaphic mosaics and centennial-scale pluvial events. Our experience indicates that integrated paleoecological and paleoclimatological studies have payoffs for ecology, paleoecology, and paleoclimatology. Perils, though real, are no different from those encountered in other interdisciplinary enterprises in the historical sciences. We identify six key challenges for continued progress in this area: (1)identifying, refining, and applying paleoclimate proxies that are sensitive to the same climate variables and at the same timescales as the ecological systems of interest. (2) correlating events in time among records, particularly when paleoecological and paleoclimate data derive from different archives. (3) identifying and modeling lags in ecological response to climate forcings. (4) determining proximal mechanisms of past ecological responses to climate changes. (5) assessing indirect responses to climate forcing, and interactions between climate and other factors (e.g., pests, wildfires). (6) determining "when to quit" - when to conclude that climate forcing of an observed ecological event is insupportable (versus assuming that the proxies examined to date simply aren't sensitive to whatever the ecological system is responding to). Meeting these challenges will require engagement and collaboration among paleoecologists, paleoclimatologists, geochronologists, and ecologists.

Jackson, S. T.; Booth, R. K.

2007-12-01

346

Review of the silicon material task  

SciTech Connect

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 in a Siemens-type process were shown by Hemlock Semiconductor Corporation. The development of other processes is described.

Lutwack, R.

1984-02-01

347

High pressure liquid jet for disintegration of wood: Technical progress report for the period May 1988--September 30, 1988  

SciTech Connect

Most newsprint is made of a mixture of seventy to eighty percent ground wood, and twenty to thirty percent unbleached sulphite or semi-bleached sulphate pulp. Presently, spruce is the most desirable species for wood pulp production, with the true firs, western hemlock, and southern pine following in order. It is anticipated that the use of hardwoods in newsprint will increase with time. In the manufacture of wood pulp for paper production, conventional practice is to grind debarked logs using a revolving grindstone. The abrasive stone causes individual wood fibers and fiber bundles to be separated from the log. Water is added to the ground pulp, during grinding, through a shower pipe which sprays water on the periphery of the stone. This water adsorbs the frictional heat generated at the interface between the stone and the wood, washes the fibers from the surface of the stone, and controls the consistency of the resulting pulp. 6 refs., 2 figs., 2 tabs.

Not Available

1988-01-01

348

Antifeedant compounds from three species of Apiaceae active against the field slug, Deroceras reticulatum (Muller).  

PubMed

Extracts of volatiles from foliage of three plants in the Apiaceae, Conium maculatum L. (hemlock), Coriandrum sativum L. (coriander), and Petroselinum crispum Mill. (Nym.) (parsley), previously shown to exhibit antifeedant activity in assays with the field slug, Deroceras reticulatum (Muller) (Limacidae: Pulmonata), were studied further to identify the active components. Coupled gas chromatography-mass spectrometry (GC-MS) and neurophysiological assays using tentacle nerve preparations resulted in the identification of 11 active compounds from the three extracts. Wheat flour feeding bioassays were used to determine which of these compounds had the highest antifeedant activity. One of the most active compounds was the alkaloid gamma-coniceine, from C. maculatum. The role of potentially toxic alkaloids as semiochemicals and the potential for using such compounds as crop protection agents to prevent slug feeding damage is discussed. PMID:15139308

Birkett, Michael A; Dodds, Catherine J; Henderson, Ian F; Leake, Lucy D; Pickett, John A; Selby, Martin J; Watson, Peter

2004-03-01

349

Host tree age as a selective pressure leading to local adaptation of a population of a polyphagous Lepidoptera in virgin boreal forest.  

PubMed

We tested the hypothesis that host tree age may act as a selective factor and lead to local adaptation of the hemlock looper (Lambdina fiscellaria), a geometrid Lepidoptera that has a wide geographical distribution and has evolved in different eco-zones characterized by different levels of floristic composition, age structure and fragmentation level. Considering that hemlock looper outbreaks mainly occurred in old forests, we compared the biological performances of two populations. The first population was collected in the northern virgin boreal forest, which is dominated by mature and overmature coniferous stands that have not suffered from human disturbance. The other population was collected in the southern mixed-wood forest, which is more diversified and has been modified by forest harvesting. Larvae were reared under controlled conditions on foliage from three age classes of balsam fir trees: juvenile, mature and overmature. Although we measured significant variations of biological performances between the two populations, no significant effect of the age of the balsam fir trees could be detected for males from both populations or for females from the southern population. However, northern females were strongly affected by the age of balsam fir trees on which they fed, as their pupal weight was 12% higher and their fecundity increased by 27% on overmature trees compared with juvenile ones. These results indicate that under the same selective pressure, females adapt their strategy to maximize their fitness, and thus they appear as the driving force of evolution through the local adaptation concept. Furthermore, the two populations evolved in distinct habitats and their adaptation reflects selective pressures occurring inside their original environment. This is the first report on local adaptation of an herbivore that is mediated by host tree age. Changes in forest age structure may have a considerable impact on insect local adaptation and presumably on their population dynamics. PMID:19224661

Berthiaume, R; Bauce, E; Hébert, C; Brodeur, J

2009-10-01

350

Early and Middle Pleistocene vegetation history of the Médoc region, southwest France  

NASA Astrophysics Data System (ADS)

Pleistocene deposits, together with their pollen, plant macrofossil, foraminiferal, dinoflagellate and coleopteran remains, from five sites along the Atlantic coast of the Médoc Peninsula are described and discussed. Sediments making up the Négade Formation are shown to have been laid down under either estuarine or lagoonal conditions when closed Quercus-Pinus-Tsuga canadensis regional woodland existed. Comparison with plant records from The Netherlands indicates that these deposits are most likely attributable to either the Early Pleistocene Bavel Interglacial (marine oxygen isotope stage (MIS) 31), or an interglacial of the Waalian (MIS 37-49) or Tiglian (MIS 63-79). In addition, clays assigned to the Argiles du Gurp sensu stricto, were similarly deposited in either an estuary or lagoon, which subsequently was cut off from the sea. A freshwater lake with vegetation dominated by Azolla filiculoides then developed. This was succeeded by reedswamp and an organic mud (termed Lignite in the corresponding French stratigraphical records) formed. Regional Quercus-Abies woodland was replaced by one with Pinus dominant and Pterocarya a minor component. Comparison with plant records from France and other parts of Europe suggest that the clays and organic mud might be correlated with the Holsteinian (Praclaux) Interglacial (MIS 11c). Copyright

O'Brien, C. E.; Jones, R. L.

2003-09-01

351

Holocene vegetation history and Lake Michigan lake-level fluctuations on the southern shore of the Upper Peninsula of Michigan  

SciTech Connect

A 250-cm sediment core with a base radiocarbon date of 7960 yrs BP was collected in June of 1993 from Elbow Lake, Mackinac Co., Michigan. Radiocarbon dates and fossil pollen preserved in lake sediments indicate that changes in vegetation are related to changes in climate and proximity to the Lake Michigan shoreline. Basal radiocarbon dates on sediment cores from a transect of ponds combined with tree-ring cores and GLO surveyor notes of a shipwreck reveal an average late-Holocene rate of regression of 3 feet per year. The pollen record, sediment stratigraphy, and sediment accumulation rates show that this general retreat of the shoreline was punctuated by periodic high stands. Radiocarbon dates of [approximately]6900 yrs BP indicate a high stand of Lake Michigan during the late-Chippewa state of Lake Michigan, prior to the classically recognized Nipissing-I high stand at [approximately]4500 yrs PB. Pollen percentages for Tsuga canadensis and Fagus grandifolia both reach > 1% by 5500 yrs BP, indicating that the northern shore of Lake Michigan provided suitable habitat for colonization by these species. Establishment of F. grandifolia at this time is associated with a rise in water table and is [approximately]2000 years prior to its expansion into the interior of the Upper Peninsula after 3500 yrs BP. A further increase in mesic hardwoods along with T. canadensis to their modern level by 2200 yrs BP is associated with an increase in sediment accumulation rate, indicative of a rising lake level and moister climate.

Petty, W.H. (Univ. of Tennessee, Knoxville, TN (United States))

1994-06-01

352

Paleoecology of late-glacial terrestrial deposits with in situ conifers from the submerged continental shelf of western canada  

NASA Astrophysics Data System (ADS)

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.

Lacourse, Terri; Mathewes, Rolf W.; Fedje, Daryl W.

2003-09-01

353

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 August 2009-30 September 2009.  

PubMed

This article documents the addition of 238 microsatellite marker loci and 72 pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Adelges tsugae, Artemisia tridentata, Astroides calycularis, Azorella selago, Botryllus schlosseri, Botrylloides violaceus, Cardiocrinum cordatum var. glehnii, Campylopterus curvipennis, Colocasia esculenta, Cynomys ludovicianus, Cynomys leucurus, Cynomys gunnisoni, Epinephelus coioides, Eunicella singularis, Gammarus pulex, Homoeosoma nebulella, Hyla squirella, Lateolabrax japonicus, Mastomys erythroleucus, Pararge aegeria, Pardosa sierra, Phoenicopterus ruber ruber and Silene latifolia. These loci were cross-tested on the following species: Adelges abietis, Adelges cooleyi, Adelges piceae, Pineus pini, Pineus strobi, Tubastrea micrantha, three other Tubastrea species, Botrylloides fuscus, Botrylloides simodensis, Campylopterus hemileucurus, Campylopterus rufus, Campylopterus largipennis, Campylopterus villaviscensio, Phaethornis longuemareus, Florisuga mellivora, Lampornis amethystinus, Amazilia cyanocephala, Archilochus colubris, Epinephelus lanceolatus, Epinephelus fuscoguttatus, Symbiodinium temperate-A clade, Gammarus fossarum, Gammarus roeselii, Dikerogammarus villosus and Limnomysis benedeni. This article also documents the addition of 72 sequencing primer pairs and 52 allele specific primers for Neophocaena phocaenoides. PMID:21565018

Abdoullaye, Doukary; Acevedo, I; Adebayo, Abisola A; Behrmann-Godel, Jasminca; Benjamin, R C; Bock, Dan G; Born, Céline; Brouat, Carine; Caccone, Adalgisa; Cao, Ling-Zhen; Casado-Amezúa, P; Catanéo, J; Correa-Ramirez, M M; Cristescu, Melania E; Dobigny, Gauthier; Egbosimba, Emmanuel E; Etchberger, Lianna K; Fan, Bin; Fields, Peter D; Forcioli, D; Furla, P; Garcia de Leon, F J; García-Jiménez, R; Gauthier, Philippe; Gergs, René; González, Clementina; Granjon, Laurent; Gutiérrez-Rodríguez, Carla; Havill, Nathan P; Helsen, P; Hether, Tyler D; Hoffman, Eric A; Hu, Xiangyang; Ingvarsson, Pär K; Ishizaki, S; Ji, Heyi; Ji, X S; Jimenez, M L; Kapil, R; Karban, R; Keller, Stephen R; Kubota, S; Li, Shuzhen; Li, Wansha; Lim, Douglas D; Lin, Haoran; Liu, Xiaochun; Luo, Yayan; Machordom, A; Martin, Andrew P; Matthysen, E; Mazzella, Maxwell N; McGeoch, Mélodie A; Meng, Zining; Nishizawa, M; O'Brien, Patricia; Ohara, M; Ornelas, Juan Francisco; Ortu, M F; Pedersen, Amy B; Preston, L; Ren, Qin; Rothhaupt, Karl-Otto; Sackett, Loren C; Sang, Qing; Sawyer, G M; Shiojiri, K; Taylor, Douglas R; Van Dongen, S; Van Vuuren, Bettine Jansen; Vandewoestijne, S; Wang, H; Wang, J T; Wang, L E; Xu, Xiang-Li; Yang, Guang; Yang, Yongping; Zeng, Y Q; Zhang, Qing-Wen; Zhang, Yongping; Zhao, Y; Zhou, Yan

2010-01-01

354

Climate Variability and Human Impacts at Tivoli North Bay, Hudson River, New York  

NASA Astrophysics Data System (ADS)

The investigation of pollen, spores, charcoal, organic carbon content, C/N ratios, and radiometric dating provides a paleoecological study of Tivoli North Bay (42oN, 74oW), lower Hudson River. This freshwater tidal marsh record reveals vegetational changes which reflect local and regional vegetational and climatic shifts. Significant charcoal maxima at the base of the core appear to be parallel to the well-dated 500-yr charcoal maxima in Piermont Marsh downriver, implying a regional climatic impact of the Medieval Warming Interval in the lower Hudson Valley. European settlement is marked by very abrupt shift in vegetation and sediment composition as a result of deforestation, invasive species introduction, and infrastructure construction. Betula became a successful replacement of forest dominants such as Quercus, Pinus, and Tsuga. Weedy species including Ambrosia, Impatiens, Chenopodiaceae and Gramineae expand as human impact increases. Higher sedimentation rate due to higher inorganic input appears to contribute to marsh composition changes as woody taxa such as Salix, Cephalanthus, Fraxinus, and Vitis appear in the wetland in the most recent centuries. Additional radiometric control linking stratigraphy from Tivoli North Bay to other Hudson River wetlands as well as pollen and spore analysis of river and air traps will lead to a better understanding of the Hudson watershed history. Significant extended droughts in the Hudson watershed due to natural variability have major implications for future water availability in this landscape.

Sritrairat, S.; Peteet, D. M.; Griffin, K.; Kurdyla, D.; Guilderson, T.

2006-12-01

355

Does Canopy Position Affect Wood Specific Gravity in Temperate Forest Trees?  

PubMed Central

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

WOODCOCK, D. W.; SHIER, A. D.

2003-01-01

356

Molecular and pathogenic variation within Melampsora on Salix in western North America reveals numerous cryptic species.  

PubMed

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. PMID:21558505

Bennett, Chandalin; Aime, M Catherine; Newcombe, George

2011-01-01

357

Small latitudinal shift in the Kuroshio Extension (Central Pacific) during glacial times: evidence from pollen transport  

NASA Astrophysics Data System (ADS)

The mid-latitude area of the Central Pacific is sensitive to ocean environmental change because latitudinal fluctuation in a transition zone between subtropical and subarctic waters has played an important role in climatic change in East Asia, the North Pacific and North America. Higher amounts of pollen and spores were found in core H3571 on the Hess Rise during the glacials than during the interglacials. Pollen originating from broadleaf deciduous forest in warm and humid environments as well as from boreal conifers and tundra/park-tundra in cold and wet environments occurred during the glacials. The boreal conifer pollen such as Tsuga, Picea, and Haploxylon could originate from the central Japanese archipelago, that Ephedra was supplied from the Asian continent, and that the main source regions for the rest of the pollen and spores were from the southern Japanese archipelago to the area around the East China Sea. Therefore, ocean current transportation was important for the transportation of pollen and spores to the Hess Rise. This evidence demonstrates a small southward shift in the Kuroshio Extension during the glacials. It also suggests that terrestrial organic matter (OM) deposited in the open sea may also be transported by ocean currents, reflecting coastal terrestrial environments, although it is widely believed that terrestrial OM in open sea sediments is of aerosol origin.

Kawahata, Hodaka; Ohshima, Hideaki

2002-08-01

358

Paleoecology of a Northern Michigan Lake and the relationship among climate, vegetation, and Great Lakes water levels  

USGS Publications Warehouse

We reconstructed Holocene water-level and vegetation dynamics based on pollen and plant macrofossils from a coastal lake in Upper Michigan. Our primary objective was to test the hypothesis that major fluctuations in Great Lakes water levels resulted in part from climatic changes. We also used our data to provide temporal constraints to the mid-Holocene dry period in Upper Michigan. From 9600 to 8600 cal yr B.P. a shallow, lacustrine environment characterized the Mud Lake basin. A Sphagnum-dominated wetland occupied the basin during the mid-Holocene dry period (???8600 to 6600 cal yr B.P.). The basin flooded at 6600 cal yr B.P. as a result of rising water levels associated with the onset of the Nipissing I phase of ancestral Lake Superior. This flooding event occured contemporaneously with a well-documented regional expansion of Tsuga. Betula pollen increased during the Nipissing II phase (4500 cal yr B.P.). Macrofossil evidence from Mud Lake suggests that Betula alleghaniensis expansion was primarily responsible for the rising Betula pollen percentages. Major regional and local vegetational changes were associated with all the major Holocene highstands of the western Great Lakes (Nipissing I, Nipissing II, and Algoma). Traditional interpretations of Great Lakes water-level history should be revised to include a major role of climate. ?? 2002 University of Washington.

Booth, R.K.; Jackson, S.T.; Thompson, T.A.

2002-01-01

359

Using Peatland Archives to Assess Climate Forcing of Holocene Vegetational Changes: Case Studies From the Great Lakes Region  

NASA Astrophysics Data System (ADS)

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 between rapid expansion and extended quiescence. The extent to which these patterns were governed by climate variations versus migration lag or geographic barriers has remained unclear. Peatland records from the Lake Superior region indicate that the migrations were paced by climate variation. For example, rapid westward expansion of yellow birch occurred during a 1200-yr period of sustained wet conditions, following on the heels of a severe multidecadal drought 4200-4000 yr BP. Widespread forest disturbance during the drought may have facilitated subsequent expansion of yellow birch. Beech expansion also occurred during wet intervals. 3. Beech populations declined and pine increased across the central Great Lakes region 1100 700 yr BP. This has been variously attributed to late Holocene cooling and to widespread fires set by Native Americans. Records from an ombrotrophic peatland in southeastern Lower Michigan reveal that the beech decline was coincident with onset of a series of severe, multidecadal drought events.

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

360

Petroleum geology of Cook Inlet basin - an exploration model  

USGS Publications Warehouse

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 between reservoir rocks and likely Middle Jurassic source rocks also implies a delay in the generation and expulsion of oil from Jurassic until late Tertiary when localized basin subsidence and thick sedimentary fill brought older, deeper rocks to the temperature required for petroleum generation. Reservoir porosities, crude oil properties, the type of oil field traps, and the tectonic framework of the oil fields on the west flank of the basin provide evidence used to reconstruct an oil migration route. The route is inferred to commence deep in the truncated Middle Jur ssic rocks and pass through the porous West Foreland Formation in the McArthur River field area to a stratigraphic trap in the Oligocene Hemlock Conglomerate and the Oligocene part of the Tyonek Formation at the end of Miocene time. Pliocene deformation shut off this route and created localized structural traps, into which the oil moved by secondary migration to form the Middle Ground Shoal, McArthur River, and Trading Bay oil fields. Oil generation continued into the Pliocene, but this higher API gravity oil migrated along a different route to the Granite Point field.

Magoon, L. B.; Claypool, G. E.

1981-01-01

361

Measuring forest structure and biomass using EchidnaRTM ground-based lidar  

NASA Astrophysics Data System (ADS)

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 2010 data. Stem density decreased and mean DBH increased at both sites, as small and weak trees were felled by the ice.

Yao, Tian

362

Kootenai River White Sturgeon Investigations; White Sturgeon Spawning and Recruitment Evaluation, 2003-2004 Annual Report.  

SciTech Connect

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 the Set and Jet Program. Sixteen larval fish were collected, but no prejuvenile white sturgeon were collected. Juvenile white sturgeon sampling started July 14, 2003 and continued through September 18, 2003. A total of 330 h of gillnetting effort captured 238 hatchery white sturgeon and three wild white sturgeon.

Rust, Pete; Wakkinen, Virginia (Idaho Department of Fish and Game, Boise, ID)

2005-06-01

363

The Effect of Lidar Point Density on LAI Estimation  

NASA Astrophysics Data System (ADS)

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 in forest inventory applications and tree health evaluations. However, such high-density data is often not available over large areas. In this study we progressively downsampled the high-density discrete lidar data and evaluated the effect on LAI estimation. The AccuPAR data was used as validation and results were compared to existing LAI metrics. This will enable us to determine the minimum point density required for airborne lidar LAI retrieval. Preliminary results show that the data may be substantially thinned to estimate site-level LAI. More detailed results will be presented at the conference.

Cawse-Nicholson, K.; van Aardt, J. A.; Romanczyk, P.; Kelbe, D.; Bandyopadhyay, M.; Yao, W.; Krause, K.; Kampe, T. U.

2013-12-01

364

Detection of long-term trends in carbon accumulation by forests in Northeastern U. S. and determination of causal factors: Final report  

SciTech Connect

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 early 2000's represents a transient pulse that will eventually end as decomposition of the accumulated carbon catches up.

J. William Munger; Steven C. Wofsy; David R. Foster

2012-01-31

365

Extracts from plants used in Mexican traditional medicine activate Ca(2+)-dependent chloride channels in Xenopus laevis oocytes.  

PubMed

The two-electrode voltage-clamp technique was employed to investigate the effects of chloroform-methanol (1:1) extracts derived from five medicinal plants on Xenopus laevis oocytes. When evaluated at concentrations of 1 to 500 microg/ml, the extracts prepared from the aerial parts of Baccharis heterophylla H.B.K (Asteraceae), Chenopodium murale L. (Chenopodiaceae), Desmodium grahami Gray (Leguminosae) and Solanum rostratum Dun (Solanaceae) produced concentration-dependent oscillatory inward currents in the oocytes, while the extract of Gentiana spathacea did not induce any response. The reversal potential of the currents elicited by the active extracts was -17 +/- 2 mV and was similar to the chloride equilibrium potential in oocytes. These ionic responses were independent of extracellular calcium. However, they were eliminated by overnight incubation with BAPTA-AM (10 microM), suggesting that the currents were dependent on intracellular Ca2+ increase. Thus the plant extracts activate the typical oscillatory Ca(2+)-dependent Cl- currents generated in the Xenopus oocyte membrane more probably via a mechanism that involves release of Ca2+ from intracellular reservoirs. These observations suggest that Xenopus oocyte electrophysiological recording constitutes a suitable assay for the study of the mechanisms of action of herbal medicines. PMID:12834007

Rojas, A; Mendoza, S; Moreno, J; Arellano, R O

2003-01-01

366

Pollen Analysis of Natural Honeys from the Central Region of Shanxi, North China  

PubMed Central

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

Song, Xiao-Yan; Yao, Yi-Feng; Yang, Wu-De

2012-01-01

367

Nano silver treatment is effective in reducing bacterial contaminations of Araucaria excelsa R. Br. var. glauca explants.  

PubMed

The downside of plant tissue culture techniques is an unwanted microbial contamination. Elimination of contaminants is the first step of any successful investigation on plant tissue culture. Preliminary experiments on Araucaria excelsa R. Br. var. glauca (Norfolk-Island pine) (syn.: A. heterophylla) showed that most common decontaminants could not successfully eliminate the contamination. Therefore, nano silver (NS) colloids were evaluated for controlling contamination. Treatments were included soaking the explants in NS solution or adding NS to the culture medium. Explants were cultured on MS medium supplemented with appropriate growth regulators for their establishment. Results showed that surface sterilization followed by treatment with 200 mg l-1 of NS with soaking time of 180 min reduced the bacterial contamination from 61.5% to 11.3% and adding 400 mg l-1 NS to the medium reduced the bacterial contamination from 81.25% to 18.75%. Nano silver could be applied without adverse effects on plant growth and development. This is the first report on in vitro establishment of A. excelsa R. Br. using NS to reduce bacterial infections. PMID:22119875

Sarmast, M K; Salehi, H; Khosh-Khui, M

2011-12-01

368

Geographical influences on content of 10-hydroxy-trans-2-decenoic acid in royal jelly in China.  

PubMed

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. PMID:24224235

Wei, Wen-Ting; Hu, Yuan-Qiang; Zheng, Huo-Qing; Cao, Lian-Fei; Hu, Fu-Liang; Hepburn, H Randall

2013-10-01

369

Method for RNA extraction and cDNA library construction from microbes in crop rhizosphere soil.  

PubMed

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 Al?(SO?)? 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 Al?(SO?)? 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. PMID:24078111

Fang, Changxun; Xu, Tiecheng; Ye, Changliang; Huang, Likun; Wang, Qingshui; Lin, Wenxiong

2014-02-01

370

Light brown apple moth in California: a diversity of host plants and indigenous parasitoids.  

PubMed

The light brown apple moth, Epiphyas postvittana (Walker), an Australia native tortricid, was found in California in 2006. A field survey of host plants used by E. postvittana was conducted in an urban region of the San Francisco Bay Area. An inspection of 152 plant species (66 families), within a 23-ha residential community, found E. postvittana on 75 species (36 families). Most (69 species) host plants were not Australian natives, but had a wide geographic origin; 34 species were new host records for E. postvittana. Heavily infested species were the ornamental shrubs Myrtus communis L., Pittosporum tobira (Thunb.) W.T. Aiton, Euonymus japonicus Thunb., and Sollya heterophylla Lindl. To survey for parasitoids, four urban locations were sampled, with E. postvittana collected from five commonly infested plants [M. communis, P. tobira, E. japonicus, Rosmarinus officinalis L., and Genista monspessulana (L.) L.A.S. Johnson]. Twelve primary parasitoid species and two hyperparasitoids were reared; the most common were the egg parasitoid Trichogramma fasciatum (Perkins), the larval parasitoids Meteorus ictericus Nees, and Enytus eureka (Ashmead), and the pupal parasitoid Pediobius ni Peck. Meteorus ictericus accounted for >80% of the larval parasitoids, and was recovered from larvae collected on 39 plant species. Across all samples, mean parasitism was 84.4% for eggs, 43.6% for larvae, and 57.5% for pupae. The results are discussed with respect to the potential for resident parasitoid species to suppress E. postvittana populations. PMID:22525062

Wang, Xin-Geng; Levy, Karmit; Mills, Nicholas J; Daane, Kent M

2012-02-01

371

Glyphosate-resistant weeds of South American cropping systems: an overview.  

PubMed

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. PMID:18161884

Vila-Aiub, Martin M; Vidal, Ribas A; Balbi, Maria C; Gundel, Pedro E; Trucco, Frederico; Ghersa, Claudio M

2008-04-01

372

Review of potential environmental impacts of transgenic glyphosate-resistant soybean in Brazil.  

PubMed

Transgenic glyphosate-resistant soybeans (GRS) have been commercialized and grown extensively in the Western Hemisphere, including Brazil. Worldwide, several studies have shown that previous and potential effects of glyphosate on contamination of soil, water, and air are minimal, compared to those caused by the herbicides that they replace when GRS are adopted. In the USA and Argentina, the advent of glyphosate-resistant soybeans resulted in a significant shift to reduced- and no-tillage practices, thereby significantly reducing environmental degradation by agriculture. Similar shifts in tillage practiced with GRS might be expected in Brazil. Transgenes encoding glyphosate resistance in soybeans are highly unlikely to be a risk to wild plant species in Brazil. Soybean is almost completely self-pollinated and is a non-native species in Brazil, without wild relatives, making introgression of transgenes from GRS virtually impossible. Probably the highest agricultural risk in adopting GRS in Brazil is related to weed resistance. Weed species in GRS fields have shifted in Brazil to those that can more successfully withstand glyphosate or to those that avoid the time of its application. These include Chamaesyce hirta (erva-de-Santa-Luzia), Commelina benghalensis (trapoeraba), Spermacoce latifolia (erva-quente), Richardia brasiliensis (poaia-branca), and Ipomoea spp. (corda-de-viola). Four weed species, Conyza bonariensis, Conyza Canadensis (buva), Lolium multiflorum (azevem), and Euphorbia heterophylla (amendoim bravo), have evolved resistance to glyphosate in GRS in Brazil and have great potential to become problems. PMID:17562462

Cerdeira, Antonio L; Gazziero, Dionsio L P; Duke, Stephen O; Matallo, Marcus B; Spadotto, Claudio A

2007-01-01

373

An integrated approach to demonstrating the ANR pathway of proanthocyanidin biosynthesis in plants.  

PubMed

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. PMID:22678031

Peng, Qing-Zhong; Zhu, Yue; Liu, Zhong; Du, Ci; Li, Ke-Gang; Xie, De-Yu

2012-09-01

374

Population dynamics of weeds in no-tillage and conventional crop systems.  

PubMed

Population dynamics of weeds in successive maize and bean crops were evaluated in two soil management systems (conventional and no-tillage), for two maize applications (grain and silage), and in four consecutive growing seasons. Every year, conventional tillage consisted in plowing and harrowing before sowing. In no-tillage, chemical weed desiccation was made with the mixture glyphosate + 2.4-D. To control weeds, the mixture fluazifop-p-butil + fomesafen was applied on the bean crop in all the planting seasons, and the herbicides nicosulfuron + atrazine on maize after crop emergence (1998--1999, 1999--2000, 2001--2002) and atrazine + metolachlor before emergence (2000--2001). Purple nutsedge (Cyperus rotundus) was the most important species under conventional soil tillage; while in no-tillage the dicotyledonous weed species (Amaranthus deflexus, Bidens pilosa, Euphorbia heterophylla, Galinsoga parviflora Ipomoea grandifolia) were the most relevant. Regardless of the maize use, the C. rotundus population and tuber bank, with prevailingly dormant tubers, was considerably reduced in no-tillage compared with the conventional system. PMID:15656169

Machado, Aroldo Ferreira Lopes; Jakelaitis, Adriano; Ferreira, Lino Roberto; Agnes, Ernani Luiz; Santos, Leonardo David Tuffi

2005-01-01

375

Bidens pilosa L. exhibits high sensitivity to coumarin in comparison with three other weed species.  

PubMed

Nine natural plant compounds were screened for phytotoxicity to Bidens pilosa L. a troublesome weed in field and plantation crops. The sensitivity of three other weed species to coumarin, the most active identified compound, was also evaluated. Coumarin, at a concentration of 500 microM, had little effect on germination and growth of Senna obtusifolia L., Euphorbia heterophylla L., and Ipomoea grandifolia L. when compared with its effects on B. pilosa L. In a concentration range of 10-100 microM, coumarin caused a dose-dependent inhibition of germination and growth of B. pilosa L. The measurements of some parameters of energy metabolism revealed that coumarin-treated root tissues exhibited characteristics of seedlings in an earlier stage of growth, including higher respiratory activity and higher activities of alcohol dehydrogenase and lipoxygenase. These results suggest that coumarin inhibition of germination and growth of B. pilosa L. was not a consequence of an impairment of energy metabolism. Rather, it seems to act as a cytostatic agent, retarding germination. At concentrations above 50 microM, coumarin increased lipoxygenase activity and the level of conjugated dienes of root extracts, suggesting that it may induce oxidative stress in seedling roots. PMID:18338136

Pergo, Erica Marusa; Abrahim, Denise; Soares da Silva, Patrícia Cristina; Kern, Kátia Aparecida; Da Silva, Lucas Jonatas; Voll, Elemar; Ishii-Iwamoto, Emy Luiza

2008-04-01

376

Vegetation mapping of the Mond Protected Area of Bushehr Province (south-west Iran).  

PubMed

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. PMID:19261068

Mehrabian, Ahmadreza; Naqinezhad, Alireza; Mahiny, Abdolrassoul Salman; Mostafavi, Hossein; Liaghati, Homan; Kouchekzadeh, Mohsen

2009-03-01

377

Antheridiogen production and response in Polypodiaceae species.  

PubMed

Antheridiogen chemicals secreted by living fern gametophytes have been shown to influence production of male gametangia and thus mating systems in a large number of terrestrial fern species. Antheridiogens have not previously been thought to be prevalent in the Polypodiaceae, a large family composed mostly of tropical epiphytes. This study presents bioassay methods more sensitive than previously used to detect antheridiogen and demonstrates that antheridiogens are also operative in the Polypodiaceae and in epiphytic species. Seven species in six genera (Campyloneurum angustifolium, C. phyllitidis, Lepisorus thunbergianus, Microgramma heterophylla, Phlebodium aureum, Phymatosorus scolopendria, and Polypodium pellucidum) were tested for the presence of an antheridiogen system. All species tested except P. aureum were induced to produce antheridia precociously by their own antheridiogen and by that of Pteridium aquilinum (APt). Phlebodium aureum responded to APt and promoted antheridium formation in Onoclea sensibilis but did not respond to its own antheridiogen. Spores of all species except P. aureum were induced to germinate in darkness by antheridiogen of the same species and by APt and to form antheridia in the dark, further enhancing the possibility of intergametophytic mating. PMID:21708616

Chiou, W; Farrar, D

1997-05-01

378

In vitro screening of medicinal plants used in Mexico as antidiabetics with glucosidase and lipase inhibitory activities.  

PubMed

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 ?-glucosidase activity. C. sinensis displayed an inhibition of 85% (IC(50)?=?299??g/mL), while Ludwigia octovalvis and Iostephane heterophylla showed the highest inhibition (82.7 %, IC(50)?=?202??g/mL and 60.6%, CI(50)?=?509??g/mL, resp.). With respect to lipase activity, L. octovalvis and Tecoma stans were the most inhibiting treatments (31.4%, IC(50)?=?288??g/mL; 27.2%, IC(50)?=?320??g/mL), while C. sinensis displayed 45% inhibition (IC(50)?=?310??g/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

Ramírez, Guillermo; Zavala, Miguel; Pérez, Julia; Zamilpa, Alejandro

2012-01-01

379

Stereoselective potencies and relative toxicities of ?-coniceine and N-methylconiine enantiomers.  

PubMed

?-Coniceine, coniine, and N-methylconiine are toxic alkaloids present in poison hemlock (Conium maculatum). We previously reported the comparison of the relative potencies of (+)- and (-)-coniine enantiomers. In this study, we synthesized ?-coniceine and the enantiomers of N-methylconiine and determined the biological activity of ?-coniceine and each of the N-methylconiine enantiomers in vitro and in vivo. The relative potencies of these piperidine alkaloids on cells expressing human fetal muscle-type nicotinic acetylcholine receptors had the rank order of ?-coniceine > (-)-N-methylconiine > (±)-N-methylconiine > (+)-N-methylconiine. The relative lethalities of ?-coniceine and (-)-, (±)-, and (+)-N-methylconiine in vivo using a mouse bioassay were 4.4, 16.1, 17.8, and 19.2 mg/kg, respectively. The results from this study suggest ?-coniceine is a more potent agonist than the enantiomers of N-methylconiine and that there is a stereoselective difference in the in vitro potencies of the enantiomers of N-methylconiine that correlates with the relative toxicities of the enantiomers in vivo. PMID:23514442

Lee, Stephen T; Green, Benedict T; Welch, Kevin D; Jordan, Glenn T; Zhang, Qian; Panter, Kip E; Hughes, David; Chang, Cheng-Wei Tom; Pfister, James A; Gardner, Dale R

2013-04-15

380

Ultrasound studies of the effects of certain poisonous plants on uterine function and fetal development in livestock.  

PubMed

Ingestion of locoweed (Astragalus spp. and Oxytropis spp.) by pregnant livestock may result in fetal malformations, delayed placentation, reduced placental and uterine vascular development, hydrops amnii, hydrops allantois, abnormal cotyledonary development, interruption of fetal fluid balance, and abortion. Ultrasonography of pregnant sheep fed locoweed demonstrated that abortion was first preceded by changes in fetal heart rate and strength of contraction and structural changes of the cotyledons, followed by increased accumulation of fetal fluid within the placental membranes and death of the fetus. During pregnancy the toxic agent in locoweed (swainsonine) apparently passes through the placental barrier to the fetus and during lactation through the milk to the neonate. Poison-hemlock (Conium maculatum), wild tree tobacco (Nicotiana glauca), and lunara lupine (Lupinus formosus) all contain piperidine alkaloids and induce fetal malformations, including multiple congenital contractures and cleft palate in livestock. Ultrasonography studies of pregnant sheep and goats gavaged with these plants during 30 to 60 d of gestation suggests that the primary cause of multiple congenital contractures and cleft palate is the degree and the duration of the alkaloid-induced fetal immobilization. PMID:1526931

Bunch, T D; Panter, K E; James, L F

1992-05-01

381

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

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, ?-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. PMID:23086230

Green, Benedict T; Lee, Stephen T; Welch, Kevin D; Pfister, James A; Panter, Kip E

2013-01-01

382

Potyviruses, novel and known, in cultivated and wild species of the family Apiaceae in Australia.  

PubMed

Three potyviruses were identified by gene sequencing and found to be widespread in species of Apiaceae in Australia. Only celery mosaic virus was found in celery crops and in one of 180 specimens of feral carrot ( Daucus carota). Another related but distinct novel potyvirus, carrot virus Y, was the only virus found in carrot crops and all except one feral carrot. A more distantly related novel potyvirus, apium virus Y, was found in plants of sea celery ( Apium prostratum), cultivated parsley ( Petroselinum crispum) and the immigrant weed species poison hemlock ( Conium maculatum). These three potyviruses, together with celery yellow mosaic virus of South America and the closely related carrot thin leaf virus and carrot virus B of North America, form a distinct subgenus of the Potyviridae most closely related to turnip mosaic virus and two potyviruses of yam; yam mosaic virus from the Ivory Coast and Japanese yam mosaic virus. Celery mosaic and carrot virus Y are probably recent migrants to Australia, but apium virus Y may have been endemic longer. In ELISA tests using polyclonal antibodies against virions of celery mosaic virus, some isolates of carrot virus Y were indistinguishable from celery mosaic virus, whereas others gave smaller absorbancy values, and those of apium virus Y did not react. This study shows the value of virus identification based on gene sequencing for planning control measures. PMID:12376749

Moran, J; van Rijswijk, B; Traicevski, V; Kitajima, E W; Mackenzie, A M; Gibbs, A J

2002-10-01

383

Silicon production process evaluations  

NASA Astrophysics Data System (ADS)

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.

1982-02-01

384

Geological and Geothermal Investigation of the Lower Wind River Valley, Southwestern Washington Cascade Range  

SciTech Connect

The Wind River Valley, on the west slope of the Cascade Range, is a northwest-trending drainage that joins the Columbia River near Carson, Washington. The region has been heavily dissected by fluvial and glacial erosion. Ridges have sharp crests and deep subsidiary valleys typical of a mature topography, with a total relief of as much as 900 m. The region is vegetated by fir and hemlock, as well as dense, brushy ground-cover and undergrowth. The lower 8 km of the valley is privately owned and moderately populated. The upper reaches lies within the Gifford Pinchot National Forest, and include several campgrounds and day parks, the Carson National Fish Hatchery, and the Wind River Ranger Station and Wind River Nursery of the US Forest Service. Logging activity is light due to the rugged terrain, and consequently, most valley slopes are not accessible by vehicle. The realization that a potential for significant geothermal resources exists in the Wind River area was brought about by earlier exploration activities. Geologic mapping and interpretation was needed to facilitate further exploration of the resource by providing a knowledge of possible geologic controls on the geothermal system. This report presents the detailed geology of the lower Wind River valley with emphasis on those factors that bear significantly on development of a geothermal resource.

Berri, Dulcy A.; Korosec, Michael A.

1983-01-01

385

Spread and persistence of a rugulosin-producing endophyte in Picea glauca seedlings.  

PubMed

We have studied Picea glauca (white spruce) endophyte colonization and its affect on the growth of Choristoneura fumiferana (spruce budworm). Here we examine the spread and persistence of a rugulosin-producing endophyte and rugulosin in needles from trees maintained in the nursery, as well as in trees planted in a test field site. Additionally, we report toxicity of rugulosin against three P. glauca needle herbivores: C. fumiferana, Lambdina fiscellaria (hemlock looper) and Zeiraphera canadensis (spruce budmoth). Reduction in body weight for both the C. fumiferana and L. fiscellaria were observed at 25 and 50mum, respectively, and head capsules were reduced at 100 and 150 microm. Z. canadensis larvae did not perform as well in tests due to an Aspergillus fumigatus infection, but were shown to be lighter when tested with 100 and 150 microm compared with controls. The endophyte and its toxin were shown to spread throughout the nursery-grown seedlings. After 3.5 and 4.5 y post-inoculation (one and two years in the test site), the inoculated endophyte and its toxin had remained present with an average rugulosin concentration of 1 microg g(-1). PMID:18487038

Sumarah, Mark W; Adams, Gregory W; Berghout, Joanne; Slack, Gregory J; Wilson, Aaron M; Miller, J David

2008-06-01

386

Biomass, net primary production and successional dynamics of a virgin white pine (Pinus strobus) stand in northern Michigan  

SciTech Connect

Eastern white pine (Pinus strobus L.), averaging 177 years in age, dominates the forests at Hartwick Pines State Park, Michigan, with a basal area of 48.4 m/sup 2//ha, 66.7% of the total. Its mean diameter and height were 58 cm and 36 m, respectively. Hartwick's total biomass, 681 mt/ha, and basal area, 72.6 m/sup 2//ha, are among the highest worldwide. However, total net primary production of trees was a relatively low 7.5 mt/ha/yr. Diameter and height distributions suggest that red maple, sugar maple and beech are succeeding white pipe. Seeding survivorship was greater in the gaps than under the canopy and greater during winter than summer. Sugar maple had the highest overall annual survival rate and red maple had the lowest. Deer browsing may retard succession. There was a significant increase in height and crown cover of unbrowsed maple seedlings because shoot length had not been reduced by browsing. Fewer white pine survived in unbrowsed areas. It was concluded that a possible successional series for this area, if uninterrupted by fire or other disturbance, would be: jack pine for the first 80 years, white pine for 170 years, white pine-northern hardwood for 200 years, hemlock-northern hardwoods for 200 years with maple dominated hardwoods following as a long term stable community. It is hypothesized that biomass would increase to a maximum when white pine dominated and then decrease when hardwoods assumed dominance.

Rose, W.M.

1985-01-01

387

Process feasibility study in support of silicon material task 1. Quarterly technical progress report (XX), June 1-August 31, 1980  

SciTech Connect

Analyses of process system properties were continued for chemical materials important in the production of silicon including compilation and collection activities of the property data for use in the final report. Major efforts in chemical engineering analysis centered on the DCS process - Case A which involves production of dichlorosilane (DCS) as a silicon source material for polysilicon production in the Hemlock Semiconductor Corporation program. The preliminary process design of a plant to produce DCS was completed including process flowsheet (100%), base case conditions (100%), reaction chemistry (100%), raw materials (100%), utilities (100%), major process equipment (100%) and production labor (100%). The process design package was forwarded for economic analysis. Economic analysis of the DCS process - Case A was completed during this reporting period. The results for dichlorosilane (DCS) indicated a total product cost without profit of 1.29 $/kg (1980 dollars). This product cost without profit includes direct manufacturing cost, indirect manufacturing cost, plant overhead and general expenses. The sales price of DCS at 15% DCF rate of return on investment is 1.47$/kg (1980 dollars). Additional results are reported for sales price of dichlorosilane at various profitability levels as measured by ROI (return on original investment) and DCF (discounted cash flow rate of return).

Yaws, C.L.; Li, K.Y.

1980-09-01

388

Effects of Pleistocene glaciations on population structure of North American chestnut-backed chickadees.  

PubMed

The postglacial recolonization of northern North America was heavily influenced by the Pleistocene glaciation. In the Pacific Northwest, there are two disjunct regions of mesic temperate forest, one coastal and the other interior. The chestnut-backed chickadee is one of the species associated with this distinctive ecosystem. Using seven microsatellite markers we found evidence of population structure among nine populations of chestnut-backed chickadees. High levels of allelic variation were found in each of the populations. Northern British Columbia and central Alaska populations contained a large number of private alleles compared to other populations, including those from unglaciated regions. The disjunct population in the interior was genetically distinct from the coastal population. Genetic and historical records indicate that the interior population originated from postglacial inland dispersal. Population structuring was found within the continuous coastal population, among which the peripheral populations, specifically those on the Queen Charlotte Islands and the central Alaska mainland, were genetically distinct. The pattern of population structure among contemporary chickadee populations is consistent with a pioneer model of recolonization. The persistence of genetic structure in western North American chestnut-backed chickadees may be aided by their sedentary behaviour, linear distribution, and dependence on cedar-hemlock forests. PMID:16842415

Burg, Theresa M; Gaston, Anthony J; Winker, Kevin; Friesen, Vicki L

2006-08-01

389

Late glacial and early Holocene Landscapes in northern New England and adjacent areas of Canada  

NASA Astrophysics Data System (ADS)

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 rates. The approximate order of arrival follows: poplars (13,000-12,000 yr B.P. in the south), spruces, paper birch, and jack pine, followed by balsam fir and larch, and possibly ironwood, ash, and elm, and somewhat later by oak, maple, white pine, and finally hemlock (10,000-9000 yr B.P. in the south).

Davis, R. B.; Jacobson, G. L.

1985-05-01

390

Cytochemical localization of cellulases in decayed and nondecayed wood  

SciTech Connect

Sawdust from undecayed western hemlock wood and from wood previously decayed by the brown-rot fungus Poria placenta or by the white-rot fungus Ganoderma applanatum was incubated with commercial cellulase from Trichoderma viride. Samples were treated cytochemically to locate cellulase activity and examined by TEM. Results showed that cellulase degraded undecayed wood extensively, with the attack starting on the outer border of a cell wall and progressing inside. Wood decayed by P. placenta, with or without cellulase incubation, and treated by the cytochemical test showed uniform distribution of electron dense particles throughout the cell walls. In wood decayed by G. applanatum, cellulase degradation was similar to that in undecayed wood. From measurements of particle diameter it is suggested that electron dense particles are cellulase. It is concluded that brown-rot and white-rot fungi have different effects on the microstructure of wood. The brown-rot fungus appears to open the wood microstructure so that cellulase can diffuse throughout the degraded tracheid wall.

Murmanis, L.; Highley, T.L.; Palmer, J.G.

1987-01-01

391

Can We Monitor Ecosystem Function Using Keeling Plot Analyses of Nocturnal Cold-Air Drainage?  

NASA Astrophysics Data System (ADS)

The carbon isotope signature of ecosystem respiration, ? 13CR, as measured by the Keeling Plot approach, has been related to short-term variations in weather and ecosystem function in several recent studies. In order to obtain an adequate range of [CO2] and to sample a consistent vegetation type, investigators typically select sampling locations in relatively flat terrain and uniform canopy cover, but these are unusual conditions for many forested ecosystems. In a pilot study, we are collecting samples for Keeling Plot analyses in cold-air drainage systems in small (60-100 ha), deeply-incised watersheds, one covered with old-growth (ca 450-years-old) Douglas-fir/hemlock forest and one covered with young (ca 45-years-old) Douglas-fir forest. We found that the nightly range of [CO2] was typically 380-460 ppm, sufficient to develop good estimates of ? 13CR. At any point in time there was little variation in [CO2] with height through the canopy (0.5-30m), so the required range was obtained by sampling over several hours. There was no indication that samples taken from different heights or at different times of night represented sources with different isotopic signatures. The isotopic signature of respired CO2 in the older watershed averaged about 1 per mil greater than that of the young watershed, and ? 13CR of both locations correlated with modeled stomatal conductance 6 days prior to flask sampling.

Bond, B. J.; Ocheltree, T.; Pypker, T.; Unsworth, M. H.; Mix, A. C.; William, R.

2003-12-01

392

Asphyxial suicides using plastic bags.  

PubMed

Fifty-three suicides using plastic bags were identified in a review of cases within the jurisdiction of the King County Medical Examiner's Office, Seattle, Washington from 1984 to 1993. We found that this method was used at a greater frequency by individuals older than 50 in comparison with other methods. The most commonly identified stressor leading to the suicide in this population was failing health. The use of this method as a means of "self deliverance," as advocated by the Hemlock Society, could be inferred in only a small minority of cases where terminal illnesses were identified. This method may be preferred by those older than 50 years because of the ready availability of plastic bags and the relative nonviolence of the death. Analysis of the autopsy findings showed no specific features for this method of suicide. In particular, petechiae, which are often considered a marker of asphyxia, were present in only a small minority of cases (3%). Furthermore, the scene investigation rarely revealed specific features, other than the plastic bag in place. Thus, if the plastic bag were removed after death, the cause and manner of death would be obscure. PMID:8947355

Haddix, T L; Harruff, R C; Reay, D T; Haglund, W D

1996-12-01

393

Simultaneous prediction of density and moisture content of wood by terahertz time domain spectroscopy  

NASA Astrophysics Data System (ADS)

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.

Inagaki, Tetsuya; Ahmed, Belal; Hartley, Ian D.; Tsuchikawa, Satoru; Reid, Matthew

2014-11-01

394

Groundwater-discharge wetlands in the Tanana Flats, interior Alaska. Study report  

SciTech Connect

In the northwest corner of the Tanana Flats, a lowland basin just south of Fairbanks in interior Alaska, there is a vast network of floating-mat wetlands or fens that appears to be unique in terms of their origin, large areal extent, and absence of sphagnum moss and associated peat. During the summers of 1989 and 1990 a study of the impacts of airboats on these wetlands included aerial and ground reconnaissance of 20 sites to characterize the vegetation, hydrology and subsurface conditions. These wetlands consist of a floating vegetation mat up to 1 m thick, forming an almost complete cover over deeper water bodies. The mats consist of a tall, dense and productive network of emergent vascular plants, including buckbean (menyanthes trifoliata), swamp horsetail(Equisetum fluviatile), sedges (Carexaquatilis), marshfivefinger(potentilla palustris),water hemlock (Cicuta mackenzieana) and bladderwort (Utricularia sp.). Evidence that these wetlands are formed by groundwater discharge includes (a) the apparent absence of permafrost under these wetlands but its presence on the adjacent forested uplands, (b) nearby winter icings resulting from artesian springs, (c) the relatively high pH, conductivity, calcium and magnesium concentrations of the water, (d) the vascular plant species composition and in particular the absence of Sphagnum moss, and (e) the flow of water and the geological history of the area. Expansion of these fens in several places is suggested by dead and dying white birch along the upland-fen margin, were permafrost thaw and subsidence (thermokarst) is taking place.

Racine, C.H.; Walters, J.C.

1991-07-01

395

Aerospace Toxicology and Microbiology  

NASA Technical Reports Server (NTRS)

Toxicology dates to the very earliest history of humanity with various poisons and venom being recognized as a method of hunting or waging war with the earliest documentation in the Evers papyrus (circa 1500 BCE). The Greeks identified specific poisons such as hemlock, a method of state execution, and the Greek word toxos (arrow) became the root of our modern science. The first scientific approach to the understanding of poisons and toxicology was the work during the late middle ages of Paracelsus. He formulated what were then revolutionary views that a specific toxic agent or "toxicon" caused specific dose-related effects. His principles have established the basis of modern pharmacology and toxicology. In 1700, Bernardo Ramazzini published the book De Morbis Artificum Diatriba (The Diseases of Workers) describing specific illnesses associated with certain labor, particularly metal workers exposed to mercury, lead, arsenic, and rock dust. Modern toxicology dates from development of the modern industrial chemical processes, the earliest involving an analytical method for arsenic by Marsh in 1836. Industrial organic chemicals were synthesized in the late 1800 s along with anesthetics and disinfectants. In 1908, Hamilton began the long study of occupational toxicology issues, and by WW I the scientific use of toxicants saw Haber creating war gases and defining time-dosage relationships that are used even today.

James, John T.; Parmet, A. J.; Pierson, Duane L.

2007-01-01

396

Modelling the hydrodynamic resistance of bordered pits.  

PubMed

Previous studies of the hydrodynamics of plant stems have shown that resistance to flow through bordered pits on the side walls of tracheids makes up a significant proportion of their total resistance, and that this proportion increases with tracheid diameter. This suggests a possible reason why tracheids with a diameter above around 100 microm have failed to evolve. This possibility has been investigated by obtaining an estimate for the resistance of a single pit, and incorporating it into analytical models of tracheid resistance and wood resistivity. The hydrodynamic resistance of the bordered pits of Tsuga canadensis was investigated using large-scale physical models. The importance of individual components of the pit were investigated by comparing the resistance of models with different pore sizes in their pit membrane, and with or without the torus and border. The estimate for the resistance of a real bordered pit was 1.70x10(15) Pa s m(-3). Resistance of pits varied with morphology as might be predicted; the resistance was inversely proportional to the pore size to the power of 0.715; removing the torus reduced resistance by 28%, while removal of the torus and border together reduced it by 72%. It was estimated that in a 'typical tracheid' pit resistance should account for 29% of the total. Incorporating the results into the model for the resistivity of wood showed that resistivity should fall as tracheid diameter increases. However, to minimize resistance wider tracheids would also need to be proportionally much longer. It is suggested that the diameter of tracheids in conifers is limited by upper limits to cell length or cell volume. This limitation is avoided by angiosperms because they can digest away the ends of their cells to produce long, wide vessels composed of many short cells. PMID:12021296

Lancashire, J R; Ennos, A R

2002-06-01

397

Interspecific Variation in Tree Growth Response to 20th Century Climate Variability in the Circumpolar Boreal Forest  

NASA Astrophysics Data System (ADS)

We examined relationships between tree ring-width and climate at 232 existing tree-ring sites around the circumpolar boreal forest (north of 55° N). The data set included ten common boreal species: Larix gmelinii, Larix sibirica, Picea abies, Picea glauca, Picea mariana, Picea obovata, Picea sitchensis, Pinus banksiana, Pinus sylvestris, Tsuga mertensiana. We used moving-window correlation analysis for eight 30-year time windows, lagged by 10 years, to characterize the climate response at each site from 1902-2002. We identified two categories of response to temperature: a browning response characterized by inverse correlations between growth and temperature, and a greening response characterized by positive correlations between growth and temperature. Inverse growth responses to temperature were widespread, occurring to some extent in all species, during all time periods, and in nearly all geographic areas. Although the browning response did occur during all time periods, its frequency increased after 1942, during which time the frequency of the greening response declined. Although the trend in the frequency of browning paralleled the rise in Northern Hemisphere temperature in recent decades, the two were not significantly correlated. Browning was concentrated in five species ( Picea abies, Picea glauca, Picea mariana, Picea obovata and Pinus banksiana), and occurred infrequently in the remaining five species. The genus Picea thus appeared to be particularly prone to experience inverse responses to temperature: the only Picea species included in the analysis in which browning did not commonly occur was Picea sitchensis, which is restricted to the coastal temperate rainforests of southeastern and south-central Alaska. Our analyses identified two possible causes of inverse growth responses. First, browning occurred significantly more frequently in the warmer parts of species" sampled ranges, supporting the hypothesis that direct temperature stress might be a cause of inverse growth responses to temperature. Second, in some species, dry sites were also more likely to experience browning; moisture stress might thus be an additional explanation in some cases.

Lloyd, A. H.; Bunn, A.

2007-12-01

398

Reconstructing a Past Climate Using Current Multi-species' Climate Spaces  

NASA Astrophysics Data System (ADS)

We present an analysis of a ghost forest on WhiteWing Mt at 3000 m in the eastern Sierra Nevada, southeast of Yosemite NP. Killed by a volcanic eruption about 650 years ago, the deadwood on WhiteWing dates by standard tree-ring analysis to 800-1330 CE, during the Medieval Warm Anomaly. Individual stems have been identified by wood anatomical characteristics as Pinus albicualis, P. monticola, P. jeffreyi, P. contorta, P. lambertiana, and Tsuga mertensiana. With the exception of P. albicualis, which is currently in krummholz form at this elevation, the other species are 200 m or more lower in elevation. One, P. lambertiana, is west of the Sierran crest and 600 m lower in elevation. Assuming that climatic conditions on Whitewing during this period were mutually compatible with all species, we reconstruct this climate by the intersection of the current climatic spaces of these species. We did this by first generating individual species' ranges in the Sierran ecoregions through selecting vegetation GIS polygons from the California Gap Analysis database (UCSB) that contain the individual species. Climatic spaces for each species were generated by the GIS intersection of its polygons with 4 km gridded polygons from PRISM climatic estimates (OSU); this was done for annual, January, and July maximum and minimum temperature, and precipitation, merged together for each species. Climatic intersections of the species were generated from the misclassified polygons of a discriminant analysis of species by the climatic data. The average data from these misclassified polygons suggest that the climate on WhiteWing during the existence of this forest community was 230 mm, 1oC, and 3oC greater than present in precipitation, and maximum and minimum temperature, respectively.

Westfall, R. D.; Millar, C. I.

2004-12-01

399

Survival and development of Lymantria monacha (Lepidoptera: Lymantriidae) on North American and introduced Eurasian tree species.  

PubMed

Lymantria monacha (L.) (Lepidoptera: Lymantriidae), the nun moth, is a Eurasian pest of conifers that has potential for accidental introduction into North America. To project the potential host range of this insect if introduced into North America, survival and development of L. monacha on 26 North American and eight introduced Eurasian tree species were examined. Seven conifer species (Abies concolor, Picea abies, P. glauca, P. pungens, Pinus sylvestris with male cones, P. menziesii variety glance, and Tsuga canadensis) and six broadleaf species (Betula populifolia, Malus x domestica, Prunus serotiaa, Quercus lobata, Q. rubra, and Q. velutina) were suitable for L. monacha survival and development. Eleven of the host species tested were rated as intermediate in suitability, four conifer species (Larix occidentalis, P. nigra, P. ponderosa, P. strobus, and Pseudotsuga menziesii variety menziesii) and six broadleaf species (Carpinus caroliniana, Carya ovata, Fagus grandifolia, Populus grandidentata, Q. alba, and Tilia cordata) and the remaining 10 species tested were rated as poor (Acer rubrum, A. platanoidies, A. saccharum, F. americana, Juniperus virginiana, Larix kaempferi, Liriodendron tulipfera, Morus alba, P. taeda, and P. deltoides). The phenological state of the trees had a major impact on establishment, survival, and development of L. monacha on many of the tree species tested. Several of the deciduous tree species that are suitable for L. monacha also are suitable for L. dispar (L.) and L. mathura Moore. Establishment of L. monacha in North America would be catastrophic because of the large number of economically important tree species on which it can survive and develop, and the ability of mated females to fly and colonize new areas. PMID:12650343

Keena, M A

2003-02-01

400

Occurrence of ectomycorrhizal fungi on the forefront of retreating Lyman Glacier (Washington, USA) in relation to time since deglaciation.  

PubMed

Glacier forefronts provide a unique system for studying primary succession of plants and fungi. We constructed a chronosequence of ectomycorrhizal fungus occurrence on the forefront of Lyman Glacier in the North Cascades mountain range in Washington, USA. The plant communities established on non-vegetated substrate as patchily distributed plant individuals and developed towards complex vegetation with a variety of ectomycorrhizal hosts, including Salix commutata, S. phylicifolia, Abies lasiocarpa, Larix lyallii, Pinus contorta, Tsuga mertensiana and additional infrequent taxa. A most probable number assay of non-vegetated substrates over the chronosequence indicated that ectomycorrhizal propagules were few or absent in the non-vegetated areas adjacent to the glacier terminus but increased with time since deglaciation. Ectomycorrhizal fungus sporocarps occurred as soon as the first host plants of substantial size were present. However, none were observed with the most recently established hosts--small A. lasiocarpa seedlings. Only four species (Cortinarius decipiens, C. tenebricus, Inocybe lacera, and Laccaria cf. montana) occurred on substrate deglaciated for less than 40 years. Three of these species (C. tenebricus, I. lacera, and L. cf. montana) occurred along the chronosequence to the terminal moraine on substrate deglaciated for 70-100 years. An additional five species (one unidentified species each of Cortinarius and Lactarius, Cortinarius mutabilis, Lactarius uvidus var. montanus, and Suillus cavipes) occurred only on the oldest substrate. Our results support the current "early- and late-stage" model of ectomycorrhizal fungus succession in that additional species enter the community over time. However, we hypothesize that diversification of the mycorrhizal fungus community in this primary successional habitat resulted from an increasing diversity of host plants along with changing habitat attributes. PMID:11968946

Jumpponen, Ari; Trappe, James M; Cázares, Efren

2002-02-01

401

AMBIENT POLLEN CONCENTRATIONS AND EMERGENCY DEPARTMENT VISITS FOR ASTHMA AND WHEEZE  

PubMed Central

Background Previous studies report associations between aeroallergen exposure and asthma exacerbations. Aeroallergen burdens and asthma prevalence are increasing worldwide and are projected to increase further with climate change, highlighting the importance of understanding population-level relationships between ambient pollen concentrations and asthma. Objective To examine short-term associations between ambient concentrations of various pollen taxa and emergency department (ED) visits for asthma and wheeze in the Atlanta metropolitan area between 1993 and 2004. Methods We assessed associations between the three-day moving average (lag 0-1-2) of Betulaceae (except Alnus), Cupressaceae, Quercus, Pinaceae (except Tsuga), Poaceae, and Ambrosia pollen concentrations and daily asthma and wheeze ED visit counts, controlling for covarying pollen taxa and ambient pollutant concentrations. Results We observed a 2–3% increase in asthma and wheeze ED visits per standard deviation increase in Quercus and Poaceae pollen and a 10–15% increased risk on days with the highest concentrations (comparing the top 5% of days to the lowest 50% of days). A standard deviation increase in Cupressaceae concentrations was associated with a 1% decrease in ED visits. The association for Quercus pollen was strongest for children age 5 to 17 years. Effects of Ambrosia pollen on asthma exacerbations were difficult to assess in this large-scale temporal analysis due to possible confounding by the steep increase in circulating rhinoviruses every September. Conclusion Poaceae and Quercus pollen contribute to asthma morbidity in Atlanta. Altered Quercus and Poaceae pollen production due to climate change could affect allergen-induced asthma morbidity in the southeastern United States. PMID:22840851

Darrow, Lyndsey A.; Hess, Jeremy; Rogers, Christine A.; Tolbert, Paige E.; Klein, Mitchel; Sarnat, Stefanie E.

2012-01-01

402

Conspecific Plant-Soil Feedbacks of Temperate Tree Species in the Southern Appalachians, USA  

PubMed Central

Many tree species have seedling recruitment patterns suggesting that they are affected by non-competitive distance-dependent sources of mortality. We conducted an experiment, with landscape-level replication, to identify cases of negative distance-dependent effects and whether variation in these effects corresponded with tree recruitment patterns in the southern Appalachian Mountains region. Specifically, soil was collected from 14 sites and used as inocula in a 62 day growth chamber experiment determining whether tree seedling growth was less when interacting with soil from conspecific (like) than heterospecific (other) tree species. Tests were performed on six tree species. Three of the tree species had been previously described as having greater recruitment around conspecifics (i.e. facilitator species group) compared to the other half (i.e. inhibitor species group). We were then able to determine whether variation in negative distance-dependent effects corresponded with recruitment patterns in the field. Across the six species, none were negatively affected by soil inocula from conspecific relative to heterospecific sources. Most species (four of six) were unaffected by soil source. Two species (Prunus serotina and Tsuga canadensis) had enhanced growth in pots inoculated with soil from conspecific trees vs. heterospecifics. Species varied in their susceptibility to soil pathogens, but trends across all species revealed that species classified as inhibitors were not more negatively affected by conspecific than heterospecific soil inocula or more susceptible to pathogenic effects than facilitators. Although plant-soil biota interactions may be important for individual species and sites, it may be difficult to scale these interactions over space or levels of ecological organization. Generalizing the importance of plant-soil feedbacks or other factors across regional scales may be especially problematic for hyperdiverse temperate forests where interactions may be spatially variable. PMID:22808231

Reinhart, Kurt O.; Johnson, Daniel; Clay, Keith

2012-01-01

403

[Quantitative analysis of different restoration stages during natural succession processes of subalpine dark brown coniferous forests in western Sichuan, China].  

PubMed

By adopting space as a substitute for time, and based on the approaches of inter-specific association, PCA and optimal division, the restoration stages of various secondary forest communities originated from the natural succession processes of bamboo-dark brown coniferous and moss-dark brown coniferous old-growth forests after clear-cut were quantified at different temporal series (20, 30, 30, 40, 50 and 160-200 years). The results showed that Betula albo-sinensis, Salix rehderiana, Acer mono, A. laxiflorum, Prunus tatsienensis, Hydrangea xanthoneura, Tilia chinensis and Salix dolia were the declining species groups with progressive restoration processes from secondary forest to mature moss and bamboo-dark brown coniferous forests, Sorbus hupehensis, S. koehneana and P. pilosiuscula were the transient species groups, and Abies faxoniana, Picea purpurea, Tsuga chinensis and P. wilsonii were the progressive species groups. During the period of 20-40 years restoration, the secondary forests were dominated by broad-leaved tree species, such as B. albo-sinensis, and the main forest types were moss--B. albo-sinensis forest and bamboo--B. albo-sinensis forest. Through 50 years natural succession, the secondary forests turned into conifer/broad-leaved mixed forest dominated by B. albo-sinensis and A. faxoniana, and the main forest types were moss--B. albo-sinensis--A. faxoniana forest and bamboo--B. albo-sinensis--A. faxoniana forest. The remained 160-200 years old coniferous forests without cutting were dominated by old-growth stage A. faxoniana, and the main forest types were moss--A. faxoniana forest and bamboo--A. faxoniana forest. PMID:17974231

Ma, Jiang-Ming; Liu, Shi-Rong; Shi, Zuo-Min; Zhang, Yuan-Dong; Chen, Bao-Yu

2007-08-01

404

Geology and paleoecology of a mid-Wisconsin peat from the Queen Charlotte Islands, British Columbia, Canada  

NASA Astrophysics Data System (ADS)

A peat bed on east-central Graham Island of the Queen Charlotte Islands occurs within a nonglacial fluvial succession that is both overlain and underlain by glacial deposits. Radiocarbon dates of 27,500 ± 400 and 45,700 ± 970 yr B.P. at the top and base of the peat, respectively, indicate that it was deposited during the mid-Wisconsin nonglacial interval. The peat is the first documented mid-Wisconsin organic deposit in northern coastal areas of British Columbia. Three local pollen zones are represented. The lowest zone (PM-1) is restricted to sandy silt directly underlying the dated peat. Very high Cyperaceae and moderate Poaceae pollen percentages characterize zone PM-1, and a variety of other herbs are common, suggesting an open landscape rather than a forested one. The middle zone (PM-2) is characterized by abundant pollen of Picea, Tsuga mertensiana, and Cyperaceae, and also contains pollen of Abies, a genus now absent from the Queen Charlotte Islands. Graham Island probably had extensive forests at this time, but abundant pollen and macrofossils of Cyperaceae and emergent aquatics such as Hippuris vulgaris, Veronica scutellata, Potentilla palustris, and Menyanthes trifoliata indicate that there also were open wetland areas. Zone PM-3 also contains abundant arboreal pollen. Large amounts of Sphagnum spores and Selaginella selaginoides megaspores indicate succession of the wetland area at the sample site to a peat bog. Paleoecological analysis of the data suggests that subalpine vegetation elements were depressed by at least 400 m, probably due to a cooler climate. Probable modern analogs in southeastern Alaska and the presence of Abies (probably A. amabilis) indicate that precipitation was higher on eastern Graham Island during the mid-Wisconsin than at present.

Warner, Barry G.; Clague, John J.; Mathewes, Rolf W.

1984-05-01

405

Distribution and hosts of Callidiellum rufipenne (Coleoptera: Cerambycidae), an asian cedar borer established in the eastern United States.  

PubMed

The distribution and hosts of the exotic cedar-boring beetle, Callidiellum rufipenne (Motschulsky) (Coleoptera: Cerambycidae), were determined in five northeastern U.S. states by capturing adults on cedar trap logs and by rearing adults from various conifers. This beetle was detected in the coastal states of Massachusetts, Rhode Island, Connecticut, New York, and New Jersey. In these states, adults emerged from the live or dead wood of four genera and eight species of Cupressaceae; species of Pinaceae were not hosts. Through its entire range, C. rufipenne is reported to infest at least 14 species of Cupressaceae, four species of Pinaceae, and one species of Taxaceae; but, records of Pinaceae and possibly Taxaceae are suspect. Based on the number of adults that emerged from coniferous poles in a five-way choice test in the field, the infestation level was significantly greater in Chamaecyparis thyoides (L.) Britton, Sterns, and Poggenburg and Juniperus virginiana L. than in Pinus rigida Miller, Pinus strobus L., and Tsuga canadensis (L.) Carribre (last three species uninfested). In a second test of host preference in the wild, beetles infested four cupressaceous species, but not Abies balsamea (L.) Miller, Picea rubens Sargent, Pinus rigida, P. strobus, and Ts. canadensis in the Pinaceae. Infestation level was highest in Ch. thyoides, followed in decreasing order by Juniperus communis L., Thuja occidentalis L., and J. virginiana. In a comparison of live and dead J. virginiana, beetles developed to adults only in dead trees (36 beetles per tree). When trunk sections of Th. occidentalis with and without bark were offered to females in cages, beetles of the next generation emerged exclusively from wood with bark. In the Northeast, only species of Cupressaceae apparently are suitable hosts for C. rufipenne. Infestation of these species may be prevented or reduced by proper care of live plants and by debarking trees after harvesting. PMID:17849882

Maier, Chris T

2007-08-01

406

Postglacial Vegetation and Climate of the Cascade Range, Central Oregon  

NASA Astrophysics Data System (ADS)

Pollen data from two sites provide information on the postglacial vegetation and climate history of the Cascade Range. Indian Prairie in the western Cascade Range was colonized by subalpine forests of Pinus, Picea, and Tsuga and open meadows prior to ca. 12,400 14C yr B.P. The treeline lay 500 to 1000 m below its modern elevation and conditions were cooler than at present. From ca. 12,400 to ca. 9950 14C yr B.P. Abies became important and the forest resembled that presently found at middle elevations in the western Cascade Range. The pollen record implies a rise in treeline and warmer conditions than before. From ca. 10,000 to 4000-4500 14C yr B.P., conditions that were warmer and effectively drier than today led to the establishment of a closed forest composed of Pseudotsuga , Abies, and, at lower elevations, Quercus and Corylus . During this period, Gold Lake Bog in the High Cascades was surrounded by closed forest of Pinus and Abies. The early-Holocene pollen assemblages at both Indian Prairie and Gold Lake Bog lack modern analogues, and it is likely that greater-than-present summer radiation fostered unique climatic conditions and vegetation associations at middle and high elevations. In the late Holocene, beginning ca. 4000-4500 14C yr B.P., cooler and more humid conditions prevailed and the modern vegetation was established. A comparison of these sites with others in the Pacific Northwest suggests that major patterns of vegetational change at individual sites were a response to large-scale changes in the climate system that affected the entire region.

Sea, Debra S.; Whitlock, Cathy

1995-05-01

407

Kootenai River White Sturgeon Investigations; White Sturgeon Spawning and Recruitment Evaluation, 2004-2005 Annual Report.  

SciTech Connect

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 response of various life stages of Kootenai River white sturgeon to mitigation flows supplied by the United States Army Corps of Engineers (USACE). Sampling for adult Kootenai River white sturgeon in 2004 began in March and continued into May. One hundred forty-two adult white sturgeon were captured with 4,146 hours of angling and set-lining effort in the Kootenai River. Kootenai River discharge and stage at Bonners Ferry in 2004 peaked in mid December. Discharge remained below 400 cubic meters per second (cms) until June 1; then, because of a systems operations request (SOR), increased and remained between 480 and 540 cms through the end of June. From July through September, discharge ranged from 360 to 420 cms, decreasing to 168 cms by the end of October. Discharge increased again to above 625 cms by November 4 to increase winter storage in Lake Koocanusa and ranged from 310 to 925 cms through the end of December. We monitored the movements of 31 adult sturgeon in Kootenay Lake, British Columbia (BC) and the Kootenai River from mid-March until late August 2004. All telemetered fish were dual tagged with external sonic and radio transmitters, and some of the fish were tagged in previous years. Eighteen of the 31 telemetered adult white sturgeon were released at Hemlock Bar reach (rkm 260.0) as part of a research project to test the feasibility of moving sexually mature adult white sturgeon to areas with habitat types thought to be more suitable for successful egg hatching and early life stage recruitment. Marked fish were monitored from the time of release until they moved downstream of Bonners Ferry. Sampling for white sturgeon eggs with artificial substrate mats began May 3 and ended June 10, 2004. We sampled 650 mat days (a mat day is one 24 h set) during white sturgeon spawning. Most of the sampling occurred in the post-Libby dam spawning reach (rkm 229.0 to 246.0) but some sampling occurred near Crossport (rkm 253.5) and in the Canyon reach above Hemlock Bar (rkm 261.0). We collected eight white sturgeon eggs near Shortys Island in 2004. Sampling for larval white sturgeon began June 8 and continued until July 22, 2004. Sampling occurred primarily at Ambush Rock (rkm 244.0) in an attempt to document any recruitment that might have occurred from the Set and Jet Program. We collected 103 larval fish, but none were white sturgeon larvae or embryos. Juvenile white sturgeon sampling started July 26 and continued through September 27, 2004. A total of 271 hours of gillnetting effort captured 256 juvenile hatchery white sturgeon and two juvenile wild white sturgeon.

Rust, Pete; Wakkinen, Virginia (Idaho Department of Fish and Game, Boise, ID)

2006-05-01

408

Redox potential: An indicator of site productivity in forest management  

NASA Astrophysics Data System (ADS)

Redox potential (Eh) is an integrated soil measurement that reflects several environmental conditions in the soil associated with aeration, moisture and carbon (organic matter) dynamics. Its measurement can be related to water table fluctuations, precipitation and landscape gradients, organic matter decomposition rates, nutrient dynamics, biological diversity and plant species distribution. Redox is an excellent indicator of soil biological processes, as it is largely a reflection of microbial activities which to a large extent govern carbon dynamics and nutrient cycling. Redox thus serves as an ecological indicator of site productivity at the ecosystem scale and may be used for management purposes as its magnitude can be altered by activities such as harvesting and drainage. A threshold value of 300 mv has been documented as the critical value below which anaerobic conditions in the soil develop. However, redox measurements and its impacts on ecosystem processes such as nutrient cycling and productivity, especially in forest ecosystems, have not received the attention that this "master" variable deserves, On northern Vancouver Island, Canada, regenerating stands of western redcedar-western hemlock (CH) sites exhibit symptoms of nutrient deficiencies and slow growth, but this phenomenon does not occur on adjacent western hemlock- amabalis fir (HA) sites. We tested the hypothesis that differences in nutrient supply and distribution of plant species was caused by differences in moisture regime and redox potential. Redox potential, pH, soil aeration depth (steel rods), organic matter thickness, bulk density, soil carbon store, plant species distribution and richness were measured at five old-growth and five 10-year-old cutover blocks. Results of investigations confirmed that CH forests were wetter, had redox values lower than the critical 300mv and a shallower aerated zone, compared with adjacent regenerating HA sites. Fifty percent of the CH plots had redox values less than +300 mv in the forest floor; whereas only 15 percent of the HA plots had such low values. Composition of the forest understory species was related to soil moisture/aeration. Soil aeration was the most important soil variable influencing plant species composition, explaining 25% of the plant community variability. Eh was always greater than +300 mv in the mineral soil of old growth HA forests but below +300 mv in HA clearcuts, suggesting paludification; however it was below or at this threshold in both CH forests and clearcuts. The reduction in measured redox without a noticeable change in the watertable in HA sites suggests that harvesting HA forests shifts the ecosystem towards more anaerobic conditions more similar to CH sites. In a complimentary study, the significance of redox was assessed in a cedar swamp cutover by exploring the relationships between soil redox potential and tree growth, and mineralization of C and soil C store along a gradient of moisture caused by drainage. Drainage improved aeration in the rooting zone, expressed as redox, and above- and below ground C storage; however C mineralization measured as CO2 evolution was not affected. Tree growth was positively correlated with redox potential. Our results indicate that drainage could be a useful silvicultural practice for improving the productivity of these ecosystems and that it may be possible to improve tree growth without stimulating loss of soil C. This requires that drainage improve aeration in the rooting zone while maintaining redox levels of less than +300 mV in the bulk soil, indicating that redox measurements should be incorporated into silviculture interventions to improve productivity of these forests.

Sajedi, Toktam; Prescott, Cindy; Lavkulich, Les

2010-05-01

409

Mercury sensing and toxicity studies of novel latex fabricated silver nanoparticles.  

PubMed

Safe and eco-friendly alternatives to currently used hazardous chemico-physical methods of silver nanoparticles (AgNPs) synthesis are need of time. Rapid, low cost, selective detection of toxic metals in environmental sample is important to take safety action. Toxicity assessment of engineered AgNPs is essential to avoid its side effects on human and non-target organisms. In the present study, biologically active latex from Euphorbia heterophylla (Poinsettia) was utilized for synthesis of AgNPs. AgNPs was of spherical shape and narrow size range (20-50 nm). Occurrence of elemental silver and crystalline nature of AgNPs was analyzed. Role of latex metabolites in reduction and stabilization of AgNPs was analyzed by FT-IR, protein coagulation test and phytochemical analysis. Latex-synthesized AgNPs showed potential in selective and sensitive detection of toxic mercury ions (Hg(2+)) with limit of detection around 100 ppb. Addition of Hg(2+) showed marked deviation in color and surface plasmon resonance spectra of AgNPs. Toxicity studies on aquatic non-target species Daphnia magna showed that latex-synthesized AgNPs (20.66 ± 1.52 % immobilization) were comparatively very less toxic than chemically synthesized AgNPs (51.66 ± 1.52 % immobilization). Similarly, comparative toxicity study on human red blood cells showed lower hemolysis (4.46 ± 0.01 %) by latex-synthesized AgNPs as compared to chemically synthesized AgNPs causing 6.14 ± 0.01 % hemolysis. PMID:24803140

Borase, Hemant P; Patil, Chandrashekhar D; Salunkhe, Rahul B; Suryawanshi, Rahul K; Salunke, Bipinchandra K; Patil, Satish V

2014-11-01

410

Agricultural impacts of glyphosate-resistant soybean cultivation in South America.  

PubMed

In the 2009/2010 growing season, Brazil was the second largest world soybean producer, followed by Argentina. Glyphosate-resistant soybeans (GRS) are being cultivated in most of the soybean area in South America. Overall, the GRS system is beneficial to the environment when compared to conventional soybean. GRS resulted in a significant shift toward no-tillage practices in Brazil and Argentina, but weed resistance may reduce this trend. Probably the highest agricultural risk in adopting GRS in Brazil and South America is related to weed resistance due to use of glyphosate. Weed species in GRS fields have shifted in Brazil to those that can more successfully withstand glyphosate or to those that avoid the time of its application. Five weed species, in order of importance, Conyza bonariensis (L.) Cronquist, Conyza canadensis (L.) Cronquist, Lolium multiflorum Lam., Digitaria insularis (L.) Mez ex Ekman, and Euphorbia heterophylla L., have evolved resistance to glyphosate in GRS in Brazil. Conyza spp. are the most difficult to control. A glyphosate-resistant biotype of Sorghum halepense L. has evolved in GRS in Argentina and one of D. insularis in Paraguay. The following actions are proposed to minimize weed resistance problem: (a) rotation of GRS with conventional soybeans in order to rotate herbicide modes of action; (b) avoidance of lower than recommended glyphosate rates; (c) keeping soil covered with a crop or legume at intercrop intervals; (d) keeping machinery free of weed seeds; and (d) use of a preplant nonselective herbicide plus residuals to eliminate early weed interference with the crop and to minimize escapes from later applications of glyphosate due to natural resistance of older weeds and/or incomplete glyphosate coverage. PMID:20839871

Cerdeira, Antonio L; Gazziero, Dionsio L P; Duke, Stephen O; Matallo, Marcus B

2011-06-01

411

Evolved glyphosate-resistant weeds around the world: lessons to be learnt.  

PubMed

Glyphosate is the world's most important herbicide, with many uses that deliver effective and sustained control of a wide spectrum of unwanted (weedy) plant species. Until recently there were relatively few reports of weedy plant species evolving resistance to glyphosate. Since 1996, the advent and subsequent high adoption of transgenic glyphosate-resistant crops in the Americas has meant unprecedented and often exclusive use of glyphosate for weed control over very large areas. Consequently, in regions of the USA where transgenic glyphosate-resistant crops dominate, there are now evolved glyphosate-resistant populations of the economically damaging weed species Ambrosia artemissifolia L., Ambrosia trifida L., Amaranthus palmeri S Watson, Amaranthus rudis JD Sauer, Amaranthus tuberculatus (Moq) JD Sauer and various Conyza and Lolium spp. Likewise, in areas of transgenic glyphosate-resistant crops in Argentina and Brazil, there are now evolved glyphosate-resistant populations of Sorghum halepense (L.) Pers and Euphorbia heterophylla L. respectively. As transgenic glyphosate-resistant crops will remain very popular with producers, it is anticipated that glyphosate-resistant biotypes of other prominent weed species will evolve over the next few years. Therefore, evolved glyphosate-resistant weeds are a major risk for the continued success of glyphosate and transgenic glyphosate-resistant crops. However, glyphosate-resistant weeds are not yet a problem in many parts of the world, and lessons can be learnt and actions taken to achieve glyphosate sustainability. A major lesson is that maintenance of diversity in weed management systems is crucial for glyphosate to be sustainable. Glyphosate is essential for present and future world food production, and action to secure its sustainability for future generations is a global imperative. PMID:18273881

Powles, Stephen B

2008-04-01

412

Sexual Conflict and Sexually Antagonistic Coevolution in an Annual Plant  

PubMed Central

Background Sexual conflict theory predicts sexually antagonistic coevolution of reproductive traits driven by conflicting evolutionary interests of two reproducing individuals. Most studies of the evolutionary consequences of sexual conflicts have, however, to date collectively investigated only a few species. In this study we used the annual herb Collinsia heterophylla to experimentally test the existence and evolutionary consequences of a potential sexual conflict over onset of stigma receptivity. Methodology/Principal Findings We conducted crosses within and between four greenhouse-grown populations originating from two regions. Our experimental setup allowed us to investigate male-female interactions at three levels of geographic distances between interacting individuals. Both recipient and pollen donor identity affected onset of stigma receptivity within populations, confirming previous results that some pollen donors can induce stigma receptivity. We also found that donors were generally better at inducing stigma receptivity following pollen deposition on stigmas of recipients from another population than their own, especially within a region. On the other hand, we found that donors did worse at inducing stigma receptivity in crosses between regions. Interestingly, recipient costs in terms of lowered seed number after early fertilisation followed the same pattern: the cost was apparent only if the pollen donor belonged to the same region as the recipient. Conclusion/Significance Our results indicate that recipients are released from the cost of interacting with local pollen donors when crossed with donors from a more distant location, a pattern consistent with a history of sexually antagonistic coevolution within populations. Accordingly, sexual conflicts may have important evolutionary consequences also in plants. PMID:19421402

Madjidian, Josefin A.; Lankinen, Asa

2009-01-01

413

Winter Soil CO2 Flux from Different Mid-Latitude Sites from Middle Taihang Mountain in North China  

PubMed Central

Winter soil respiration is a very important component of the annual soil carbon flux in some ecosystems. We hypothesized that, with all other factors being equal, shorter winter SR result in reduced contribution to annual soil C flux. In this study, the contribution of winter soil respiration to annual soil respiration was measured for three sites (grassland: dominated by Artemisia sacrorum, Bothriochloa ischaemum and Themeda japonica; shrubland: dominated by Vitex negundo var. heterophylla; plantation: dominated by Populus tomatosa) in a mountainous area of north China. Diurnal and intra-annual soil CO2 flux patterns were consistent among different sites, with the maximum soil respiration rates at 12?00 or 14?00, and in July or August. The lowest respiration rates were seen in February. Mean soil respiration rates ranged from 0.26 to 0.45 µmol m?2 s?1 in the winter (December to February), and between 2.38 to 3.16 µmol m?2 s?1 during the growing season (May-September). The winter soil carbon flux was 24.6 to 42.8 g C m?2, which contributed 4.8 to 7.1% of the annual soil carbon flux. Based on exponential functions, soil temperature explained 73.8 to 91.8% of the within year variability in soil respiration rates. The Q10 values of SR against ST at 10 cm ranged from 3.60 to 4.90 among different sites. In addition, the equation between soil respiration and soil temperature for the growing season was used to calculate the “modeled” annual soil carbon flux based on the actual measured soil temperature. The “measured” annual value was significantly higher than the “modeled” annual value. Our results suggest that winter soil respiration plays a significant role in annual soil carbon balance, and should not be neglected when soil ecosystems are assessed as either sinks or sources of atmospheric CO2. PMID:24614868

Zhang, Wanjun; Zeng, Xinhua; Wang, Huaru

2014-01-01

414

Evaluation of developmental toxicity of coniine to rats and rabbits.  

PubMed

Conium maculatum (poison hemlock, CM) is teratogenic in several domestic species, presumably due to its piperidine alkaloids, including coniine, which has been verified to be teratogenic in cattle. Coniine/CM teratogenicity culminates in production of arthrogryposis. The purpose of this study was to evaluate coniine-induced teratogenicity in two laboratory animal species, Sprague-Dawley rats and New Zealand white rabbits. Pregnant rats were given coniine (25 mg/kg body weight) by oral gavage at 8-hour intervals on gestation days 16-18. Pregnant rabbits were given coniine (40 mg/kg body weight) by oral gavage at 8-hour intervals on gestation days 20-24. Rats were killed on day 19 and rabbits on day 29. Fetuses were immediately removed, weighed, and examined for external abnormalities. Alternate fetuses were either stained for skeletal examinations with alizarin red-S or fixed in Bouin's solution for visceral examination. Symptoms of maternal intoxication due to coniine administration were observed in both the rat and the rabbit, and higher doses were uniformly lethal. Rabbits treated with coniine appeared to lose more weight and eat less than controls, but there was no statistically significant difference between groups. Fetal weights were significantly lower in coniine-exposed rat and rabbit fetuses indicating fetotoxicity. The only statistically significant treatment-related visceral or skeletal malformation was a reduction of cranial ossification of rabbit fetuses, probably related to maternal toxicity. Coniine-exposed rabbit litters tended to be affected by arthrogryposis (no bony deformities noted on skeletal exam) more than controls (2/6 vs. 0/9). PMID:8351649

Forsyth, C S; Frank, A A

1993-07-01

415

Comparison of nicotinic receptor binding and biotransformation of coniine in the rat and chick.  

PubMed

Coniine, an alkaloid from Conium maculatum (poison hemlock), is a known teratogen in many domestic species with maternal ingestion resulting in arthrogryposis of the offspring. We have previously shown that rats are not susceptible and rabbits only weakly susceptible to coniine-induced arthrogryposis. However, the chick embryo does provide a reproducible laboratory animal model of coniine-induced teratogenesis. The reason for this cross-species variation is unknown. The purpose of this study was to evaluate coniine binding to nicotinic receptors and to measure coniine metabolism in vitro between susceptible and non-susceptible species. Using the chick model, neither the peripheral nicotinic receptor antagonist d-tubocurarine chloride nor the central nicotinic receptor antagonist trimethaphan camsylate blocked the teratogenesis or lethality of 1.5% coniine (50 microliters/egg). Trimethaphan camsylate enhanced coniine-induced lethality in a dose-dependent manner. Neither nicotinic receptor blocker prevented nicotine sulfate-induced malformations but d-tubocurarine chloride did block lethality in a dose-dependent manner. Competition by coniine for [125I]-alpha-bungarotoxin to nicotinic receptors isolated from adult rat diaphragm and chick thigh muscle and competition by coniine for [3H]-cytisine to receptors from rat and chick brain were used to assess coniine binding to nicotinic receptors. The IC50 for coniine in rat diaphragm was 314 microM while that for chick leg muscle was 70 microM. For neuronal nicotinic receptors, the IC50s of coniine for maternal rat brain, fetal rat brain, and chick brain were 1100 microM, 820 microM, and 270 microM, respectively. There were no differences in coniine biotransformation in vitro by microsomes from rat or chick livers. Differences in apparent affinity of coniine for nicotinic receptors or differences in the quantity of the nicotinic receptor between the rat and chick may explain, in part, the differences in susceptibility of coniine-induced teratogenesis between these two species. PMID:9001585

Forsyth, C S; Speth, R C; Wecker, L; Galey, F D; Frank, A A

1996-12-31

416

Effect of coniine on the developing chick embryo.  

PubMed

Coniine, an alkaloid from Conium maculatum (poison hemlock), has been shown to be teratogenic in livestock. The major teratogenic outcome is arthrogryposis, presumably due to nicotinic receptor blockade. However, coniine has failed to produce arthrogryposis in rats or mice and is only weakly teratogenic in rabbits. The purpose of this study was to evaluate and compare the effects of coniine and nicotine in the developing chick. Concentrations of coniine and nicotine sulfate were 0.015%, 0.03%, 0.075%, 0.15%, 0.75%, 1.5%, 3%, and 6% and 1%, 5%, and 10%, respectively. Both compounds caused deformations and lethality in a dose-dependent manner. All concentrations of nicotine sulfate caused some lethality but a no effect level for coniine lethality was 0.75%. The deformations caused by both coniine and nicotine sulfate were excessive flexion or extension of one or more toes. No histopathological alterations or differences in bone formation were seen in the limbs or toes of any chicks from any group; however, extensive cranial hemorrhage occurred in all nicotine sulfate-treated chicks. There was a statistically significant (P < or = 0.01) decrease in movement in coniine and nicotine sulfate treated chicks as determined by ultrasound. Control chicks were in motion an average of 33.67% of the time, while coniine-treated chicks were only moving 8.95% of a 5-min interval, and no movement was observed for nicotine sulfate treated chicks. In summary, the chick embryo provides a reliable and simple experimental animal model of coniine-induced arthrogryposis. Data from this model support a mechanism involving nicotinic receptor blockade with subsequent decreased fetal movement. PMID:8073369

Forsyth, C S; Frank, A A; Watrous, B J; Bohn, A A

1994-04-01

417

Rapid in situ detection of alkaloids in plant tissue under ambient conditions using desorption electrospray ionization.  

PubMed

Desorption electrospray ionization (DESI) mass spectrometry is applied to the in situ detection of alkaloids in the tissue of poison hemlock (Conium maculatum), jimsonweed (Datura stramonium) and deadly nightshade (Atropa belladonna). The experiment is carried out by electrospraying micro-droplets of solvent onto native or freshly-cut plant tissue surfaces. No sample preparation is required and the mass spectra are recorded under ambient conditions, in times of a few seconds. The impact of the sprayed droplets on the surface produces gaseous ions from organic compounds originally present in the plant tissue. The effects of operating parameters, including the electrospray high voltage, heated capillary temperature, the solvent infusion rate and the carrier gas pressure on analytical performance are evaluated and optimized. Different types of plant material are analyzed including seeds, stems, leaves, roots and flowers. All the previously reported alkaloids have been detected in C. maculatum, while fifteen out of nineteen known alkaloids for D. stramonium and the principal alkaloids of A. belladonna were also identified. All identifications were confirmed by tandem mass spectrometry. Results obtained show similar mass spectra, number of alkaloids, and signal intensities to those obtained when extraction and separation processes are performed prior to mass spectrometric analysis. Evidence is provided that DESI ionization occurs by both a gas-phase ionization process and by a droplet pick-up mechanism. Quantitative precision of DESI is compared with conventional electrospray ionization mass spectrometry (after sample workup) and the RSD values for the same set of 25 dicotyledonous C. maculatum seeds (one half of each seed analyzed by ESI and the other by DESI) are 9.8% and 5.2%, respectively. PMID:16284661

Talaty, Nari; Takáts, Zoltán; Cooks, R Graham

2005-12-01

418

Pharmacologically active plant metabolites as survival strategy products.  

PubMed

The fact that plant organisms produce chemical substances that are able to positively or negatively interfere with the processes which regulate human life has been common knowledge since ancient times. One of the numerous possible examples in the infusion of Conium maculatum, better known as Hemlock, a plant belonging to the family umbelliferae, used by the ancient Egyptians to cure skin diseases. The current official pharmacopoeia includes various chemical substances produced by secondary plant metabolisms. For example, the immunosuppressive drugs used to prevent organ transplant rejection and the majority of antibiotics are metabolites produced by fungal organisms, pilocarpin, digitalis, strophantus, salicylic acid and curare are examples of plant organism metabolites. For this reason, there has been an increase in research into plants, based on information on their medicinal use in the areas where they grow. The study of plants in relation to local culture and traditions is known as "ethnobotany". Careful study of the behaviour of sick animals has also led to the discovery of medicinal plants. The study of this subject is known as "zoopharmacognosy". The aim of this article is to discuss the fact that "ad hoc" production of such chemical substances, defined as "secondary metabolites", is one of the modes in which plant organisms respond to unfavourable environmental stimuli, such as an attack by predatory phytophagous animals or an excessive number of plant individuals, even of the same species, in a terrain. In the latter case, the plant organisms produce toxic substances, called "allelopathic" which limit the growth of other individuals. "Secondary metabolites" are produced by metabolic systems that are shunts of the primary systems which, when required, may be activated from the beginning, or increased to the detriment of others. The study of the manner in which such substances are produced is the subject of a new branch of learning called "ecological biochemistry". PMID:12705091

Attardo, C; Sartori, F

2003-01-01

419

Kootenai River Fisheries Investigations; Rainbow and Bull Trout Recruitment, 1999 Annual Report.  

SciTech Connect

Our 1999 objectives were to determine sources of rainbow trout Oncorhynchus mykiss and bull trout Salvelinus confluentus spawning and recruitment in the Idaho reach of the Kootenai River. We used a rotary-screw trap to capture juvenile trout to determine age at out-migration and to estimate total out-migration from the Boundary Creek drainage to the Kootenai River. The out-migrant estimate for March through August 1999 was 1,574 (95% C. I. = 825-3,283) juvenile rainbow trout. Most juveniles out-migrated at age-2 and age-3. No out-migrating bull trout were caught. Five of 17 rainbow trout radio-tagged in Idaho migrated upstream into Montana waters during the spawning season. Five bull trout originally radio-tagged in O'Brien Creek, Montana in early October moved downstream into Idaho and British Columbia by mid-October. Annual angler exploitation for the rainbow trout population upstream of Bonners Ferry, Idaho was estimated to be 58%. Multi-pass depletion estimates for index reaches of Caboose, Curley, and Debt creeks showed 0.20, 0.01, and 0.13 rainbow trout juveniles/m{sup 2}, respectively. We estimated rainbow trout (180-415 mm TL) standing stock of 1.6 kg/ha for the Hemlock Bar reach (29.4 ha) of the Kootenai River, similar to the 1998 estimate. Recruitment of juvenile rainbow and bull trout from Idaho tributaries is not sufficient to be the sole source of subsequent older fish in the mainstem Kootenai River. These populations are at least partly dependent on recruitment from Montana waters. The low recruitment and high exploitation rate may be indicators of a rainbow trout population in danger of further decline.

Walters, Jody P.; Downs, Christopher C.

2001-08-01

420

Wind River Watershed Restoration Project; Underwood Conservation District, Annual Report 2002-2003.  

SciTech Connect

The goal of the Wind River project is to preserve, protect and restore Wind River steelhead. In March, 1998, the National Marine Fisheries Service listed the steelhead of the lower Columbia as 'threatened' under the Endangered Species Act. In 1997, the Washington Department of Fish and Wildlife rated the status of the Wind River summer run steelhead as critical. Due to the status of this stock, the Wind River summer steelhead have the highest priority for recovery and restoration in the state of Washington's Lower Columbia Steelhead Conservation Initiative. The Wind River Project includes four cooperating agencies. Those are the Underwood Conservation District (UCD), United States Geological Service (USGS), US Forest Service (USFS), and Washington State Department of Fish & Wildlife (WDFW). Tasks include monitoring steelhead populations (USGS and WDFW), Coordinating a Watershed Committee and Technical Advisory Group (UCD), evaluating physical habitat conditions (USFS and UCD), assessing watershed health (all), reducing road sediments sources (USFS), rehabilitating riparian corridors, floodplains, and channel geometry (UCD, USFS), evaluate removal of Hemlock Dam (USFS), and promote local watershed stewardship (UCD, USFS). UCD's major efforts have included coordination of the Wind River Watershed Committee and Technical Advisory Committee (TAC), water temperature and water chemistry monitoring, riparian habitat improvement projects, and educational activities. Our coordination work enables the local Watershed Committee and TAC to function and provide essential input to Agencies, and our habitat improvement work focuses on riparian revegetation. Water chemistry and temperature data collection provide information for monitoring watershed conditions and fish habitat, and are comparable with data gathered in previous years. Water chemistry information collected on Trout Creek should, with 2 years data, determine whether pH levels make conditions favorable for a fish parasite, Heteropolaria lwoffi. Educational activities further the likelihood that future generations will continue to understand and enjoy the presence of native fish stocks in the Wind River basin.

White, Jim

2004-02-01

421

Education and distance learning: changing the trends.  

PubMed

Training and instruction are activities deeply ingrained in human relations and derive from the critical need for the young to learn survival skills. The responsibility in primitive society for such training almost certainly fell to parents who continued their pedagogical role after childhood issues to include hunting, gathering, fine motor activities and other life skills needed for personal or family survival. Such instruction only ended when the young were ready for independent life and- contribution to tribal well-being. Delegation of teaching to others was inevitable. Teaching has become a specialty and has at least one interesting story in ancient literature. Ulysses was certain to be away at the Trojan War and subsequent adventures for many years. He would not be able to provide his son, Telemachus, with the guidance and training to prepare him for adulthood. Therefore, he asked Mentor to act In Loco Parentis and instruct the young man toward competence and adult success. Teaching as a profession and discipline has been through many stages and many controversies. Socrates was a great teacher with a distinct technique for learning by questioning. His influence on his students was profound. Plato was such a good student he recorded all the master's works. Socrates has never been credited with even the briefest lecture note. As great as he was Socrates was forced to drink the bitter hemlock because his teaching was considered a corruption of youth rather than a proper preparation for effective adulthood. Dissonance between the expectations of learners, parents and teachers has a rich history. Certainly even now education is not something the professoriate may invent for the naïve learner and then expect grateful acquiesce with faithful learning. Learning has -dimensions in human psychology and communication. The learners' autonomy, privacy and motivation cannot be denied. Learning is collaboration with teacher and the endpoint is the acquisition of new knowledge or skill. PMID:15747972

Merrell, Ronald C

2004-01-01

422

Favorable fragmentation: river reservoirs can impede downstream expansion of riparian weeds.  

PubMed

River valleys represent biologically rich corridors characterized by natural disturbances that create moist and barren sites suitable for colonization by native riparian plants, and also by weeds. Dams and reservoirs interrupt the longitudinal corridors and we hypothesized that this could restrict downstream weed expansion. To consider this "reservoir impediment" hypothesis we assessed the occurrences and abundances of weeds along a 315-km river valley corridor that commenced with an unimpounded reach of the Snake River and extended through Brownlee, Oxbow, and Hells Canyon reservoirs and dams, and downstream along the Snake River. Sampling along 206 belt transects with 3610 quadrats revealed 16 noxious and four invasive weed species. Ten weeds were upland plants, with Canada thistle (Cirsium arvense) restricted to the upstream reaches, where field morning glory (Convolvulus arvensis) was also more common. In contrast, St. John's wort (Hypericum perforatum) was more abundant below the dams, and medusahead wildrye (Taeniatherum caput-medusae) occurred primarily along the reservoirs. All seven riparian species were abundant in the upstream zones but sparse or absent below the dams. This pattern was observed for the facultative riparian species, poison hemlock (Conium maculatum) and perennial pepperweed (Lepidium latifolium), the obligate riparian, yellow nut sedge (Cyperus esculentus), the invasive perennial, reed canary grass (Phalaris arundinacea), and three invasive riparian trees, Russian olive (Elaeagnus angustifolia), false indigo (Amorpha fruticosa), and tamarisk (Tamarix spp.). The hydrophyte purple loosestrife (Lythrum salicaria) was also restricted to the upstream zone. These longitudinal patterns indicate that the reservoirs have impeded the downstream expansion of riparian weeds, and this may especially result from the repetitive draw-down and refilling of Brownlee Reservoir that imposes a lethal combination of drought and flood stress. The dams and reservoirs may also interrupt hydrochory, the downstream flow of seeds and clonal fragments. We thus conclude that with some operational patterns, dams and reservoirs can impede the downstream expansion of riparian weeds. PMID:20945766

Rood, Stewart B; Braatne, Jeffrey H; Goater, Lori A

2010-09-01

423

Biomass accumulation and soil nitrogen availability in an 87-year-old Populus grandidentata chronosequence  

USGS Publications Warehouse

The Upper Lake States region is marked by major disturbances of fire and logging over 100 years ago that created a landscape mosaic of early successional forests. Given the intimate link between soil N availability and forest growth in this region, it is important to understand how temporal changes in soil N constrain the rate at which forest biomass accumulates following a stand-destroying disturbance. Bigtooth aspen (Populus grandidentata Michx.) currently dominates sites where primarily old-growth pine-hemlock-oak forests once thrived, which provides an opportunity to observe nearly 100 years of succession following severe disturbance. In this study, we examine the relationship between soil N availability and biomass accrual in a series of plots undergoing secondary succession following logging and burning. Our results demonstrate that total aboveground biomass and nitrogen accrual patterns are strongly and positively related on a highly disturbed, bigtooth aspen-dominated ecosystem in northern Lower Michigan. Nitrogen mineralization and nitrification were highest immediately following disturbance, and then decreased over the next approximately 20 years of succession. Following this short-term decrease, these processes increased and attained a maximum value after 70 years of forest succession. Understory biomass accumulation showed the opposite trend of nutrient availability, with highest values during the first 20 years of succession, followed by a dramatic decrease for the next 70 years. Understory biomass began to decrease as plants grew into the overstory or died. Total aboveground biomass was correlated with N mineralization (r=0.894; P=0.041) and nitrification (r=0.782; P=0.118) and appears to be increasing steadily to some maximum that has not yet been reached. ?? 2003 Elsevier B.V. All rights reserved.

White, L.L.; Zak, D.R.; Barnes, B.V.

2004-01-01

424

pale larkspur Status: State Endangered, USFWS Species of Concern  

E-print Network

General Description: A slender perennial that grows from a cluster of small bulbs. The flowering stems range from 8 inches to 2 feet in height. The leaves are distributed evenly along the stem and the lower ones are divided palmately into 5 lobes. The flower head may have from 6 to 30 individual flowers. The flowers range from white to cream colored and the petals may have lavender edges. Identification Tips: D. leucophaeum and D. pavonaceum are the only white or cream colored larkspurs west of the Cascades. D. pavonaceum has a longer spur and glandular-pubescent petals. D. leucophaeum is not glandular or pubescent. Phenology: Flowers from May through June and fruits from May to August. Range: Northern Willamette Valley in western Oregon and one site in Lewis County, Washington in the Puget Trough physiographic province. Habitat: Undisturbed sites on dry bluffs, open ground, and moist lowland meadows within the Western Hemlock Zone of Franklin and Dyrness (1973). Now largely restricted to roadside ditches and fence rows. Associated species include Garry oak (Quercus garryana), oceanspray (Holodiscus discolor), licorice fern (Polypodium glycorrhiza), broadleaf stonecrop (Sedum spathulifolium), red fescue (Festuca rubra), blue wildrye (Elymus glaucus), snowberry (Symphoricarpos albus), and hardhack (Spiraea douglasii). Elevation: 125 to 200 feet. Ecology: Seeds germinate in the winter to produce cotyledons on a slender stem. Seedlings may not develop further during the first year and second year plants consist of only one small leaf with three leaflets approximately the same size as the first year seedlings. The above ground portion of both first and second year plants usually dies back by late spring. Two or more leaves ©1964 University of Washington Press. Illustration by Jeanne R. Janish. Known distribution of

Ranunculaceae (buttercup Family; Rank Gqs

425

Last glacial pollen record from Lanzhou (Northwestern China) and possible forcing mechanisms for the MIS 3 climate change in Middle to East Asia  

NASA Astrophysics Data System (ADS)

The vegetation on the northeastern margin of the Tibetan Plateau is highly sensitive to climatic changes and thus represents a potentially interesting environmental archive. Pollen samples from the Fanjiaping Loess section in Lanzhou on the western Chinese Loess Plateau (CLP) were analyzed in conjunction with OSL dating. The results indicate that pollen zone B (60.6-46.0 ka, correlative to the early MIS 3) had the greatest abundances of Cupressaceae, Tsuga, Gramineae and Cyperaceae of the entire section, suggesting a warm phase during the last glacial period. These pollen taxa decreased significantly in abundance in the zones C (46.0-39.0 ka) and D (39.0-27.0 ka), reflecting a substantial climate cooling from the middle MIS 3 to MIS 2. These results correlate with climate records from the South China Sea, the CLP, Baikal Lake, North America, North Atlantic Ocean and other regions, and probably correspond with the decline of northern high-latitude insolation and the increase of global ice volume from 50 to 20 ka. In particular, arboreal pollen, fern spore and algae abundances declined sharply since ˜40 ka, while shrub and herb pollen reached the highest abundances. Conifer pollen Picea and Abies abundance also rose markedly and increased up the section. This implies significant climate deterioration and likely corresponded with substantial growth of the polar ice sheets since ˜40 ka. The decreasing temperature caused by an insolation decline during the last glacial period probably reinforced the cooling effect in a 'snow/ice/albedo' feedback, which would result in less climate sensitivity to radiative forcing. Meanwhile, vegetation decline in the Northern Hemisphere during the last glacial period and tundra development at high latitudes possibly caused additional cooling, enhancing the growth of polar ice sheets since 40 ka. The development of polar ice sheets increased the polar-to-equator temperature and pressure gradients, strengthening the westerlies and supplying plenty of moisture to Northwest China during 40-30 ka. Lake sediments developed widely on the Tibetan Plateau during 40-30 ka, probably related to an increase in the seasonality of middle-to-low latitude insolation which caused an enhancement of glacier melting on the Plateau.

Jiang, Hanchao; Mao, Xue; Xu, Hongyan; Thompson, Jessica; Wang, Ping; Ma, Xiaolin

2011-03-01

426

Soil greenhouse gas fluxes from different tree species on Taihang Mountain, North China  

NASA Astrophysics Data System (ADS)

The objectives of this study were to investigate seasonal variation of greenhouse gas fluxes from soils on sites dominated by plantation (Robinia pseudoacacia, Punica granatum, and Ziziphus jujube) and natural regenerated forests (Vitex negundo var. heterophylla, Leptodermis oblonga, and Bothriochloa ischcemum), and to identify how tree species, litter exclusion, and soil properties (soil temperature, soil moisture, soil organic carbon, total N, soil bulk density, and soil pH) explained the temporal and spatial variation in soil greenhouse gas fluxes. Fluxes of greenhouse gases were measured using static chamber and gas chromatography techniques. Six static chambers were randomly installed in each tree species. Three chambers were randomly designated to measure the impacts of surface litter exclusion, and the remaining three were used as a control. Field measurements were conducted biweekly from May 2010 to April 2012. Soil CO2 emissions from all tree species were significantly affected by soil temperature, soil moisture, and their interaction. Driven by the seasonality of temperature and precipitation, soil CO2 emissions demonstrated a clear seasonal pattern, with fluxes significantly higher during the rainy season than during the dry season. Soil CH4 and N2O fluxes were not significantly correlated with soil temperature, soil moisture, or their interaction, and no significant seasonal differences were detected. Soil organic carbon and total N were significantly positively correlated with CO2 and N2O fluxes. Soil bulk density was significantly negatively correlated with CO2 and N2O fluxes. Soil pH was not correlated with CO2 and N2O emissions. Soil CH4 fluxes did not display pronounced dependency on soil organic carbon, total N, soil bulk density, and soil pH. Removal of surface litter significantly decreased in CO2 emissions and CH4 uptakes. Soils in six tree species acted as sinks for atmospheric CH4. With the exception of Ziziphus jujube, soils in all tree species acted as sinks for atmospheric N2O. Tree species had a significant effect on CO2 and N2O releases but not on CH4 uptake. The lower net global warming potential in natural regenerated vegetation suggested that natural regenerated vegetation were more desirable plant species in reducing global warming.

Liu, X. P.; Zhang, W. J.; Hu, C. S.; Tang, X. G.

2014-03-01

427

A review and synthesis of monoterpene speciation from forests in the United States  

NASA Astrophysics Data System (ADS)

The monoterpene composition (emission and tissue internal concentration) of major forest tree species in the United States is discussed. Of the 14 most commonly occurring compounds ( ?-pinene, ?-pinene, ? 3-carene, d-limonene, camphene, myrcene, ?-terpinene, ?-phellandrene, sabinene, ?-cymene, ocimene, ?-thujene, terpinolene, and ?-terpinene), the first six are usually found to be most abundant. Expected regional variability based on the monoterpene composition fingerprints and corresponding tree species distribution and abundance is examined. In the southeast, ?-pinene and ?-pinene seem to dominate monoterpene emissions, while in the northern forests emissions are distributed more evenly among the six major compounds. In some parts of western forests, ?-pinene and ? 3-carene can be more abundant than ?-pinene. Among the other eight compounds, ?-phellandrene and sabinene occasionally are significant percentages of expected local monoterpene emissions. Ocimene and ?-cymene are estimated to be more common in regions dominated by deciduous broadleaf forests, although total emission rates are generally lower for these forests relative to those dominated by conifers. These percentages are compared with monoterpene composition measured in ambient air at various sites. Estimated monoterpene emission composition based on local forest species composition agrees fairly well with ambient measurements for the six major compounds. The past assumption that ?-pinene composes approximately 50% of total monoterpene emissions appears reasonable for many areas, except for possibly the northern coniferous forests and some areas in the west dominated by true firs, spruce, and western pines (lodgepole and ponderosa pines). The oxygenated monoterpenes such as camphor, bornyl acetate, and cineole often compose high percentages of the monoterpenes within plant tissues, but are much less abundant in emission samples. Even after adjusting for lower vapor pressures of these compounds, emission rates relative to the hydrocarbon monoterpenes are often lower than would be expected from