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1

TSUGA CHINENSIS AS A SOURCE OF HOST RESISTANCE TO THE HEMLOCK WOOLLY ADELGID  

Technology Transfer Automated Retrieval System (TEKTRAN)

The native eastern hemlock, Tsuga canadensis, and the Carolina hemlock, T. caroliniana, suffer injury and death following infestation by the hemlock woolly adelgid(HWA), Adelges tsugae, an introduced pest. Asian hemlocks are reported to be more tolerant. Research on the nature of genetic resistance ...

2

Evaluation of Hemlock ( Tsuga ) Species and Hybrids for Resistance to Adelges tsugae (Hemiptera: Adelgidae) Using Artificial Infestation  

Microsoft Academic Search

Hemlock (Tsuga) species and hybrids were evaluated for resistance to the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae). The adelgid was accidentally intro- duced from Asia to the eastern United States, where it is causing widespread mortality of the native hemlocks,Tsugacanadensis (L.) Carriere andTsugacaroliniana Engelm. These two native species plus the Asian speciesTsugachinensis (Franch.) E. Pritz andT.dumosa (D.Don) Eichler

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

2009-01-01

3

Allozyme variation and recent evolutionary history of eastern hemlock ( Tsuga canadensis ) in the southeastern United States  

Microsoft Academic Search

Eastern hemlock (Tsuga canadensis [L.] Carr.) is a widespread and ecologically important conifer species of eastern North America that is threatened by the\\u000a hemlock woolly adelgid (Adelges tsugae Annand), a pest introduced into the United States from Asia in the 1920s. Information about the genetic composition of eastern\\u000a hemlock is necessary to guide ex situ conservation efforts in the southeastern

K. M. Potter; W. S. Dvorak; B. S. Crane; V. D. Hipkins; R. M. Jetton; W. A. Whittier; R. Rhea

2008-01-01

4

Electrophoretic evidence for genetic differentiation in two host races of hemlock dwarf mistletoe (Arceuthobium tsugense)  

Microsoft Academic Search

Key Word Index--Arceuthobium tsugense; Viscaceae; dwarf mistletoe; electrophoresis; allozymes; host race. Abstract--Three host races of hemlock dwarf mistletoe have been described: the western hemlock race (mainly parasitic on Tsuga heterophylla), the shore pine race (mainly on Pinus contorta ssp. contorta) and the mountain hemlock race (mainly on Tsuga mertensiana and R monticola). Mistletoe shoots from 21 populations representing the three

Daniel L. Nickrent; Adam L. Stell

1990-01-01

5

Evaluation of hemlock (Tsuga) species and hybrids for resistance to ...  

Treesearch

These two native species plus the Asian species Tsuga chinensis (Franch.) ... Many of the hybrids grow well, have attractive form, and are promising as resistant landscape ... to Adelges tsugae (Hemiptera: Adelgidae) using artificial infestation.

6

Structural and compositional change in an old-growth eastern hemlock Tsuga canadensis forest, 1965–2004  

Microsoft Academic Search

Eastern hemlock (Tsuga canadensis; hereafter hemlock) was once relatively common in the northeastern United States. However, recent disturbances – including exotic pests and white-tailed deer overpopulation – have exacerbated declines in hemlock forest in the 20th century. As a previously undisturbed stand, the Mianus River Gorge Preserve (MRGP) provided an ideal site to investigate the potential impact of these factors

Mark Weckel; John M. Tirpak; Chris Nagy; Rod Christie

2006-01-01

7

Effects of fertilization of four hemlock species on Adelges tsugae ...  

Treesearch

Fertilizer was applied biweekly with 240 ppm N by using water-soluble fertilizer ... Plants (>1 yr old) were artiÞcially infested with adelgids on 31 March 2009. ... tsugae (Hemiptera: Adelgidae) growth and feeding preference of predators.

8

Persistence of Western Hemlock and Western Redcedar Trees 38 Years After Girdling at Cat Island in Southeast Alaska.  

National Technical Information Service (NTIS)

Dead western hemlock (Tsuga heterophylla) and western redcedar (Thuja plicata) trees were examined 38 years after intentional girdling (cuts made into the wood around the bole) at Cat Island, Alaska, to describe their condition as wildlife habitat. All bu...

P. E. Hennon E. M. Loopstra

1991-01-01

9

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

Microsoft Academic Search

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

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

1999-01-01

10

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

PubMed

We studied the distribution of hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), within hemlock trees for three summer (progrediens) and two winter (sistens) generations in northern Georgia. Eastern hemlock, Tsuga canadensis (L.) Carrière, trees were treated with 0, 10, or 25% of 1.5 g of imidacloprid per 2.5 cm of tree diameter at breast height and fertilized or not in a factorial design. Adelgid ovisacs per centimeter of branch were more abundant from June 2007 to June 2008 in the upper tree crown of insecticide untreated trees and when all trees were combined and that was the general trend for most comparisons. However, ovisacs were more abundant in the lower crown of insecticide treated trees in June 2008. More sistens nymphs settled on the upper crown branches than on the lower branches in summers 2007 and 2008. Higher eggs per ovisac were observed in the upper crown in February 2008 and in both the winter and summer 2009. In contrast, adelgids were more fecund in the lower crown in June 2008. On fertilized trees, eggs laid per adult were higher in the upper crown in February 2008. In summer 2008, eggs per ovisac were higher in the lower crown, but this reversed again to the upper crown by summer 2009. New growth of branches also varied among sample dates. These data demonstrate the variable distribution of adelgid and hemlock growth within trees over time and suggest that sampling only one crown area will not provide accurate estimates of adelgid densities. PMID:22299353

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

2011-12-01

11

Occurrence of vesicular-arbuscular mycorrhizae in Pseudotsuga menziesii and Tsuga heterophylla seedlings grown in Oregon Coast Range soils  

Microsoft Academic Search

Vesicular-arbuscular mycorrhizae (VAM) were common in seedlings of Pseudotsuga menziesii and Tsuga heterophylla grown in a greenhouse soil bioassay in soils collected from the Oregon Coast Range. Although root samples were heavily colonized\\u000a by ectomycorrhizal fungi (EM), VAM colonization was observed in the cortical cells of both secondary and feeder roots. Vesicles,\\u000a arbuscules, and hyphae typical of VAM occurred in

E. Cázares; J. E. Smith

1995-01-01

12

Natural infection of two new hosts by hemlock dwarf mistletoe in British Columbia  

Microsoft Academic Search

The dwarf mistletoe, Arceuthobium tsugense, exists as two pathotypes in British Columbia: one primarily infects western hemlock (Tsuga heterophylla), the other shore pine (Pinus contorta var. contorta). This is the first report of natural occurrence of either pathotypes on Douglas-fir (Pseudotsuga menziesi\\/) and the first of the hemlock dwarf mistletoe pathotype on western white pine (Pinus monticola) north of Oregon.

R. S. Hunt; R. B. Smith

13

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

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

Parasitoids reared from predators of hemlock woolly adelgid (Hemiptera: Adelgidae), and the hymenopterous parasitoid community on western hemlock in the Pacific Northwest.  

PubMed

In western North America, infestations of the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), are common on orchard, ornamental, and roadside western hemlock, Tsuga heterophylla (Raf.) Sargent. However, these infestations rarely cause T. heterophylla mortality. Host tolerance and presence of endemic predators may be contributing to the relatively low levels of injury to T. heterophylla caused by A. tsugae. Field surveys of the arthropod community associated with A. tsugae infestations on 116 T. heterophylla at 16 sites in Oregon and Washington were conducted every 4-6 wk from January 2005 through November 2006. Fourteen uninfested T. heterophylla were also surveyed across 5 of the 16 sites. Immature A. tsugae predators collected in the field were brought to the laboratory for rearing. Eight species of hymenopterous parasitoids were reared from pupae of predators of A. tsugae in the laboratory. Two Pachyneuron spp. (Pteromalidae) and a Melanips sp. (Figitidae) were reared from Leucopis spp. (Diptera: Chamaemyiidae) puparia. Syrphoctonus pallipes (Gravenhorst) (Ichneumonidae), Woldstedtius flavolineatus (Gravenhorst) (Ichneumonidae), Syrphophagus sp. (Encyrtidae), and Pachyneuron albutius Walker were reared from Syrphidae (Diptera) puparia. A Helorus sp. (Heloridae) was reared from a Chrysoperla sp. (Neuroptera: Chrysopidae) cocoon. Laboratory rearing did not show any direct association between parasitoids and A. tsugae. In the field survey, a total of 509 adult parasitic Hymenoptera representing 19 families and at least 57 genera were collected from T. heterophylla. Nonparametric analysis of community structure showed Pachyneuron spp. were strongly correlated to abundance of their Leucopis spp. hosts and to A. tsugae population score in the field. The possible impact of parasitism on Leucopis spp., potential A. tsugae biological control candidates for the eastern United States, is discussed. PMID:19161691

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

2008-12-01

16

Host specificity of Laricobius nigrinus Fender (Coleoptera: Derodontidae), a potential biological control agent of the hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae)  

Microsoft Academic Search

Host specificity tests of Laricobius nigrinus Fender (Coleoptera: Derodontidae) were conducted under quarantine in Blacksburg, Virginia, to determine the suitability of this beetle as a biological control agent of the hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae), in the eastern United States. Members of the genus Laricobius are known to feed on adelgids. L. nigrinus, native to western North

G. M. G. Zilahi-Balogh; L. T. Kok; S. M. Salom

2002-01-01

17

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

Microsoft Academic Search

This report presents results from a study characterizing the weight and volume of trees from overstocked (doghair) mixed conifer stands of Douglas-fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla) and western redcedar (Thuja plicata) located on the Quilcene Ranger District, Olympic National Forest. There are approximately 20,000 acres classed as doghair on the Quilcene District. In order to evaluate their harvesting

W. Y. Pong; Dale R. Waddell

1986-01-01

18

H-NMR studies of water interactions in sitka spruce and western hemlock: moisture content determination and second moments  

Microsoft Academic Search

Summary  The purpose of this study was to examine the influence of the moisture level on the cell-wall material in wood using pulsed proton nuclear magnetic resonance. The wood species used were western hemlock (Tsuga heterophylla (Raf.) Sarg.) and sitka spruce (Picea sitchensis (Bong.) Carr.), distinguishing between heartwood and sapwood regions. The moisture contents of the specimens were below the fibre

Ian D. Hartley; Stavros Avramidis; Alex L. MacKay

1996-01-01

19

Differential response of western hemlock from low and high elevations to inoculation with plant growth-promoting Bacillus polymyxa  

Microsoft Academic Search

The influence of inoculation with plant growth-promoting Bacillus polymyxa strains L5 and L6-16R was evaluated on the performance of western hemlock [Tsuga heterophylla (Raf.) Sarg.] using seed that originated from six British Columbia provenances that differed primarily in elevation (from 152 to 1190 m above sea level). Preliminary analysis revealed a tendency for hemlock originating from high and low elevations

C. P. Chanway

1995-01-01

20

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

21

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

SciTech Connect

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

Taylor, A.H. [Pennsylvania State Univ., University Park, PA (United States)

1995-08-01

22

Stand conditions associated with truffle abundance in western hemlock\\/Douglas-fir forests  

Microsoft Academic Search

Truffles are a staple food source for many forest small mammals yet the vegetation or soil conditions associated with truffle abundance are unknown. We examined the spatial distribution of forest structures, organic layer depth, root density, and two of the most common western North American truffles (Elaphomyces granulatus and Rhizopogon parksii), in managed-young, natural-mature and old-growth western hemlock (Tsuga heterophylla)\\/Douglas-fir

Malcolm North; Joshua Greenberg

1998-01-01

23

Eastern Hemlock: A Market Perspective  

Microsoft Academic Search

Although it is an important component of the northern forest, eastern hemlock (Tsuga canadensis (L.) Carr.) is a secondary species in its regions' markets. In this paper, we examine the markets for hemlock, analyze price trends for stumpage, and suggest implications of market forces for management of forests containing hemlock. The characteristics of hemlock wood limit its use to relatively

Theodore Howard; Paul Ser rldak; Claudia Codrescu

24

The mid-Holocene Tsuga canadensis (hemlock) decline, eastern North America–age versus causes: a reply to Payette  

Microsoft Academic Search

A reply is made to comments by Payette (2004) concerning the paper that attempted to determine the age of the Tsuga canadensis decline in eastern North America (Bennett and Fuller, 2002). It is pointed out that his criticisms of the methods used are all aspects covered in the original paper, and which make little, if any, difference to the result

K. D. Bennett; J. L. Fuller

2004-01-01

25

Vegetation Response Following Hemlock Woolly Adelgid Infestation Hemlock Decline and Hemlock Salvage Logging  

Microsoft Academic Search

Abstract Ten heavily logged hemlock (Tsuga canadensis(L.) Carr.) stands in Connecticut and Massachusetts were examined to compare the vegetation response following intense harvesting with chronic hemlock woolly adelgid (HWA) (Adelges tsugaeAnnand) infestations. All stands were dominated by hemlock, with 66 to 99% of total stand basal area. Salvage or pre-emptive cutting removed more than 50% of overstory stems and more

David A. Orwig; Matthew L. Kizlinski

26

Elongate Hemlock Scale - Treesearch - USDA Forest Service  

Treesearch

Jul 21, 2013 ... Description: The elongate hemlock scale, Fiorinia externa Ferris, native to ... and in nine states from Virginia to southern New England and west to Ohio. ... (Marlatt ), and the hemlock woolly adelgid, Adelges tsugae Annand.

27

Impacts of Hemlock Woolly Adelgid Infestation on Decomposition: An Overview  

Microsoft Academic Search

Hemlock woolly adelgid (HWA), Adelges tsugae Annand, a small aphid-like pest, is initiating rapid and widespread changes in composition and structure in southern New England hemlock forests. Rapid HWA expansion and extensive eastern hemlock (Tsuga canadensis) salvage logging threaten a region-wide reduction of this ecologically unique, culturally and economically important forest type. The purpose of this paper is to describe

Richard C. Cobb; David A. Orwig

28

A geographically variable model of hemlock woolly adelgid spread  

Microsoft Academic Search

The hemlock woolly adelgid (HWA) (Adelges tsugae) has spread through the range of eastern hemlock (Tsuga canadensis) leaving dead hemlock trees in its wake. We combined county and previously unavailable township level infestation records\\u000a with geographic variables including plant hardiness zone, elevation, forest cover type, urbanization, precipitation, temperature,\\u000a and hemlock range in a geographic information system to build models linking

Alexander M. Evans; Timothy G. Gregoire

2007-01-01

29

Stand Dynamics Associated with Chronic Hemlock Woolly Adelgid Infestations in Southern New England  

Microsoft Academic Search

Abstract Vegetation dynamics were monitored for 6 years in eight hemlock (Tsuga canadensis(L.) Carriere) stands with varying levels of hemlock woolly adelgid (HWA) (Adelges tsugaeAnnand) damage in southcentral Connecticut to examine the patterns of overstory hemlock mortality and subsequent community reorganization associated with chronic HWA infestations. Since 1995, overstory and understory mortality has risen 5 to 15% per year to

David A. Orwig; Harvard Forest

30

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

PubMed

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an exotic insect pest that is killing eastern hemlock, Tsuga canadensis (L.) Carrière, and Carolina hemlock, Tsuga caroliniana Engelmann, in the eastern United States. We used the sequential interval procedure to develop a binomial sequential sampling plan for A. tsugae sistens on individual eastern hemlock trees that uses nondestructive sampling of new shoots. The actual a (type I) and beta (type II) error rates were essentially 5 and 10%, respectively. Tallies of new shoots infested by at least one A. tsugae sistens were compared with stop values for thresholds of 10 and 30% of new hemlock shoots infested. Twenty to 80 new shoots had to be examined per tree to render a low, high, or indeterminate classification, which took < 2 min per tree regardless of the threshold used. This plan should be an efficient and cost-effective tool in the management of A. tsugae infestations on individual, high-value eastern hemlock trees. PMID:16937709

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

2006-08-01

31

Stand, Landscape, and Ecosystem Analyses of Hemlock Woolly Adelgid Outbreaks in Southern New England: An Overview  

Microsoft Academic Search

Hemlock woolly adelgid (HWA) (Adelges tsugae), an introduced aphid-like insect from Asia, is expanding across the northeastern United States through the range of eastern hemlock (Tsuga canadensis (L.) Carr.) and has the potential to severely reduce or eliminate this important late- successional species. While infestation and unimpeded migration of HWA presents a tremendous management problem, it also has provided an

David A. Orwig; David R. Foster

32

Direct and indirect ecosystem consequences of an invasive pest on forests dominated by eastern hemlock  

Microsoft Academic Search

Aim This study compares the magnitude and trajectory of vegetation and ecosystem function dynamics associated with the direct impact of hemlock woolly adelgid (Adelges tsugae Annand; HWA) infestation vs. the indirect consequences of HWA-induced damage in the form of salvage and pre-emptive logging of hemlock (Tsuga canadensis (L.) Carriere) forests. Location The study was conducted within an area extending from

Matthew L. Kizlinski; David A. Orwig; Richard C. Cobb; David R. Foster

2002-01-01

33

Forest Dynamics Of Two Multi-Aged Hemlock-Mixed Mesophytic Forests In The Northern Cumberland Plateau, Kentucky  

Microsoft Academic Search

Tsuga canadensis (eastern hemlock) is a foundation species that performs a unique ecological role within the Appalachian mixed mesophytic forest of the eastern United States. However, the non-native hemlock woolly adelgid (HWA; Adelges tsugae Annand), a novel invasive colonizer, is significantly altering the natural processes within T. canadensis ecosystems. Few studies have documented T. canadensis forests before, during, and after

Kacie Lee Tackett

2012-01-01

34

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

35

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

SciTech Connect

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

Pong, W.Y.; Waddell, Dale R.; Biomass and Energy Project (Portland, Or.)

1985-03-15

36

Understory vegetation in old-growth and second-growth Tsuga canadensis forests in western Massachusetts  

Microsoft Academic Search

We compared the understory communities (herbs, shrubs, and tree seedlings and saplings) of old-growth and second-growth eastern hemlock forests (Tsuga canadensis) in western Massachusetts, USA. Second-growth hemlock forests originated following clear-cut logging in the late 1800s and were 108–136 years old at the time of sampling. Old-growth hemlock forests contained total ground cover of herbaceous and shrub species that was

Anthony W. D’Amato; David A. Orwig; David R. Foster

2009-01-01

37

Ecological and genetic factors that define the natural distribution of Carolina hemlock in the southeastern United States and their role in ex situ conservation  

Microsoft Academic Search

Carolina hemlock (Tsuga caroliniana Engelm.) is a rare endemic found in the Appalachian Mountains and Upper Piedmont of the southeastern United States. It is being decimated by the hemlock woolly adelgid (Adelges tsugae Annand), an exotic pest introduced into the region from Japan several decades ago. We examine ecological, genetic and climatic factors in natural stands that characterize the species’

Robert M. Jetton; William S. Dvorak; W. Andrew Whittier

2008-01-01

38

Tsuga shimokawaensis , a new species of permineralized conifer leaves from the Middle Miocene Shimokawa Group, Hokkaido, Japan  

Microsoft Academic Search

Silicified pinaceous leaves from the late Middle Miocene bed of Shimokawa Town, central Hokkaido, Japan are described asTsuga shimokawaensis sp. nov. Comparisons with leaves of extant species ofTsuga show that the new species is assigned to sect.Tsuga, resembling the extant speciesT. heterophylla in having usually one-cell-layered hypodermis, andT. sieboldii in having mesophyll cells between the resin canal and the hypodermis.

Midori Matsumoto; Takeshi Ohsawa; Makoto Nishida

1995-01-01

39

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

2013-07-31

40

Variation in Winter Survival of the Invasive Hemlock Woolly Adelgid (Hemiptera: Adelgidae) Across the Eastern United States  

Microsoft Academic Search

The hemlock woolly adelgid (Adelgestsugae Annand) is a small, aphid-like insect native to East Asia and western North America. First documented in the eastern United States in Richmond, VA, in 1951, it has spread to at least 17 states, where it causes increased mortality among both eastern and Carolina hemlocks (Tsuga canadensis Carriere and T. caroliniana Engelmann., respectively). Previous work

R. Talbot Trotter; Kathleen S. Shields

2009-01-01

41

Silviculture and Stand Dynamics of Hemlock-dominated Stands in Southern New England: Some Lessons from Early Research  

Microsoft Academic Search

In the early part of this century, considerable interest existed in the silviculture of hemlock (Tsuga canadensis (L.) Carr.) in the southern New England region, where it occurs in mixture with oak (Quercus spp.), white pine (Pinus strobus L.), birches (Betula spp.), and maples (Acer spp.). Difficulties encountered with the regeneration of white pine led to the idea that hemlock

Matthew J. Keltyl

42

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

SciTech Connect

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

Pong, W.Y.; Waddell, Dale R.; Biomass and Energy Project (Portland, Or.)

1986-05-30

43

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

44

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

45

Limnologic consequences of the decline in hemlock 4800 years ago in three Southern Ontario lakes  

Microsoft Academic Search

Four thousand eight hundred years ago hemlock (Tsuga canadensis) populations were decimated throughout eastern North America. We have studied the effects of this loss from the terrestrial community on three Southern Ontario lakes: Little Round Lake, Sunfish Lake, and McKay Lake. This study includes the use of cladocerans, diatoms, chrysophytes, and bacterial pigments to assess the limnologic changes that occurred

Mary M. Boucherle; John P. Smol; Tracie C. Oliver; S. R. Brown; R. McNeely

1986-01-01

46

Composition and Structure of Hemlock-Dominated Riparian Forests of the Northern Allegheny Plateau: A Baseline Assessment  

Microsoft Academic Search

We assessed the species composition and structure of three riparian forest stands of differing ages (old-growth, late- successional, mid-successional), dominated by eastern hemlock (Tsuga canadensis Carr.), in the Allegheny National Forest of northwestern Pennsylvania. Our objectives were to: 1) quantify structural and compositional attributes of hemlock-dominated riparian forests along a successional chronosequence; 2) describe in-stream coarse woody debris (CWD; logs

Charles E. Williams; William J. Moriarity

47

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

PubMed

The hemlock woolly adelgid (HWA, Adelges tsugae Annand) is currently causing a severe decline in vitality and survival of eastern hemlock in North American forests. We analyzed the effects of light HWA infestation on vertical energy and nutrient fluxes from the canopy to the forest floor. Canopy throughfall, litter lysimeters, and laboratory litter microcosms were used to examine the effects of HWA-affected and unaffected throughfall on litter type, leachate, and litter chemistry. Early in the season adelgid infestation caused higher dissolved organic carbon (DOC; +24.6%), dissolved organic nitrogen (DON; +28.5%), and K (+39.3%) fluxes and lower inorganic nitrogen fluxes (-39.8%) in throughfall and in adjacent litter solutions collected beneath infested compared to uninfested trees. Needle litter collected beneath uninfested hemlock had significantly lower N concentrations compared to needles collected beneath infested trees, while no difference in N concentrations was found in birch litter. Bacteria were significantly more abundant on hemlock and birch litter beneath infested trees, while yeasts and filamentous fungi showed no consistent response to HWA throughfall. Litter microcosms showed that less DOC was leaching from birch than from hemlock needles when exposed to HWA throughfall. Overall, NH4-N and DON leachate concentrations were higher from birch than from hemlock litter. Thus, HWA-affected throughfall leads to qualitative and quantitative differences in nitrogen export from the litter layer. The N concentration of hemlock litter did not change with time, but the N concentration in birch litter increased significantly during the course of the experiment, especially when HWA-affected throughfall was applied. We suggest a nonlinear conceptual model for the temporal and vertical transition of energy and nutrient fluxes relative to progressing HWA infestation from a pure hemlock to a birch/maple-dominated forest. Progressive needle loss and changes in needle chemistry are likely to produce a humped-shaped DOC curve, while N fluxes initially decrease as infestation continues but rise eventually with hemlock decline and immigration of hardwood species. These findings suggest that it is necessary to understand the biology and specific physiological/trophic effects of exotic pests on their hosts and associated ecosystem processes in order to decipher the temporal dynamics, direction of change, and functional consequences. PMID:16922328

Stadler, Bernhard; Müller, Thomas; Orwig, David

2006-07-01

48

Survival of tree seedlings on different species of decaying wood maintains tree distribution in Michigan hemlock-hardwood forests  

Microsoft Academic Search

Summary 1. Seedlings of some tree species are strongly associated with decaying wood in the germination or establishment period. Despite recognition of this pattern in forests around the world, few studies have compared the ability of different species of decaying wood to support seedlings. 2. We measured the abundance, survival, and age distribution of seedlings of Tsuga canadensis (eastern hemlock),

Laura Marx; Michael B. Walters

49

Crown openness as influenced by tree and site characteristics for yellow birch, sugar maple, and eastern hemlock  

Microsoft Academic Search

Crown openness (CO) of mature trees influences light transmission within the forest canopy. However, in mod- eling, this variable is often considered constant within species, and its potential regional variability is ignored. The objec- tive of this study was to evaluate if CO values of yellow birch (Betula alleghaniensis Britt.), sugar maple (Acer saccharum Marsh.), and eastern hemlock (Tsuga canadensis

Marie-Lou Lefrançois; Marilou Beaudet; Christian Messier

2008-01-01

50

The effect of disturbance by Phellinus weirii on decomposition and nutrient mineralization in a Tsuga mertensiana forest  

Microsoft Academic Search

Microbial biomass in the upper 7 cm of soil and needle decomposition on the forest floor were measured seasonally for 10 months in a mountain hemlock (Tsuga mertensiana) old-growth forest and in a regrowth forest after Phellinus weirii, a root-rot pathogen infection, had caused disturbance. The microbial biomass was higher in the old-growth forest soil than in the regrowth forest

K. Cromack; J. A. Entry; T. Savage

1991-01-01

51

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

52

Growth of planted tree seedlings in response to ambient light levels in northwestern interior cedar-hemlock forests of British Columbia  

Microsoft Academic Search

Insights into field-planted conifer seedling growth were gained by fitting height and diameter growth to relative irradiance over the growing season using Michaelis-Menten functions. There was little difference among tree species (Abies lasiocarpa (Hook.) Nutt., Picea glauca (Moench) Voss ? Picea sitchensis (Bong.) Carr., Pinus contorta Dougl. ex Loud., Thuja plicata Donn ex D. Don, Tsuga heterophylla (Raf.) Sarg.) in

K. Dave Coates; Philip J. Burton

1999-01-01

53

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

PubMed

Infestation of eastern hemlock (Tsuga canadensis (L.) Carr.) with hemlock woolly adelgid (HWA, Adelges tsugae) has caused widespread mortality of this key canopy species throughout much of the southern Appalachian Mountains in the past decade. Because eastern hemlock is heavily concentrated in riparian habitats, maintains a dense canopy, and has an evergreen leaf habit, its loss is expected to have a major impact on forest processes, including transpiration (E(t)). Our goal was to estimate changes in stand-level E(t) since HWA infestation, and predict future effects of forest regeneration on forest E(t) in declining eastern hemlock stands where hemlock represented 50-60% of forest basal area. We used a combination of community surveys, sap flux measurements, and empirical models relating sap flux-scaled leaf-level transpiration (E(L)) to climate to estimate the change in E(t) after hemlock mortality and forecast how forest E(t) will change in the future in response to eastern hemlock loss. From 2004 to 2011, eastern hemlock mortality reduced annual forest E(t) by 22% and reduced winter E(t) by 74%. As hemlock mortality increased, growth of deciduous tree species--especially sweet birch (Betula lenta L.), red maple (Acer rubrum L.), yellow poplar (Liriodendron tulipifera L.), and the evergreen understory shrub rosebay rhododendron (Rhododendron maximum L.)--also increased, and these species will probably dominate post-hemlock riparian forests. All of these species have higher daytime E(L) rates than hemlock, and replacement of hemlock with species that have less conservative transpiration rates will result in rapid recovery of annual stand E(t). Further, we predict that annual stand E(t) will eventually surpass E(t) levels observed before hemlock was infested with HWA. This long-term increase in forest E(t) may eventually reduce stream discharge, especially during the growing season. However, the dominance of deciduous species in the canopy will result in a permanent reduction in winter E(t) and possible increase in winter stream discharge. The effects of hemlock die-off and replacement with deciduous species will have a significant impact on the hydrologic flux of forest transpiration, especially in winter. These results highlight the impact that invasive species can have on landscape-level ecosystem fluxes. PMID:23865229

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

2013-06-01

54

Hemlock declines rapidly with hemlock woolly adelgid infestation ...  

Treesearch

US Forest Service Treesearch. Hemlock declines rapidly with hemlock woolly adelgid infestation: impacts on the carbon cycle of the Southern Appalachian forests ... Language: English. Continent: North America. Country: United States. State:.

55

Propagation, synchrony, and impact of introduced and native Laricobius spp. (Coleoptera: Derodontidae) on hemlock woolly adelgid in Virginia.  

PubMed

Synchrony and impact of the predators Laricobius nigrinus Fender and Laricobius rubidus LeConte, on hemlock woolly adelgid, Adelges tsugae Annand, were studied in an eastern hemlock field insectary in Virginia. First, a field insectary for propagation of the introduced L. nigrinus was established by planting hemlocks in 2001, infesting them with hemlock woolly adelgid in 2002 and 2003, followed by releasing 258 L. nigrinus in 2003. Initial sampling showed that the native L. rubidus was present in the area. Hemlock woolly adelgid and both Laricobius species populations increased annually, from which 305 F3 L. nigrinus adults were collected and redistributed to forests in 2007. Second, the phenology of hemlock woolly adelgid and Laricobius spp. life cycles were monitored in 2005 and 2006. Adult L. nigrinus (F2) and L. rubidus were active on hemlock from fall through mid-spring and overlapped with second-instar sistentes nymphs through progredientes eggs. The predators' eggs were oviposited and larvae developed (i.e., F3 L. nigrinus) from late winter to mid-spring on progredientes eggs, indicating synchrony with suitable prey life stages. Third, a predator exclusion experiment was used to examine the relationships between the predators and prey in 2005 and 2006. When exposed to L. nigrinus (F2 adults and F3 larvae) and L. rubidus, hemlock woolly adelgid survival and ovisac density were lower and ovisac disturbance was higher than hemlock woolly adelgid protected in cages. The establishment and production of L. nigrinus at a field insectary, synchronization with, and impacts on hemlock woolly adelgid after a small release 2 yr earlier makes it an important potential biological control agent of hemlock woolly adelgid. PMID:19161693

Mausel, D L; Salom, S M; Kok, L T; Fidgen, J G

2008-12-01

56

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.

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

2012-01-01

57

Spatial pulses of water inputs in deciduous and hemlock forest stands  

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

58

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.

Feucht, Walter; Schmid, Markus; Treutter, Dieter

2011-01-01

59

Western Hemlock Ecosystem  

Microsoft Academic Search

We report measurements of rates of sap flow in dominant trees, changes in soil moisture, and evaporation from coarse woody debris in an old- growth Douglas-fir-western hemlock ecosystem at Wind River, Washington, USA, during dry periods in summer. The measurements are compared with eddy-covariance measurements of water-vapor fluxes above the forest (Ee) and at the forest floor (Eu) to examine

Michael H. Unsworth; Kyaw Tha

60

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

61

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

NASA Astrophysics Data System (ADS)

Ecological forest successions associated with introduction of invasive species, human disturbance, and climate change may alter biogeochemical cycles within forested New England watersheds. Spread of the invasive insect hemlock wooly adelgid (Adelges tsungae, HWA) to eastern North America is causing decline and mortality of the eastern hemlock (Tsuga canadensis). To evaluate whether changes in nutrient cycling could be altered by this disturbance, we investigated differences in soil geochemistry in secondary growth forest located at the MacLeish Field Station, Whately, MA, where HWA occurrences recently have been observed. Eastern hemlock on this property was selectively logged 20 years ago, with black birch regrowth succeeding hemlock. We hypothesize that such a succession could repeat should hemlock on the property experience mortality due to the HWA. Between 2010-2011, we measured soil pH, exchangeable acidity (Al3+ and H+), exchangeable base cations (Ca2+, Mg2+, Na+, and K+), and nitrogen mineralization rates of soil cores collected beneath a hemlock stand and beneath an adjacent, younger black birch stand that succeeded hemlock following logging. Although soil pH of organic horizons between hemlock and black birch are both acidic (pH<4.5), the concentration of exchangeable base cations in the organic horizon beneath black birch is approximately 1.5 times higher than hemlock, reflecting its higher total cation exchange capacity. These results suggest that the acidity typically associated with soils that support hemlock forests has not been neutralized by black birch regrowth, and soil acidity may be stabilized by exchangeable Al3+, which is similar for the two sites. More base cations may be becoming available within the cation exchange pool of the black birch soil, possibly reflecting variation in inputs of base cations from throughfall and leaf litter. Net nitrogen mineralization and nitrification rates determined for incubated soil cores, measured between May - July 2011, showed no significant difference between black birch and hemlock tree stands. Percent N mineralization due to nitrification is slightly less than 10%. Both tree stands do show a significant rise in nitrogen mineralization rates between the May-June and June-July incubation periods, primarily due to production of NH4+. Additional data will be presented to assess nitrogen mineralization rates for the remainder of the 2011 growing season.

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

2011-12-01

62

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

63

The Hemlock Sawfly in Southeast Alaska.  

National Technical Information Service (NTIS)

The hemlock sawfly has one generation per year and overwinters in the egg stage. There are apparently four feeding male larval instars and five female instars. Cocoon measurements provide a fairly reliable means of sexing sawfly pupae. Females produce an ...

J. S. Hard D. C. Schmiege

1968-01-01

64

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

PubMed

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. PMID:12108590

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

2002-06-01

65

Xanthine oxidase inhibitory lanostanoids from Ganoderma tsugae.  

PubMed

Two new lanostanoids, 3?-acetoxy-22-oxo-5?-lanosta-8,24-dien-21-oic acid, named tsugaric acid D (1) and 16?-hydroxy-3-oxo-5?-lanosta-6,8,24(24(1))-trien-21-oic acid, named tsugaric acid E (2) were isolated from the fruit bodies of Ganoderma tsugae. The structures 1 and 2 were determined by spectroscopic methods. Compound 1 and known compounds 3 and 6 exhibited significant inhibitory effects on xanthine oxidase (XO) activity with an IC50 values of 90.2±24.2, 116.1±3.0, and 181.9±5.8 ?M, respectively. Known compound 5 was able to protect human keratinocytes against damage induced by UVB light, which showed 5 could protect keratinocytes from photodamage. The 1 and 5 ?M 1 combined with 5 ?M cisplatin, respectively, enhanced the cytotoxicity induced by cisplatin. It suggested that 1 and 5 ?M 1 combined with low dose of cisplatin may enhance the therapeutic efficacy of cisplatin and reduce side effect and cisplatin resistant. PMID:23769935

Lin, Kai-Wei; Chen, Yen-Ting; Yang, Shyh-Chyun; Wei, Bai-Luh; Hung, Chi-Feng; Lin, Chun-Nan

2013-06-13

66

Errors from Application of Western Hemlock Site Curves to Mountain Hemlock.  

National Technical Information Service (NTIS)

Application of coastal western hemlock site curves to mature and overmature mountain hemlock stands may lead to large errors in estimation of growth and yield. Overestimation of site by 25 feet, for example leads to volume estimation errors of 60 to 240 p...

F. R. Herman J. F. Franklin

1976-01-01

67

Property value impacts of hemlock woolly adelgid in residential forests  

Treesearch

The data span a decade of residential property value transactions in West Milford , New ... Hemlock health in naturally regenerated hemlock stands was measured ... This article was written and prepared by U.S. Government employees on ...

68

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

Microsoft Academic Search

This report presents an assessment of macronutrients and their distribution within highly stocked, stagnant stands of mixed conifers on the Quilcene Ranger District, Olympic National Forest, northwest Washington. These stands consisted of predominantly three species: western hemlock (Tsuga heterophylla), coast Douglas-fir (Pseudotsuga menzeisii), and western redcedar (Thuja plicata). Preliminary investigation suggests that the living crown contains a small portion of

S. N. Little; D. R. Waddell

1987-01-01

69

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

EPA Science Inventory

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

70

Examples of Fire Restoration in Glacier National Park  

Microsoft Academic Search

Covering just over 1 million acres, Glacier National Park straddles the Continental Divide in northwestern Montana. Diverse vegetation communities include moist western ce- dar-western hemlock ( Thuja plicata -Tsuga heterophylla ) old growth forests similar to those of the Pacific Coast, dry western grasslands and prairies, dense lodgepole pine for- ests (Pinus contorta var. latifolia), ponderosa pine (P. ponde- msa

Laurie L. Kurth

1996-01-01

71

Historical fires in Douglas-fir dominated riparian forests of the southern Cascades, Oregon  

Microsoft Academic Search

Despite the ecological importance of fire in Pa cific Northwest forests, its role in riparian forests is just beginning to be documented. This study reconstructed the historical occurrence of fire within riparian forests along different stream sizes in coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirbel) Franco) dominated forests within the drier western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest series of

Diana L. Olson; James K. Agee

2005-01-01

72

Effects of clearcutting and alternative silvicultural systems on rates of decomposition and nitrogen mineralization in a coastal montane coniferous forest  

Microsoft Academic Search

Rates of litter decomposition and N mineralization were measured in an old growth forest and in adjacent areas harvested by clearcut, patch cut, shelterwood and green tree retention systems. The site was a montane forest of western hemlock (Tsuga heterophylla (Raf.) Sarg.) and amabilis fir (Abies amabilis Dougl.) on Vancouver Island, in British Columbia, Canada. During the first two years

C. E. Prescott

1997-01-01

73

Factors limiting the early survivorship of Thuja plicata on northern Vancouver Island, British Columbia  

Microsoft Academic Search

Adrian Weber, Benjamin Gilbert, J.P. (Hamish) Kimmins, and C.E. Prescott Abstract: Western redcedar (Thuja plicata Donn ex D. Don), a late successional species on northern Vancouver Island, has a low seedling survival in mature hemlock (Tsuga heterophylla (Raf.) Sarg.) - amabilis fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes) (HA) stands. Shade, moss competition, and substrate were tested

Adrian Weber; Benjamin Gilbert; C. E. Prescott

2003-01-01

74

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

75

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

USGS Publications Warehouse

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

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

2009-01-01

76

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

PubMed

Various human-induced changes to the atmosphere have caused carbon dioxide (CO?), nitrogen dioxide (NO?) and nitrate deposition (NO??) to increase in many regions of the world. The goal of this study was to examine the simultaneous influence of these three factors on tree seedlings. We used open-top chambers to fumigate sugar maple (Acer saccharum) and eastern hemlock (Tsuga canadensis) with ambient or elevated CO? and NO? (elevated concentrations were 760 ppm and 40 ppb, respectively). In addition, we applied an artificial wet deposition of 30 kg ha?¹ year?¹ NO?? to half of the open-top chambers. After two growing seasons, hemlocks showed a stimulation of growth under elevated CO?, but the addition of elevated NO? or NO?? eliminated this effect. In contrast, sugar maple seedlings showed no growth enhancement under elevated CO? alone and decreased growth in the presence of NO? or NO??, and the combined treatments of elevated CO? with increased NO? or NO?? were similar to control plants. Elevated CO? induced changes in the leaf characteristics of both species, including decreased specific leaf area, decreased %N and increased C:N. The effects of elevated CO?, NO? and NO?? on growth were not additive and treatments that singly had no effect often modified the effects of other treatments. The growth of both maple and hemlock seedlings under the full combination of treatments (CO??+?NO??+?NO??) was similar to that of seedlings grown under control conditions, suggesting that models predicting increased seedling growth under future atmospheric conditions may be overestimating the growth and carbon storage potential of young trees. PMID:21470979

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

2011-04-06

77

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

78

Product Quality and Drying Characteristics of Intermittent Heat Pump Drying of Ganoderma tsugae Murrill  

Microsoft Academic Search

Intermittent drying has been reported as an innovative drying technique for the drying of thermolabile materials in terms of energy cost and product quality. However, the effect of intermittency (?) on the quality of Ganoderma tsugae during intermittent drying process remains unknown. In this study, drying characteristics and product quality of continuous and intermittent drying of Ganoderma tsugae in a

Siew Kian Chin; Chung Lim Law

2010-01-01

79

Thin-Layer Drying Characteristics and Quality Evaluation of Air-Dried Ganoderma Tsugae Murrill  

Microsoft Academic Search

Ganoderma is normally dried to extend its shelf life without using chemical preservative and to concentrate the medicinal value in the fruiting body. Convective hot air drying characteristics of Ganoderma tsugae Murrill were evaluated in hot air circulated oven at different drying temperatures, sizes, and air flow rates. The drying kinetics of Ganoderma tsugae in kidney shape and slices were

Siew Kian Chin; Chung Lim Law; Christina Vimala Supramaniam; Poh Guat Cheng

2009-01-01

80

Foliar terpenoids in Tsuga species and the fecundity of scale insects  

Microsoft Academic Search

The relationship between the reproductive success of two Japanese scale insects, Fiorinia externa Ferris and Nuculaspis tsugae (Marlatt) (Homoptera: Diaspididae) and the concentrations of 15 terpenoids in needles of Tsuga sieboldii, the Japanese host, and T. canadensis, the North American host, was investigated during 1981 and 1982 in a field plot of 8-year-old trees in New Haven, CT, USA. Both

Mark S. McClure; J. Daniel Hare

1984-01-01

81

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 H2 O2 . GAs dissipated the cellular reactive oxygen species imposed by H2 O2 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

2013-04-23

82

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

83

Antiinflammatory triterpenoids and steroids from Ganoderma lucidum and G. tsugae  

Microsoft Academic Search

The antiinflammatory properties of triterpenoids and steroids from both Ganoderma lucidum and Ganoderma tsugae were studied. Twelve compounds, including ergosta-7,22-dien-3?-ol (1), ergosta-7,22-dien-3?-yl palmitate (2), ergosta-7,22-dien-3-one (3), ergosta-7,22-dien-2?,3?,9?-triol (4), 5?,8?-epidioxyergosta-6,22-dien-3?-ol (5), ganoderal A (6), ganoderal B (7), ganoderic aldehyde A (8), tsugaric acid A (9), 3-oxo-5?-lanosta-8,24-dien-21-oic acid (10), 3?-acetoxy-5?-lanosta-8,24-dien-21-oic acid ester ?-d-glucoside (11), and tsugaric acid B (12), were assessed in

Horng-Huey Ko; Chi-Feng Hung; Jih-Pyang Wang; Chun-Nan Lin

2008-01-01

84

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

85

Eastern hemlock decline in riparian areas from Maine to Alabama  

Treesearch

We found hemlock woolly adelgid present at 25 of 49 stands from ... New England states, Ohio, western Pennsylvania, Kentucky, and Alabama had good ... many of which are in the mid-Atlantic and southern states at sites dominated by shrubs ...

86

Silviculture and stand dynamics of hemlock-dominated stands in ...  

Treesearch

Science.gov - We Participate ... Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station: 11-13 ... Difficulties encountered with the regeneration of white pine led to the idea that hemlock ...

87

Density-dependent eÄects on tree survival in an old- growth Douglas fir forest  

Microsoft Academic Search

Summary 1 We mapped the locations of live and dead trees in a large forest plot dominated by pioneer Douglas fir (Pseudotsuga menziesii) with an understorey of the invading late-successional species western hemlock (Tsuga heterophylla) and western red cedar (Thuja plicata) on Vancouver Island, British Columbia, Canada, to test for intra- and interspecific density-dependent eÄects on tree survival. 2 We

FANGLIANG HE; RICHARD P. DUNCAN

88

Energy Values for Whole Trees and Crowns of Selected Species  

Microsoft Academic Search

Background Energy values, Btu's (British thermal units) per ovendry pound, were determined for whole-tree and crown materials from western hemlock {Tsuga heterophylla (Raf.) Sarg.), coast Douglas-fir {Pseudotsuga menziesii (Mirb.) Franco var. menziesii), and western redcedar (Thuja plicata Donn ex D. Don). Samples were collected from small-diameter stands in northwest Washington where whole-tree harvesting is underway. Samples of crown material representing

James O. Howard

89

Nitrogen source effects on rhizosphere pH and nutrient accumulation by Pacific Northwest conifers  

Microsoft Academic Search

Nitrogen source effects on rhizosphere pH were evaluated for Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco], Sitka spruce [Picea sitchensis (Bong.) Carr.] and western hemlock [Tsuga heterophylla (Raf.) Sarg.] seedlings and a 40-year-old second growth Douglas-fir stand. Nitrogen additions of 400 mg kg?1 decreased rhizosphere pH up to 0.7 units in ammonium treatments and increased pHr by up to 1.2 units in

B. A. Rollwagen; R. J. Zasoski

1988-01-01

90

Impact of Imidacloprid for control of Hemlock Woolly Adelgid on ...  

Treesearch

International Institute of Tropical Forestry ... Title: Impact of Imidacloprid for control of Hemlock Woolly Adelgid on nearby aquatic macroinvertebrate asseblages. ... woolly adelgid control near streams adversely affects aquatic invertebrates. ... in the southern Appalachian region of Georgia and North Carolina were treated ...

91

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

92

Spatial pattern and regeneration dynamics in a temperate Abies–Tsuga forest in southwestern Japan  

Microsoft Academic Search

This article reports the regeneration dynamics of a temperate Abies–Tsuga forest in Kirishima Yaku National Park, southwestern Japan, and examines the influence of species coexistence mediated by\\u000a gap disturbances on biomass production. All trees taller than 2?m in a 1-ha plot were monitored over four growing seasons.\\u000a Three growth-form groups occupied different vertical layers. Evergreen conifers and deciduous broad-leaved trees

Yasuhiro Kubota

2006-01-01

93

Water-storage capacity of Thuja, Tsuga and Acer stems measured by dehydration isotherms  

Microsoft Academic Search

Water-storage capacity was measured inThuja occidentalis L.,Tsuga canadensis (L.) Carr., andAcer saccharum Marsh. during the dehydration of stem segments 1.5–2.5 cm in diameter. Stem water potential was measured with a temperature-corrected\\u000a stem hygrometer and cavitations were detected acoustically. Water loss was measured by weight change. Dehydration isotherms\\u000a consistently displayed three phases. The first phase, from water potential (?) 0 to

Melvin T. Tyree; Shudong Yang

1990-01-01

94

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

Microsoft Academic Search

The hemlock looper, Lambdina fiscellaria, is an economically important insect pest of Canadian forests which overwinters as eggs. Although the hemlock looper causes extensive damages, no information on the mechanisms related to its cold tolerance is known. The objective of this study was to determine the effect of temperature and exposure duration on hemlock looper winter survival but also to

Sophie Rochefort; Richard Berthiaume; Christian Hébert; Martin Charest; Éric Bauce

2011-01-01

95

Using AVIRIS to assess hemlock abundance and early decline in the Catskills, New York  

Microsoft Academic Search

In order to aid land managers in monitoring and controlling the ongoing hemlock woolly adelgid outbreak, more accurate landscape scale tools are required to locate the hemlock resource, identify infestation and spot early decline. To this end, NASA's Airborne Visible Infra-red Imaging Spectrometer was flown over the infestation front in the Catskills region of New York during the summer of

Jennifer Pontius; Richard Hallett; Mary Martin

2005-01-01

96

Patterns of bryophyte diversity in humid coastal and inland cedar–hemlock forests of British Columbia  

Microsoft Academic Search

Mosses and hepatics (bryophytes) are the most diverse and abundant understorey vegetation within the Coastal Western Hemlock (CWH) and Interior Cedar-Hemlock (ICH) zones of British Columbia. This study intensively sampled bryophytes in 287 young- and old-growth stands in the CWH and ICH zones. Two major variables strongly influence the patterning of bryophyte diversity in these zones: stand age and habitat

Steven G. Newmaster; René J. Belland; André Arsenault; Dale H. Vitt

2003-01-01

97

Water hemlock poisoning in cattle: Ingestion of immature Cicuta maculata seed as the probable cause  

Technology Transfer Automated Retrieval System (TEKTRAN)

Immature water hemlock seed heads caused the death of 9 cows in a herd of 81 in central Utah. This is the first documented case of poisoning and death in cattle from ingesting immature water hemlock seed. Field investigation of the poisoning and follow up diagnostic, chemical and toxicological eva...

98

[Anther development and sperm isolation of Pseudostellaria heterophylla (Miq.)].  

PubMed

Anther wall is general and tapetum is glandular. The process of meiosis of microspore mother cells is simultaneous and the tetrads are tetrahedral. The mature pollen of Pseudostellaria heterophylla (Miq.) is tree-celled. There are 22-30 germ pores on the pollen wall. Many pollen grains could burst in 10% mannitol or 15% sucrose solution and release a pair of sperm cells which could keep alive for 25-50 min by FDA fluorescence. Using micromanipulator the released sperm cells could be collected. When pollen grains were put into a solution containing 0.03% CaCl2, 0.01% H3BO3, 0.01% KH2PO4 and 20% PEG for 2-5 min, they would germinate and the pollen tubes would reach 815 microm at 2h after cultured. A pair of sperms would enter into pollen tube when it grew to 500-600 microm. The fluorescence of both sperms would be observed clearly in pollen tube after DAPI staining. When the pollen tubes were burst in a bursting solution, a pair of sperms would be released from pollen tube. PMID:18198585

Ye, Zu Yun; Deng, Hua; Jian, Ming Xia; Zheng, Song; Tian, Hui Qiao

2007-12-01

99

A fatal case of apparent water hemlock poisoning.  

PubMed

A 14-y-o North American native boy died 20 h after ingesting "wild carrot". He was gathering edible plants with his family on Canadian Thanksgiving. A sample of the plant he ingested couldn't be positively identified but it contained cicutoxin on chromatography. Bioassay caused death in mice which demonstrated clinical signs similar to water hemlock (Cicuta maculata) poisonings. Cicutoxin could not be demonstrated in postmortem tissue or gastric lavage. The boy's clinical signs and laboratory tests were consistent with other reported cases of this poisoning. PMID:11205076

Heath, K B

2001-02-01

100

Isolation and partial characterization of a lectin from Euphorbia heterophylla seeds.  

PubMed Central

An N-acetylgalactosamine-specific lectin was isolated from Euphorbia heterophylla seeds by affinity chromatography on cross-linked arabinogalactan. It is a dimeric protein of two identical subunits of Mr 32 000, and differs structurally from all previously known Euphorbiaceae lectins. Its distribution over the seed is typical in that it is merely confined to the primary axes. Images Fig. 2.

Nsimba-Lubaki, M; Peumans, W J; Carlier, A R

1983-01-01

101

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

Federal Register 2010, 2011, 2012, 2013

...Environmental Assessment for a Biological Control Agent for Hemlock Woolly Adelgid...United States for use as a biological control agent to reduce the severity...United States for use as a biological control agent to reduce the...

2012-08-03

102

Harvesting Overstocked Stands of Small Diameter Trees : Stem Densities of Trees from Overstocked Mixed Conifer Stands of Western Hemlock, Douglas-Fir and Western Redcedar. [Hemlocks  

Microsoft Academic Search

Stem density (wood and bark combined) on overstocked mixed conifer stands of Douglas-fir, westernn hemlock and wester redcedar was studied in the Quilcene Ranger District, Olympic National Forest in the State of Washington. This study was to better understand the economics, technology, and impacts of harvesting overstocked stands of small diameter timber. Previous studies on the density of stem wood

W. Y. Pong; Dale R. Waddell

1985-01-01

103

The Role of Site Conditions in Survival of Hemlocks Infested with the Hemlock Woolly Adelgid: Amelioration through the Use of Organic Biostimulants  

Microsoft Academic Search

increasing tolerance to stress. plants over a period of 1, 2 or 5 years respectively, if they Were well watered and received sufficient nutrients. Another Background Information greenhouse study found that drought hastened the death of infested hemlock seedlings. This was reflected in the rapid fall in the rate of chlorophyll fluorescence. In this study the effect of the adelgids

Saroj Sivaramakrishnan; Graeme P Berlyn

104

Potential use of leaf biomass, Araucaria heterophylla for removal of Pb+2.  

PubMed

The present investigation attempt to analyze the biosorption behavior of novel biosorbent, Araucaria heterophylla (green plant) biomass, for removal of Pb(+2) from solution as the function of initial metal ion concentration, pH, temperature, sorbent dosage and biomass particle size. The maximum biosorption was found to be 95.12% at pH 5 and biosorption capacity (q(e)) of Cd(+2) is 9.643 mg/g. The Langmuir and Freundlich equilibrium adsorption isotherms were studied and observed that Freundlich model is best fit than the Langmuir model with correlation coefficient of 0.9927. Kinetic studies indicated that the biosorption process of Cd(+2) followed well pseudo second order model with R2 0.999. The process is exothermic and, spontaneous. The chemical functional groups -OH, CH2 stretching vibrations, C=O of alcohol, C=O of amide, P=O stretching vibrations, -CH, were involved in the process. The XRD pattern of the A. heterophylla was found to be mostly amorphous in nature. The SEM studies showed Pb(+2) biosorption on selective grains of the biosorbent. It was concluded that A. heterophylla leaf powder can be used as an effective, low cost, and environmentally friendly biosorbent for the removal of Pb(+2) from aqueous solution. PMID:23819273

Sarada, B; Prasad, M Krishna; Kumar, K Kishore; Murthy, Ch V R

2013-01-01

105

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

2012-10-11

106

A CASE OF ACUTE WATER HEMLOCK (CICUTA MACULATA) POISONING AND DEATH IN CATTLE AFTER INGESTION OF GREEN SEED HEADS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A case of acute water hemlock (Cicuta maculata) poisoning in cattle was reported. Nine cattle died acutely after grazing immature water hemlock seed. Chemical analysis and bioassay confirmation determined that the immature seeds contained the highly toxic long chain diols including cicutoxin, cicu...

107

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

108

Ganoderma tsugae hepatoprotection against exhaustive exercise-induced liver injury in rats.  

PubMed

Several studies have been shown that accelerated apoptosis is involved in post-exercise lymphocytopenia and tissue damage after high-intensity exercise. Ganoderma tsugae (GT) is one of the well-known medicinal mushrooms that possess various pharmacological functions. This mushroom has traditionally been used for health promotion purposes. This study investigates the hepatoprotective effects of GT on exhaustive exercise-induced liver damage. Twenty-four male Sprague-Dawley rats were randomly divided into four groups and designated as exhaustive exercise only (E), exhaustive exercise with low dosage (EL), medium dosage (EM) and high dosage (EH) GT at 0, 0.1875, 0.9375 and 1.875 g/kg/day, respectively. After 30 days all rats were euthanized immediately after an exhaustive running challenge on a motorized treadmill. The rat livers were immediately harvested. Evidence of apoptotic liver cell death was revealed using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and caspases mediated cascade events. DNA fragmentation, an apoptosis process, can be examined using TUNEL assay. A few TUNEL-positive hepatocytes, compared to the exercise only group, were observed in the livers from exhaustive animals supplemented with GT. Immunoblot analysis also showed that caspase-6-mediated specific cleavage of lamin A/C was increased significantly in the livers of group E, but was significantly decreased in the EM and EH groups. Our observations demonstrate that GT possesses anti-apoptotic and hepatoprotective potential after exhaustive exercise. PMID:23434860

Huang, Chi-Chang; Huang, Wen-Ching; Yang, Suh-Ching; Chan, Chih-Chi; Lin, Wan-Teng

2013-01-29

109

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

110

Dead Wood and Fire Relationships in Southwestern Oregon Western Hemlock Forests1  

Microsoft Academic Search

The densities of large snags and down wood in western hemlock forests of southwestern Oregon are highly variable. Fire is a major disturbance process that contributes to the composition and structure of these complex forests. This study examines levels of dead wood by plant association, and relationships of dead wood with fire. Data were collected from 169 plots on the

Diane E. White; Thomas Atzet; Patricia A. Martinez

2002-01-01

111

Application of solid-phase extraction to quantitatively determine cyproconazole and tebuconazole in treated wood using liquid chromatography with UV detection.  

PubMed

Solid-phase extraction (SPE) procedures were developed to avoid interference during the quantitative determination of cyproconazole and tebuconazole co-existing in wood extractives. 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). Methanol extractives from the heartwood of all wood samples, except western hemlock, interfered with the quantitative determination of cyproconazole and tebuconazole using liquid chromatography (LC) with UV detection (LC-UV). SPE with Oasis MCX was effective in avoiding this interference. This method also reduced the time and volume of mobile phase required for LC-UV, since wood extractives with long retention times were also removed. PMID:15700465

Miyauchi, Teruhisa; Mori, Mitsunori; Ito, Katsuhiko

2005-01-21

112

Growth and Yield of Western Hemlock in the Pacific Northwest Following Thinning Near the Time of Initial Crown Closing.  

National Technical Information Service (NTIS)

Growth, stand development, and yield were studied for young, thinned western hemlock. Two similar studies were located at Cascade Head Experimental Forest in western Oregon and near Clallam Bay on the Olympic Peninsula in Washington. The studies suggest t...

G. E. Hoyer J. D. Swanzy

1986-01-01

113

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

Microsoft Academic Search

The measurement of western hemlock bark samples from three coastal sites in British Columbia revealed that inner bark relative density (0.382) is less than that of the adjacent sapwood (0.413) and markedly less than that of outer bark (0.463). The equilibrium moisture content of the inner and outer bark are equivalent at both 70 and 30% relative humidity, and slightly

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

1980-01-01

114

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

PubMed

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 to each other (95.6-98.8% nucleotide sequence identity). The DNA-A sequences shared a maximum nucleotide sequence identity of 87.3% with euphorbia mosaic Peru virus (EuMPV) and thus were classified as belonging to a novel begomovirus species, tentatively named Euphorbia yellow mosaic virus (EuYMV). The EuYMV DNA-B sequences share a maximum nucleotide sequence identity of 56.2% with a euphorbia mosaic virus (EuMV) isolate from Mexico. Phylogenetic analysis demonstrated that this new virus belongs to a different lineage than EuMV isolates from Central America. PMID:21779908

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

2011-07-22

115

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

2012-11-23

116

Research and Resource Planning: Delaware Water Gap National Recreation Area, 2003 Annual Report.  

National Technical Information Service (NTIS)

Hemlock forests continue to decline at Delaware Water Gap National Recreation Area (DEWA), and hemlock woolly adelgid (Adelges tsugae, HWA) is the main cause of this decline. However, other stressors such as the droughts of recent years, and infestations ...

R. A. Evans

2004-01-01

117

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

SciTech Connect

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

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

1993-01-01

118

Harvesting Overstocked Stands of Small Diameter Trees : Stem Densities of Trees from Overstocked Mixed Conifer Stands of Western Hemlock, Douglas-Fir and Western Redcedar. [Hemlocks  

SciTech Connect

Stem density (wood and bark combined) on overstocked mixed conifer stands of Douglas-fir, westernn hemlock and wester redcedar was studied in the Quilcene Ranger District, Olympic National Forest in the State of Washington. This study was to better understand the economics, technology, and impacts of harvesting overstocked stands of small diameter timber. Previous studies on the density of stem wood that generally have been derived from trees growing in stands of normal stocking levels. Stem densities, an essential parameter in the determination of stem biomass, has not previously been investigated for trees growing in overstocked conditions. Predictive estimators of density based on data derived from studies of normally stocked stands can not be applied to trees growing in an overstocked condition with reliability. Thus the need to specifically examine stem densities in trees grown under these adverse conditions exists. 3 tabs.

Pong, W.Y.; Waddell, Dale R.

1985-03-15

119

Ecosystem function in Appalachian headwater streams during an active invasion by the Hemlock Woolly Adelgid.  

PubMed

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

2013-04-22

120

A Technique to Identify Changes in Hemlock Forest Health over Space and Time Using Satellite Image Data  

Microsoft Academic Search

The objective of this study was to develop a technique to classify health of eastern hemlock stands using historical satellite images. While remote sensing and geographic information systems have been used successfully to classify forest health using recent images, applying this process to older images is problematic because contemporaneous field data are not available to measure the accuracy of the

Laurent R. Bonneau; Kathleen S. Shields; Daniel L. Civco

1999-01-01

121

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

PubMed

We describe seasonal patterns of parasitism by Telenomus coloradensis Crawford, Telenomus droozi Muesebeck, Telenomus flavotibiae Pelletier (Hymenoptera: Scelionidae), and Trichogramma spp. (Hymenoptera: Trichogrammatidae), egg parasitoids of the hemlock looper, Lambdina fiscellaria (Guenée) (Lepidoptera: Geometridae), after a 3-yr survey of defoliated stands in the lower St. Lawrence region (Quebec, Canada). Results from sentinel trap sampling indicate that T. coloradensis and T. droozi are the most common species, whereas parasitism by T. flavotibiae and Trichogramma spp. is rare. Telenomus coloradensis and T. droozi show similar seasonal periods of parasitism, both species being active in early spring (late April) at temperatures as low as 4°C. Using thermal threshold (T(0)) and thermal constant (K) for immature development of T. coloradensis males and females from egg to adult emergence, we estimated that the spring progeny emerges in the middle of the summer while hemlock looper eggs are absent from the forest environment. Parasitoid females would then mate and remain in the environment to 1) exploit alternate host species, 2) enter into quiescence and later parasitize eggs laid by hemlock looper females in the fall, 3) enter into a reproductive diapause and parasitize hemlock looper eggs only the next spring, or all of these. Although previous studies have shown that T. coloradensis can overwinter in its immature form within the host egg, our field and laboratory results indicate that in the lower St. Lawrence region, this species principally enters diapause as fertilized females, with a mean supercooling point of -30.6°C in the fall. PMID:23321076

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

2012-12-01

122

Impacts of hemlock looper defoliation on growth and survival of balsam fir, black spruce and white birch in Newfoundland, Canada  

Microsoft Academic Search

Hemlock looper (Lambdina fiscellaria fiscellaria (Guen.)) is an economically damaging defoliator that undergoes periodic outbreaks in Newfoundland, Canada. It defoliates and causes extensive tree mortality to its primary host, balsam fir (Abies balsamea [L.] Mill.). We quantified tree survival using data from permanent sample plots (PSPs) and growth reduction or release using dendrochronology, and related these impacts to defoliation severity

Javed Iqbal; David A. MacLean; John A. Kershaw

2011-01-01

123

G-Quadruplex DNAzyme Molecular Beacon for Amplified Colorimetric Biosensing of Pseudostellaria heterophylla  

PubMed Central

With an internal transcribed spacer of 18 S, 5.8 S and 26 S nuclear ribosomal DNA (nrDNA ITS) as DNA marker, we report a colorimetric approach for authentication of Pseudostellaria heterophylla (PH) and its counterfeit species based on the differentiation of the nrDNA ITS sequence. The assay possesses an unlabelled G-quadruplex DNAzyme molecular beacon (MB) probe, employing complementary sequence as biorecognition element and 1:1:1:1 split G-quadruplex halves as reporter. In the absence of target DNA (T-DNA), the probe can shape intermolecular G-quadruplex structures capable of binding hemin to form G-quadruplex-hemin DNAzyme and catalyze the oxidation of ABTS2? to blue-green ABTS•? by H2O2. In the presence of T-DNA, T-DNA can hybridize with the complementary sequence to form a duplex structure, hindering the formation of the G-quadruplex structure and resulting in the loss of the catalytic activity. Consequently, a UV-Vis absorption signal decrease is observed in the ABTS2?-H2O2 system. The “turn-off” assay allows the detection of T-DNA from 1.0 × 10?9 to 3.0 × 10?7 mol·L?1 (R2 = 0.9906), with a low detection limit of 3.1 × 10?10 mol·L?1. The present study provides a sensitive and selective method and may serve as a foundation of utilizing the DNAzyme MB sensor for identifying traditional Chinese medicines.

Zheng, Zhenzhu; Han, Jing; Pang, Wensheng; Hu, Juan

2013-01-01

124

Functional expression of FIP-gts, a fungal immunomodulatory protein from Ganoderma tsugae in Sf21 insect cells.  

PubMed

The mushrooms of diverse Lingzhi species have been traditionally consumed as luxurious functional food supplements in Chinese society. FIP-gts, a fungal immunomodulatory protein found in Song-Shan Lingzhi (Ganodera tsugae) has been proposed to possess therapeutic effects on cancer and autoimmune diseases. To produce active FIP-gts for evaluation of oral administration, a recombinant FIP-gts (rFIP-gts) fused with a 6His-tag at its C-terminus was expressed in Sf21 insect cells by the baculovirus expression system. High yield (about 70%) and purity (about 90%) of rFIP-gts was obtained by one-step nickel-affinity chromatography. The correctness of the harvested rFIP-gts was verified by Western blot and MALDI-MS analyses. Optimal expression of rFIP-gts was observed when the Sf21 cells were infected with multiplicity of infection of 10 for 72 h, and the yield was up to 47.2 microg/3 x 10(6) infected cells. The immunomodulatory activity of the purified rFIP-gts was detected as the induction of interleukin 2 released from murine splenocytes. Compared with the rFIP-gts produced in Escherichia coli cells, the rFIP-gts produced in Sf21 cells possessed evidently higher specific immunomodulatory activity. PMID:17090952

Jinn, Tzyy-Rong; Wu, Chi-Ming; Tu, Wu-Chun; Ko, Jiunn-Liang; Tzen, Jason T C

2006-11-07

125

Proceedings: Symposium on Sustainable Management of Hemlock Ecosystems in Eastern North America. Held in Durham, New Hampshire on June 22-24, 1999.  

National Technical Information Service (NTIS)

The purpose of this symposium was to bring together researchers and managers to exchange information and foster discussion on managing the extensive ecosystems in which hemlock occurrs in eastern North America. The five themes addressed at the symposium i...

D. R. Souto K. A. McManus K. S. Shields

2000-01-01

126

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

127

Three-dimensional Structure of an Old-growth Pseudotsuga-Tsuga Canopy and Its Implications for Radiation Balance, Microclimate, and Gas Exchange  

Microsoft Academic Search

We describe the three-dimensional structure of an old-growth Douglas-fir\\/western hemlock forest in the central Cascades of southern Washington, USA. We concentrate on the vertical distribution of foliage, crowns, external surface area, wood biomass, and several components of canopy volume. In addition, we estimate the spatial variation of some aspects of structure, including the topography of the outer surface, and of

Geoffrey G. Parker; Mark E. Harmon; Michael A. Lefsky; Jiquan Chen; Robert Van Pelt; Stuart B. Weiss; Sean C. Thomas; William E. Winner; David C. Shaw; Jerry F. Frankling

2004-01-01

128

Components and Controls of Water Flux in an Old-growth Douglas-fir–Western Hemlock Ecosystem  

Microsoft Academic Search

We report measurements of rates of sap flow in dominant trees, changes in soil moisture, and evaporation from coarse woody debris in an old-growth Douglas-fir–western hemlock ecosystem at Wind River, Washington, USA, during dry periods in summer. The measurements are compared with eddy-covariance measurements of water-vapor fluxes above the forest (E e) and at the forest floor (E u) to

Michael H. Unsworth; Nathan Phillips; T. Link; Barbara J. Bond; Matthias Falk; Mark E. Harmon; Thomas M. Hinckley; Danny Marks; Kyaw Tha Paw U

2004-01-01

129

Differential effects of sugar maple, red oak, and hemlock tannins on carbon and nitrogen cycling in temperate forest soils.  

PubMed

Tannins are abundant secondary chemicals in leaf litter that are hypothesized to slow the rate of soil-N cycling by binding protein into recalcitrant polyphenol-protein complexes (PPCs). We studied the effects of tannins purified from sugar maple, red oak, and eastern hemlock leaf litter on microbial activity and N cycling in soils from northern hardwood-conifer forests of the northeastern US. To create ecologically relevant conditions, we applied tannins to soil at a concentration (up to 2 mg g(-1) soil) typical of mineral soil horizons. Sugar maple tannins increased microbial respiration significantly more than red oak or hemlock tannins. The addition of sugar maple tannins also decreased gross N mineralization by 130% and, depending upon the rate of application, decreased net rates of N mineralization by 50-290%. At low concentrations, the decrease in mineralization appeared to be driven by greater microbial-N immobilization, while at higher concentrations the decrease in mineralization was consistent with the formation of recalcitrant PPCs. Low concentrations of red oak and hemlock tannins stimulated microbial respiration only slightly, and did not significantly affect fluxes of inorganic N in the soil. When applied to soils containing elevated levels of protein, red oak and hemlock tannins decreased N mineralization without affecting rates of microbial respiration, suggesting that PPC formation decreased substrate availability for microbial immobilization. Our results indicate that tannins from all three species form recalcitrant PPCs, but that the degree of PPC formation and its attendant effect on soil-N cycling depends on tannin concentration and the pool size of available protein in the soil. PMID:18210159

Talbot, Jennifer M; Finzi, Adrien C

2008-01-19

130

Bipolaris euphorbiae as a Biological Control Agent for Wild Poinsettia ( Euphorbia heterophylla ): Host-Specificity and Variability in Pathogen and Host Populations  

Microsoft Academic Search

Bipolaris euphorbiae (anamorphic Ascomycota: Pleosporaceae) has been studied since the early 1980s as a potential biocontrol agent of wild poinsettia\\u000a (Euphorbia heterophylla), a noxious invader of soybean fields in Brazil. A new isolate (KLN05) was arbitrarily selected after the aggressiveness\\u000a of six isolates of the fungus obtained from different sites was evaluated on wild poinsettias grown from seeds obtained from

Kátia Lima De Nechet; Robert Weingart Barreto; Eduardo S. G. Mizubuti

2006-01-01

131

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

132

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

133

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.

2013-01-01

134

Acid Fog Effects on Conifer Seedlings.  

National Technical Information Service (NTIS)

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

D. P. Turner D. T. Tingey W. E. Hogsett

1989-01-01

135

Convergence of leaf display and photosynthetic characteristics of ...  

Treesearch

Forest Products Lab ... Title: Convergence of leaf display and photosynthetic characteristics of understory Abies amabilis and Tsuga ... than those of T. heterophylla, which resulted in lower mass-based photosynthetic rate for A. amabilis.

136

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

2013-04-07

137

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

2005-10-05

138

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.

139

Identifying Core Habitat and Connectivity for Focal Species in the Interior Cedar-Hemlock Forest of North America to Complete a Conservation Area Design  

Microsoft Academic Search

To identify the remaining areas of the Interior Cedar-Hemlock Forest of North America and prioritize them for conservation planning, the Craighead Environmental Research Institute has developed a 2-scale method for mapping critical habitat utilizing 1) a broad-scale model to identify important regional locations as the basis for a Conservation Area Design (CAD), and 2) fine-scale models for analyzing habitat quality

Lance Craighead; Baden Cross

140

Feasibility of producing value-added wood products from reclaimed ...  

Treesearch

Help ... The authors believe yield could be increased with better on-site trimming. ... lumber, wood, timber, reclaimed, recycling, reuse, recycled products, value added, feasibility studies, buildings, eastern hemlock, recycling, Tsuga canadensis.

141

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

142

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

143

Base-cation Cycling by Individual Tree Species in Old-growth Forests of Upper Michigan, USA  

Microsoft Academic Search

The influence of individual tree species on base-cation (Ca, Mg, K, Na) distribution and cycling was examined in sugar maple (Acer saccharum Marsh.), basswood (Tilia americana L.), and hemlock (Tsuga canadensis L.) in old-growth northern hardwood – hemlock forests on a sandy, mixed, frigid, Typic Haplorthod over two growing seasons in northwestern Michigan. Base cations in biomass, forest floor, and

Ryo Fujinuma; James Bockheim; Nick Balster

2005-01-01

144

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

145

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

PubMed

Forests dominated by Douglas-fir and western hemlock in the Pacific Northwest of the United States have strongly influenced concepts and policy concerning old-growth forest conservation. Despite the attention to their old-growth characteristics, a tendency remains to view their disturbance ecology in relatively simple terms, emphasizing infrequent, stand-replacing (SR) fire and an associated linear pathway toward development of those old-growth characteristics. This study uses forest stand- and age-structure data from 124 stands in the central western Cascades of Oregon to construct a conceptual model of stand development under the mixed-severity fire regime that has operated extensively in this region. Hierarchical clustering of variables describing the age distributions of shade-intolerant and shade-tolerant species identified six groups, representing different influences of fire frequency and severity on stand development. Douglas-fir trees > 400 years old were found in 84% of stands, yet only 18% of these stands (15% overall) lack evidence of fire since the establishment of these old trees, whereas 73% of all stands show evidence of at least one non-stand-replacing (NSR) fire. Differences in fire frequency and severity have contributed to multiple development pathways and associated variation in contemporary stand structure and the successional roles of the major tree species. Shade-intolerant species form a single cohort following SR fire, or up to four cohorts per stand in response to recurring NSR fires that left living trees at densities up to 45 trees/ha. Where the surviving trees persist at densities of 60-65 trees/ha, the postfire cohort is composed only of shade-tolerant species. This study reveals that fire history and the development of old-growth forests in this region are more complex than characterized in current stand-development models, with important implications for maintaining existing old-growth forests and restoring stands subject to timber management. PMID:24015517

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

2013-08-01

146

Spatial variability of terrestrial laser scanning based leaf area index  

NASA Astrophysics Data System (ADS)

Forest stand point clouds generated from multiple scan locations using terrestrial laser scanning (TLS) have diverse range of spatial distribution patterns. These in turn have an effect on the direct leaf area index (LAI) estimation from the point cloud. However, the most effective placement of the scanning equipment in homogeneous vs. heterogeneous stands has not been investigated. In this research, TLS was used to sample an evenly planted Douglas-fir (Pseudotsuga menziesii) seedling forest stand and a mature heterogeneous forest stand dominated by Douglas-fir (P. menziesii) and Western hemlock (Tsuga heterophylla). A new method, circular point cloud slicing, was developed to explore the spatial variation of point density for both azimuthal angular and radial directions. The results show that alone, a central location 360° scan data, does not capture all of the stand characteristics and less than 50% of variation of the estimation of effective leaf area index (LAIe) of a mature heterogeneous stand. Thus, reducing occlusion, by incorporating additional lateral side view scans, is necessary to comprehensively represent the canopy structure, and structural variation of the heterogeneous forest stand. It was also shown, based on the assumption that the comprehensive scan combination can fully represent the forest stand, and that LAIe estimated from the comprehensive multi-direction mosaiced dataset are higher by twofold compared to the result from central scan only.

Zheng, Guang; Moskal, L. Monika

2012-10-01

147

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

148

Ectomycorrhizal fungal community structure across a bog-forest ecotone in southeastern Alaska.  

PubMed

We examined the ectomycorrhizal (ECM) fungal community across a bog-forest ecotone in southeastern Alaska. The bog and edge were both characterized by poorly drained Histosols and a continuous layer of Sphagnum species, ericaceous shrubs, Carex species, and shore pine [Pinus contorta Dougl. ex Loud. var. contorta]. The forest had better-drained Inceptisols and Spodosols, a tree community comprised of western hemlock [Tsuga heterophylla (Raf.) Sarg.], yellow cedar (Thuja plicata Donn ex D. Don.), Sitka spruce [Picea sitchensis (Bong.) Carr.] and shore pine, and an understorey of ericaceous shrubs and herbs. ECM root tip density (tips cm(-3) soil) was significantly greater in the forest than the edge or bog and ECM colonization was significantly different in all three plant communities. The below ground ECM fungal taxa were analyzed using molecular techniques (PCR-RFLP and DNA sequencing). Three ECM fungal taxa, Suillus tomentosus (Kauffman) Singer, Cenococcum geophilum Fr.:Fr, and a Russula species, differed in relative frequency, yet were among the four most frequent in all three plant communities. Although differences in ECM fungal richness were observed across plant communities, unequal sampling of ECM roots due to root density and colonization differences confounded richness comparisons. Using resampling procedures for creating taxon-accumulation curves as a function of sampled ECM roots revealed similarities in cumulative ECM fungal taxa richness across the ecotone. PMID:14999551

Wurzburger, Nina; Hartshorn, Anthony S; Hendrick, Ronald L

2004-03-04

149

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

150

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

151

Ganoderma tsugae Induces S Phase Arrest and Apoptosis in Doxorubicin-Resistant Lung Adenocarcinoma H23/0.3 Cells via Modulation of the PI3K/Akt Signaling Pathway.  

PubMed

Ganoderma tsugae (GT) is a traditional Chinese medicine that exhibits significant antitumor activities against many types of cancer. This study investigated the molecular mechanism by which GT suppresses the growth of doxorubicin-resistant lung adenocarcinoma H23/0.3 cells. Our results reveal that GT inhibits the viability of H23/0.3 cells in vitro and in vivo and sensitizes the growth suppression effect of doxorubicin on H23/0.3 cells. The data also show that GT induces S phase arrest by interfering with the protein expression of cyclin A, cyclin E, CDK2, and CDC25A. Furthermore, GT induces cellular apoptosis via induction of a mitochondria/caspase pathway. In addition, we also demonstrate that the suppression of cell proliferation by GT is through down-regulation of the PI3K/Akt signaling pathway. In conclusion, this study suggests that GT may be a useful adjuvant therapeutic agent in the treatment of lung cancer. PMID:22792123

Yu, Yang-Hao; Kuo, Han-Peng; Hsieh, Hui-Hsia; Li, Jhy-Wei; Hsu, Wu-Huei; Chen, Shih-Jung; Su, Muh-Hwan; Liu, Shwu-Huey; Cheng, Yung-Chi; Chen, Chih-Yi; Kao, Ming-Ching

2012-06-26

152

Ganoderma tsugae Induces S Phase Arrest and Apoptosis in Doxorubicin-Resistant Lung Adenocarcinoma H23/0.3 Cells via Modulation of the PI3K/Akt Signaling Pathway  

PubMed Central

Ganoderma tsugae (GT) is a traditional Chinese medicine that exhibits significant antitumor activities against many types of cancer. This study investigated the molecular mechanism by which GT suppresses the growth of doxorubicin-resistant lung adenocarcinoma H23/0.3 cells. Our results reveal that GT inhibits the viability of H23/0.3 cells in vitro and in vivo and sensitizes the growth suppression effect of doxorubicin on H23/0.3 cells. The data also show that GT induces S phase arrest by interfering with the protein expression of cyclin A, cyclin E, CDK2, and CDC25A. Furthermore, GT induces cellular apoptosis via induction of a mitochondria/caspase pathway. In addition, we also demonstrate that the suppression of cell proliferation by GT is through down-regulation of the PI3K/Akt signaling pathway. In conclusion, this study suggests that GT may be a useful adjuvant therapeutic agent in the treatment of lung cancer.

Yu, Yang-Hao; Kuo, Han-Peng; Hsieh, Hui-Hsia; Li, Jhy-Wei; Hsu, Wu-Huei; Chen, Shih-Jung; Su, Muh-Hwan; Liu, Shwu-Huey; Cheng, Yung-Chi; Chen, Chih-Yi; Kao, Ming-Ching

2012-01-01

153

Fate of Precipitation-borne N in a Maine Spruce-Hemlock Forest: Results of First-year Ammonium Nitrate Canopy Fertilization  

NASA Astrophysics Data System (ADS)

Nitrogen oxides emitted as a result of fuel combustion and ammonia volatilization due to agriculture account for a large increase in N available to temperate forests in the northern hemisphere. Northern forests are thought to be limited in growth by the availability of N and increased inputs have coincided with increased carbon contents reported in northern forest inventories. The fate of anthropogenic N, residence time and the significance of an N-fertilization effect upon forest growth, however, remains unknown. We report throughfall findings from an ecosystem-level nitrogen addition made as wet precipitation to the canopy of a spruce-hemlock forest in central Maine. Ammonium nitrate and potassium nitrate were sprayed on 21 hectares of canopy by helicopter in six applications throughout the growing season; a final addition rate of 18 kg N per hectare per year. We measured N in canopy needles, senesced needles, throughfall (TF) and soils and soil water throughout this first-year application. TF-N in precipitation events following fertilization suggested retention to be highly variable but removing substantial N from the canopy addition. Moreover, while inorganic N in TF remained similar in ratio, 33% ammonium and 66% nitrate, as that added to the canopy; the single largest flux of N to the forest floor was in the form of DON. TF data from subsequent rain events were often indistinguishable from non-fertilized controls. The retention of N in the canopy and the preponderance of DON in TF should be considered when investigating effects of anthropogenic N on forest growth.

Dail, D. B.; Hoovler, L.; Davidson, E. A.

2001-12-01

154

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

155

Differential Tree Colonization of Old Fields in a Temperate Rain Forest  

Microsoft Academic Search

Most old fields in the Queets Valley of Olympic National Park, USA, remain dominated by exotic herbs 60 y after abandonment although the fields are surrounded by temperate rain forest. However, areas of some fields have been invaded byPiceasitchensis, one of three dominant forest species (with Alnus rubra and Tsuga heterophylla). This provided an opportunity to examine local variation of

DENNIS A. RIEGE; ROGER DEL MORAL

2004-01-01

156

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

157

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

Microsoft Academic Search

Large wood recruitment and redistribution mechanisms were investigated in a 3.9 km2 basin with an old- growth Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. forest, located in the southern Coast Range of Oregon. Stream size and topographic setting strongly influenced processes that delivered wood to the channel network. In small colluvial channels draining steep hillslopes, processes associated with

Christine L. May; Robert E. Gresswell

2003-01-01

158

Patterns of conifer tree regeneration following an autumn wildfire event in the western Oregon Cascade Range, USA  

Microsoft Academic Search

We investigated the effect of fire severity and environmental conditions on conifer tree regeneration 11 years after an autumn wildfire in the western Oregon Cascade Range. Conifer tree seedlings, including those of Pseudotsuga menziesii, established promptly and at high densities following fire, in contrast to long establishment periods documented for many other sites. P. menziesii, Tsuga heterophylla and Thuja plicata

Andrew J. Larson; Jerry F. Franklin

2005-01-01

159

Fire and canopy species composition in the Great Lakes-St. Lawrence forest of Témiscamingue, Québec  

Microsoft Academic Search

Large severe fires are typically rare in the northern hardwood forests of eastern North America, with estimated return intervals as high as 1400–4500 years. We investigated the history of large severe fires in western Québec, Canada, where sugar maple (Acer saccharum Marsh.), yellow birch (Betula alleghaniensis Britt.), and eastern hemlock ((Tsuga canadensis (L.) Carr.) dominate a landscape at northern limit

C. Ronnie Drever; Christian Messier; Yves Bergeron; Frédérik Doyon

2006-01-01

160

Analysis of the Dielectric Properties of Trunk Wood in Dominant Conifer Species from New England and Siberia  

Microsoft Academic Search

Data presented were collected for dominant conifer species from Durham, NH (white pine, Pinus strobus, Eastern hemlock, Tsuga canadensis); Howland, ME (red spruce, Picea rubens); and the Ermakovsky Permanent Study Area in south central Siberia, Russia (Siberian fir, Abies siberica and Siberian pine, Pinus siberica). Dielectric properties of trunk wood were measured using a C-band dielectric probe. For the Durham

K. J. Ranson; B. N. Rock; W. A. Salas; K. Smith; D. L. Williams

1992-01-01

161

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

162

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

163

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

PubMed

Turbulent fluxes of carbon, water and energy were measured at the Wind River Canopy Crane, Washington, USA from 1999 to 2004 with eddy-covariance instrumentation above (67 m) and below (2.5 m) the forest canopy. Here we present the decomposition of net ecosystem exchange of carbon (NEE) into gross primary productivity (GPP), ecosystem respiration (R(eco)) and tree canopy net CO(2) exchange (DeltaC) for an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)-western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest. Significant amounts of carbon were recycled within the canopy because carbon flux measured at the below-canopy level was always upward. Maximum fluxes reached 4-6 micromol m(-2) s(-1) of CO(2) into the canopy air space during the summer months, often equaling the net downward fluxes measured at the above-canopy level. Ecosystem respiration rates deviated from the expected exponential relationship with temperature during the summer months. An empirical ecosystem stress term was derived from soil water content and understory flux data and was added to the R(eco) model to account for attenuated respiration during the summer drought. This attenuation term was not needed in 1999, a wet La Niña year. Years in which climate approximated the historical mean, were within the normal range in both NEE and R(eco), but enhanced or suppressed R(eco) had a significant influence on the carbon balance of the entire stand. In years with low respiration the forest acts as a strong carbon sink (-217 g C m(-2) year(-1)), whereas years in which respiration is high can turn the ecosystem into a weak to moderate carbon source (+100 g C m(-2) year(-1)). PMID:18244938

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

2008-04-01

164

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

165

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

166

Calcium weathering in forested soils and the effect of different tree species  

Microsoft Academic Search

Soil weathering can be an important mechanism to neutralize acidity inforest soils. Tree species may differ in their effect on or response to soilweathering. We used soil mineral data and the natural strontium isotope ratio87Sr\\/86Sr as a tracer to identify the effect of treespecies on the Ca weathering rate. The tree species studied were sugar maple(Acer saccharum), hemlock (TsugaCanadensis), American

Feike A. Dijkstra; Nico Van Breemen; Antoine G. Jongmans; Gareth R. Davies; Gene E. Likens

2003-01-01

167

Hemlock woolly adelgid phenology and predacious beetle ...  

Treesearch

USA.gov Government Made Easy ... Morgantown, WV: U.S. Forest Service, Forest Health Technology Enterprise Team: 261-266. ... The phenology of HWA life stages were monitored by collecting branches and ... Please contact Sharon Hobrla, shobrla@fs.fed.us if you notice any errors which make this publication unusable.

168

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

NASA Astrophysics Data System (ADS)

Influences of Forest Tree Species and Early Spring Temperature on Surface-Atmosphere Transfers of Water and Carbon in the Northeastern U.S. Julian Hadley, Paul Kuzeja, Safina Singh and Thomas Mulcahy Transfers of water vapor from terrestrial ecosystems to the atmosphere affect regional hydrology, weather and climate over short time scales, and forest-atmosphere CO2 exchange affects global climate over long timescales. To better understand these effects for forests dominated by two very different tree species, we measured forest-atmosphere water vapor and CO2 transfers by the eddy flux technique to at two sites in central Massachusetts USA for three years. Average annual evapotranspiration (ET) for a young deciduous forest dominated by red oak (Quercus rubra L., the most abundant tree species in the area), was about 430 mm or 25 percent greater than for a coniferous forest dominated by 100 to 230 year old eastern hemlock (Tsuga canadensis L.). The difference in ET was most pronounced in July and August when the deciduous forest lost about 50 percent more water by ET in the average year (192 mm for oak forest versus 130 mm for hemlock). These data indicate that if deciduous trees with similar physiology to red oak replace hemlocks, summertime ET will increase while summer streamflow, soil water content and the extent of year- round wetlands will decrease. Increased summertime ET should also lead to slightly higher regional atmospheric humidity and precipitation. Hemlock-to-deciduous forest conversion has occurred from North Carolina to southern New England and is continuing northward as a lethal insect pest, the hemlock woolly adelgid (Adelges tsugae Annand) continues to kill hemlocks. Average annual carbon storage for the old hemlock forest in our study was about 3.3 Mg C/ha, nearly equal to the average for the deciduous forest, 3.5 Mg C/ha. This calls into question ecological theory that predicts large declines in the rate of carbon uptake for old forests, and indicates that annual carbon storage will not necessarily increase over the long term after hemlock trees are killed by the hemlock woolly adelgid and replaced by deciduous species. Maximum monthly carbon storage in the hemlock forest occurred in spring (April and May) and was enhanced by early soil thawing and cessation of nighttime frost. This pattern is probably common to many evergreen conifers in the northeastern U.S., so climate warming that includes an earlier end to freezing temperatures in spring should increase C storage by conifer forests in the northeastern U.S. - unless this effect is canceled out by reduced C uptake or enhanced C loss due to changes in summer and fall climate.

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

2008-12-01

169

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

170

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

171

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.

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

2013-01-01

172

Evaluation of aestival diapause in hemlock woolly adelgid  

Treesearch

In June, after sistens eggs hatch, they settle at the base of needles and immediately go into ... sistens (Bob Chianese, N.J. Dept. of Agric., personal communication). ... of Agriculture, Forest Service, Northeastern Forest Experiment Station: 200.

173

Chinese Coccinellidae for biological control of the hemlock woolly ...  

Treesearch

Newtown Square, PA: U.S. Department of Agriculture, Forest Service, ... generally believed to be native to Asia and is known to occur in India, Japan, and China. ... of their native range compared with potential release sites in the United States.

174

Foliar respiration in an old-growth Pseudotsuga-Tsuga forest  

Microsoft Academic Search

Old-growth forest ecosystems accrue carbon at small mean rates and may function as carbon sinks in some years and as carbon sources in others. Foliar respiration is a large component of stand carbon balance and could be variable enough to substantially affect source-sink behaviors. However, foliar respiration has not been well studied in old-growth canopies. We examined seasonal, interannual, spatial,

Clifton E. Cooper; Sean C. Thomas; William E. Winner

2006-01-01

175

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

176

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

177

Allelopathic Effects of Aconitic Acid on Wild Poinsettia (Euphorbia heterophylla) and Morningglory (Ipomoea grandifolia)  

Microsoft Academic Search

High infestations of alexandergrass (Brachiaria plantaginea) in experimental area have reduced seedbank of some weed species in soil at a greater degree compared to those obtained with the use of an efficient herbicide. Aconitic acid (AA) has been identified in those plants in high concentration. Thus, two experiments were carried out in the laboratory to determine the effects of pure

Elemar Voll; Cristiano Elemar Voll; Ricardo Victória Filho

2005-01-01

178

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

SciTech Connect

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

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

1995-04-01

179

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

PubMed

The development of paediatric medicine as a formal field of medical specialisation is usually traced to the mid-nineteenth century at the earliest. While it is true that formal specialisation in children's medicine was not, on the whole, typical for eighteenth-century medical practitioners, many displayed a deep and lasting interest in the diseases of children, and were consequently eager to develop therapeutic practices which could be targeted at infants and children. This led to a variety of attempts at innovation, many of which benefitted from the co-operation of, and opportunities afforded by, institutions. By examining the efforts of several medical practitioners at the London Foundling Hospital and at the Dispensary for the Infant Poor, this article explores how eighteenth-century medical practitioners used their affiliations with institutions to address the problems of devising or adapting therapeutic practices and treatments for children. In tailoring medical practice to suit children and, more specifically, in using institutions to do so, medical practitioners were demonstrating that child patients required special consideration, that children's diseases could be managed medically and with the benefit of new approaches and methods, and that children's health, as a whole, was the province of medical practitioners. PMID:23393401

Mathisen, Ashley

2013-01-01

180

Integrated responses of hydraulic architecture, water and carbon relations of western hemlock to dwarf mistletoe infection  

Microsoft Academic Search

Dwarf mistletoe (Arceuthohium spp.) is a hemiparasite that is said to he the single-most destructive pathngeu of commercially valuable coniferous trees in many regions of the world. Although its destructive nature is well docu- mented in many respects, its effects on the physiology of its host are poorly understood. In the present study, water and carl)on relatiofts were characterized over

F. C. MEINZER; D. R. WOODRUFF; D. C. SHAW

2004-01-01

181

Spatial pulses of water inputs in deciduous and hemlock forest stands  

Microsoft Academic Search

Trees intercept and redistribute precipitation in time and space. While spatial patterns of throughfall are challenging to link to plant and canopy characteristics, many studies have shown that the spatial patterns persist through time. This persistence leads to wet and dry spots under the trees, creating spatial pulses of moisture that can affect infiltration, transpiration, and biogeochemical processes. In the

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

2010-01-01

182

Stand dynamics of an old-growth eastern hemlock-hardwood forest ...  

Treesearch

In 2006, field plots established in 2000 were re-measured to assess adelgid- induced changes to forest structure and species composition. ... during the 2006 growing season to describe how the ground flora has changed since it was originally ...

183

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

184

Interactions of Carbon Gain and Nitrogen Addition in a Temperate Forest  

NASA Astrophysics Data System (ADS)

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

Bazzaz, F. A.

2001-12-01

185

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

186

Individual Papers from Proceedings: symposium on sustainable ...  

Treesearch

Wildlife habitat associations in eastern hemlock - birds, smaller mammals, and forest carnivores. ... Milling and marketing of eastern hemlock lumber. ... Use of satellite image data to identify changes in hemlock health over space and time.

187

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

USGS Publications Warehouse

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

May, Christine L.; Gresswell, Robert E.

2003-01-01

188

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

189

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

SciTech Connect

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

Puckett, L.J.

1982-07-01

190

Nonadditive effects of leaf litter species diversity on breakdown dynamics in a detritus-based stream.  

PubMed

Since species loss is predicted to be nonrandom, it is important to understand the manner in which those species that we anticipate losing interact with other species to affect ecosystem function. We tested whether litter species diversity, measured as richness and composition, affects breakdown dynamics in a detritus-based stream. Using full-factorial analyses of single- and mixed-species leaf packs (15 possible combinations of four dominant litter species; red maple [Acer rubrum], tulip poplar [Liriodendron tulipifera], chestnut oak [Quercus prinus], and rhododendron [Rhododendron maximum]), we tested for single-species presence/absence (additive) or species interaction (nonadditive) effects on leaf pack breakdown rates, changes in litter chemistry, and microbial and macroinvertebrate biomass. Overall, we found significant nonadditive effects of litter species diversity on leaf pack breakdown rates, which were explained both by richness and composition. Leaf packs containing higher litter species richness had faster breakdown rates, and antagonistic effects of litter species composition were observed when any two or three of the four litter species were mixed. Less-consistent results were obtained with respect to changes in litter chemistry and microbial and macroinvertebrate biomass. Our results suggest that loss of litter species diversity will decrease species interactions involved in regulating ecosystem function. To that end, loss of species such as eastern hemlock (Tsuga canadensis) accompanied by predicted changes in riparian tree species composition in the southeastern United States could have nonadditive effects on litter breakdown at the landscape scale. PMID:17536403

Kominoski, J S; Pringle, C M; Ball, B A; Bradford, M A; Coleman, D C; Hall, D B; Hunter, M D

2007-05-01

191

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

192

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

193

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

Microsoft Academic Search

The partial pressure of nitrogen dioxide (NO2) in the earth's atmosphere has been rising since the industrial revolution and is likely to continue rising due to the burning of fossil fuels. When NO2 enters plant leaves, it can undergo reactions that produce nitrate, which can be a source of nutrient nitrogen for the plant. However, NO2 is also an oxidant

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

2005-01-01

194

Five-year growth response of western red cedar, western hemlock, and amabilis fir to chemical and organic fertilizers  

Microsoft Academic Search

The hypothesis that growth responses of conifers to application of organic fertilizers are of longer duration than responses to chemical fertilizers was tested in two trials on northern Vancouver Island. Both trials were in 10-year-old plantations of conifers on a salal-dominated cutover known to have poor N supply. In Trial 1, western red cedar (Thuja plicata Donn ex D. Don),

C. E. Prescott; S. M. Brown

1998-01-01

195

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

196

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

EPA Science Inventory

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

197

Plant Association and Management Guide for the Mountain Hemlock Zone: Gifford Pinchot and Mt. Hood National Forests.  

National Technical Information Service (NTIS)

The forest ecosystem is a mosaic of environments, each having a particular set of characteristics and processes that shape the communities of animals and plants that occur there, and circumscribe the opportunities and limitatoins for land management. In t...

C. Topik C. T. High D. E. Smith N. M. Diaz T. K. Mellen

1997-01-01

198

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

199

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.

Mathewson, DD; Hocking, MD; Reimchen, TE

2003-01-01

200

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

201

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

202

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

203

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

204

Effect of bryophytes on survival of conifer seedlings in subalpine forests of central Japan  

Microsoft Academic Search

Bryophytes form the major seedbed for coniferous trees in the subalpine forests of central Japan. Field experiments were conducted\\u000a on the floor of a closed stand dominated byTsuga on Mt Fuji to examine the seedling survival ofAbies veitchii andTsuga diversifolia in seven substrate types in relation to the morphological characteristics of the seeds and seedlings. NeitherAbies norTsuga seedlings could survive

Toshihiko Nakamura

1992-01-01

205

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

206

A Pacific Northwest old-growth forest's response to climate variability and extreme climate events over 10 years.  

NASA Astrophysics Data System (ADS)

This study analyses eddy-covariance (EC) measurements carried out over a 10 year period in a Pacific Northwest old-growth Douglas-fir (Pseudotsuga menzesii) and Western Hemlock (Tsuga heterophyllia) forest (500-years old) in southern Washington State, USA and characterizes the seasonal and interannual variability in net ecosystem productivity (NEP), gross primary productivity (GPP) and ecosystem respiration (Reco) and primary climatic controls on these fluxes. This forest acted on average as a carbon (C) sink during the study period. However the forest transitioned from an annual net carbon sink (NEP = + 217 g C m-2 year-1) in 1999 to a source (NEP = - 100 g C m-2 year-1) in 2003. The measurement period included three moderate to strong ENSO events, a major shift in the PDO as well as seasonal drought and cold extremes. The carbon sink year (1999) occurred during a strong La Niña while the source year (2003) occurred during El Niño. When ocean-atmospheric ciculations were in- phase, i.e. all were negative (cool) or positive (warm), the greatest anomalies in carbon flux and mechanistic variables (light use-, water use-efficiency) were observed. Annual averages were + 0.63 g C m-2 day-1 (- 0.27 g C m-2 day-1) for NEP, 3.1 mg C / g H2O (4.1 mg C / g H2O) for WUE, and 1.7 g C MJ-1 (2.1 g C MJ-1) for diffuse LUE during in-phase cool (warm) years. Over the 10 years, we observed high variability in seasonal temperature and precipitation including severe summer drought (2002) and record annual rainfall (1998-1999, 2000-2001). Seasonal to interannual variability in precipitation and the consequent water balance appears to influence the timing of the switch from photosynthesis-dominance to respiration-dominance, ultimately determining whether the forest will be an annual net carbon sink (switches in late summer) or source (switches in early summer). Years with average climate were observed to be average both in NEE and Reco, but enhanced (1999) or suppressed (2003) ecosystem respiration had a significant influence on the carbon balance of the old- growth forest.

Falk, M.; Wharton, S.; Paw U, K. T.; Ustin, S. L.; Schroeder, M.

2008-12-01

207

The spatial pattern of a northern conifer-hardwood landscape  

Microsoft Academic Search

A geographic information system, fractal analyses, and statistical methods were used to examine the spatial distributions\\u000a of old growth hemlock, northern hardwood, mixed hardwood\\/hemlock stands and wetlands with respect to each other and also soils\\u000a and topography. Greater than 80% of the stands of any covertype were less than 20 ha in area. Nearly pure hemlock and northern\\u000a hardwood stands

John Pastor; Michael Broschart

1990-01-01

208

Chromosome evolution in the Gibasis linearis group (Commelinaceae)  

Microsoft Academic Search

Karyotypes, DNA amounts, and meiotic behaviour were examined in population samples of two closely related species, Gibasis venustula and G. heterophylla, and their F1 hybrids. All samples were diploid (2n=12). DNA amount was similar in G. heterophylla, G. venustula ssp. robusta, and some populations of G. venustula ssp. venustula but in 13 samples of the latter, it showed as much

A. Kenton

1984-01-01

209

Mapping Forest Change Walk  

NSDL National Science Digital Library

The representation depicts a virtual walk through a Virginia forest to examine the impact of a non-native, invasive insect, the hemlock woolly adelgid, on a population of eastern hemlocks. Field research is conducted using the same scientific methodologies and tools that Smithsonian scientists use to monitor forest biodiversity, including scatter graph comparisons and field observations.

210

Inocybe hirsuta var. maxima  

NSDL National Science Digital Library

Inocybe hirsuta var. maxima A. H. Smith (SAT 01-279-08) photographed in the Hoh River Valley in Olympic National Park, Washington, USA. This variety is common in Washington under western hemlock and is also known from eastern North America under eastern hemlock.

Trudell, Steve

2004-03-09

211

Individual Papers from Proceedings, 15th central hardwood forest ...  

Treesearch

A diameter distribution approach to estimating average stand dominant ... Development of interim oak assessment guidelines for the silvah decision- support system. ... Predicting the cover-up of dead branches using a simple single regressor ... Impact of the hemlock woolly adelgid on radial growth of Eastern hemlock in ...

212

Phosphorus forms and related soil chemistry of Podzolic soils on northern Vancouver Island. I. A comparison of two forest types  

Microsoft Academic Search

When cedar-hemlock (CH) and hemlock - amabalis fir (HA) forests of northern Vancouver Island are clearcut and replanted, growth of replanted trees is often poor on CH clearcuts but not adjacent HA clearcuts. This poor growth can be overcome with nitrogen (N) and phosphorus (P) fertilization, which suggests differences in nutrient cycling between CH and HA forests. The objective of

Barbara J. Cade-Menun; Shannon M. Berch; Caroline M. Preston; L. M. Lavkulich

2000-01-01

213

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

214

The taxonomic status of physalis lanceolata (Solanaceae) in the Carolina Sandhills  

Microsoft Academic Search

In the most recent monograph of the genus in North America,Physalis lanceolata was considered to be a hybrid betweenP. heterophylla andP. virginiana. Comparative morphological and Chromatographic studies indicate, however, thatP. lanceolata is not intermediate between its supposed parents. This evidence plus its high pollen viability and seed set indicate that\\u000a the species is not a hybrid. Natural hybrids betweenP. heterophylla

W. Frederick Hinton

1970-01-01

215

Relation of Tolerant Species to Habitat in the White Mountains of New Hampshire.  

National Technical Information Service (NTIS)

The occurence of red spruce, hemlock, beech, and sugar maple stands was related to habitat classified by substratum (generally C horizon or parent material), drainage, aspect, and elevation. Softwoods were found on rocky, outwashed, compacted, and poorly ...

W. B. Leak

1976-01-01

216

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

Federal Register 2010, 2011, 2012, 2013

...No Significant Impact for a Biological Control Agent for Hemlock Woolly Adelgid...United States for use as a biological control agent to reduce the severity...the proposed release of this biological control agent into the...

2011-07-19

217

78 FR 14509 - Availability of an Environmental Assessment and Finding of No Significant Impact for a Biological...  

Federal Register 2010, 2011, 2012, 2013

...No Significant Impact for a Biological Control Agent for Hemlock Woolly Adelgid...United States for use as a biological control agent to reduce the severity...the proposed release of this biological control agent into the eastern...

2013-03-06

218

Pre-release host range assessment for classical biological controls ...  

Treesearch

The hemlock woolly adelgid in the eastern United States symposium; 2002 February ... and pathogens, used as classical biological control agents in the United States. ... This article was written and prepared by U.S. Government employees on ...

219

Treatability of Underutilized Northeastern Species with CCA and Alternative Wood Preservatives.  

National Technical Information Service (NTIS)

Opportunities for use of northeastern species such as balsam fir, eastern spruce, eastern hemlock, and red maple could be improved if these species could be adequately penetrated with preservatives and subsequently shown to be durable in outdoor exposures...

S. T. Lebow S. A. Halverson C. A. Hatfield

2005-01-01

220

Subalpine conifer fuel dynamics  

USGS Publications Warehouse

Litter and woody fuel accumulation rates over 4 years for 4 subalpine Sierra Nevada conifer species, including western white pine, lodgepole pine, whitebark pine and mountain hemlock. Data are for four size classes per species. Nonspatial, georeferenced.

van Wagtendonk, J. W.; Moore, P. E.

2000-01-01

221

Pacific Northwest Research Station - Treesearch  

Treesearch

Description: The coniferous forests of the Western Hemlock Zone of western Oregon ... long intervals between stand-replacing events, capacity to produce timber, diversity ... But the current battle among those primarily interested in short- term ...

222

Growth Response of Managed Uneven-Aged Northern Conifer Stands.  

National Technical Information Service (NTIS)

The growth response of trees in spruce-fir-hemlock stands was recorded from plots that were managed to control stand density, species composition, length of harvest interval, and salvage of mortality. Basal area, volume, and diameter increment are present...

D. S. Solomon R. M. Frank

1983-01-01

223

Treesearch - Forest Service Research & Development  

Treesearch

Natural regeneration following timber harvest in interior cedar-hemlock-white pine ... Insecticidal activity of floral, foliar, and root extracts of Tagetes minuta ( Asterales: Asteraceae) against adult mexican bean weevils (Coleoptera: Bruchidae) ...

224

Changes in forest soils as the result of exotic diseases, timber ...  

Treesearch

... cold forests often dominated by spruces (Picea), and moist forests dominated by hemlocks ... The soils within each of these forest classifications are a product of their ... Normally, in the absence of disturbance, early-seral (shade intolerant) ...

225

Treesearch - Forest Service Research & Development  

Treesearch

... using artificial infestation, Montgomery, Michael E.; Bentz, S.E.; Olsen, Richard T. NRS ... 2003, Mapping forest risk associated with the hemlock woolly adelgid ... Bentz, S. E.; Griesbach, Robert J.; Pooler, Margaret R.; Townsend, A. M., NRS.

226

Recognition of imported lady beetles in the tribe Scymnini released ...  

Treesearch

... in the tribe Scymnini imported for biological control of hemlock woolly adelgid, ... the body lacks pronounced spines and is neither black or heavily sclerotized. ... as one-segmented, but our examination indicates that they are two-segmented.

227

Silicon Production Process Evaluation. Quarterly Technical Progress Report (I), May 18-July 31, 1981.  

National Technical Information Service (NTIS)

Chemical engineering analysis of the HSC process (Hemlock Semiconductor Corporation) for producing silicon from dichlorosilane has been initiated. For the preliminary process design, a process flowsheet is provided which best represents the HSC process at...

1981-01-01

228

Diagenesis of conifer needles in a coastal marine environment  

Microsoft Academic Search

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

John I. Hedges; K. Weliky

1989-01-01

229

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

230

Region 6 Interim Old Growth Definition for Douglas-Fir Series, Grand Fir/White Fir Series, Interior Douglas Fir Series, LodgePole Pine Series, Pacific Silver Fir Series, Ponderosa Pine Series, Port-Orford-Cedar and Tanoak (Redwood) Series, Subalpine Fir Series and Western Hemlock Series.  

National Technical Information Service (NTIS)

The following describes the ecologically important structural features of old-growth ecosystems. Measurable criteria for these attributes will be established in more specific definitions for forest types, habitat types, plant associations, or groupings of...

1993-01-01

231

Natural enemies of adelgids in North America: Their prospect for ...  

Treesearch

USA.gov Government Made Easy ... The seasonal life history of these two species indicates that their effect on A. tsugae will be ... Please contact Sharon Hobrla, shobrla@fs.fed.us if you notice any errors which make this publication unusable. ... Agriculture, Forest Service, Forest Health Technology Enterprise Team: 89-102.

232

Craterellus fallax , a Black Trumpet mushroom from eastern North America with a broad host range  

Microsoft Academic Search

Phylogenetic analysis of ITS sequences of members of the Craterellus cornucopioides complex (Black Trumpet mushrooms) supports the taxonomic separation of Craterellus fallax apart from C. cornucopioides, with which it has been synonymized in the past. Examination of Pinus virginiana ectomycorrhizal (ECM) root tips and sequence comparison with other insufficiently identified environmental sequences from\\u000a roots of Tsuga, Quercus, and possibly Castanea

Patrick Brandon Matheny; Emily A. Austin; Joshua M. Birkebak; Aaron D. Wolfenbarger

2010-01-01

233

Postglacial history of subalpine forests, Olympic Peninsula, Washington, USA  

Microsoft Academic Search

To investigate subalpine vegetation history on the Olympic Peninsula, Washington (USA), two pollen, macrofossil and charcoal records were studied in climatically distinct zones: Martins Lake (1415 m) in the moist Tsuga mertensiana zone and Moose Lake (1508 m) in the drier Abies lasiocarpa zone. The interpretation of fossil pollen assemblages was aided by comparisons with 308 modern assemblages from the

Daniel G. Gavin; Jason S. Mclachlan; Linda B. Brubaker; Kyle A. Young

2001-01-01

234

Climatic change causes abrupt changes in forest composition, inferred from a high-resolution pollen record, southwestern Quebec, Canada  

NASA Astrophysics Data System (ADS)

A pollen profile from a lake with varved sediments sampled at continuous 10-year intervals and spanning the past 1000 years was analyzed to understand the effects of climate change and anthropogenic activity on forests in southwestern Quebec. Pollen assemblages were dominated by arboreal taxa, primarily Pinus, Tsuga, Betula and Fagus. Between 990 and 1560 AD, pollen accumulation rates and percentages of hardwoods (Betula, Fagus, Acer, Ulmus, Tilia) and Tsuga were relatively high. At 1560 AD, PARs of many hardwood taxa (Fagus, Acer, Betula, Fraxinus, Ulmus) and Tsuga abruptly decreased, some remaining low for the remainder of the record (Tsuga, Fagus, Acer), but others increasing after 50 years (Betula, Fraxinus). An increase in non-arboreal pollen between 1810 and 2010 AD was caused by European settlement of the area. The transition in the pollen assemblages beginning at 1560 AD and a climate reconstruction based on these data shows an abrupt climate cooling had a significant impact on the pollen accumulation rates of the region within a couple of decades. A synthesis of this record with other high-resolution and well-dated pollen data from the conifer-hardwood forest of eastern North America shows consistent results across the whole area, indicating that very-high resolution pollen data can provide insight into multi-decadal climate variability and its impact on forest vegetation.

Paquette, Nathalie; Gajewski, Konrad

2013-09-01

235

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

SciTech Connect

Earlier laboratory studies demonstrated that red-backed salamanders, Plethodon cinereus, are susceptible to osmotic disruption by low pH substrates. In natural systems, however, acidic input from precipitation may be mediated by soils before it impacts salamanders. We tested the effect of acidic rain on sodium balance in salamanders by confining individuals in enclosure in two forest types (hemlock, beech) for 34 d. Enclosures received artificial rain of either pH 3 or 5 every 3-4 d. Soils inside enclosures in the hemlock forest were more acidic than those in the beech forest at the outset. At termination, [H[sup +

Frisbie, M.P.; Wyman, R.L. (Eastern Kentucky Univ., Richmond, KY (United States))

1994-06-01

236

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

237

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

238

Liquid culture production of chlamydospores of Lewia chlamidosporiformans (Ascomycota: Pleosporales), a mycoherbicide candidate for wild poinsettia  

Microsoft Academic Search

Lewia chlamidosporiformans (Ascomycota) is a recently described fungal species that is a highly virulent pathogen of wild poinsettia (Euphorbia heterophylla — Euphorbiaceae), one of the worst weeds in Brazilian agriculture and an aggressive invader of soybean fields. A mycoherbicide\\u000a against this weed is presently being developed with L. chlamidosporiformans. Methods for production of chlamydospores, the asexual resting spores of L.

B. S. Vieira; R. W. Barreto

2010-01-01

239

Disturbance and succession in a coniferous forest of northwestern North America: simulations with dryades, a spatial gap model  

Microsoft Academic Search

In this paper we describe a model of forest development that has been adapted for use in a coniferous forest of northwestern North America. The simulator, dryades, is a spatial gap model used to examine the effects of disturbances of different types, sizes, and frequencies in mature Douglas fir dominated forests on zonal sites of the Coastal Western Hemlock drier

D. Mailly; J. P. Kimmins; R. T. Busing

2000-01-01

240

Effects of Ash Leachates on Growth and Development of 'Armillaria mellea' in Culture.  

National Technical Information Service (NTIS)

Ash leachates from recently burned litter in a ponderosa pine forest in central Oregon were tested for their effects on growth and development of Armillaria mellea in culture. Two isolates were used: one from an infected western hemlock and the other from...

J. L. Reaves C. G. Shaw R. E. Martin J. E. Mayfield

1984-01-01

241

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

242

Quail Consumption can be Harmful  

Microsoft Academic Search

Background: Intoxication due to quail consumption is rarely seen. Such a toxicological syndrome (also called coturnism) occurs during the migration of quails from north to south, when they consume hemlock seeds. The clinical symptoms and laboratory results are indicative of acute rhabdomyolysis. Objectives: Acute rhabdomyolysis has a wide range of etiologies. Coturnism is a rare cause of acute rhabdomyolysis that

?lhan Korkmaz; Fatma Mutlu Kukul Güven; ?evki Hakan Eren; Zeki Dogan

2011-01-01

243

Harvesting Overstocked Stands of Small Diameter Trees. Report No. 5: Energy Value of Whole-Trees and Crowns  

Microsoft Academic Search

The objective of the study was to determine the higher heating value of whole-tree chips and crown materials for species being harvested in the doghair stands on the Quilcene Ranger district, Olympic National Forest. Values, in terms of Btu's per oven dry pound, were derived for the three major species occurring in these stands: western hemlock, Douglas-fir, and western redcedar.

James O

1987-01-01

244

The interception dynamics of a seasonal temperate rainforest  

Technology Transfer Automated Retrieval System (TEKTRAN)

Net canopy interception I net during rainfall in an old-growth Douglas-fir'western hemlock ecosystem was 22.8 and 25.0 percent of the gross rainfall (PG) for 1999 and 2000, respectively. The average direct throughfall proportion (p) and canopy storage capacity (S) derived from high-temporal resolut...

245

Haida Food Gathering and Preparation.  

ERIC Educational Resources Information Center

|Students are introduced to the Haida language as well as to traditional Haida foods in this booklet, one in a series of curriculum materials on Southeast Alaska Natives. Ten selections written in simple language describe a Haida barbecue, Indian bread, sea cucumbers, black sea weed, the edible pulp sap of Hemlock, Indian ice cream made from soap…

Cogo, Robert

246

Carolyn's Crown/Shafter Creek Research Natural Area. Guidebook Supplement 28.  

National Technical Information Service (NTIS)

This guidebook describes the Carolyns Crown/Shafer Creek Research Natural Area, a 323-ha (798-ac) tract of coniferous forest containing stands of 600- to 900-year-old oldgrowth Douglas-fir along the transition between the western hemlock zone and the silv...

R. Schuller

2003-01-01

247

Modeling Shrinkage Response to Tensile Stresses in Wood Drying: I. Shrinkage-Moisture Interaction in Stress-Free Specimens  

Microsoft Academic Search

This article reports on the wood shrinkage during drying in relationship with the temperature and moisture content. All tests were performed perpendicular to the grain on small clear wood specimens of green Western hemlock while drying at 40, 60, and 80°C to 17, 11, and 5% final moisture contents. Overall, wood dimensional changes and moisture loss phenomena were successfully analyzed

Ciprian Lazarescu; Stavros Avramidis; Luiz Oliveira

2009-01-01

248

Modeling Shrinkage Response to Tensile Stresses in Wood Drying II. Stress–Shrinkage Correlation in Restrained Specimens  

Microsoft Academic Search

This article reports on the effect of tensile stresses, temperature, and target moisture content on shrinkage behavior of short and thin Western hemlock specimens as part of a series of papers dealing with these issues. All tests were performed perpendicular to fiber grain while drying at 40, 60, and 80°C to 17, 11, and 5% final moisture contents at each

Ciprian Lazarescu; Stavros Avramidis; Luiz Oliveira

2010-01-01

249

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

250

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

251

Green Jobs in Tennessee: Economic Impact of Green Investments  

Microsoft Academic Search

The term green jobs has been widely used to describe jobs in businesses that are particularly related to renewable energy, energy efficiency, or environmental sustainability. The Business and Economic Research Center has partnered with the Tennessee Department of Labor and Workforce Development to estimate the economic impact of six ground-breaking green investments in Tennessee: Hemlock Semiconductor, Wacker Chemie AG, Volkswagen,

Murat Arik

2011-01-01

252

Process feasibility study in support of silicon material Task I. Quarterly technical progress report (XIX), March 1-May 31, 1980  

SciTech Connect

Analyses of process system properties were continued for chemical materials important in the production of silicon. Major physical, thermodynamic and transport property data are reported for silicon including critical constants, vapor pressure, heat of vaporization, heat of sublimation, heat capacity, density, surface tension, viscosity and thermal conductivity. The property data covers both liquid and solid phases and are reported as a function of temperature for rapid engineering usage. Major efforts in chemical engineering analysis centered on the HSC process (Hemlock Semiconductor Corporation). The approach for the process involves performing initial analysis for DCS production (dichlorosilane) and then perorming analysis of polysilicon production from the DCS. For the DCS production, status and progress are reported for primary activities of base case conditions (65%), reaction chemistry (65%), process flowsheet (60%), material balance (50%) and energy balance (40%). Two key features - redistribution reactor relocation and final distillation - are introduced to increase yield of DCS by about 10 to 20%, help insure purity and reduce potential dust (fine particle nucleation) components in the polysilicon feed material. The preliminary flowsheet for DCS production was forwarded to Hemlock Semiconductor Corporation for initial screening and review. Hemlock Semiconductor is in agreement in regards to relocation of the redistribution reactor to increase yield. Additional follow-up review is in progress including boron removal options identified by Hemlock Semiconductor. 166 references.

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

1980-06-01

253

Treesearch - Forest Service Research & Development  

Treesearch

Jul 1, 2013 ... Assessing surface area of coarse woody debris with line intersect and ... western hemlock forest stands: a matrix model with stand diversity effects. ... soil fumigation and surface containment treatment in bare-root forest nurseries ... Predicting Potential Changes in Suitable Habitat and Distribution by 2100 ...

254

Data Base for Early Postfire Succession on the Sundance Burn, Northern Idaho.  

National Technical Information Service (NTIS)

The report provides baseline data on secondary plant succession and the development of plant species and life forms for the initial 6 to 15 years following a stand-replacing forest fire in the western redcedar-western hemlock type in northern Idaho. Infor...

P. F. Stickney

1985-01-01

255

Successional change of forest pattern along topographical gradients in warm-temperate mixed forests in Mt Kiyosumi, central Japan  

Microsoft Academic Search

Forest patterns along topographical gradients were compared between second- and old-growth forested watersheds in a warm-temperate\\u000a zone of Mt Kiyosumi, central Japan. Three community types were distinguished depending on the topographical habitat type in\\u000a each watershed, for example, conifer forest was dominated byAbies firma andTsuga sieboldii on ridge sites, evergreen broad-leaved forest was dominated byQuercus acuta, Q. salicina andCastanopsis cuspidata

Kemurio Ozaki; Masahiko Ohsawa

1995-01-01

256

Coexistence mechanisms of evergreen, deciduous and coniferous trees in a mid-montane mixed forest on Mt. Emei, Sichuan, China  

Microsoft Academic Search

Structure and regeneration of a mid-montane (2200 m a.s.l.)mixed forest codominated by evergreen (Lithocarpuscleistocarpus), deciduous (Acer flabellatum)andconiferous (Tsuga chinensis, Abies fabri, andTaxus chinensis) trees were analyzed in a 40m× 60 m plot on Mt. Emei, Sichuan, China. Plant communitystructure and composition varied depending on topographic micro-habitat withinthe plot. Four topographic communities (topo-communities) were distinguishedwith dominant species corresponding to topography: (1)Abies

Cindy Q. Tang; Masahiko Ohsawa

2002-01-01

257

Effects of dwarf bamboo ( Sasa sp.) and forest floor microsites on conifer seedling recruitment in a subalpine forest, Japan  

Microsoft Academic Search

To clarify the effects of dwarf bamboo (Sasa sp.) and forest floor microsites on coniferous (Abies mariesii, A. veitchii, Picea jezoensis var. hondoensis, and Tsuga diversifolia) seedling recruitment, occurrence and survivorship of current and old (age?1 year old, height?15cm) seedlings on soil and fallen logs were examined in quadrats (2m×2m) set systematically in a 1ha permanent plot located in stands

Y. Narukawa; S. Yamamoto

2002-01-01

258

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

259

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

260

Neofusicoccum parvum, a causal agent associated with cankers and decline of Norfolk Island pine in Australia  

Microsoft Academic Search

Canker and decline of Araucaria heterophylla (Norfolk Island pine) trees were observed during surveys conducted in the costal suburbs of Perth in 2009 and 2010. Samples\\u000a from symptomatic and asymptomatic parts of trees were collected and morphological characteristics of the consistently isolated\\u000a fungus analysed. The isolated fungus was identified as Neofusicoccum parvum using phylogenetic analysis of combined sequence data from

Hossein Golzar; Treena I. Burgess

261

Differential response of foliage plants to iron deficiency  

Microsoft Academic Search

Eight species of tropical foliage plants were screened to determine their response to Fe?stress conditions. Plants were grown for 120 days in modified Hoagland's nutrient solution at pH 6.3 containing either 0, 0.22 or 5.52 mg\\/liter Fe (as Fe?HEEDTA). Araucaria heterophylla and Dracaena marginata showed leaf chlorosis and decreased growth at 0 and 0.22 mg\\/liter Fe. Ficus benjamina and Nephrolepis

Harvey J. Lang; David Wm. Reed

1987-01-01

262

Munkoyo beverage, a traditional Zambian fermented maize gruel using Rhynchosia root as amylase source  

Microsoft Academic Search

A typical munkoyo beverage was made by fermenting Rhynchosia heterophylla root extract-cooked maize meal mixture with Lactobacillus confusus LZ1 and Saccharomyces cerevisiae YZ20. The fermented munkoyo beverage had a pH of 3.3, lactic acid content of 60 mmol\\/l, ethanol 320–410 mmol\\/l and a characteristic ‘munkoyo’ aroma. L. confusus, used alone, produced a beverage with a faint munkoyo flavour note whilst

R. M. Zulu; V. M. Dillon; J. D. Owens

1997-01-01

263

Woody tissue maintenance respiration of four conifers in contrasting climates  

Microsoft Academic Search

We estimate maintenance respiration for boles of four temperate conifers (ponderosa pine, western hemlock, red pine, and slash pine) from CO2 efflux measurements in autumn, when construction respiration is low or negligible. Maintenance respiration of stems was linearly related to sapwood volume for all species; at 10°C, respiration per unit sapwood volume ranged from 4.8 to 8.3 µmol CO2 m-3

Michael G. Ryan; Stith T. Gower; Robert M. Hubbard; Richard H. Waring; Henry L. Gholz; Wendell R Cropper Jr; Steven W. Running

1995-01-01

264

Can They Be Fixed: Some Thoughts After 40 Years in the Business  

Microsoft Academic Search

If there is one thing the great Greek teachers taught us, it was to question what is, and to dream about what can be. In this\\u000a audience, unafraid that no one will ask me to drink the hemlock, but humbled by the realization that I am walking along the\\u000a beach where great thinkers of the past have walked, I nonetheless

Yale N. Patt

2008-01-01

265

Application of a dual unscented Kalman filter for simultaneous state and parameter estimation in problems of surface-atmosphere exchange  

Microsoft Academic Search

A dual unscented Kalman filter (UKF) was used to assimilate net CO2 exchange (NEE) data measured over a spruce-hemlock forest at the Howland AmeriFlux site in Maine, USA, into a simple physiological model for the purpose of filling gaps in an eddy flux time series. In addition to filling gaps in the measurement record, the UKF approach provides continuous estimates

J. H. Gove; D. Y. Hollinger

2006-01-01

266

Effects of area on old-growth forest attributes: implications for the equilibrium landscape concept  

Microsoft Academic Search

To investigate applicability of the equilibrium landscape concept to various attributes of vegetation, the effects of sampling area (or grain size) on structural and compositional stand parameters were determined in an old-growth hemlock-hardwood forest. Three 1-ha plots, each gridded into 100 0.01-ha subplots, were established on the Roaring Fork watershed in Great Smoky Mountains National Park, Tennessee, USA. Estimates for

R. T. Busing; P. S. White

1993-01-01

267

Electron-dense particles in wood decayed by Ganoderma applanatum  

Microsoft Academic Search

Hemlock sawdust samples degraded by Ganoderma applanatum showed no electron-dense particles either in hyphae or in wood cell walls after aldehyde\\/OsO4 fixation. After KMnO4 fixation at early stage of attack, particles were in hyphae, hyphal sheath and wood cell walls. In samples prepared by a cytochemical technique which localizes cellulase activity at the ultrastructural level, particles were in hyphae, hyphal

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

1985-01-01

268

Availability of residual 15N in a coniferous forest soil: a greenhouse bioassay and comparison with chemical extractions  

Microsoft Academic Search

The assessment of soil N availability by chemical extraction methods often needs to be checked by methods which directly measure plant N uptake such as a greenhouse bioassay. In this paper, the recovery of residual 15N, from humus material samples with 15N labelled for 24-h, seven-month, and 31-month, in western redcedar (Thuja plicata Donn ex D. Don) and western hemlock

Scott X. Chang; Caroline M. Preston; Gordon F. Weetman

1999-01-01

269

Fiber 3.0: An ecological growth model for northeastern forest types. Forest Service general technical report (Final)  

Microsoft Academic Search

Fiber, a stand projection growth model, simulates the growth and structural development of stands in the Northeast. The internal structure of the model is specified and constructed by the ecological type classifications of sugar maple--ash, beech--red maple, oad--white pine, spruce--fir, hemlock--spruce, and cedar--black spruce. Guidelines are provided on operational procedures for the major commercial species growing on these different ecologic

D. S. Solomon; D. A. Herman; W. B. Leak

1995-01-01

270

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

271

Carbon Sequestration at the Howland Forest in Maine: Where Does the Carbon go?  

Microsoft Academic Search

Eddy covariance towers provide information on net carbon exchange between terrestrial ecosystems and the atmosphere, but they provide little information on the location of carbon sources and sinks. We measured net ecosystem exchange (NEE) of CO2 in a mature, old-growth mixed spruce\\/hemlock\\/red maple forest at the Howland Forest beginning in 1996. Live biomass at Howland Forest is about 110 Mg

N. A. Scott; D. Y. Hollinger; E. A. Davidson; J. B. Gaudinski; S. E. Trumbore; H. Hughes; J. Ranson

2002-01-01

272

Response of conifer seedlings to nitrate and ammonium sources of nitrogen  

Microsoft Academic Search

Summary  Differences in growth responses of Douglas fir, western hemlock, Sitka spruce, and white spruce to nitrate and ammonium N\\u000a sources were examined in sand culture and artificial soil culture. Effects of the two forms of N on growth, needle area, and\\u000a N uptake of three Douglas fir halb-sib progenies were examined in a second sand culture. Response of Douglas fir

R. Van Den Driessche

1971-01-01

273

Effects of Woody Debris on Anadromous Salmonid Habitat, Prince of Wales Island, Southeast Alaska  

Microsoft Academic Search

The effects of woody debris on anadromous salmonid habitat in eight streams on Prince of Wales Island, southeast Alaska, were investigated by comparing low-gradient (1-9%) first- or second-order streams flowing through either spruce-hemlock forests or 6-10-year-old clear-cuts, and by observing changes after debris was selectively removed from clear-cut reaches. Woody debris decreased the rate of shallowing as discharge decreased, thus

Thomas E. Lisle

1986-01-01

274

Effects of Woody Debris on Anadromous Salmonid Habitat, Prince of Wales Island, Southeast Alaska  

Microsoft Academic Search

The effects of woody debris on anadromous salmonid habitat in eight streams on Prince of Wales Island, southeast Alaska, were investigated by comparing low-gradient (1-9%) first- or second-order streams flowing through either spruce-hemlock forests or 6-10-year-old clear- cuts, and by observing changes after debris was selectively removed from clear-cut reaches. Woody debris decreased the rate of shallowing as discharge decreased,

THOMAS E. LISLE

1986-01-01

275

Native American influences on the forest composition of the Allegheny Plateau, northwest Pennsylvania  

Microsoft Academic Search

We integrate witness tree distribution, Native American archaeological sites, and geological and topographic variables to investigate the relationships between Native American populations and pre-European settlement forest types on the Allegheny Plateau, northwest Pennsylvania. Detrended correspondence analysis of witness tree data separated the presettlement forests into oak-hickory-chestnut and beech-hemlock-maple communities. Oak, hickory, and chestnut forests were centered on Native American village

Bryan A. Black; Charles M. Ruffner; Marc D. Abrams

2006-01-01

276

Bald eagle nest site and nest tree characteristics in select biogeoclimatic zones of the 100 Mile House Forest District, British Columbia  

Microsoft Academic Search

Bald eagle (Haliaeetus leucocephalus) nest site and nest tree characteristics were studied in the Sub-Boreal Spruce (SBS), Interior Cedar-Hemlock (ICH), Sub-Boreal Pine-Spruce (SBPS), and Interior Douglas-fir (IDF) biogeoclimatic zones in the 100 Mile House Forest District, British Columbia. Dominant or codominant Douglas-fir (Pseudotsuga menziesii) containing large trunk forks or multiple forks of the trunk comprised 85% of 121 bald eagle

Roger Packham

277

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

2002-01-01

278

RADIO FREQUENCY\\/VACUUM DRYING OF B.C. SOFTWOODS; PRELIMINARY EXPERIMENTS  

Microsoft Academic Search

Five exploratory drying runs were carried out in a commercial size (23 m3), radio frequency\\/vacuum hardwood kiln. The species investigated were Pacific coast hemlock, Douglas-fir and western red cedar of different sizes and grades. Evaluation of the dried lumber showed that the three species can be dried in very short times and low amount of degrade irrespective of thickness with

Stavros Avramidis; Robert L. Zwick

279

Growth, condition factor, and bioenergetics modeling link warmer stream temperatures below a small dam to reduced performance of juvenile steelhead  

USGS Publications Warehouse

We investigated the growth and feeding performance of juvenile steelhead Oncorhynchus mykiss using field measures and bioenergetics modeling. Juvenile steelhead populations were sampled from mid-June through August 2004 at study sites upstream and downstream of Hemlock Dam. The growth and diet of juvenile steelhead were determined for a warm (summer) and subsequent (late summer) transitional period at each study site. Empirical data on the growth and diet of juvenile steelhead and mean daily temperatures were used in a bioenergetics model to estimate the proportion of maximum consumption achieved by juvenile steelhead by site and period. Modeled estimates of feeding performance were better for juvenile steelhead at the upstream compared to the downstream site during both periods. The median condition factor of juvenile steelhead did not change over the summer at the upstream site, but showed a significant decline over time at the downstream site. A negative trend in median condition factor at the downstream site supported bioenergetics modeling results that suggested the warmer stream temperatures had a negative impact on juvenile steelhead. Bioenergetics modeling predicted a lower feeding performance for juvenile steelhead rearing downstream compared to upstream of Hemlock Dam although food availability appeared to be limited at both study sites during the warm period. Warmer water temperatures, greater diel variation, and change in diel pattern likely led to the reduced feeding performance and reduced growth, which could have affected the overall survival of juvenile steelhead downstream of Hemlock Dam. ?? 2010 by the Northwest Scientific Association.

Sauter, S. T.; Connolly, P. J.

2010-01-01

280

Pollen record from Colle Curti and Cesi: Early and Middle Pleistocene mammal sites in the Umbro-Marchean Apennine Mountains (central Italy)  

NASA Astrophysics Data System (ADS)

The palynological record from the Colle Curti and Cesi continental deposits has been examined in order to identify the main palaeofloristic and vegetational changes between 0.99 and 0.6-0.7 Ma. These data show a progressive increase in aridity, as well as a progressive decrease in temperature, which are associated with the transition in dominance from the 41 to 100 ka cyclicity in the Milankovitch orbital record during the Middle Pleistocene. The disappearance of Tsuga, recorded during the lower part of the Brunhes Chron, also has been related to a shift in global aridity. During the successive open vegetational phases (glacials), Chenopodiaceae and Artemisia progressively increase, whereas Cyperaceae decrease. Forest phases (interglacials) are successively dominated by Tsuga, Abies with Picea and, finally, Pinus; but all lack significant expansion of broad-leaved deciduous taxa. Palynological and sedimentological data, in addition to taphonomic interpretations, demonstrate the occurrence of several hiatuses in the lower parts of the interglacials. These hiatuses are considered to represent the palaeoenvironmental response to climatic changes affecting local sedimentological and geomorphological conditions.

Bertini, Adele

2000-12-01

281

Flavanol binding of nuclei from tree species.  

PubMed

Light microscopy was used to examine the nuclei of five tree species with respect to the presence of flavanols. Flavanols develop a blue colouration in the presence of a special p-dimethylaminocinnamaldehyde (DMACA) reagent that enables those nuclei loaded with flavanols to be recognized. Staining of the nuclei was most pronounced in both Tsuga canadensis and Taxus baccata, variable in Metasequoia glyptostroboides, faint in Coffea arabica and minimal in Prunus avium. HPLC analysis showed that the five species contained substantial amounts of different flavanols such as catechin, epicatechin and proanthocyanidins. Quantitatively, total flavanols were quite different among the species. The nuclei themselves, as studied in Tsuga seed wings, were found to contain mainly catechin, much lower amounts of epicatechin and traces of proanthocyanidins. Blue-coloured nuclei located centrally in small cells were often found to maximally occupy up to 90% of a cell's radius, and the surrounding small rim of cytoplasm was visibly free of flavanols. A survey of 34 gymnosperm and angiosperm species indicated that the first group has much higher nuclear binding capacities for flavanols than the second group. PMID:14595514

Feucht, W; Treutter, D; Polster, J

2003-11-01

282

High-level expression, purification and production of the fungal immunomodulatory protein-gts in baculovirus-infected insect larva.  

PubMed

Fip-gts, a fungal immunomodulatory protein (Fip) isolated from Ganoderma tsugae (gts), has been reported to possess therapeutic effects in the treatment of cancer and autoimmune disease. To cost-effectively produce Fip-gts and bypass the bottleneck involved in its time-consuming purification from G. tsugae, in this study, we incorporated the SP(bbx) secretion signal into recombinant baculovirus for expressing glycosylated and bioactive rFip-gts in baculovirus-infected insect cells and Trichoplusia ni larva. This is the first study to employ the aerosol infecting T. ni larva with recombinant baculovirus for economical and high-level production of foreign proteins. In this study, one purification could yield 10 mg of rFip-gts protein merely from ?100 infected T. ni larvae by aerosol inoculation, corresponding to 5 L (5?×?10? cells) of the infected Sf21 culture. In addition, the rFip-gts purified from T. ni larvae could induce the expression of interleukin-2 in murine splenocytes with an immunoresponsive level similar to that induced by LZ-8 (a known potent immunomodulatory protein purified from Ling zhi, Ganoderma lucidum). Thus, our results demonstrated that the larva-based baculovirus expression system can successfully express rFip-gts with the assembling capability required for maintaining immunomodulatory and anticancer activity. Our approach will open a new avenue for the production of rFip-gts and facilitate the immunoregulatory activity of rFip-gts available in the future. PMID:23296801

Wu, Tzong-Yuan; Chen, Hsin-An; Li, Feng-Yin; Lin, Ching-Ting; Wu, Chi-Ming; Hsieh, Feng-Chia; Tzen, Jason Tze-Cheng; Hsieh, Sheng-Kuo; Ko, Jiunn-Liang; Jinn, Tzyy-Rong

2013-01-08

283

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.

284

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

285

Euthanasia and physician assisted suicide; a social work update.  

PubMed

Considering the recent actions of Dr. Jack Kevorkian, Dr. Timothy Quill and the Hemlock Society's initiatives for legalizing physician assisted suicide for special cases in the state of Washington, Oregon, and California, arguments for and against euthanasia and physician assisted suicide have grown into a substantial and impassioned debate. This paper outlines and analyzes salient issues within the controversy of legalizing physician assisted suicide for terminally ill patients. It highlights significant issues for state and federal policy formation and further suggests unique roles which medical social workers might play in developing and implementing a compassionate and reliable system for caring for the terminally ill. PMID:8839460

Smokowski, P R; Wodarski, J S

1996-01-01

286

Operational experience at a `dog-hair` site. Forest Service research note  

SciTech Connect

The authors installed plots in a nine-year-old Douglas-fir plantation established after clearcutting a grossly overstocked stand. One plot sampled the slash-burned portion. In the nonburned portion, two plots were in areas thinned three years earlier by machete combined with pulling small seedlings, and four were in areas thinned by chainsaw. Stumps with sprouts averaged 5,665 per acre in saw-thinned plots and only 250 per acre in plots thinned by machete and pulling. Most seedlings and sprouts were western hemlock. Machete cutting and pulling proved more effective than chainsaws for reducing stem density. Slash burning destroyed most new seedlings.

Ricketts, S.R.; Miller, R.E.

1995-04-01

287

A study of weeds as potential inoculum sources for a tomato-infecting begomovirus in central Brazil.  

PubMed

Tomato severe rugose virus (ToSRV) is the most important begomovirus species in Brazilian tomato production. Many weeds are associated with tomato, and some are hosts of begomoviruses. Only one species of weed, Nicandra physaloides, has been found to be infected with ToSRV. In this study, four weed species were investigated for their capacity to be infected by ToSRV and serve as a potential source of inoculum for tomato. Begomoviruses from naturally infected Crotalaria spp., Euphorbia heterophylla, N. physaloides, and Sida spp. were successfully transferred to tomato plants by biolistic inoculation. ToSRV was the major virus transferred to tomato. In contrast, other begomoviruses were transferred to weeds, such as Sida micrantha mosaic virus and Euphorbia yellow mosaic virus. Furthermore, a new strain of Sida micrantha mosaic virus is reported. We also confirmed that Crotalaria spp., E. heterophylla, and Sida spp. are infected with ToSRV but at low viral titers and in mixed infections with weed-infecting begomoviruses. Thus, it was demonstrated that weeds are potential sources of ToSRV for tomato in central Brazil. PMID:23489523

Barreto, S S; Hallwass, M; Aquino, O M; Inoue-Nagata, A K

2013-05-01

288

Effects of reforestation practices on Staphylinid beetles (Coleoptera: Staphylinidae) in Southwestern China forests.  

PubMed

In 2004, Staphylinid beetle (Coleoptera) assemblages were studied via pitfall trapping to examine the effects of reforestation in southwestern China forests. Sites included two 100-yr-old mature forest types (hemlock-spruce forest and birch forest), and three 40-yr-old forest types established after harvesting (spruce plantation, larch plantation, and natural broad-leaved forest). Staphylinid species richness was greater in natural broad-leaved forests than those in hemlock-spruce forests and spruce plantations, but no significant difference was found in abundance among the five forest types. Beetle assemblages from young forest stands were significantly different from those in older forest stands, and some environmental characteristics, i.e., elevation, proportion of broad-leaved trees, and coarse woody debris, significantly affected species abundances. Moreover, some staphylinid species predominantly found only in older forest stands indicate that mature forest specialists might be threatened by loss of habitat. So it is necessary to retain adequate patches of older successional stages for conserving these beetle assemblages. PMID:23339781

Luo, Tian-Hong; Yu, Xiao-Dong; Zhou, Hong-Zhang

2013-02-01

289

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

290

Identification of Begomoviruses Infecting Crops and Weeds in Belize  

PubMed Central

Plants including pepper, red kidney bean, squash, string bean and tomato, as well as weeds with viral symptoms were collected from five districts in Belize over a three year period with the aim of determining the diversity of the begomoviruses present. Sixty five percent of the samples screened via DNA hybridization produced signals indicative of begomovirus infection. Subsequent PCR amplifications and nucleotide sequence analyses revealed the presence of four begomoviruses in Belize. Pepper golden mosaic virus and Tomato mottle virus-[Flo] were found associated with tomato and sweet pepper and the former was also isolated from hot pepper. Merremia mosaic virus was found infecting hot pepper, sweet pepper and the weed species Euphorbia heterophylla. Euphorbia mosaic virus-[Yucatan Peninsula] was found in hot pepper and Euphorbia. This is the first report of the identification of begomoviruses in Belize.

McLaughlin, Pamela D.; McLaughlin, Wayne A.; Maxwell, Douglas P.; Roye, Marcia E.

2010-01-01

291

Corroborating molecular species discovery: Four new pine-feeding species of Chionaspis (Hemiptera, Diaspididae)  

PubMed Central

Abstract The genus Chionaspis (Hemiptera, Diaspididae) includes two North American species of armored scale insects feeding on Pinaceae: Chionaspis heterophyllae Cooley, and Chionaspis pinifoliae (Fitch). Despite the economic impact of conifer-feeding Chionaspis on horticulture, the species diversity in this group has only recently been systematically investigated using samples from across the group’s geographic and host range. This paper provides morphological recognition characters for four new species that were recently hypothesized to exist on the basis of molecular evidence. The new species, here described, are Chionaspis brachycephalon Vea sp. n., Chionaspis caudata Vea sp. n., Chionaspis sonorae Vea sp. n. and Chionaspis torreyanae Vea sp. n.  One of the new species, Chionaspis caudata Vea, has a gland spine at the apex of the pygidium, between the median lobes, unlike any other species of Chionaspis. An identification key to the species of Chionaspis feeding on pine in North America is provided.

Vea, Isabelle M.; Gwiazdowski, Rodger A.; Normark, Benjamin B.

2013-01-01

292

Sensitivity analysis for solar plates  

NASA Astrophysics Data System (ADS)

Economic evaluation methods and analyses of emerging photovoltaic (PV) technology since 1976 was prepared. This type of analysis was applied to the silicon research portion of the PV Program in order to determine the importance of this research effort in relationship to the successful development of commercial PV systems. All four generic types of PV that use silicon were addressed: crystal ingots grown either by the Czochralski method or an ingot casting method; ribbons pulled directly from molten silicon; an amorphous silicon thin film; and use of high concentration lenses. Three technologies were analyzed: the Union Carbide fluidized bed reactor process, the Hemlock process, and the Union Carbide Komatsu process. The major components of each process were assessed in terms of the costs of capital equipment, labor, materials, and utilities. These assessments were encoded as the probabilities assigned by experts for achieving various cost values or production rates.

Aster, R. W.

1986-02-01

293

Pioneer exotic tree search for the douglas-fir region. Forest Service general technical report  

SciTech Connect

After three-quarters of a century of introduction of 152 conifer and broadleaf species, no promising candidate exotic was found for the Douglas-fir region. Growth curves spanning 50 years or longer are figured for many species. Firs, pines, larches, spruces, hemlocks, and cedars orginating in northwestern North America had superior growth rates to those from other forest regions. The probable basis for these differences is discussed. The record highlights a general failure of introduced hardwoods, the slow decline of most introduced conifers, the long time needed to express failures, dramatic effects of climatic extremes or introduced pests, failure of native species of continental origin at Wind River, striking similarities of growth rate for the species originating in each country, and many important contrasts between results from early reports and long-term conclusions.

Silen, R.R.; Olson, D.L.

1992-03-01

294

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

295

A review of the silicon material task  

NASA Astrophysics Data System (ADS)

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.

1984-02-01

296

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

297

Water quality and the effects of changes in phosphorus loading, Red Cedar Lakes, Barron and Washburn Counties, Wisconsin  

USGS Publications Warehouse

The Red Cedar Lakes consist of three mainstem lakes (Balsam, Hemlock and Red Cedar) on the Red Cedar River in Barron and Washburn Counties, Wisconsin. These lakes are productive because of high phosphorus loading, and classified as mesotrophic to eutrophic. Because of concerns that the water quality of these lakes was degrading, three cooperative studies were conducted by the U.S. Geological Survey between 1993 and 2003. As part of these studies, water quality in the lakes was documented in 1993?94, 1996?97, and 2000?01, and water and phosphorus budgets were constructed for water year 2001. Historical water-quality data indicated that the lakes have changed little since the late 1980s. A detailed phosphorus budget indicated that most of the 14,100 pounds of phosphorus input to the lakes during 2001 came from the upstream lakes, streams draining relatively undeveloped land upstream of Hemlock Lake, and ground water. Simulation results from two water-quality models (BATHTUB and WiLMS) indicated that about a 50-percent reduction in phosphorus loading from that measured in 2001 is required for all three lakes to be classified as mesotrophic; therefore, appreciable improvements in the water quality would require improvements in the water quality of the upstream lakes. Although the water quality of the lakes has not changed appreciably in recent years and major improvements in water quality are unlikely without major improvements to upstream lakes, continued efforts to protect the susceptible watershed are necessary to maintain the current level of water quality.

Robertson, Dale M.; Rose, William J.; Garn, Herbert S.

2003-01-01

298

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

2009-02-19

299

Stratigraphy of Kenai Group, Cook Inlet, Alaska, and application of ecological shift plot  

SciTech Connect

Regional well-to-well correlations within the five nonmarine formations of the Kenai Group in Cook Inlet, Alaska, are poor at best. The erratic nature of these fluvial deposits, indistinct heavy mineral zonations, and long-ranging palynomorphs have made correlations difficult. Correlations are even more difficult along the basin margin where increased paleotectonic uplift and subsidence have affected deposition. These changes in depositional environments strongly affect electric log character, enough to give the impression that they are correlating like depostional cycles instead of time-stratigraphic units. This leads to incorrect paleodepositional and paleotectonic reconstructions. A new statistical technique called an Ecological Shift Plot was used to help solve these correlation problems. Standard palynological slides are prepared from composite ditch samples every 90 ft. The slides are examined, and spores and pollen characteristic of warm and cold climatic extremes within the total flora are identified and counted. A ratio of specific warm and cool spore-pollen taxa is calculated, and the value for each 90-ft interval is plotted on semilog paper. On a completed profile for the Kenai Group, the two upper formations, the Sterling and Beluga, shift rapidly between warm and cool cycles. However, below the unconformity at the base of the Beluga, a strong, distinct shift to warm climatic conditions occurred during deposition of the upper Tyonek Formation. A strong, distinct cool shift then occurs within the lower Tyonek Formation and persists down through the Hemlock Formation. This cool shift occurs below a local unconformity which is informally called the Middle Ground Shoal unconformity. Below the base of the Hemlock, the flora again shift to a warm cycle within the West Foreland Formation.

Wiggins, V.D.; Hill, J.M.

1987-05-01

300

The problem of conifer species migration lag in the Pacific Northwest region since the last glaciation  

NASA Astrophysics Data System (ADS)

Multiproxy evidence indicates that warmer-than-present summers became established in Eastern Beringia as early as 14,000-13,000 years ago, but the dispersal of spruces, pines, cedars and hemlocks across the Pacific Northwest (PNW) region of southern Alaska did not begin until at least 1500 years afterwards, and took many thousands of years to be completed. There are many potential reasons for this slow spread of PNW conifers towards their modern range limits. The absence of mycorrhizae in the soils of southern Alaska may have slowed conifer establishment. The availability of soil moisture was another limiting factor. With the exception of Pinus contorta, the other PNW conifers become established most readily from seeds that fall on moist, shaded substrates, thus they are not good pioneering species. Competition with alder and birch played an important role, especially along Prince William Sound and the Kenai Peninsula. Alder or alder and birch dominated these regions until the mid- to late Holocene. The other key element for most PNW conifer species is the precipitation regime. The hemlocks, cedars and Sitka spruce are not drought-hardy. So although the PNW temperature regime may have been warm enough in early postglacial times to support the growth of PNW conifers, it was probably too dry for them to successfully become established in new regions. The conflation of these environmental factors limits our present understanding of the problem, but the recent trend of multi-proxy analysis in Quaternary paleoecology will certainly sharpen our reconstructions. Such proxies as conifer needle stomata and insect fossil remains hold significant promise.

Elias, Scott A.

2013-10-01

301

The problem of conifer species migration lag in the Pacific Northwest region since the last glaciation  

NASA Astrophysics Data System (ADS)

Multiproxy evidence indicates that warmer-than-present summers became established in Eastern Beringia as early as 14,000–13,000 years ago, but the dispersal of spruces, pines, cedars and hemlocks across the Pacific Northwest (PNW) region of southern Alaska did not begin until at least 1500 years afterwards, and took many thousands of years to be completed. There are many potential reasons for this slow spread of PNW conifers towards their modern range limits. The absence of mycorrhizae in the soils of southern Alaska may have slowed conifer establishment. The availability of soil moisture was another limiting factor. With the exception of Pinus contorta, the other PNW conifers become established most readily from seeds that fall on moist, shaded substrates, thus they are not good pioneering species. Competition with alder and birch played an important role, especially along Prince William Sound and the Kenai Peninsula. Alder or alder and birch dominated these regions until the mid- to late Holocene. The other key element for most PNW conifer species is the precipitation regime. The hemlocks, cedars and Sitka spruce are not drought-hardy. So although the PNW temperature regime may have been warm enough in early postglacial times to support the growth of PNW conifers, it was probably too dry for them to successfully become established in new regions. The conflation of these environmental factors limits our present understanding of the problem, but the recent trend of multi-proxy analysis in Quaternary paleoecology will certainly sharpen our reconstructions. Such proxies as conifer needle stomata and insect fossil remains hold significant promise.

Elias, Scott A.

2013-10-01

302

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

303

Fungal mycelia as the source of chitin and polysaccharides and their applications as skin substitutes.  

PubMed

A wovenable skin substitute (Sacchachitin) made from the residue of the fruiting body of Ganoderma tsugae was developed in this study. Chemical analysis revealed that the treated residue was a copolymer of beta-1,3-glucan (ca 60%) and N-acetylglucosamine (ca 40%) with a filamental structure of mycelia form, as demonstrated by both optical and scanning electron microscopy. The pulp-like white residue was then woven into thin, porous sheets 7.0 cm in diameter and 0.1-0.2 mm in thickness by filtration and lyophilized for use as a skin substitute. The wound area produced by dissecting rat skin of full thickness was found to almost completely heal on the side covered with Sacchachitin, whereas the control side covered with cotton gauge was around 6.0 cm2 on the 28th day. Furthermore, the wound healing effects of the chitin sheet from crab shell (Beschitin) and Sacchachitin were not found to be significantly different. PMID:9259514

Su, C H; Sun, C S; Juan, S W; Hu, C H; Ke, W T; Sheu, M T

1997-09-01

304

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

305

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

306

Late Holocene Environment in the Lower Hudson Valley, New York: Medieval Warming, Little Ice Age, and European Impact  

NASA Astrophysics Data System (ADS)

Two sediment cores from Piermont Marsh, located in the southern Hudson River Valley, provide a well-dated bi-decadal record of vegetation, climate, land use, and fire frequency. The classic Medieval Warm Period is evident through striking increases in charcoal and Pinus dominance from A.D.800-1350, paralleling records southward along the Atlantic seaboard. Higher inputs of inorganic sediment during this interval suggest increased watershed erosion during drought conditions. Increases in Picea and Tsuga with corresponding decreases in Liquidambar, coupled with increasing organic percentages due to cooler, moister conditions indicate the presence of the Little Ice Age. European impact is manifested by increased weedy plant cover (i.e., Ambrosia, Plantago, and Rumex), decline in arboreal pollen due to land clearance, and increase in inorganic particles to the watershed. Radionuclide dating using Cs-137 and Pb-210 from the southern end of the marsh shows that little disturbance of sediments has occurred, adding validity to the high resolution results and supporting the sedimentation rates obtained using radiocarbon dating. Comparison with other marsh records in the Hudson River estuary shows general agreement in chronology with interesting differences in species changes and sedimentation rates.

Pederson, D. C.; Peteet, D. M.; Kurdyla, D.; Guilderson, T.

2004-05-01

307

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

308

Fuel deposition rates of montane and subalpine conifers in the central Sierra Nevada, California, USA  

USGS Publications Warehouse

Fire managers and researchers need information on fuel deposition rates to estimate future changes in fuel bed characteristics, determine when forests transition to another fire behavior fuel model, estimate future changes in fuel bed characteristics, and parameterize and validate ecosystem process models. This information is lacking for many ecosystems including the Sierra Nevada in California, USA. We investigated fuel deposition rates and stand characteristics of seven montane and four subalpine conifers in the Sierra Nevada. We collected foliage, miscellaneous bark and crown fragments, cones, and woody fuel classes from four replicate plots each in four stem diameter size classes for each species, for a total of 176 sampling sites. We used these data to develop predictive equations for each fuel class and diameter size class of each species based on stem and crown characteristics. There were consistent species and diameter class differences in the annual amount of foliage and fragments deposited. Foliage deposition rates ranged from just over 50 g m-2 year-1 in small diameter mountain hemlock stands to ???300 g m-2 year-1 for the three largest diameter classes of giant sequoia. The deposition rate for most woody fuel classes increased from the smallest diameter class stands to the largest diameter class stands. Woody fuel deposition rates varied among species as well. The rates for the smallest woody fuels ranged from 0.8 g m-2 year-1 for small diameter stands of Jeffrey pine to 126.9 g m-2 year-1 for very large diameter stands of mountain hemlock. Crown height and live crown ratio were the best predictors of fuel deposition rates for most fuel classes and species. Both characteristics reflect the amount of crown biomass including foliage and woody fuels. Relationships established in this study allow predictions of fuel loads to be made on a stand basis for each of these species under current and possible future conditions. These predictions can be used to estimate fuel treatment longevity, assist in determining fuel model transitions, and predict future changes in fuel bed characteristics.

van, Wagtendonk, J. W.; Moore, P. E.

2010-01-01

309

Forest fuel reduction alters fire severity and long-term carbon storage in three Pacific Northwest ecosystems.  

PubMed

Two forest management objectives being debated in the context of federally managed landscapes in the U.S. Pacific Northwest involve a perceived trade-off between fire restoration and carbon sequestration. The former strategy would reduce fuel (and therefore C) that has accumulated through a century of fire suppression and exclusion which has led to extreme fire risk in some areas. The latter strategy would manage forests for enhanced C sequestration as a method of reducing atmospheric CO2 and associated threats from global climate change. We explored the trade-off between these two strategies by employing a forest ecosystem simulation model, STANDCARB, to examine the effects of fuel reduction on fire severity and the resulting long-term C dynamics among three Pacific Northwest ecosystems: the east Cascades ponderosa pine forests, the west Cascades western hemlock-Douglas-fir forests, and the Coast Range western hemlock-Sitka spruce forests. Our simulations indicate that fuel reduction treatments in these ecosystems consistently reduced fire severity. However, reducing the fraction by which C is lost in a wildfire requires the removal of a much greater amount of C, since most of the C stored in forest biomass (stem wood, branches, coarse woody debris) remains unconsumed even by high-severity wildfires. For this reason, all of the fuel reduction treatments simulated for the west Cascades and Coast Range ecosystems as well as most of the treatments simulated for the east Cascades resulted in a reduced mean stand C storage. One suggested method of compensating for such losses in C storage is to utilize C harvested in fuel reduction treatments as biofuels. Our analysis indicates that this will not be an effective strategy in the west Cascades and Coast Range over the next 100 years. We suggest that forest management plans aimed solely at ameliorating increases in atmospheric CO2 should forgo fuel reduction treatments in these ecosystems, with the possible exception of some east Cascades ponderosa pine stands with uncharacteristic levels of understory fuel accumulation. Balancing a demand for maximal landscape C storage with the demand for reduced wildfire severity will likely require treatments to be applied strategically throughout the landscape rather than indiscriminately treating all stands. PMID:19425428

Mitchell, Stephen R; Harmon, Mark E; O'Connell, Kari E B

2009-04-01

310

[Effects of relative abundance of Quercus mongolica acorns on five tree species seed dispersal in Xiaoxing' an Mountains, Northeast China].  

PubMed

An investigation was conducted in a forest farm in the Xiaoxing' an Mountains in autumn, 2009 and 2010 to study the effects of Quercus mongolica acorn quantity and rodent density on the seed dispersal of five tree species (Juglans mandshurica, Pinus koraiensis, Corylus mandshurica, Corylus heterophylla, and Q. mongolica). In the farm, there was an annual change in rodent density. The total capture rate of small rodents in 2009 (31.0%) was significantly higher than that in 2010 (16.7%). The acorn quantity and relative seed abundance (per capita rodent) of Quercus mongolica in 2009 (6.2 +/- 2.1 acorns x m(-2) and 20.0, respectively) were significantly lower than those in 2010 (26.7 +/- 10.2 acorns x m(-2) and 160.0, respectively). In 2009, all the seeds of the five tree species except J. mandshurica were dispersed or eaten in situ, among which, the acorns of Q. mongolica were scatter-hoarded most, and their average dispersal distance was the furthest. In 2010, the seeds of J. mandshurica were scatter-hoarded most, and their average dispersal distance was the furthest. The relative seed abundance of Q. mongolica could be the key factor determining the seed dispersal of the other tree species in the study area. PMID:24066536

Yu, Fei; Shi, Xiao-Xiao; Yi, Xian-Feng; Wang, De-Xiang

2013-06-01

311

Taxonomic significance of trichomes micromorphology in cucurbits  

PubMed Central

Studies on trichomes micromorphology using Scanning Electron Microscope (SEM) were undertaken in 23 species with one variety under 13 genera of the family Cucurbitaceae (viz., Benincasa hispida (Thunb.) Cogn., Citrullus lanatus (Thunb.) Matsum. & Nakai, Cucumis melo var. agrestis Naudin, Cucumis sativus L., Diplocyclos palmatus (L.) C. Jeffrey, Edgaria dargeelingensis C.B. Clarke, Gynostemma burmanicum King ex Chakr., Gynostemma pentaphyllum (Thunb.) Makino, Gynostemma pubescens (Gagnep.) C.Y. Wu, Hemsleya dipterygia Kuang & A.M. Lu, Lagenaria siceraria (Molina) Standl., Luffa acutangula (L.) Roxb., Luffa cylindrica M. Roem., Luffa echinata Roxb., Melothria heterophylla (Lour.) Cogn., Melothria leucocarpa (Blume) Cogn., Melothria maderspatana (L.) Cogn., Sechium edule (Jacq.) Sw., Thladiantha cordifolia (Blume) Cogn., Trichosanthes cucumerina L., T. cucumerina var. anguina (L.) Haines, Trichosanthes dioica Roxb., Trichosanthes lepiniana (Naudin) Cogn. and T. tricuspidata Lour.). The trichomes in the family Cucurbitaceae vary from unicellular to multicellular, conical to elongated, smooth to ridges, with or without flattened disk at base and cyctolithic appendages, thin to thick walled, curved at apices to blunt. Trichomes micromorphology in the family Cucurbitaceae was found significant taxonomically.

Ali, Mohammad Ajmal; Al-Hemaid, Fahad M.A.

2010-01-01

312

Taxonomic significance of trichomes micromorphology in cucurbits.  

PubMed

Studies on trichomes micromorphology using Scanning Electron Microscope (SEM) were undertaken in 23 species with one variety under 13 genera of the family Cucurbitaceae (viz., Benincasa hispida (Thunb.) Cogn., Citrullus lanatus (Thunb.) Matsum. & Nakai, Cucumis melo var. agrestis Naudin, Cucumis sativus L., Diplocyclos palmatus (L.) C. Jeffrey, Edgaria dargeelingensis C.B. Clarke, Gynostemma burmanicum King ex Chakr., Gynostemma pentaphyllum (Thunb.) Makino, Gynostemma pubescens (Gagnep.) C.Y. Wu, Hemsleya dipterygia Kuang & A.M. Lu, Lagenaria siceraria (Molina) Standl., Luffa acutangula (L.) Roxb., Luffa cylindrica M. Roem., Luffa echinata Roxb., Melothria heterophylla (Lour.) Cogn., Melothria leucocarpa (Blume) Cogn., Melothria maderspatana (L.) Cogn., Sechium edule (Jacq.) Sw., Thladiantha cordifolia (Blume) Cogn., Trichosanthes cucumerina L., T. cucumerina var. anguina (L.) Haines, Trichosanthes dioica Roxb., Trichosanthes lepiniana (Naudin) Cogn. and T. tricuspidata Lour.). The trichomes in the family Cucurbitaceae vary from unicellular to multicellular, conical to elongated, smooth to ridges, with or without flattened disk at base and cyctolithic appendages, thin to thick walled, curved at apices to blunt. Trichomes micromorphology in the family Cucurbitaceae was found significant taxonomically. PMID:23961108

Ali, Mohammad Ajmal; Al-Hemaid, Fahad M A

2010-10-16

313

Evaluation of the antimicrobial potential of two flavonoids isolated from limnophila plants.  

PubMed

The antimicrobial potential of two bioflavonoids, i.e., 5,7-dihydroxy-4',6,8-trimethoxyflavone (1) and 5,6-dihydroxy-4',7,8-trimethoxyflavone (2), isolated from Limnophila heterophylla Benth. and L. indica (Linn.) Druce (Scrophulariaceae), respectively, were evaluated against the microbial strains Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Alternaria solani, and Candida albicans. Compounds 1 and 2 exhibited moderate but broad antimicrobial activities against both Gram-positive and Gram-negative bacteria and also against the fungal pathogens. Moreover, the mechanism of action of 1 and 2 on the cellular functions or structures of some of the microorganisms was studied. Compound 1 showed a bactericidal effect against E. coli and S. aureus (MICs of 200 and 250??g/ml, resp.), while compound 2 was found to effectively kill B. subtilis by cell lysis. The growth of A. solani and C. albicans was inhibited by compounds 1 and 2, respectively. The effects of the flavonoids on the cellular structures and the carbohydrate metabolic pathways were studied by scanning electron microscopy (SEM) of the treated cells and by assessing the specific activity of key enzymes of the pathways, respectively. At sublethal doses, they enhanced the activity of gluconeogenic fructose bisphosphatase, but decreased the activity of phosphofructokinase and isocitrate dehydrogenase, the key enzymes of the Embden?Meyerhof?Parnas pathway and the tricarboxylic acid cycle, respectively. PMID:21674786

Brahmachari, Goutam; Mandal, Narayan C; Jash, Shyamal K; Roy, Rajiv; Mandal, Lalan C; Mukhopadhyay, Arijit; Behera, Biswajit; Majhi, Sasadhar; Mondal, Avijit; Gangopadhyay, Arindam

2011-06-01

314

In Vitro Screening of Medicinal Plants Used in Mexico as Antidiabetics with Glucosidase and Lipase Inhibitory Activities  

PubMed Central

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% (IC50?=?299??g/mL), while Ludwigia octovalvis and Iostephane heterophylla showed the highest inhibition (82.7 %, IC50?=?202??g/mL and 60.6%, CI50?=?509??g/mL, resp.). With respect to lipase activity, L. octovalvis and Tecoma stans were the most inhibiting treatments (31.4%, IC50?=?288??g/mL; 27.2%, IC50?=?320??g/mL), while C. sinensis displayed 45% inhibition (IC50?=?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.

Ramirez, Guillermo; Zavala, Miguel; Perez, Julia; Zamilpa, Alejandro

2012-01-01

315

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

2012-06-08

316

Voluntary intake, chemical composition and in vitro digestibility of fresh forages fed to guinea pigs in periurban rearing systems of Kinshasa (Democratic Republic of Congo).  

PubMed

The daily voluntary intake (DVI) of Guinea pigs (GP) fed 15 fresh forages used in periurban rearing systems of Kinshasa (Democratic Republic of Congo) was investigated. In order to determine the best forages combination for GP diet, DVI was compared to their nutritional value measured in vitro using (1) a pepsin-pancreatin hydrolysis, (2) an gas fermentation test on the hydrolysed residues with an inoculum prepared from GP faeces, and (3) the chemical composition of the offered feeds and the hydrolysis residues. The forages ranking based on the DVI was correlated to the NDF content, but not to their nutritional values determined in vitro. According to their high DVI (from 4.23 to 7.75 g/kg liveweigth), and their valuable in vitro nutritional values (crude protein ranging from 261 to 279 g crude protein kg(-1) DM, pepsin-pancreatin digestibilities of the dry matter from 0.55 to 0.59 and final gas production from 170 to 196 1 kg(-1) DM), Desmodium intortum, Euphorbia heterophylla or Amaranthus hybridus, can be suggested to the farmers to complement the usual diet distributed to the GP based on Panicum maximum. PMID:17966272

Bindelle, J; Ilunga, Y; Delacollette, M; Kayij, M Muland; di M'Balu, J Umba; Kindele, E; Buldgen, A

2007-08-01

317

Feeding and attraction of Agelastica coerulea (Coleoptera: Chrysomelidae) to Betulaceae plants.  

PubMed

The feeding and attraction of Agelastica coerulea (Baly) to nine species of Betulaceae in four genera (Alnus, Betula, Carpinus, and Corylus) were examined in the laboratory by using choice and no-choice as well as olfactometer bioassays. In no-choice feeding bioassays with A. coerulea larvae, Alnus hirsuta (Spach) Ruprecht, Alnus japonica Steudel, Corylus sieboldiana variety mandshurica (Max.) c. k. Schneider, and Corylus heterophylla variety thunbergii Blume were the most preferred, whereas Betula davurica Pallas, Betula schmidtii Regel, and Carpinus cordata Blume were the least preferred. The larvae showed moderate preference for Alnus maximowiczii Callier and Carpinus tschonoskii variety brevicalycina Nakai. In choice feeding bioassays, no differences in preference between A. hirsuta and A. japonica were observed. However, there were significant differences in preference between A. hirsuta and each of the other seven plant species. In olfactometer bioassays with adult female A. coerulea, fresh leaf odor from A. hirsuta attracted significantly more adults than that from A. japonica and C. sieboldiana variety mandshurica. These results indicate that A. coerulea differed in its ability to discriminate among the Betulaceae plants at the feeding preference and attraction of host selection. PMID:15666753

Park, Il-Kwon; Lee, Sang-Gil; Shin, Sang-Chul; Kim, Chul-Su; Ahn, Young-Joon

2004-12-01

318

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

319

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

320

Cotterillia bromelicola nov. gen., nov. spec., a gonostomatid ciliate (Ciliophora, Hypotricha) from tank bromeliads (Bromeliaceae) with de novo originating dorsal kineties  

PubMed Central

Cotterillia bromelicola nov. gen., nov. spec. was discovered in the tanks of the Mexican bromeliad Tillandsia heterophylla. Its morphology, ontogenesis, and 18S rDNA were studied with standard methods. Cotterillia has many cirral rows on both sides of the body. Uniquely, and thus used to diagnose the new genus Cotterillia, it has dorsal kineties originating de novo, producing neokinetal waves where the parental dorsal kineties reorganize to “combined rows”, consisting of dorsal bristles anteriorly and of cirri posteriorly. Thus, up to four generations of bristles and cirri occur on the dorsal body surface. Cotterillia bromelicola has a gonostomatid body and adoral zone of membranelles, while the dense ciliature and the neokinetal waves resemble kahliellid hypotrichs. However, the de novo origin of anlage 1 and the molecular analyses show convincingly that Cotterillia belongs to the Gonostomatidae Small and Lynn, 1985, for which an improved diagnosis is provided. Thus, neokinetal waves originated several times independently. The molecular differences between Trachelostyla, Gonostomum, and Cotterillia are small (?5%) compared to their distinct morphologies and ontogeneses, suggesting that the 18S rDNA underestimates generic diversity. Our study emphasizes the need of combined morphological, ontogenetic, and molecular investigations to unravel the complex phylogeny and evolution of hypotrich ciliates.

Foissner, Wilhelm; Stoeck, Thorsten

2012-01-01

321

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

322

[Consensuses on lung cancer treatment by Chinese medicine experts from Beijing and Guangzhou and medication features in the North and South China].  

PubMed

To study the consensuses on lung cancer treatment by Chinese medicine experts from North China and South China, and to analyze their medication features from viewpoints such as the medication frequency, combination laws, medication classification by collecting 800 recipes on the treatment of lung cancer patients prescribed by 8 Chinese oncologists from Guanganmen Hospital of China Academy of Chinese Medical Sciences, the Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, and Guangdong Provincial Hospital of Traditional Chinese Medicine. Results showed that coix seed, poria, pinelliae tuber were the three herbs most commonly used in treatment of lung cancer by all experts. They generally accepted Pi invigorating and phlegm removing method as the basic treatment method for treating lung cancer. Secondly, they usually used white peony root, heterophylla falsestarwort root, and ophiopogonis tuber, etc. (with higher medication frequency) to nourish yin and moisten Fei. Thirdly, consistency was also shown in clearing heat, detoxication, and anticancer. Smilacis glabra, Rhizoma Smilacis Glabrae, Herba Hedyotis diffusae, Herba Scutellariae Barbatae were herbs used by all experts. However, there were differences between oncologists in North China and South China. Oncologists in South China paid more attention to heat toxin and blood stasis, while those in North China paid more attention to supplementing both qi and yin. PMID:21866673

Wang, Shu-mei; Lin, Li-zhu; Nie, Hui

2011-07-01

323

Pollen analysis of natural honeys from the central region of Shanxi, North China.  

PubMed

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

2012-11-21

324

Co-dominance and succession in forest dynamics: the role of interspecific differences in crown transmissivity.  

PubMed

Forests that are composed of two or more tree species with similar ecological strategies appear to contradict the competitive exclusion principle. Beech-maple communities are a well-known example of such a system. On a local scale, a number of mechanisms have been proposed to explain the coexistence of these two species. These are reciprocal replacement, external factors that favour alternatively one or the other species and demographic stochasticity. This paper presents and analyses a simple mathematical model that shows that external factors are not an essential requirement for coexistence. Rather, coexistence requires interspecific differences in light transmissivity through the crowns of adult trees. However, all the three mechanisms mentioned above can be interpreted within the framework of the model. Furthermore, many models of forest dynamics make use of shade tolerance as a key feature in describing successional dynamics. Despite its importance, however, shade tolerance does not have a commonly accepted quantitative definition. Here, a simple scheme is proposed where the relationship between shade tolerance, individual traits (growth and survival) and successional status is defined. This might have important implications in understanding the overall dynamics. Theoretical results have been compared with a number of studies carried out in North American forests. In particular, coexistence in beech-maple communities and the relation between shade tolerance and successional status in a beech-hemlock-birch community have been discussed. PMID:21740915

Cammarano, Mario

2011-07-03

325

Comparative toxicity of the HD-1 and NRD-12 strains of Bacillus thuringiensis subsp. kurstaki to defoliating forest Lepidoptera.  

PubMed

Insecticidal activities of sporulated cultures of the HD-1 and NRD-12 strains of Bacillus thuringiensis subsp. kurstaki were compared against four species of defoliating forest lepidopterans in diet-incorporation assays. There was no difference in LC50 between the two strains to larvae of spruce budworm (Choristoneura fumiferana), gypsy moth (Lymantria dispar), eastern hemlock looper (Lambdina fiscellaria fiscellaria), and whitemarked tussock moth (Orgyia leucostigma), whether expressed as total alkaline soluble protein, activated toxin protein, or International Units as determined by bioassay against Trichoplusia ni. Both strains were consistently more toxic than HD-1-S-1980 when compared on the basis of alkali-soluble protein, but not on the basis of activated toxin or International Units. Hybridization of genomic DNA after restriction with HindIII revealed the presence of all three cryIA toxin genes in each of the isolates used in this study, including HD-1-S-1980, which was previously reported to have lost the cryIA(b) gene. PMID:1607666

van Frankenhuyzen, K; Milne, R; Brousseau, R; Masson, L

1992-03-01

326

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

327

Ecosystem Consequences of Forest Fragmentation in the Pacific Northwest: Biogeochemical Edge Effects within Old-Growth Forest Remnants  

NASA Astrophysics Data System (ADS)

Our research includes quantifying the long term impact of clear-cut edges on biogeochemical processes affecting carbon and nitrogen retention within fragmented old-growth Douglas-fir/western hemlock forests in the Pacific Northwest. In addition to quantifying the magnitude and depth of influence of edge effects on soil processes, this research seeks broader application to conservation biology, using a mechanistic approach. Along 360-m gradients spanning clear-cut to forest at nine sites, long-term monitoring of edge effects integrates microclimate, above-ground structure, litter fall, decomposition, and soil nitrogen dynamics. Abrupt changes in height and structure at edges induce increased microclimatic variability in adjacent forest, which, in turn, alters rates of nitrogen and carbon cycling in soils. Field and laboratory assays reveal increases in litter decomposition and nitrogen availability in near edge (0-30 m from edge) forest, and higher rates of litter fall and soil organic matter storage within far edge (30-120 m from edge) forest, relative to interior forest (more than 120 m from edge). Abiotic structural effects, by modulating microclimatic variability, change the complex biotic interactions involved in biogeochemical cycling in forest soils within 120 m of edges. Due to such interactions, organic-matter and nitrogen pool sizes in soil and vegetation, and net ecosystem production, vary in a nonlinear, but predictable, manner with distance into forest from edge. Mixed-effects statistical models most precisely quantify depth of influence for over 100 microclimatic, structural, and biogeochemical variables.

Hayes, T. D.; Swanson, A.; D'Antonio, C. M.; Griffiths, R. P.

2005-12-01

328

A novel microphysiometer based on MLAPS for drugs screening.  

PubMed

This paper presents a novel microphysiometer for simultaneous measurements of several extracellular ions concentrations in living cells based on MLAPS (multi-light addressable potentiometric sensor). In the microphysiometer, different sensitive membranes are illuminated in parallel with n light sources at different frequencies, the response amplitudes of each frequency component can be measured on-line by parallel processing algorithm. By the experiments, we can analyze the relations of the extracellular environmental H(+), Na(+), K(+), Ca(2+) under the effects of western medicines (dilantin, phenobarbital sodium, penicillin sodium) and Chinese drugs (scutellaria, medlar, hemlock parsley), and estimate the effects of several drugs. As the novel microphysiometer works under regular cell culture conditions, cells can be repeatedly simulated with drugs to complete dose-response curve within a few hours. With the detection of a general parameter (extruded protons and ions), the system can be used to monitor the real-time process of the cells' metabolism, observe the functional responses of different kinds of membrane-bound receptors, evaluate the drugs. PMID:11390215

Yicong, W; Ping, W; Xuesong, Y; Qingtao, Z; Rong, L; Weimin, Y; Xiaoxiang, Z

2001-06-01

329

Impact of Canopy Nitrogen Deposition on Forest Carbon Storage: Initial Results from a manipulative Experiment at the Howland AmeriFlux Site  

NASA Astrophysics Data System (ADS)

We are conducting a large-scale ecosystem manipulation experiment to evaluate the hypothesis that anthropogenic nitrogen (N) deposition is enhancing forest ecosystem carbon sequestration. About 21 ha of spruce-hemlock forest in central Maine was fertilized at a rate of 18 kg N/ha/y in 2001 with additional applications planned in 2002-3. The N application is in liquid form to the canopy to more closely duplicate actual N deposition processes than previous studies that have applied fertilizer to the forest floor. The impact of this treatment on net ecosystem CO2 exchange (NEE) is being evaluated with the eddy covariance technique. Model simulations suggest that with low-moderate N uptake efficiency (20-50 percent), canopy photosynthesis (GEE) and NEE will each increase in the experimental treatment by readily detectable amounts (7-17 percent and 12-33 percent) after the first year of N addition, with further increases possible in subsequent years. We are using 15N labeled fertilizer on subplots in the treatment area and biomass measurements to independently assess C sequestration changes and partitioning following N addition.

Hollinger, D. Y.; Aber, J.; Dail, B.; Davidson, E.; Fernandez, I.; Goltz, S.; LeClerc, M.; Sievering, H.

2001-12-01

330

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

331

Kevorkian v. Thompson.  

PubMed

The United States District Court of the Eastern District of Michigan, 6 January 1997 [date of decision], held that a mentally competent patient who is terminally ill or intractably suffering does not have a liberty interest in assisted suicide under the due process clause of the Fourth Amendment and is not denied equal protection under the Fourteenth Amendment. Plaintiff Jack Kevorkian is a physician who advocates the right to die and assisted patients to commit suicide. Plaintiff Janet Good, the former president of the Michigan Hemlock Society, suffers from terminal pancreatic cancer. The plaintiffs claimed that Michigan's statute prohibiting physician-assisted suicide is unconstitutional. The District Court held there is no cognizable constitutional right to assisted suicide because the right to suicide or assisted suicide is not deeply rooted in the nation's history and traditions, and because the statute does not infringe on any fundamental right or liberty. The court noted a difference between the withdrawal of life support and acts to hasten death by assisted suicide, and further held that the law against physician-assisted suicide furthered legitimate state interests in denying to physicians "the role of killers of their patients," in regulating circumstances under which life may be ended, and in protecting the vulnerable but viable from "self-interested importuning of third parties." PMID:16285100

1997-01-01

332

Kevorkian v. Thompson.  

PubMed

Court Decision: 947 Federal Supplement 1152; 1997 Jan 6 (date of decision). The United States District Court of the Eastern District of Michigan held that a mentally competent patient who is terminally ill or intractably suffering does not have a liberty interest in assisted suicide under the due process clause of the Fourth Amendment and is not denied equal protection under the Fourteenth Amendment. Plaintiff Jack Kevorkian is a physician who advocates the right to die and assisted patients to commit suicide. Plaintiff Janet Good, the former president of the Michigan Hemlock Society, suffers from terminal pancreatic cancer. The plaintiffs claimed that Michigan's statute prohibiting physician-assisted suicide is unconstitutional. The District Court held that there is no cognizable constitutional right to assisted suicide because the right to suicide or assisted suicide is not deeply rooted in the nation's history and traditions, and because the statute does not infringe on any fundamental right or liberty. The court noted a difference between the withdrawal of life support and acts to hasten death by assisted suicide. The court also held that the law against physician-assisted suicide furthered legitimate state interests in denying to physicians "the role of killers of their patients," in regulating circumstances under which life may be ended, and in protecting the vulnerable but viable from "self-interested importuning of third parties." PMID:16320473

1997-01-01

333

Potential impacts of climate change on Pacific Northwest forest vegetation  

SciTech Connect

Despite the limitations of the models used in the climate change analyses, some overall conclusions can be made concerning climate change impacts on Northwest forests. The foremost of these is that the distribution and composition of forests in Washington and Oregon could change substantially under the GCM scenarios of regional climate change. The Holdridge, climate/forest correlations, and forest gap models (except for the CLIMACS results) all forecast shifts to forests better adapted to warmer and drier conditions. Temperate forests in the Holdridge scenarios are generally restricted to upper elevations and total forest acreage decreases by 5% to 25% depending on the climate scenario used. In central Oregon, total forested area is projected to decrease by almost half under a 5C warming. Oak woodlands and dry Douglas-fir dominated forests are likely to increase in areal extent, while the more productive western hemlock - Douglas-fir forest will undergo significant contraction. Subalpine and alpine vegetation are likely to be reduced substantially. Declines in moisture availability would decrease forest productivity and long-term timber production.

King, G.A.; Tingey, D.T.

1992-05-01

334

Effects of Urbanization on Allochthonous Inputs to Small Puget Sound Lowland Streams  

NASA Astrophysics Data System (ADS)

Urbanization produces fundamental changes to abiotic and biotic functions in streams, with shifts affecting everything from flow regimes to benthic communities. However, development patterns are manifested in changes to riparian vegetation communities as well, and these changes alter the sources and fate of organic matter in streams. This ongoing study in the Puget Sound Lowlands evaluates the influences of urbanization on allochthonous inputs to small streams. The study area includes 16 litterfall sites with riparian vegetation composition spanning the disturbance spectrum. Vegetation types include minimally altered conifer and mixed forests (western hemlock, big leaf maple, red alder), deciduous (red alder), landscape trees associated with residential development, and minimal forest cover with prevalent invasive species. While conifer/mixed and red alder forests produce similar peak litterfall rates, as much as 10 g m-2d-1, red alder litter contains more nitrogen, resulting in higher nitrogen loads to streams. Short-term laboratory leaching studies indicate that red alder leaves lose 25% of their mass within 24 hours, as compared with 1% for conifer materials. Highly disturbed areas with little or no riparian vegetation produce low allochthonous inputs (peak 0.1 g m-2d-1); grass clippings, for example, do not compensate for the loss of tree cover.

Roberts, M. L.

2005-05-01

335

The SHARE 2012 data campaign  

NASA Astrophysics Data System (ADS)

A multi-modal (hyperspectral, multispectral, and LIDAR) imaging data collection campaign was conducted just south of Rochester New York in Avon, NY on September 20, 2012 by the Rochester Institute of Technology (RIT) in conjunction with SpecTIR, LLC, the Air Force Research Lab (AFRL), the Naval Research Lab (NRL), United Technologies Aerospace Systems (UTAS) and MITRE. The campaign was a follow on from the SpecTIR Hyperspectral Airborne Rochester Experiment (SHARE) from 2010. Data was collected in support of the eleven simultaneous experiments described here. The airborne imagery was collected over four different sites with hyperspectral, multispectral, and LIDAR sensors. The sites for data collection included Avon, NY, Conesus Lake, Hemlock Lake and forest, and a nearby quarry. Experiments included topics such as target unmixing, subpixel detection, material identification, impacts of illumination on materials, forest health, and in-water target detection. An extensive ground truthing effort was conducted in addition to collection of the airborne imagery. The ultimate goal of the data collection campaign is to provide the remote sensing community with a shareable resource to support future research. This paper details the experiments conducted and the data that was collected during this campaign.

Giannandrea, AnneMarie; Raqueno, Nina; Messinger, David W.; Faulring, Jason; Kerekes, John P.; van Aardt, Jan; Canham, Kelly; Hagstrom, Shea; Ontiveros, Erin; Gerace, Aaron; Kaufman, Jason; Vongsy, Karmon M.; Griffith, Heather; Bartlett, Brent D.; Ientilucci, Emmett; Meola, Joseph; Scarff, Lauwrence; Daniel, Brian

2013-05-01

336

PCB and PBDE levels in wild common carp (Cyprinus carpio) from eastern Lake Erie.  

PubMed

Male common carp (Cyprinus carpio) from eastern Lake Erie, which is greatly effected by urbanization, agriculture, and industry, were analyzed for PCB and PBDE concentrations in plasma, muscle, and liver to evaluate exposure to these chemicals through habitat interactions. Additional male carp from two nearby relatively clean lakes (Bear Lake and Hemlock Lake, NY) were also sampled as controls. While PCBs were detected in muscle, liver, and plasma of Lake Erie carp, the largest concentrations were found in muscle, which also had the most number of congeners. The dominant congeners were PCB 138 and PCB 153. Concentrations of PCB 153 in the muscle were correlated with fish length, total weight, and age. Therefore, larger (and generally older) carp had the highest concentrations of PCB 153. In contrast, PBDEs were found only in muscle with the predominant congener being PBDE 47. The total PCB concentrations in muscle of male carp from eastern Lake Erie (ranging from nd to 15,000 ng g(-1) lipid) were 100-fold higher than the total PBDE observed (1.5-100 ng g(-1) lipid), indicating a higher level of contamination of PCBs in Lake Erie. The high PCB levels in carp points to PCB resistance to metabolic degradation. PMID:20609460

Pérez-Fuentetaja, Alicia; Lupton, Sara; Clapsadl, Mark; Samara, Fatin; Gatto, Louis; Biniakewitz, Robert; Aga, Diana S

2010-07-06

337

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

338

Ecological Impacts of High Deer Densities  

NSDL National Science Digital Library

This Figure Set explores the complexity of forest ecosystems with particular emphasis on the effects of expanding white-tailed deer (Odocoileus virginianus) populations on trees, birds, and people. Once at the brink of extinction throughout their range, deer populations in the eastern and midwestern United States have grown rapidly over the last several decades. This has created unwelcome consequences for farmers, orchardists, homeowners, and motorists, including crop damage and more vehicle accidents. Of concern to conservation biologists is the possibility that high deer densities might have detrimental effects on the abundance and diversity of forest vegetation and wildlife. This issue addresses the questions: 1) How do deer impact the composition of forest vegetation? 2) How do deer influence habitat for other wildlife? and 3) What challenges exist in the management of white-tailed deer populations? The issue draws upon three primary papers, which examine: 1) deer browse and other factors influencing hemlock regeneration, 2) effects of manipulating deer populations on the abundance and diversity of breeding birds, and 3) decision-making processes for resolving deer management controversies.

Schusler, Tania

2010-02-16

339

Natural forests of Maryland: an explanaton of the vegetation map of Maryland  

SciTech Connect

The forests of Maryland have been mapped at a scale of 1:250,000 on the basis of 15 regional associations: (1) tamarack, (2) bald cypress, (3) hemlock-yellow birch-black birch, (4) river birch-sycamore, (5) sycamore-green ash-box elder-silver maple, (6) shingle oak, (7) chestnut oak-post oak-blackjack oak, (8) chestnut oak-bear oak, (9) chestnut oak, (10) loblolly pine, (11) basket oak-lobolly pine, (12) willow oak-loblolly pine, (13) basket oak, (14) sugar maple-basswood, and (15) tulip poplar. The associations differ from each other in species composition and in abundances of species common to many associations. Each was identified in the field by the presence of relatively few common discontinuous tree species referred to as characteristic species. Correlations between forest associations and geologic, topographic, and soils units mapped at a similar scale suggest that patterns of available water are important in controlling distribution of woody species throughout Maryland.

Brush, G.S.; Lenk, C.; Smith, J.

1980-03-01

340

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.

Madjidian, Josefin A.; Lankinen, Asa

2009-01-01

341

The stomatal CO2 proxy does not saturate at high atmospheric CO2 concentrations: evidence from stomatal index responses of Araucariaceae conifers.  

PubMed

The inverse relationship between the number of stomata on a leaf surface and the atmospheric carbon dioxide concentration ([CO(2)]) in which the leaf developed allows plants to optimise water-use efficiency (WUE), but it also permits the use of fossil plants as proxies of palaeoatmospheric [CO(2)]. The ancient conifer family Araucariaceae is often represented in fossil floras and may act as a suitable proxy of palaeo-[CO(2)], yet little is known regarding the stomatal index (SI) responses of extant Araucariaceae to [CO(2)]. Four Araucaria species (Araucaria columnaris, A. heterophylla, A. angustifolia and A. bidwillii) and Agathis australis displayed no significant relationship in SI to [CO(2)] below current ambient levels (~380 ppm). However, representatives of the three extant genera within the Araucariaceae (A. bidwillii, A. australis and Wollemia nobilis) all exhibited significant reductions in SI when grown in atmospheres of elevated [CO(2)] (1,500 ppm). Stomatal conductance was reduced and WUE increased when grown under elevated [CO(2)]. Stomatal pore length did not increase alongside reduced stomatal density (SD) and SI in the three araucariacean conifers when grown at elevated [CO(2)]. These pronounced SD and SI reductions occur at higher [CO(2)] levels than in other species with more recent evolutionary origins, and may reflect an evolutionary legacy of the Araucariaceae in the high [CO(2)] world of the Mesozoic Era. Araucariacean conifers may therefore be suitable stomatal proxies of palaeo-[CO(2)] during periods of "greenhouse" climates and high [CO(2)] in the Earth's history. PMID:21461935

Haworth, Matthew; Elliott-Kingston, Caroline; McElwain, Jennifer C

2011-04-03

342

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

343

Accurate and cost-effective natural resource data from super large scale aerial photography  

NASA Astrophysics Data System (ADS)

Increasing amounts and types of timely and accurate data are required for monitoring to ensure compliance with natural resource regulatory requirements. This study developed a cost-effective method to partially fulfill these data requirements using super large scale aerial photography (Scale: greater than 1:2,000). Two synchronized, metric, Rolleiflex 70mm (2.76in) cameras mounted 12m (40ft) apart on a rigid platform and carried at 5.6 km/hr (3 knots) by a helicopter collected this high resolution, 3D imagery from Alaska and Washington. The overlapping photo pairs provided 3D views of natural resource objects as fine as twigs. The 12m (40ft) inter-camera distance improved ground visibility between tree crowns of dense old growth forests. Analytical stereoplotters and the application of photogrammetric principles enabled measurement and interpretation of photo objects such as trees and their height in a cost-effective way. Horizontal and vertical measurement accuracy was within 2% and 3% of field measurement, respectively. Forest inventory and riparian buffer monitoring applications were used to test this method. Although field work is still required to develop photo-field relationships unique to each ecosystem and for quality assurance, the photo estimates of individual tree height, volume, diameter, type, and location, as well as down tree decay class and landing spot, plot timber volume, and area were comparable to and may replace approximately 95% of field effort. For example, the average of the absolute differences between field and photo estimates for tree height was 2.4m (7.8ft) (s.d. = 2.1m (6.8ft), n = 376), diameter at breast height (1.4m (4.5ft) above ground on uphill tree side) was 5.8cm (2.3in) (s.d. = 5.6cm (2.2in), n = 109), and plot volume in gross board feet was within 10.9% to 13.4% (n = 10) depending on the estimator used. Forest type was correctly classified 99.4% (n = 180) of the time. Timber inventory, species identification, sample distribution, down wood detection, and mapping of habitat features such as streams and trees provided improvement over field methods alone. For example, tree species was correctly identified 90% (n = 176) of the time for alder, Alaska cedar, lodgepole pine, mountain hemlock, Sitka spruce, western hemlock, and western redcedar. The spatial position of tree bases using digital elevation models was within 2.6m (8.4ft) of the actual position (s.d. = 1.4m (4.5ft), n = 20). Tree height, riparian buffer, and forest inventory plot volume data photo collection costs were one-fourth to one-half those of field methods. The new variables of tree crown closure and tree branch density were developed but did not contribute significantly to tree volume estimation. Physiographic limitations and sampling bias were eliminated by helicopter use.

Grotefendt, Richard Alan

344

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

345

Fine-scale, multidimensional spatial patterns of forest canopy structure derived from remotely sensed and simulated datasets  

NASA Astrophysics Data System (ADS)

Forests are not simply storehouses of timber or wood fibre for human consumption and economic development. They represent structurally and ecologically rich habitat for an estimated 40 percent of the earth's extant species, and form the functional interface between the biosphere and atmosphere for some 27 percent of the earth's terrestrial surface. Forests, therefore, play a vital role in the maintenance of biodiversity and the regulation of local to global scale ecosystem processes and functions. Present strategies for conserving biodiversity in managed forests are based on the notion that maintaining the full range of structural conditions historically present in natural forests is the best approach for assuring the long-term persistence of a broad range of native species. The overarching goal of this dissertation is to contribute to the development of novel forest measurements that are relevant to organisms and ecosystems, and much needed by forest scientists and managers to recognize and retain the key elements and patterns of forest structure that are crucial for the conservation of forest biodiversity. This study focuses explicitly on fine-spatial-scale, multidimensional patterns of forest canopy structure based on the assumption that the 'canopy' is the primary focal site of complex interactions between vegetation and the physical environment. Two disparate remote sensing technologies---ground-based hemispherical (fisheye) canopy photography and airborne discrete-return LiDAR---are employed to characterize angular, vertical, and horizontal patterns of forest canopy structure. A quantitative technique is developed for precise measurements of gap fraction (P), element clumping (O), mean projection coefficient (G), and leaf area index (L) from sequences (sets) of black and white pixels extracted at specific view angles in digital fisheye photos. Results are compared with three other leading techniques and validated using well-documented simulated and real fisheye photosets. Variables P, O, G, and L control light capture and penetration in forest canopies, and are key input parameters for process-based models of stand productivity, stand dynamics, and material (CO2 and H2O) and energy fluxes between the canopy and atmosphere. Findings show that this new technique consistently produced the best estimates of stand LAI in each of the three experimental forest sites. However, further validation work is required to determine the adequacy of these methods in other closed and discontinuous canopies. Finally, a methodological framework is devised for quantifying, classifying, and comparing fine-spatial-scale vertical and horizontal patterns of canopy structure derived from airborne LiDAR data. This methodology is tested with simulated forest canopies and ultimately demonstrated using an airborne LiDAR dataset collected over very young to old, coastal Douglas-fir/western hemlock forests on Vancouver Island, British Columbia. A pseudo 'space-for-time substitution' sampling approach is used to investigate age-related developmental changes in canopy structure at decadal and century time scales. Discrete classes of vertical and horizontal canopy structure are identified by k-means partitioning. The structural differences found among age-classes were consistent with the characteristics, patterns, and dynamics predicted by generalized models of stand development for similar coastal Douglas-fir/western hemlock forests of northwestern North America.

Frazer, Gordon Wilson

346

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

347

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

348

Seasonal variation in the temperature sensitivity of proteolytic enzyme activity in temperate forest soils  

NASA Astrophysics Data System (ADS)

Increasing soil temperature has the potential to alter the activity of the extracellular enzymes that mobilize nitrogen (N) from soil organic matter (SOM) and ultimately the availability of N for primary production. Proteolytic enzymes depolymerize N from proteinaceous components of SOM into amino acids, and their activity is a principal driver of the within-system cycle of soil N. The objectives of this study were to investigate whether the soils of temperate forest tree species differ in the temperature sensitivity of proteolytic enzyme activity over the growing season and the role of substrate limitation in regulating temperature sensitivity. Across species and sampling dates, proteolytic enzyme activity had relatively low sensitivity to temperature with a mean activation energy (Ea) of 33.5 kJ mol-1. Ea declined in white ash, American beech, and eastern hemlock soils across the growing season as soils warmed. By contrast, Eain sugar maple soil increased across the growing season. We used these data to develop a species-specific empirical model of proteolytic enzyme activity for the 2009 calendar year and studied the interactive effects of soil temperature (ambient or +5°C) and substrate limitation (ambient or elevated protein) on enzyme activity. Declines in substrate limitation had a larger single-factor effect on proteolytic enzyme activity than temperature, particularly in the spring. There was, however, a large synergistic effect of increasing temperature and substrate supply on proteolytic enzyme activity. Our results suggest limited increases in N availability with climate warming unless there is a parallel increase in the availability of protein substrates.

Brzostek, Edward R.; Finzi, Adrien C.

2012-03-01

349

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

350

Xiphinema bernardi n. sp. (Nematoda: Longidoridae) from the Great Smoky Mountain National Park  

PubMed Central

In October 1985 during a survey of fauna of the Great Smoky Mountains National Park, Ernest Bernard recovered a limited number of specimens of a non-described species of Xiphinema (Nematoda: Longidoridae) and sent them to the senior author. The species is distinct from other species by its large size and having Z-organs in the genital tract. During July 2006, Dr. Bernard's survey crew took samples in the area where the species was first found and was successful in finding it again. Without Dr. Bernard's efforts, this species could not have been described and thus the new species is named X. bernardi n. sp. in his honor. Several female and juvenile specimens of the new species were recovered in a sample from a mixed forest of maple, hemlock, and silverbell. It is distinct from all others in Xiphinema group 4 species (with Z-organs) by having a longer total stylet length, 259.8 to 284.2 ?m vs < 253 ?m for all other species in this group. Xiphinema bernardi n. sp. is distinctive because of its long body length (4.45 to 6.00 mm), tail shape, and c' ratio. Of the group 4 species, it most closely resembles X. phoenicis. Second, third and fourth stage juvenile descriptions and morphometrics are included. The polytomous key code for X. bernardi n. sp. is A4-B1-C6-D56-E56-F(4)5-G4-H2-I34-J5-K?-L1. Molecular approaches using the internal transcribed spacer 1 sequences of nuclear ribosomal DNA suggested that X. bakeri and X. diversicaudatum are the most closely related species from the species examined.

Bae, Chang-Hwan; Ye, Weimin; Pedram, Majid

2009-01-01

351

Xiphinema bernardi n. sp. (Nematoda: Longidoridae) from the Great Smoky Mountain National Park.  

PubMed

In October 1985 during a survey of fauna of the Great Smoky Mountains National Park, Ernest Bernard recovered a limited number of specimens of a non-described species of Xiphinema (Nematoda: Longidoridae) and sent them to the senior author. The species is distinct from other species by its large size and having Z-organs in the genital tract. During July 2006, Dr. Bernard's survey crew took samples in the area where the species was first found and was successful in finding it again. Without Dr. Bernard's efforts, this species could not have been described and thus the new species is named X. bernardi n. sp. in his honor. Several female and juvenile specimens of the new species were recovered in a sample from a mixed forest of maple, hemlock, and silverbell. It is distinct from all others in Xiphinema group 4 species (with Z-organs) by having a longer total stylet length, 259.8 to 284.2 ?m vs < 253 ?m for all other species in this group. Xiphinema bernardi n. sp. is distinctive because of its long body length (4.45 to 6.00 mm), tail shape, and c' ratio. Of the group 4 species, it most closely resembles X. phoenicis. Second, third and fourth stage juvenile descriptions and morphometrics are included. The polytomous key code for X. bernardi n. sp. is A4-B1-C6-D56-E56-F(4)5-G4-H2-I34-J5-K?-L1. Molecular approaches using the internal transcribed spacer 1 sequences of nuclear ribosomal DNA suggested that X. bakeri and X. diversicaudatum are the most closely related species from the species examined. PMID:22661783

Robbins, R T; Bae, Chang-Hwan; Ye, Weimin; Pedram, Majid

2009-06-01

352

Taking the pulse of mountains: Ecosystem responses to climatic variability  

USGS Publications Warehouse

An integrated program of ecosystem modeling and field studies in the mountains of the Pacific Northwest (U.S.A.) has quantified many of the ecological processes affected by climatic variability. Paleoecological and contemporary ecological data in forest ecosystems provided model parameterization and validation at broad spatial and temporal scales for tree growth, tree regeneration and treeline movement. For subalpine tree species, winter precipitation has a strong negative correlation with growth; this relationship is stronger at higher elevations and west-side sites (which have more precipitation). Temperature affects tree growth at some locations with respect to length of growing season (spring) and severity of drought at drier sites (summer). Furthermore, variable but predictable climate-growth relationships across elevation gradients suggest that tree species respond differently to climate at different locations, making a uniform response of these species to future climatic change unlikely. Multi-decadal variability in climate also affects ecosystem processes. Mountain hemlock growth at high-elevation sites is negatively correlated with winter snow depth and positively correlated with the winter Pacific Decadal Oscillation (PDO) index. At low elevations, the reverse is true. Glacier mass balance and fire severity are also linked to PDO. Rapid establishment of trees in subalpine ecosystems during this century is increasing forest cover and reducing meadow cover at many subalpine locations in the western U.S.A. and precipitation (snow depth) is a critical variable regulating conifer expansion. Lastly, modeling potential future ecosystem conditions suggests that increased climatic variability will result in increasing forest fire size and frequency, and reduced net primary productivity in drier, east-side forest ecosystems. As additional empirical data and modeling output become available, we will improve our ability to predict the effects of climatic change across a broad range of climates and mountain ecosystems in the northwestern U.S.A.

Fagre, D. B.; Peterson, D. L.; Hessl, A. E.

2003-01-01

353

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

354

Four Centuries of Change in Northeastern United States Forests  

PubMed Central

The northeastern United States is a predominately-forested region that, like most of the eastern U.S., has undergone a 400-year history of intense logging, land clearance for agriculture, and natural reforestation. This setting affords the opportunity to address a major ecological question: How similar are today's forests to those existing prior to European colonization? Working throughout a nine-state region spanning Maine to Pennsylvania, we assembled a comprehensive database of archival land-survey records describing the forests at the time of European colonization. We compared these records to modern forest inventory data and described: (1) the magnitude and attributes of forest compositional change, (2) the geography of change, and (3) the relationships between change and environmental factors and historical land use. We found that with few exceptions, notably the American chestnut, the same taxa that made up the pre-colonial forest still comprise the forest today, despite ample opportunities for species invasion and loss. Nonetheless, there have been dramatic shifts in the relative abundance of forest taxa. The magnitude of change is spatially clustered at local scales (<125 km) but exhibits little evidence of regional-scale gradients. Compositional change is most strongly associated with the historical extent of agricultural clearing. Throughout the region, there has been a broad ecological shift away from late successional taxa, such as beech and hemlock, in favor of early- and mid-successional taxa, such as red maple and poplar. Additionally, the modern forest composition is more homogeneous and less coupled to local climatic controls.

Thompson, Jonathan R.; Carpenter, Dunbar N.; Cogbill, Charles V.; Foster, David R.

2013-01-01

355

Late Miocene (Pannonian) Vegetation from the Northern Part of Central Paratethys  

NASA Astrophysics Data System (ADS)

During Late Miocene, the Western Carpathian paleogeography started to change. The Lake Pannon retreated southwards, and the northern coast of the back arc basin was slightly elevated due to progradation of deltaic and alluvial facies, especially in the lowlands. The studied „Pannonian lake" sediments come from the Czech and Slovak parts of Central Paratethys. Changes of the sedimentary environment from deep to shallow lake and deltaic environment, followed by development of alluvial plains were noticed. Salinity crisis due to Paratethys isolation led to development of total freshwater environment to the end of this period. Samples from 3 surficial localities and 15 boreholes were palynologically studied. Occasional occurences of Dinoflagellates indicate a slightly higher salinity, whereas green algae Pediastrum, aquatic ferns Azolla, and aquatic and coastal plants (Nelumbo, Nymphaea, Myriophyllum, Sparganium, Potamogeton, Cyperaceae etc.) represent a freshwater environment. Due to paleogeographic changes and climatic oscillations the number of thermophilous taxa decreased and some of them disappeared completely from this area (f. e. Sapotaceae, Palmae). Mostly broad-leaved deciduous elements of mixed mesophytic forests (Quercus, Celtis, Carya, Tilia, Carpinus, Betula, Juglans) with some thermophilous elements admixture of Engelhardia, Castanea, Trigonobalanopsis, Symplocos, Cornaceaepollis satzveyensis generally dominate. Variously high relief of the uplifted mountainy chains created ideal conditions for higher presence of extrazonal vegetation (Cedrus, Tsuga, Picea, Cathaya) in the investigated area. Zonal type of vegetation including marshes, riparian forests with Alnus, Salix, Pterocarya, Liquidambar, Betula, Fraxinus, shrubs and lianas on dryer substrates associated riparian forest (Buxus, Ericaceae, Vitaceae, Lonicera, Rosaceae type Rubus), and coastal swamps with Taxodiaceae, Nyssa, Myrica, Sciadopitys were growing in the floodplain lowlands of Vienna Basin. Accumulations of the Chenopodiaceae in the interfluve areas probably indicate local saline swampy environments during sea level fall. The increasing amounts of herbs indicate the existence of wet prairie areas (Thalictrum, Rumex, Valeriana, Dipsacaceae, Lamiaceae, Galium) or steppes (Artemisia - up to 17%, Asteraceae, Campanula, Fabaceae, Daucaceae, Caryophyllaceae, Plantago). This is the contribution to the projects ESF -EC-009-07, APVT 51-011305, APVV-0280-07 (Slovakia) and MSM0021622427 (Czech republic).

Ková?ová, M.; Doláková, N.

2009-04-01

356

Impacts of traditional land use practices on soil organic carbon and nitrogen pools of mountain ecosystems in Nepal  

NASA Astrophysics Data System (ADS)

Crop production, animal husbandry and forestry are three closely interlinked components of land use systems in the mountains of Nepal. Forests are the major source of fuel wood, construction materials, fodder and litter. The latter is used as a bedding material for livestock and forms an important component of farmyard manure. In addition forest grazing by cattle is a common practice. Excessive extraction of biomass from the forest leads to a decline of soil organic matter and nutrient contents. On the landscape scale these negative effects will partly be compensated by positive effects on soil organic matter and nutrient stocks of arable soils. The experimental data base for a quantification of such effects at the scale of communities is however poor, in particular for Nepal. Understanding the impact of subsistence farming on ecosystems is imperative in order to recommend successful and sustainable land management practices. The aim of our study is to quantify effects of land use on carbon and nitrogen pools and fluxes for mountain communities in Nepal. Results of a case study in the buffer zone area of the Sagarmatha National Park are presented. The potential vegetation comprises mixed forests of Quercus semicarpifolia, Rhododendron arboreum and Tsuga dumosa. Carbon and nitrogen stocks in soil and vegetation were quantified for three different land use types, namely: forest with low human impact, forests with high human impact and agricultural land. The scale of disturbance of the forests has been classified by visual estimation considering the percentage of litter raked, number of lopped trees, and grazing intensity assessed by signs of trampling and the number of trails. After stratification of the community area, 20 plots of 10 m radius were established (17 forest plots, 3 plots for arable land) where biometric data of the vegetation were determined and sub-samples were taken for chemical analyses. Organic layers (litter remaining after litter raking) and soil samples were collected (volumetric sampling of geometric horizons down to 1 m depth). Fluxes of carbon and nitrogen from the forests were accounted by combining results of sub samples of biomass extracted by local people during the field survey and information on amounts and source areas provided by the farmers. Also the amount of carbon and nutrients applied with farmyard manure and the extraction by harvest was determined for the arable land. First estimates of carbon and nitrogen cycling at the community level and on impacts on soil status will be presented.

Giri, Anjana; Katzensteiner, Klaus

2010-05-01

357

Day-roosts of female long-eared myotis in Western Oregon  

USGS Publications Warehouse

Roosts are a critical habitat component for bats and may influence their survival and fitness. We used radiotelemetry to investigate characteristics of day-roosts of female long-eared myotis (Myotis evotis) in watersheds characterized by different forest conditions and the spatial relationships between day-roosts and available water. We tracked 21 bats to 73 roosts (n = 102 occasions) from June to August 1996 and 1997 on the western slope of the Cascade Mountains, Oregon. Bats primarily used conifer stumps as day-roosts in watersheds dominated by younger forests and used conifer snags, and to a lesser extent conifer stumps, in watersheds with greater proportions of older forests. Individual long-eared myotis used different types of structures as day-roosts, and type of structure used did not differ with reproductive condition. Day-roosts were primarily located in upslope habitat and averaged 0.59 A? 0.03 km from available water and 0.66 A? 0.02 km from capture sites. Roosts were not located closer to available water than random points, but were closer than random points to captures sites. Conifer snags used as day-roosts averaged 34 A? 5 m in height and 93 A? 12 cm diameter at breast height (dbh); snags in intermediate stages of decay had highest use. Use of conifer snags was positively associated with the number of snags within 20 m and negatively associated with distance from stand edge. Conifer stumps used as day-roosts averaged 133 A? 9 cm in height and 59 A? 4 cm dbh. Western hemlock and Douglas-fir stumps were used more often than western redcedar stumps as day-roosts. Odds of a stump being used as a day-roost increased with increasing height of the stump (downhill side) and whether it was situated in a gap in vegetation. We contend that management of day-roosts for forest-dwelling bats should focus on maintaining large conifer snags across landscapes through space and time. In landscapes where there are relatively few large conifer snags, stumps appear to provide important, but ephemeral, roosts for long-eared myotis.

Waldien, David L.; Hayes, J. P.; Arnett, Edward B.

2000-01-01

358

Stemflow amount, intensity and timing in a mature forest in coastal British Columbia, Canada  

NASA Astrophysics Data System (ADS)

Stemflow is the portion of precipitation that falls on the forest canopy and flows along tree branches and stems to the soil at the base of the tree. Previous studies have shown the importance of stemflow for nutrient cycling, groundwater recharge, plant water uptake and soil moisture dynamics; however little is known about stemflow in mature coastal British Columbia forests. Furthermore, most studies focus on the amount of stemflow; few studies have looked at the timing or intensity of stemflow relative to precipitation intensity. We therefore measured stemflow from 18 trees of four different species within a ~1 ha mature western hemlock-western redcedar stand within the Malcolm Knapp Research Forest in British Columbia, Canada, using water collecting containers and tipping bucket rain gauges. Measurements between February and November 2010 showed that stemflow amount was highly variable between the different trees. It did not vary much between species but instead varied mainly with tree size. Trees smaller than 35 cm in diameter contributed relatively more stemflow than larger trees; they represented 24% of the total basal area but contributed ~72% of total stemflow at this site. Funneling ratios were larger than one for the trees smaller than 35 cm in diameter and increased with event size up to 50 mm. Funneling ratios for larger trees were less than one and did not vary much with event size. Stemflow started on average after 3 mm of precipitation. Peak stemflow intensities were much larger than peak precipitation intensity for some events and did not always occur at the same time as peak precipitation intensity; peak stemflow intensities tended to increase for consecutive precipitation bursts and occurred approximately 15 minutes after the corresponding peak precipitation intensity. Peak stemflow intensities were not related to tree species or tree size. Even though stemflow accounted for only ~1% of precipitation, high peak stemflow intensities could contribute to fast groundwater recharge and influence soil moisture dynamics around the trees. Dye tracer experiments showed that stemflow infiltrated primarily along roots and was more frequently found at depth than at the soil surface.

van Meerveld, Ilja; Spencer, Sheena

2013-04-01

359

Environmental history and tephrostratigraphy at Carp Lake, southwestern Columbia Basin, Washington, USA  

USGS Publications Warehouse

Sediment cores from Carp Lake provide a pollen record of the last ca. 125,000 years that helps disclose vegetational and climatic conditions from the present day to the previous interglaciation (120-133 ka). The core also contained 15 tephra layers, which were characterised by electron-microprobe analysis of volcanic glass shards. Identified tephra include Mount St. Helens Ye, 3.69 ka; Mazama ash bed, 7.54 ka; Mount St. Helens layer C, 35-50 ka; an unnamed Mount St. Helens tephra, 75-150 ka; the tephra equivalent of layer E at Pringle Falls, Oregon, <218 ka; and an andesitic tephra layer similar to that at Tulelake, California, 174 ka. Ten calibrated radiocarbon ages and the ages of Mount St. Helens Ye, Mazama ash, and the unnamed Mount St. Helens tephra were used to develop an age-depth model. This model was refined by also incorporating the age of marine oxygen isotope stage (IS) boundary 4/5 (73.9 ka) and the age of IS-5e (125 ka). The justification for this age-model is based on an analysis of the pollen record and lithologic data. The pollen record is divided into 11 assemblage zones that describe alternations between periods of montane conifer forest, pine forest, and steppe. The previous interglacial period (IS-5e) supported temperate xerothermic forests of pine and oak and a northward and westward expansion of steppe and juniper woodland, compared to their present occurrence. The period from 83 to 117 ka contains intervals of pine forest and parkland alternating with pine-spruce forest, suggesting shifts from cold humid to cool temperate conditions. Between 73 and 83 ka, a forest of oak, hemlock, Douglas-fir, and fir was present that has no modem analogue. It suggests warm wet summers and cool wet winters. Cool humid conditions during the mid-Wisconsin interval supported mixed conifer forest with Douglas-fir and spruce. The glacial interval featured cold dry steppe, with an expansion of spruce in the late-glacial. Xerothermic communities prevailed in the early Holocene, when temperate steppe was widespread and the lake dried intermittently. The middle Holocene was characterised by ponderosa pine forest, and the modem vegetation was established in the last 3900 yr, when ponderosa pine, Douglas-fir, fir, and oak were part of the local vegetation.

Whitlock, C.; Sarna-Wojcicki, A. M.; Bartlein, P. J.; Nickmann, R. J.

2000-01-01

360

Using Land Surface Phenology as the Basis for a National Early Warning System for Forest Disturbances  

NASA Astrophysics Data System (ADS)

The National Early Warning System (EWS) provides an 8-day coast-to-coast snapshot of potentially disturbed forests across the U.S.. A prototype system has produced national maps of potential forest disturbances every eight days since January 2010, identifying locations that may require further investigation. Through phenology, the system shows both early and delayed vegetation development and detects all types of unexpected forest disturbances, including insects, disease, wildfires, frost and ice damage, tornadoes, hurricanes, blowdowns, harvest, urbanization, landslides, drought, flood, and climate change. The USDA Forest Service Eastern Forest Environmental Threat Assessment Center is collaborating with NASA Stennis Space Center and the Western Wildland Environmental Threat Assessment Center to develop the tool. The EWS uses differences in phenological responses between an expectation based on historical data and a current view to strategically identify potential forest disturbances and direct attention to locations where forest behavior seems unusual. Disturbance maps are available via the Forest Change Assessment Viewer (FCAV) (http://ews.forestthreats.org/gis), which allows resource managers and other users to see the most current national disturbance maps as soon as they are available. Phenology-based detections show not only vegetation disturbances in the classical sense, but all departures from normal seasonal vegetation behavior. In 2010, the EWS detected a repeated late-frost event at high elevations in North Carolina, USA, that resulted in delayed seasonal development, contrasting with an early spring development at lower elevations, all within close geographic proximity. Throughout 2011, there was a high degree of correspondence between the National Climatic Data Center's North American Drought Monitor maps and EWS maps of phenological drought disturbance in forests. Urban forests showed earlier and more severe phenological drought disturbance than surrounding non-urban forests. An EWS news page (http://www.geobabbble.org/~hnw/EWSNews) highlights disturbances the system has detected during the 2011 season. Unsupervised statistical multivariate clustering of smoothed phenology data every 8 days over an 11-year period produces a detailed map of national vegetation types, including major disturbances. Examining the constancy of these phenological classifications at a particular location from year to year produces a national map showing the persistence of vegetation, regardless of vegetation type. Using spectral unmixing methods, national maps of evergreen decline can be produced which are a composite of insect, disease, and anthropogenic factors causing chronic decline in these forests, including hemlock wooly adelgid, mountain pine beetle, wildfire, tree harvest, and urbanization. Because phenology shows vegetation responses, all disturbance and recovery events detected by the EWS are viewed through the lens of the vegetation.

Hargrove, W. W.; Spruce, J.; Norman, S. P.; Hoffman, F. M.

2011-12-01

361

Carbon Sequestration at the Howland Forest in Maine: Where Does the Carbon go?  

NASA Astrophysics Data System (ADS)

Eddy covariance towers provide information on net carbon exchange between terrestrial ecosystems and the atmosphere, but they provide little information on the location of carbon sources and sinks. We measured net ecosystem exchange (NEE) of CO2 in a mature, old-growth mixed spruce/hemlock/red maple forest at the Howland Forest beginning in 1996. Live biomass at Howland Forest is about 110 Mg C ha-1 in the stand with the eddy covariance tower. Between 1996 and 2000, Howland Forest was a net carbon sink, taking up on average about 1.95\\pm0.46 Mg C ha-1 y-1. Forest mensurational measurements between 1989 and 1998 indicate that, over this entire time period, carbon storage due to tree growth increased by about 1.65 Mg C ha-1 y-1; about 23% of this carbon is stored in roots. However, mortality between 1998-2002 was about 0.28 Mg C ha-1 y-1. Soil C storage also contributes to carbon sequestration, ranging from 0.07-0.24 Mg C ha-1 y-1 in well-drained soils; this does not include changes in soil C storage in poorly-drained soils (roughly 15% of the area). Down-dead wood, measured using the point-relascope method, contains about 4.1 Mg C ha-1. Based on an empirical relationship between temperature and respiration, down-dead wood respires about 0.27 Mg C ha-1 y-1, but estimates of input rates over four years suggests a similar rate of down-dead wood production; this pool appears to be neither gaining nor losing significant amounts of carbon. Standing dead wood contains about 10 Mg C ha-1, but its contribution to NEE is poorly understood. Our results suggest that changes in carbon storage in live vegetation and soils contribute the most to carbon sequestration at Howland Forest and, within the estimates of uncertainty, equate to average NEE estimates over a four-year period.

Scott, N. A.; Hollinger, D. Y.; Davidson, E. A.; Gaudinski, J. B.; Trumbore, S. E.; Hughes, H.; Ranson, J.

2002-12-01

362

Meltwater discharge and the triggering of Younger Dryas : new data on the chronology of Champlain Sea transgression in the St-Lawrence River Valley  

NASA Astrophysics Data System (ADS)

Accurate chronology of ice retreat is crucial to understand the Ocean-Atmosphere couple at the end of the Pleistocene. The St-Lawrence River Valley is key in this regard, and two sedimentary sequences from Mount Saint-Hilaire, in the middle of the valley, contain a record that sheds new lignt on ice retreat and the penecontemporaneous proglacial marine invasion. Basal AMS-dates on terrestrial plant macrofossils coupled with an extrapolation from the pollen content of underlying postglacial lake sediments at Hemlock Carr (243 m), show that local ice retreat occurred around 11 350 14C yr BP. Cross-dating of such macrofossils (10 510 ± 60 14C yr BP) with shells from marine sediments (~12 200 14C yr BP) catched in the neighbouring Lake Hertel's basin (169 m) show a ca. 1700 14C years difference mainly ascribed to the effect of old, glacially-derived carbon in the upper shallow waters of the Champlain Sea. The pollen-based chronological extrapolation at Lake Hertel indicates that the marine invasion occurred around 11 100 ± 100 14C yr BP. This result supports the chronology based on deep-water invertebrate marine fauna (Rodrigues, 1988). The 14C assessment of the New-England varve chronology (Ridge et al., 1999) is thus confirmed. Deglaciation of the entire Saint-Lawrence River Valley took place within 1000 14C years. The chronology of ice retreat in southern Québec is shortened and made younger. This prompts major revision of all the associated paleohydrological events. Routing of the glacial meltwaters to the North Atlantic was impossible before 11 100 14C yr BP. The abrupt transition from Glacial Lake Candona (ca. 220 m) to the proglacial phase of the Champlain Sea (ca. 190 m) at 11 100 14C yr BP implies an input of glacial meltwater to the ocean estimated at 1500 km3. This may well have affected the thermohaline circulation in the North Atlantic and triggered the Younger Dryas oscillation.

Richard, P.; Occhietti, S.

2004-05-01

363

Legacies of historical land use on regional forest composition and structure in Wisconsin, USA (mid-1800s-1930s-2000s).  

PubMed

Historical land use can influence forest species composition and structure for centuries after direct use has ceased. In Wisconsin, USA, Euro-American settlement in the mid- to late 1800s was accompanied by widespread logging, agricultural conversion, and fire suppression. To determine the maximum magnitude of change in forest ecosystems at the height of the agricultural period and the degree of recovery since that time, we assessed changes in forest species composition and structure among the (1) mid-1800s, at the onset of Euro-American settlement; (2) 1930s, at the height of the agricultural period; and (3) 2000s, following forest regrowth. Data sources included the original U.S. Public Land Survey records (mid-1800s), the Wisconsin Land Economic Inventory (1930s), and U.S. Forest Service Forest Inventory and Analysis data (2000s). We derived maps of relative species dominance and tree diameters for the three dates and assessed change using spatial error models, nonmetric multidimensional scaling ordination, and Sørenson distance measures. Our results suggest that since the mid-1800s, hemlock and white pine have declined in absolute area from 22% to 1%, and the proportion of medium (25-<50 cm) and large-diameter (> or = 50 cm) trees of all species has decreased from 71% to 27% across the entire state. Early-successional aspen-birch is three times more common than in the mid-1800s (9% vs. 3%), and maple and other shade-tolerant species are increasing in southern areas formerly dominated by oak forests and savannas. Since the peak agricultural extent in the 1930s, species composition and tree size in northern forests have shown some recovery, while southern forests appear to be on a novel trajectory of change. There is evidence of regional homogenization, but the broad north-south environmental gradient in Wisconsin constrains overall species composition. Although the nature of the future forests will be determined in part by climate change and other exogenous variables, land use is likely to remain the driving factor. PMID:19544743

Rhemtulla, Jeanine M; Mladenoff, David J; Clayton, Murray K

2009-06-01

364

The Northern Apennines palynological record as a contribute for the reconstruction of the Messinian palaeoenvironments  

NASA Astrophysics Data System (ADS)

The Messinian stage has long been associated with an overall warm and dry climate whereas recent researches indicate either a warm and humid or a cool and dry climate. The integrated stratigraphic record of vegetation and climatic changes from Northern Apennines sites provides the solution to this apparent contradiction. Its integration with the updated geological and sedimentological studies provides additional data for the reconstruction of the depositional palaeoenvironments in both marginal and deeper sub-basins of the Apennines foredeep. The onset of the Mediterranean salinity crisis (MSC) is recorded in the Gessoso Solfifera of the Vena del Gesso (marginal sub-basin). Cyclical humid conditions, corresponding to precession minima, developed during the deposition of the shales interbedded with the gypsum (5.9 to 5.6 Ma); some cooler events took also place under the effects of global (glacial stadials) and regional factors (Apennines uplift). At present no major changes from moist to dry conditions are attested to just before the salinity crisis, as well as in Sicily. So climate did not play a major role in the onset of the MSC despite the favourable context provided by inferred thermo-xeric conditions in southern Italy. A drier episode indicated by the expansion of the open vegetation including the northward migration of Lygeum postdates the onset of the salinity crisis of about 400 kyr, in the lower post-evaporitic deposits of Maccarone (deeper sub-basin). It falls within a period of global warming whereas at a regional scale it could correlate p.p. to the evaporite deposition in deeper basins and to hiatuses in the marginal basins of Sicily and of the western sector of Northern Apennines. Its sudden end, about 100 kyr later, in coincidence with a significant increase of Pinaceae, indicates a turnover in the terrestrial setting not linked to major climate changes but possibly to a complex interaction between other palaeoenvironmental factors (e.g., tectonics and eustatism). In contrast organic-walled dinoflagellate cysts exclude significant modifications in aquatic settings (insaturation of either open marine or brackish conditions). In the latter, a later change is marked by the arrival of Impagidinium (?) sp. 1., a species here referred instead to Caspidinium rugosum, about 7 m below the first colombaccio. This occurrence together with the spread of Pediastrum indicates a freshwater dilution i.e. the “Lago-Mare” event during wetter climatic conditions on the adjacent landmass (increase of Tsuga and Cedrus). The successive arrival and/or dominance of other “Paratethyan” taxa such as I. (?) sp. 2, I. (?) sp. 3 and Galeacysta etrusca indicate highly variable water environments (marine vs. continental water inputs) during the deposition of the uppermost post-evaporitic deposits. The Lago-Mare is stratigraphically sandwiched between an ash layer (130 m below) dated at 5.5 Ma and the beginning of the Pliocene where a peak of Impagidinium patulum marks the onset of open marine conditions. The dominant humid, subtropical to warm temperate climate indicates differences in both temperature and moisture values with respect to the coeval southern sections, revealing climatic gradients within the Mediterranean, at least from the Messinian. No dramatic vegetation and climate changes have been recorded during the MSC; major changes occurred later as indicated by the palynological record from 2.6 Ma. This palynostratigraphic record is a good reference for more recent models of the development of the MSC and for establishing time-relationships between the Apennine and Sicilian successions.

Bertini, Adele

2006-06-01

365

Deglacial-postglacial paleoclimatic reconstruction in NE Japan based on pollen records from Tashiro Marsh  

NASA Astrophysics Data System (ADS)

The Tashiro Marsh is located in the northmost part of Northeast (NE) Japan (40°41' N, 144°55' E) at an altitude of 570 m above sea level. The marsh is covered by heavy snow in winter. After fast completion of the plant growth process during summer, the plants die fast with the arrival of the long cold season. It is probable that the degree of humification of the dead plants is lower and the plant remains preserved in peat deposition are more intact. As the Tashiro Marsh does not receive river input and is not drained by rivers, the swamp water originates from precipitation. Therefore the formed peat layer was not disturbed. We collected an 880-cm-long core from the central part of the marsh. The core sediments are composed mainly of peat sediments, with five tephra layers interbedded in the peat, and many layers consist of undecomposed Sphagnum. The main objective of this study is to evaluate the climate changes, particularly moisture and air temperature fluctuations, in NE Japan through the deglacial and the postglacial stages. We carried out fossil pollen analysis on the sediment core from the Tashiro Marsh covering the last 15 cal ka BP. For pollen extraction, 200 samples (~1 cm3) were taken from the core. A standard pretreatment procedure was used, including KOH-HF treatment, heavy liquid separation by acetolysis. For confirming the precise chronostratigraphy of vegetational changes, we conducted 42 radiocarbon analyses of bulk sediment samples. The measured 14C values were calibrated to calendar ages using the calibration program CALIB-6.0 (http://calib.qub.ac.uk/calib/). And then, we regard carbon content obtained during graphite preparation as total organic carbon (TOC). About 40 pollen spectra were identified, and total pollen concentration in the core started to increase after 11-10 cal ka BP, and the high pollen concentration (up to 9.0 × 105 grains /cm3) was observed during the interval from 10 to 5 cal ka BP. Before 11.3 cal ka BP, sub-boreal coniferous and broad-leaved plants (e.g. Abies, Picea, Tsuga, Pinus and Betula) dominated. After that, sub-boreal coniferous retreated and cool-temperate broad-leaved plants (e.g. Quercus, Carpinus, Juglans and Pterocarya) dominated. At about 8.4 cal ka BP, Quercus had a little decrease and Fagus increased greatly and it keeps high rate still now. We applied the best modern analogue technique for determining climate indices quantitatively from pollen records. From 11.3 cal ka BP, annual temperature started to increase and reached maximum at about 8.8 cal ka BP by 8~9°C. Annual precipitation mainly reflect winter precipitation, which shows a sudden increase at about 8 cal ka BP. This abrupt increase correspond to the beginning of intrusion of the Tsushima Current into the Japan Sea, showing the establishment of modern winter climate in NE Japan at that time.

Hayashibara, K.; Minoura, K.; Yamanoi, T.; Nishi, H.

2011-12-01

366

Vegetation and fire dynamics in different geological settings since the last ice age, Klamath Mountains, northwestern, CA  

NASA Astrophysics Data System (ADS)

The Klamath Mountains of northwestern California are a floristic hotspot and their diversity likely results from a combination of geological, ecological and historical factors (e.g., long-term climate change). To evaluate how climate change has influenced past composition, structure, and disturbance regime of the Klamath forests in different geological settings, vegetation and fire histories from four sites, Bolan (1), Sanger (in prog.), Campbell (in prog.), and Bluff (2) lakes are compared. Bolan and Sanger lakes are underline by nutrient-rich diorite soils, Campbell Lake by nutrient-poor and poorly-drained soils derived from mudstone and shales and Bluff Lake by ultramafics which pose severe nutrient limitations to plants. All sites experience the same modern climate and vegetation. The vegetation and fire records from the four sites suggest that substrates have influenced the sensitivity of plant communities and fire regimes to past variations in climate. Cool, dry late-glacial (>11ka cal yr BP) conditions resulted in a subalpine parkland in the Klamath region. P. jeffreyi and Abies were the main tree species at Bluff Lake and fires occurred frequently. Campbell Lake supported more species than Bluff (excluding P. jeffreyi) such as P. monticola, Picea and T. mertensiana and experienced few fires. Bolan and Sanger Lake harbored similar species as Campbell, as well as a small population of Pseudotsuga and experienced few fires. Warm, dry Early Holocene (7-11ka cal yr BP) conditions led to an increase in C. decurrens and a slight decrease in P. jeffreyi at Bluff Lake than before and fires were very frequent. At Campbell Lake, P. monticola increased, C. decurrens became more abundant than before, and Abies, Picea and T. mertensiana were scarce. Similar vegetation occurred at Bolan and Sanger lakes although the sites continued to harbor Pseudotsuga. Campbell, Bolan and Sanger all experienced frequent fires. Cool, wet conditions in the Middle Holocene (3-7ka cal yr BP) allowed P. jeffreyi to increase at the expense of C. decurrens at Bluff Lake. At Campbell, Sanger and Bolan lakes there was a decrease in P. monticola and a significant increase in Abies than before. Bolan and Sanger lakes still maintained a significant population of Pseudotsuga. Fire frequency at all sites was moderate. Modern (3ka cal yr BP to present) climate conditions in the Late Holocene resulted in increases in P. jeffreyi and Abies than before at Bluff Lake. P. monticola and Abies were abundant at Campbell Lake with minor amounts of Pseudotsuga and T. mertensiana. Most tree species occurred at Bolan and Sanger Lake (with the exception of P. jeffreyi at both sites and T. mertensiana at Sanger Lake). Abies and P.monticola were the primary species in the Bolan, Sanger and Campbell lake forests. Fires were frequent at all sites. In conclusion, Bluff Lake was dominated by ultramafic tolerant taxa such as Pinus jeffreyi, Calocedrus decurrens and Abies, while Bolan and Sanger lakes harbored mostly ultramafic intolerant species such as Pinus monticola, Pseudotsuga, Picea, and Tsuga mertensiana since the last ice age. The forest at Campbell Lake was more open, was dominated by Pinus monticola and had less Picea and T. mertensiana than Bolan and Sanger lakes since the last ice age. REFS. 1 Briles, C. et al 2005. Quaternary Research 64. 2 Mohr, J.A. et al 2000. The Holocene 10.

Briles, C.; Whitlock, C.; Bartlein, P.

2006-12-01

367

Conifer root and butt rot caused by Heterobasidion annosum (Fr.) Bref. s.l.  

PubMed

SUMMARY The root and butt rot caused by Heterobasidon annosum is one of the most destructive diseases of conifers in the northern temperate regions of the world, particularly in Europe. Economic losses attributable to Heterobasidion infection in Europe are estimated at 800 million euros annually. The fungus has been classified into three separate European intersterile species P (H. annosum), S (H. parviporum) and F (H. abietinum) based on their main host preferences: pine, spruce and fir, respectively. In North America, two intersterile groups are present, P and S/F, but these have not been given scientific names. The ecology of the disease spread has been intensively studied but the genetics, biochemistry and molecular aspects of pathogen virulence have been relatively little examined. Recent advances in transcript profiling, molecular characterization of pathogenicity factors and establishment of DNA-transformation systems have paved the way for future advances in our understanding of this pathosystem. Taxonomy: Heterobasidion annosum (Fr.) Bref., H. parviporum Niemelä & Korhonen and H. abietinum Niemelä & Korhonen; kingdom Fungi; class Basidiomycotina; order Aphyllophorales; family Bondarzewiaceae; genus Heterobasidion. Identification: presence of the fungus fruit bodies, basidiocarps whitish in the margins, upper surface is tan to dark brown, usually irregular shaped, 3.5 (-7) cm thick and up to 40 cm in diameter; pores 5-19, 7-22 and 13-26 mm(2) for the P, F and S groups, respectively. Small brownish non-sporulating postules develop on the outside of infected roots. Asexual spores (conidiospores) are 3.8-6.6 x 2.8-5.0 microm in size. Mating tests are necessary for identification of intersterility groups. Host range: The fungus attacks many coniferous tree species. In Europe, particularly trees of the genera Pinus and Juniperus (P), Picea (S), Abies (F) and in North America Pinus (P) and Picea, Tsuga and Abies (S/F). To a lesser extent it causes root rot on some decidous trees (Betula and Quercus). Disease symptoms: symptoms (e.g. exhudation of resin, crown deterioration) due to Heterobasidion root rot in living trees are not particularly characteristic and in most cases cannot be distinguished from those caused by other root pathogens. Heterobasidion annosum s.l. is a white rot fungus. Initial growth in wood causes a stain that varies in colour depending on host tree species. Incipient decay is normally pale yellow and it develops into a light brown decay to become a white pocket rot with black flecks in its advanced stage. Control: silvicultural methods (e.g. stump removal), chemicals (urea, borates) and biological control agent (Phlebiopsis gigantea, marketed as PG Suspension(R) in the UK, PG IBL(R) in Poland and Rotstop(R) in Fennoscandia) are commonly used approaches for minimizing the disease spread. PMID:20565666

Asiegbu, Fred O; Adomas, Aleksandra; Stenlid, Jan

2005-07-01

368

Old and Not-So-Old: Examining Changes in Forest Ecosystem Carbon Exchange With Stand Age in the Upper Midwest U.S.  

NASA Astrophysics Data System (ADS)

Forest stand age is an important determinant of ecosystem carbon uptake. Though there are biometric measurements and ecological models for forests of all ages, there are few stand-scale eddy-flux measurements of net carbon exchange in older forests, though the number is increasing. In order to scale carbon fluxes from sites to regions, where stands of multiple ages may exist, it is necessary to measure to the effect of stand age on carbon exchange. Measuring the effect of stand age on carbon exchange is also necessary when trying to predict future or past carbon exchange (scaling across time). Many researchers have noted that site disturbance history is the fundamental factor in determining carbon uptake by forests over time scales of decades to centuries. The 8,500 ha Sylvania Wilderness in the upper peninsula of Michigan is one of several large tracts of old-growth forest in the Midwest. Trees range from 0-350 years old. Primary species are sugar maple, eastern hemlock and yellow birch. Catastrophic disturbance is rare. A research plot near the wilderness was established in late 2001 to measure the net ecosystem exchange (NEE) of carbon and water using eddy-flux, component flux and biometric methods. This site is part of the Chequamegon Ecosystem Atmosphere Study (ChEAS, http://cheas.psu.edu), a loose affiliation of researchers conducting carbon and water research in northern Wisconsin and upper Michigan. Another similar research plot within ChEAS and not far from Sylvania is the Willow Creek mature uplands site. This forest is about 70 years old and the primary species are sugar maple, basswood and green ash. The site had presettlement old-growth vegetation similar to what is currently seen in the Sylvania Wilderness. Thus, the carbon exchange seen at Sylvania may be representative of carbon uptake at Willow Creek had it not been logged in the early 20th century, and may also represent the future (or past) carbon uptake for similar forests in northern Wisconsin/upper Michigan. Initial results from 2002 show that both Sylvania and Willow Creek were sinks of carbon, though the annual NEE of carbon at Sylvania was only -72 gC/m2/yr, while it was -447 gC/m2/yr at Willow Creek. The lack of carbon balance at the old-growth site may be caused by growth enhancement due to carbon/nutrient fertilization, climate warming, or recent local-scale disturbances. A standard moving-window Arrenhius-style temperature-nighttime NEE relationship was used to separate total ecosystem respiration from gross ecosystem production (GEP). Total annual respiration was much greater at Sylvania (965 gC/m2/yr) than Willow Creek (667 gC/m2/yr), while GEP at Sylvania (1045 gC/m2/yr) was only slightly smaller than Willow Creek (1136 gC/m2/yr). The largest differences in respiration between the two sites occurred in early summer, whereas the largest difference in GEP occurred in late summer. The observed differences between the two sites matches well with theory. Ecosystem respiration is expected to increase steadily with stand age while gross ecosystem production is expected to increase rapidly as new species are established, but eventually level off. Current ongoing component flux measurements will help determine the mechanisms for the observed differences in carbon uptake at the two sites and provide insight on the causes of declining carbon exchange with stand age.

Desai, A. R.; Cook, B.; Davis, K. J.; Bolstad, P.; Carey, E.; Martin, J.; Kreller, L.; Wang, W.

2003-12-01

369

Do Fungi Transport 10Be During Wood Degradation?  

NASA Astrophysics Data System (ADS)

Meteoric cosmogenic 10Be is increasingly used to determine erosion and soil transport rates. To calculate these rates, it is assumed that 10Be is a conservative passive tracer of soil particles. However, there is experimental evidence that beryllium is mobilized in natural soils complexed with organic acids. For example, up to 50% of beryllium can be mobilized by humic acids in soils at pH 7 (Takahashi et al., 1999). Beryllium is also known to be taken up in plants such as tobacco and vegetables (World Health Organization, 1990) at ppm levels, primarily as organic acid chelates. It is not known to what extent biological beryllium transport in the environment affects the cosmogenic 10Be budget, or how it influences beryllium mobility. In this study, we address a problem recognized early in the development of meteoric 10Be methods. It has been observed that decayed organic matter in soils and sediments contains very high concentrations of 10Be of up to 109-1010 atoms/g (Lundberg, et al., 1983). On the other hand, living trees contain much lower concentrations of 106 atoms/g (Klein et al., 1982). The driving question for this study is how 10Be becomes bound to decayed organic matter. Direct fallout seems unlikely as the residence time of organic matter in soil is too short. One possibility is that 10Be is transported by fungi. Wood-degrading fungi are known to transport and bioaccumulate metals from large areas, facilitated by acids such as oxalic acid in the fungal hyphae. To test the hypothesis that fungi transport 10Be, we analyzed both intact and fungally degraded wood of oak, hickory, and hemlock. From these data, we reached two conclusions (observations?): 1) Oak has a 10Be concentration of about 2x106 at/g, similar to that observed by Klein et al. (1982). Hickory has a significantly higher concentration of about 3x107 atoms/g, confirming observations that hickory bioaccumulates beryllium. Using these data, the inventory of 10Be in a temperate forest is expected to be about 6x106 atoms/cm2, equivalent to only a few years of fallout. The flux of beryllium remains unconstrained. 2) We observed two patterns of metal accumulation by wood-degrading fungi. One group of samples showed enrichment in Mn, Fe, and Cr, which are metals that can be used for energy by fungi in a Fenton-like process. This group showed no enrichment in 10Be. Another group of samples showed enrichment primarily in Al and Ti, and also five-fold enrichment in 10Be. Neither group showed fungal enrichment of 10Be sufficient to account for the 1000-fold difference between living trees and soil organic matter. References Klein, J, Middleton, R, & Tang, Hongqing. (1982). Nucl. Instr. Meth., 193:601-616. Lundberg, L., et al. (1983). JGR 88(C7):4498-4504. Takahashi, Y, et al. (1999). Geochim. Cosmochim. Acta, 63: 815-836. World Health Organization, (1990). Beryllium, Environmental Health Criteria 106.

Conyers, G.; Granger, D. E.

2010-12-01