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Ecosystem Function in Appalachian Headwater Streams during an Active Invasion by the Hemlock Woolly Adelgid  [PDF]
Robert M. Northington, Jackson R. Webster, Ernest F. Benfield, Beth M. Cheever, Barbara R. Niederlehner
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061171
Abstract: 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.
Spatial Distribution of Hemlock Woolly Adelgid Induced Hemlock Mortality in the Southern Appalachians  [PDF]
Tuula Kantola, P?ivi Lyytik?inen-Saarenmaa, Robert N. Coulson, Sheryl Strauch, Maria D. Tchakerian, Markus Holopainen, Hannu Saarenmaa, Douglas A. Streett
Open Journal of Forestry (OJF) , 2014, DOI: 10.4236/ojf.2014.45053
Abstract: Hemlock woolly adelgid (Adelges Tsugae Annand, HWA) outbreaks are posing a major threat to eastern hemlock (Tsuga canadensis L. Carr.) and Carolina hemlock (Tsuga caroliniana Engelm.) forest landscapes in the eastern USA. As foundation species, hemlocks play a variety of functional roles in forest landscapes. These species usually occur as isolated canopies and mixed species in landscapes where variation in topography is extreme. Spatially explicit inventory information on HWA induced hemlock mortality at landscape scale does not exist. High resolution aerial imageries enable landscape scale assessment even at the individual tree level. Accordingly, our goal was to investigate spatial pattern and distribution of HWA induced hemlock mortality using a high resolution aerial image mosaic in the Linville River Gorge, Southern Appalachians, western North Carolina. Our study objectives were: 1) to detect dead trees within the Lower Linville River watershed; 2) to estimate the area occupied by dead trees in the forest canopy surface; 3) to investigate the relationship of dead hemlocks and topography; and 4) to define the spatial pattern of the dead trees. We found ca. 10,000 dead trees within the study area, occupying over 7 ha of the canopy surface with an average area of 36 m2 per dead tree. The density of the dead trees was higher in proximity to the Linville River, at higher elevations, and on northern and northwestern aspects. Spatial pattern of the dead trees was generally clustered at all spatial scales. We suggest that although the reduction in plant biomass resulting from herbivory within the landscapes is modest, impact of the clustered distribution of hemlock mortality, especially in the riparian zones, is noteworthy. Our analysis of the pattern of hemlock decline provides new means for projecting future impacts of HWA on the range of hemlock distribution in eastern North America.
Laboratory Rearing of Laricobius nigrinus (Coleoptera: Derodontidae): A Predator of the Hemlock Woolly Adelgid (Hemiptera: Adelgidae)
S. M. Salom,L. T. Kok,A. B. Lamb,C. Jubb
Psyche , 2012, DOI: 10.1155/2012/936519
Abstract: Coleopteran species are biological control agents of numerous invasive pests. Laricobius nigrinus (Coleoptera: Derodontidae), a predaceous, univoltine species, spends the summer aestivating but is active for the rest of the year. Laricobius nigrinus possesses many essential attributes for effective biological control of the hemlock woolly adelgid (Hemiptera: Adelgidae). The predator must be reared in large numbers for field releases. We describe some of the studies that led to the successful procedures currently used for mass rearing L. nigrinus.
Identifying Subalpine Fir (Abies lasiocarpa) Attacked by the Balsam Woolly Adelgid (Adelges piceae) Using Spectral Measurements of the Foliage  [PDF]
Stephen P. Cook,Karen S. Humes,Ryan Hruska,Grant Fraley,Christopher J. Williams
International Journal of Forestry Research , 2010, DOI: 10.1155/2010/498189
Abstract: Balsam woolly adelgid is an invasive pest of firs in the United States. Aerial surveys are conducted for detection of adelgid infestations but other remotely sensed data may also be useful. Our objective was to determine if high spectral resolution, branch-level data can be used to distinguish infested from noninfested trees. Stepwise discriminant analysis yielded a three-variable model (the red-green index and two narrow-bands (one at 670?nm and the other at 1912?nm)) that classified infested versus non-infested trees with 94% accuracy compared with the 83% accuracy obtained with a single-variable model. The response of trees in narrow spectral bands was integrated across wavebands to simulate measurements from the multispectral SPOT5-HRVIR sensor. Stepwise discriminant analysis again yielded a three-variable model (simple ratio, the SPOT5-HRVIR band in the SWIR region and NDVI) with similar accuracy (93%) at discriminating infested from non-infested trees compared with the 83% accuracy obtained with a single-variable model. 1. Introduction Balsam woolly adelgid, Adelges piceae (Ratzeburg) (Hemiptera: Adelgidae), is an invasive pest of true firs in the United States. The adelgid is native to the fir forests of central Europe and was introduced into North America around 1900 [1]. The life cycle of balsam woolly adelgid consists of the egg, three larval instars, and the adult female (see [2] for a more thorough description). The only life stage capable of movement is the first instar larva (termed the crawler) that, upon locating a suitable feeding site, inserts her stylet into the bark and transforms (without molting) into a neosistens, after which the insect is permanently attached to the host tree. As she feeds, the female secretes a dense waxy covering that ultimately covers the entire insect. The crawler stage does not have wings, and between-tree dispersal is a passive process in which individuals are carried primarily by wind. The adult female produces as many as 248 eggs that are oviposited within the woolly mass which acts to protect all of the life stages except the crawler [2]. All native, North American true firs (Abies) show some degree of susceptibility to the balsam woolly adelgid and four species (subalpine fir, A. lasiocarpa, Fraser fir, A. fraseri, balsam fir, A. balsamea, and Pacific silver fir, A. amabilis) are highly susceptible to infestation [3]. The insect is currently established on susceptible hosts in both the eastern and western United States where it is responsible for significant levels of mortality within some stands. In
Woolly Hair
Thappa Devinder M,Thadeus J,Garg B R
Indian Journal of Dermatology , 1995,
Abstract: A 6 year old boy with woolly hair is reported for an unusual curling of eyelashes and associated keratosis pillaris.
Woolly hair nevus - Case report
Usha V,Nair T
Indian Journal of Dermatology, Venereology and Leprology , 1997,
Abstract: A case of woolly hair nevus with associated Mongolian spot is reported
The Appalachian Rural Systemic Initiative  [cached]
Stephen A. Henderson,Wimberly C. Royster
Education Policy Analysis Archives , 2000,
Abstract: This article was written in response to "Top-Down, Routinized Reform in Low-income, Rural Schools: NSF's Appalachian Rural Systemic Initiative, by Robert Bickel, Terry Tomaskek, and Teresa Hardman Eagle which was published in the Education Policy Analysis Archives as Number 12 of Volume 8 on February 21, 2000.
Familial woolly hair  [cached]
Prasad G
Indian Journal of Dermatology, Venereology and Leprology , 2002,
Abstract: Woolly hair is tightly coiled hair occurring over the entire scalp or part of it, in an individual of non- Negroid origin. Two such cases occurring in a family is reported due to its rarity.
Circumferential ′ Woolly Hair Naevus  [cached]
Thadeus J,Thappa D M,Souza M D,Jaisankar T J
Indian Journal of Dermatology , 1998,
Abstract: Woolly hair naevus presents as a circumscribed area of tightly coiled hair since birth, in an individual of non-negroid origin. We report a 10 year old boy of Indian origin who presented with woolly hair in the periphery of the scalp and normal straight hair in the center-mimicking a straight hair naevus.
SOME ASPECTS OF WESTERN HEMLOCK AIR PERMEABILITY
Rayirath,Prasad; Avramidis,Stavros;
Maderas. Ciencia y tecnología , 2008, DOI: 10.4067/S0718-221X2008000300002
Abstract: knowledge of the variability of fluid permeability of wood in general and of western hemlock in particular is of significant importance to the primary and secondary wood products processing industry of coastal british columbia. for the purpose of this study, ten hemlock trees were randomly selected and specimens were prepared from three tree heights from each tree, namely, 1, 4 and 7 m. the air permeability of sapwood and heartwood in the longitudinal direction was measured using a dynamic method. tracheid lengths were also obtained with a fiber quality analyzer and densities were measured by water displacement. the effect of tree height, tracheid length and density on the specific permeability of gross wood was then evaluated. the data revealed that height within the range measured has no effect on longitudinal permeability on heartwood whereas in sapwood the longitudinal permeability increases above 4 m of tree height. it was also found that longitudinal permeability was not significantly influenced by the tracheid length and wood density.
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