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Showing 1 to 11 of 11 for “"Hemlocks"”.
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A Phylogenetic Analysis of Species Relationships in Hemlocks, the Genus <em>Tsuga</em> (Pinaceae).
<p>The genus <em>Tsuga</em> is comprised of eight extant species found in North America and East Asia and four species represented by fossils from Europe and Japan. This study presents the first phylogenetic analysis based on structural, biochemical, and molecular sequence data. Characters obtained …
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Fitness and Physiology of the Hemlock Woolly Adelgid, Adelges tsugae, in Relation to the Health of the Eastern Hemlock, Tsuga canadensis
… States. Studies have shown that once healthy hemlocks become infested by the adelgid, nutrients are depleted from the tree, leading to both tree decline and a reduction of the adelgid population. Since A. tsugae is dependent on hemlock for nutrients, feeding on trees in poor health may affect …
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Studies on the Subterranean Activity of Laricobius spp. (Coleoptera: Derodontidae) using 3D X-ray Analysis and Three Imidacloprid Soil Application Techniques
… spread throughout most of the range of eastern hemlocks, Tsuga canadensis (L.) and the entire range of Carolina hemlocks, Tsuga caroliniana (Engelman) in eastern North America. Forest managers often implement an integrated pest management (IPM) strategy that combines chemical, silvicultural, and …
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Abundance Of Songbirds In Eastern Hemlock Stands Following Chemical Treatment For Hemlock Woolly Adelgid
… on canopy vigor, and (3) the importance value of hemlocks between years in treated vs. control sites. Generalized linear mixed models were used to ask if indicator bird species, abundances were related to percent dead hemlock, hemlock importance value, the hemlock decline index, chemical …
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Radial growth response of eastern hemlock to infestation of hemlock woolly adelgid
… were selected. At each site, 23 infested eastern hemlocks were cored and two trees were felled at the Virginia site and thin-sectioned using a sliding microtome for analysis of wood anatomy. Tree cores were cross-dated and ring widths were measured. For each site, t-tests were used to determine if …
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Assessing hemlock woolly adelgid induced decline and susceptibility using hyperspectral technologies
… species, successful colonization of uninfested hemlocks was associated with higher N, and lower Ca and P concentrations. Regionally, higher concentrations of Ca, Mn, N and P were correlated with higher HWA densities. We hypothesize that higher N and K concentrations may have a palatability …
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Interactive effects of hemlock mortality and nitrogen availability on nutrient pools and fluxes in the southern Appalachian Mountains
… N:P ratios were lower in stands with declining hemlocks, suggesting trees are incorporating available P into biomass. Higher foliar N and P concentrations as well as observed increases in the growth of hardwood species in high elevation stands post-HWA infestation suggest that hemlock decline …
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Laboratory rearing, establishment, subterranean survivorship, and thermal requirements of Laricobius spp. (Coleoptera: Derodontidae), biological control agents released for Adelges tsugae (Hemiptera: Adelgidae)
… of the surveyed grids containing HWA infested hemlocks. The establishments of these species in easily accessible locations allowed for the use of field-caught larvae, in addition to laboratory-produced larvae, for experiments. Experiments were conducted in 2019-2020 to determine the overall …
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Prey-mediated effects of imidacloprid on Laricobius nigrinus (Coleoptera: Derodontidae) and Sasajiscymnus tsugae (Coleoptera: Coccinellidae), two predators of hemlock woolly adelgid
… ppm range and tissue samples from field-treated hemlocks are often in the ppb range, making this technique less desirable than more sensitive analytical methods. Lethal and sublethal effects on both predators were evident after eastern hemlock branches infested with HWA were spiked with …
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Impact of predation by Laricobius nigrinus (Coleoptera: Derodontidae) and Leucotaraxis spp. (Diptera: Chamaemyiidae) on Adelges tsugae (Hemiptera: Adelgidae) and Tsuga canadensis (Pinales: Pinaceae) tree health
… have been used to temporarily protect hemlocks, however; this does not provide a permanent solution. In the 1990's a classical biological control program for HWA was created with the goal to suppress HWA populations below damaging levels to reduce tree mortality, and to reduce the …