A Quantitative Study of Nonstructural Carbodyrates in Eastern Hemlock, Tsuga canadensis, and the effects of hemlock woolly adelgid, adelgis tsugae, and elongate hemlock scale, florinia externa ferris, infestation
Abstract
Nonstructural carbohydrates (NSC), starch and sugars, in eastern hemlock infested and not infested with hemlock woolly adelgid (HWA) and elongate hemlock scale (EHS) were analyzed. The use of microwave dried and Wiley milled tissue samples is a superior method for determining NSC content than processing fresh samples of eastern hemlock (roughly 76% higher results than fresh samples). However, the microwave dried and Wiley milled samples should not be stored at room temperature for later enzymatic processing. Spatial patterns studied showed no statistically significant differences in NSC of twigs based on cardinal direction and location in the tree canopy, but there were statistically significantly differences among individual trees within the sample group. Twigs from Tsuga chinensis, a HWA resistant species, had a different NSC content from T. canadensis, with statistically significantly lower sugar and starch contents, when compared after budbreak. The starch in the needles contributes the highest percentage towards the total NSC, and the starch in the twigs contributes the least. The starch had more variation (year of growth or infestation) than sugar, signifying starch may break down for translocation more frequently than previously thought, serving a multitude of functions besides nutrient storage. Quantitatively, HWA infestation alters the NSC content of eastern hemlock, in certain tissues of particular ages and at specific times in a season. The greatest statistically significant differences (all higher) in sugars and starch content caused by HWA feeding are found in the previous year’s growth, for sugars in both twigs and IV needles, and starch in twigs only. However, NSC was affected more by the time (season) of collection and between the years of growth (new growth versus the previous year’s growth) than by HWA infestation. A preliminary test for detecting the presence of a bacteria or virus was undertaken by inserting ground HWA into insect-free seedlings of T. canadensis. After one year, the sample group of inoculated with ground HWA showed no difference in health than another inoculated with deionized water. The NSC of the previous year’s growth needles from EHS infested branches with new growth are not significantly different than without new growth. On the previous year’s growth, EHS infested needles differ from HWA infested needles, with EHS infested needles having statistically significant higher free sugars and lower starch. The EHS infested needles (presumable fed upon by a sugar feeder) had statistically significantly higher sugars, just as the HWA infested twigs (presumable fed upon by a starch feeder) had statistically significantly higher starch. My data suggests that overall, the changes in NSC content caused by HWA feeding alone does not seem sufficient to be responsible for the decline and mortality of eastern hemlock.Collections
Related items
Showing items related by title, author, creator and subject.
-
Assessment of a Forest Stand for Old-Growth Status at Point au Roche State Park, Clinton County, New YorkPotential old-growth stands continue to be located and quantified. Although there is no generally-accepted definition of oldgrowth, there is a set of attributes that describe old-growth forests. The Hemlock-northern hardwood stand at Point au Roche State Park in Clinton County, New York has been proposed for old-growth classification. The composition and structure of this stand were sampled between September and November, 2008. Attributes of this stand were compared with old-growth conifernorthern hardwoods. The list of attributes included species composition of overstory and understory, maximum tree ages, stand structure, standing dead trees (snags) and fallen trees (logs). The Hemlock-northern hardwood stand in this study compared favorably with old-growth conifer-northern hardwood stands for all measured attributes except the number and size of logs on the forest floor. Although abundance of large logs is an important component of old-growth stands, the Hemlock-northern hardwood stand at Point au Roche State Park could be described as old-growth.
-
Land Use Effects on Benthic Macroinvertebrate Communities in Conesus, Hemlock, Canadice, and Honeoye LakesConesus, Hemlock, Canadice and Honeoye lakes are among the smallest Finger Lakes, but they are important for drinking water, recreation and homes along their shorelines. Farms and forests are the major land uses in their watersheds. Hemlock and Canadice lakes are both within a state forest, which provides a buffer along the shoreline. Conesus and Honeoye lakes are unprotected. While the chemical water quality of these lakes is relatively well understood, the benthic macroinvertebrate communities in these lakes have not been studied. This study established baseline macroinvertebrate community data for all four lakes and determined the presence or absence of eight potential invasive species (Bithynia tentaculata, Cipangopaludina chinensis malleata, Viviparus georgianus, Dreissena polymorpha, Dreissena rostriformis bugensis, Corbicula fluminea, Echinogammarus ischnus, and Hemimysis anomala). Five of the eight species (B. tentaculata, C. c. malleata,V. georgianus, D. polymorpha, and D. r. bugensis) were found in at least one lake. All five of these species were found in Honeoye. All species but B. tentaculata were found in Conesus. Only Dreissenid mussels were found in Hemlock and Canadice. This study also explored whether having a near-shore forest buffer improves water quality in lakes and whether relationships exist between individual sub-watershed land use and biotic indicators of water quality and, as determined by biotic indices using benthic macroinvertebrates. While significant differences were found in the overall benthic community compositions between the lakes, biotic indices were similar between lakes and did not follow the expected water quality patterns. In addition, no correlations were found between sub-watershed land use and biotic indices of water quality. This suggests that near-shore buffers in Hemlock and Canadice Lakes have no effect on biotic indicators of water quality and only whole-watershed management might positively influence water quality.
-
Pesticide Residues in Hemlock and Canadice Lakes and their Tributaries in Western New York, 1997-98In 1997, the U.S.Geological Survey (USGS) and the City of Rochester began a cooperative program to study the presence of pesticides (herbicides and insecticides) that occur at trace levels in Hemlock and Canadice Lakes and their tributaries. The most frequently detected pesticides in streamflow and lake-water samples were herbicides commonly used in agriculture — atrazine, metolachlor, and simazine. None of the concentrations of these compounds in the samples exceeded Federal or State water-quality standards. Differences in the concentrations among stream samples can be attributed to land use and streamflow, and the timing of rainfall in relation to herbicide application. The north (lower) end of Hemlock Lake can receive pesticides in agricultural runoff from northern parts of its watershed and Canadice Creek. These pesticide inputs bypass most of the lake and could periodically affect the water quality periodically affect the water quality at the City of Rochester intake. Pesticide concentrations in samples from the intake during this study, however, were about 100 times less than current Federal and State standards for drinking water. Residues of DDT, dieldrin, and mirex are present in low concentrations in the bottom sediments of both lakes, but none were detected in water samples. The use of these insecticides was banned in 1972,and their persistence in the lakebed sediments is probably due to erosion of contaminated soils from agricultural lands.
