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9 results for “foliar chemistry”
Foliar and Soil Chemistry at Harvard Forest Chronic Nitrogen Amendment Experiment 1995-2009
The aim of the chronic N study at Harvard Forest is to increase our understanding of ecosystem nitrogen dynamics in response to elevated nitrogen inputs. In recent, nitrogen deposition in the Northeastern United States has been 10 to 20 times above historic background levels which could possibly saturate the retention capacity of a forest ecosystem. Long-term elevated N deposition typically leads to an increase in the concentration of total foliar N, with or without similar changes in the important base elements such as Ca, Mg and K. This increase in leaf N content also leads to significant shifts in the internal partitioning of N within the leaf. For example, in conifers, N deposition has been shown to significantly increase leaf N present in the form of free amino acids such as arginine. Little is known about N partitioning for hardwoods under these conditions. These changes in N partitioning are possibly connected to leaf function. The present study was conducted to experimentally test whether the alterations in N partitioning do occur due to long-term N deposition and if so do they have a positive or a negative effect on photosynthetic capacity and biomass production. A possible decoupling of the relationship between foliar N and photosynthetic rate may occurs under these conditions. The treatment plots used in this study are part of the Chronic Nitrogen Amendment Study at the Harvard Forest LTER site (42.5°N, 72°W). The site has a temperate climate with monthly temperatures ranging from -7°C in January to 20°C in July. Average annual precipitation is 110 cm (http://harvardforest.fas.harvard.edu). The site averages approximately 8 kg ha-1 year-1 of total N deposition. As reported earlier, the land-use history of the pine and hardwood stands used in this study is very different. Two adjacent stands were chosen for the study: an even-aged red pine (Pinus resinosa Ait.) stand and a 50-year-old mixed hardwood stand that had regenerated naturally after clearcutting i
Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE): Foliar Chemistry 2008-2022 in Bartlett, Hubbard Brook, and Jeffers Brook
We are conducting nutrient manipulations in three study sites in the White Mountain National Forest in New Hampshire: Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook. We monitored foliar chemistry in 13 of our stands (including HBCa and excluding C3) pre-treatment (2008-2010) and post-treatment (2014-2016 and 2021-22). In 2021-22, we also measured specific leaf area, leaf dry matter content, carbon isotope composition, and stomatal density. We found that foliar N concentrations were higher with N addition and foliar P concentrations were higher with P addition. More interestingly, P addition reduced foliar N concentrations and N addition reduced foliar P concentrations. Some interactive effects were observed (i.e. NxP, Species x N, Species x P, Species x N x P). This dataset contains pre- and post- treatment foliar chemistry and trait data, and data from the analysis of quality control standard samples. Changes to pre-treatment data from version 1 include switching white birch trees #8272 and #8252 in stand JBM plots 2 and 3 (8272 is now in the nitrogen plot and 8252 is now in the control plot), correcting the species of tree #1628 in stand HBCa plot 1 (changed from red maple to sugar maple) and tree #8457 in stand HBO plot 3 (changed from sugar maple to red maple), and updating nutrient concentrations for C8 plot 3 sugar maple trees #28 and #30 to include averages of subsamples re-run in 2022. Tree tags were also updated to the tag ID present during the 2023 tree inventory. Additional detail on the MELNHE project, including a datatable of site descriptions and a pdf file with the project description and diagram of plot configuration can be found in this data package: https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-hbr&identifier=344 These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained
Hubbard Brook Nitrogen Oligotrophication (HBNO): Foliar resorption, leaf mass per area, and leaf chemistry of sugar maple and American beech, 2020-2022
We quantified nitrogen (N) resorption of the two dominant tree species of northern hardwood forests along an elevation gradient using 14 sites at Hubbard Brook Experimental Forest, NH. For these calculations, we also quantified the leaf mass per area for both species, sugar maple and American beech. The original data before averaging for combining with chemistry data is available in an earlier revision of this dataset. Foliar N of sugar maple increased, and N resorption proficiency (NRP) decreased with increasing elevation. In contrast, foliar N and NRP of American beech did not vary significantly with elevation, suggesting that the mechanisms driving patterns of N resorption were distinct between these co-occurring species. While both species exhibited strong correlations between resorption efficiency of C and N, resorption of both elements was much greater for beech than maple. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
Effects of Hurricane Opal on foliar chemistry and insect herbivores at the Coweeta Hydrologic Laboratory in 1997: foliar chemistry data
Hurricane damage results in tree mortality and variation in both light and nutrient availability for the individuals that remain. In turn, resource availability influences the interactions between plants and insect herbivores. We report effects of Hurricane Opal on the phenolic chemistry and levels of defoliation on surviving trees at the Coweeta Hydrologic Laboratory in North Carolina. We measured foliar astringency, hydrolysable tannins, and condensed tannins in the foliage of red maple and red oak saplings in hurricane damaged and undamaged sites. We estimated inorganic nitrogen and phosphorus availability in the soil, and the accumulated leaf area removed by insect herbivores. The foliar astringency of both red maple and red oak was higher in sites damaged by the hurricane. Later in the growing season, condensed tannin levels were significantly higher in the foliage of red oak in damaged sites. There were no consistent differences in ammonium, nitrate, or phosphate availability between damaged and undamaged sites. Despite higher foliar astringency of trees in sites damaged by Hurricane Opal, levels of defoliation by insect herbivores were higher in damaged than in control sites on both tree species. Apparent increases in putative defensive compounds following hurricane damage did not protect trees from herbivory.
White oak and red maple foliar chemistry of urban and reference forests of the eastern US
Foliar chemistry values were obtained from two important native tree species (white oak (Quercus alba L.) and red maple (Acer rubrum L.)) across urban and reference forest sites of three major cities in the eastern United States during summer 2015 (New York, NY (NYC); Philadelphia, PA; and Baltimore, MD). Trees were selected from secondary growth oak-hickory forests found in New York, NY; Philadelphia, PA; and Baltimore, MD, as well as at reference forest sites outside each metropolitan area. In all three metropolitan areas, urban forest patches and references forest sites were selected based on the presence of red maple and white oak canopy dominant trees in patches of at least 1.5 hectares with slopes less than 25%, and well-drained soils of similar soil series within each metropolitan area. Within each city, several forest patches were selected to capture the variation in forest patch site conditions across an individual city. All reference sites were located in protected areas outside of the city and within intermix wildland-urban interface landscapes, in order to target similar contexts of surrounding land use and population density (Martinuzzi et al. 2015). Several reference sites were selected for each city, located within the same protected area considered representative of rural forests of the region. White oaks were at least 38.1 cm diameter at breast height (DBH), red maples were at least 25.4 cm DBH, and all trees were dominant or co-dominant canopy trees. The trees had no major trunk cavities and had crown vigor scores of 1 or 2 (less than 25% overall canopy damage; Pontius & Hallett 2014). From early July to early August 2015, sun leaves were collected from the periphery of the crown of each tree with either a shotgun or slingshot for subsequent analysis to determine differences in foliar chemistry across cities and urban vs. reference forest site types. The data were used to invstigate whether differences in native tree physiology occur between urban
Data from: Varyingly hungry caterpillars: predictive models and foliar chemistry suggest how to eat a rainforest
A long-term goal in evolutionary ecology is to explain the incredible diversity of insect herbivores and patterns of plant host use in speciose groups like tropical Lepidoptera. Here we used standardised food-web data, multigene phylogenies of both trophic levels and plant chemistry data to model interactions between Lepidoptera larvae (caterpillars) from two lineages (Geometridae and Pyraloidea) and plants in species-rich lowland rainforest in New Guinea. Model parameters were used to make and test blind predictions for two hectares of exhaustively sampled forest. For pyraloids we relied on phylogeny alone and predicted 54% of species level interactions, translating to 79% of all trophic links for individual insects, by sampling insects from only 15% of local woody plant diversity. The phylogenetic distribution of host plant associations in polyphagous geometrids was less conserved, reducing accuracy. In a truly quantitative food-web only 40% of pair-wise interactions were described correctly in geometrids. Polyphenol oxidative activity (but not protein precipitation capacity), was important for understanding the occurrence of geometrids (but not pyraloids) across their hosts. When both foliar chemistry and plant phylogeny were included, we predicted geometrid-plant occurrence with 89% concordance. Such models help to test macroevolutionary hypotheses at the community level.
Data from: Varyingly hungry caterpillars: predictive models and foliar chemistry suggest how to eat a rainforest
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Data from: Differential effects of soil chemistry on the foliar resorption of nitrogen and phosphorus across altitudinal gradients
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Data from: Plant nutrient supply alters the magnitude of indirect interactions between insect herbivores: from foliar chemistry to community dynamics
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