Search for: All records

Freshly senesced leaf litter was collected during autumn in New Hampshire at the Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook as part of the Multiple Elementation Limitation in Northern Hardwood Ecosystems (MELNHE) study. Leaf litter was collected in October 2021 and 2022 at peak litterfall (i.e., mid-October) during a rain-free period. These leaf-litter samples were analyzed for nutrient concentrations for use in resorption analyses. This dataset includes photos of all of the leaf-litter samples used for chemical analysis. For the corresponding chemistry data, please see the following data package: Zukswert, J., K. Gonzales, S. Hong, C. See, B. Quintero, and R.D. Yanai. 2025. Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE): Fresh Litter Chemistry ver 3. Environmental Data Initiative. https://doi.org/10.6073/pasta/f52a613213855e4b4a03fa4a0e2f2922 (Accessed 2025-01-14). These leaf litter samples correspond with green foliage samples collected in late July and early August of the same years: the green foliage data can be found in the following data package: Zukswert, J.M., S.D. Hong, K.E. Gonzales, C.R. See, and R.D. Yanai. 2025. Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE): Foliar Chemistry 2008-2022 in Bartlett, Hubbard Brook, and Jeffers Brook ver 4. Environmental Data Initiative. https://doi.org/10.6073/pasta/ef3696a753150d0a420fd9009f73b1e9 (Accessed 2025-01-14). Photos of the corresponding foliage samples can be found in the following data package: Zukswert, J.M. 2024. Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE): Foliage Scans and Photographs ver 2. Environmental Data Initiative. https://doi.org/10.6073/pasta/7d93f50f9f2e848805b4aac9ed24689c (Accessed 2025-01-14). 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 by the USDA Forest Service, Northern Research Station. 

The functioning of mycorrhizal symbioses is tied to soil nutrient status, suggesting that nutrient availability should influence the reproduction of mycorrhizal fungi. To quantify the effects of nitrogen (N) and phosphorus (P) availability on ectomycorrhizal fungal fruiting, we collected >4000 epigeous sporocarps representing 19 families during the course of a season in a full factorial NxP addition experiment in six replicate forest stands. Nutrient effects on fruiting shifted as the season progressed, with early fruiting species responding more to P and late-fruiting species responding more to N. The composition of species fruiting in young successional forests differed more with nutrient addition than in mature forests. Sporocarp abundance and species richness were suppressed by N addition. This work shows that N and P availability affect ectomycorrhizal fungal fruiting, with these effects taking place within a context defined by stand age and the progression of fruiting across the season. 

Root cores were obtained in 2010 (pre-treatment) from two soil depths, 0-10 cm and 30-50 cm, in two MELNHE stands, C5 and C7, at Bartlett Experimental Forest. Arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) colonization and root length were quantified in each core to determine if AM or EM was more prevalent in shallow or deep soils. Detailed description and analyses of these data can be found in: Nash, J.M., Diggs, F.M. & Yanai, R.D. Length and colonization rates of roots associated with arbuscular or ectomycorrhizal fungi decline differentially with depth in two northern hardwood forests. Mycorrhiza 32, 213–219 (2022). https://doi.org/10.1007/s00572-022-01071-8 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. 

Leaf area index (LAI) is commonly used to assess forest canopies, and is calculated as the area of all leaves per unit area of ground. In September 2004, LAI was measured in all Bartlett Experimental Forest stands (C1-C9) of the MELNHE study in New Hampshire, using an LAI-2000 Plant Canopy Analyzer. Variables reported are leaf area index (LAI), standard error of LAI (SEL), diffuse non-interceptance (DIFN), mean tip angle (MTA), standard error of mean tip angle (SEM), and sample size (SMP). Additional detail on the MELNHE project, including a data table 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 by the USDA Forest Service, Northern Research Station. 

Freshly senesced leaf litter was collected during autumn in New Hampshire at the Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook as part of the Multiple Elementation Limitation in Northern Hardwood Ecosystems (MELNHE) study. Leaf litter was collected in October of 2009, 2010, 2014, 2015, 2016, 2021, and 2022 at peak litterfall (i.e., mid-October) during a rain-free period. These leaf-litter samples were analyzed for nutrient concentrations for use in resorption analyses. Besides adding 2021 and 2022 to the previous version of this data package, this version includes updated values for some samples from 2009 and 2010. Some were re-run to check unusual values, and 8 samples from 2010 for which fresh litter was not collected were estimated by analyzing litter samples collected in litter traps in the same plots in that year. These additions and corrections are indicated in the comments section of the data. These leaf litter samples correspond with green foliage samples collected in late July and early August of the same years: the green foliage EDI package can be found at the following citation: Zukswert, J.M., S.D. Hong, K.E. Gonzales, C.R. See, and R.D. Yanai. 2025. Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE): Foliar Chemistry 2008-2022 in Bartlett, Hubbard Brook, and Jeffers Brook ver 4. Environmental Data Initiative. https://doi.org/10.6073/pasta/ef3696a753150d0a420fd9009f73b1e9 (Accessed 2025-01-13). 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. 

Stomatal density and length were measured on leaves of sugar maple (Acer sacharrum Marsh.) and yellow birch (Betula alleghaniensis Britton.) trees in New Hampshire at the Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook as part of the Multiple Elementation Limitation in Northern Hardwood Ecosystems (MELNHE) study. Leaves were collected in late July and early August in 2021 and 2022 from the tops of dominant and codominant trees using a shotgun. These measurements were made on 3 leaves from each tree. These data correspond with other foliar trait data collected from the same trees in 2021 and 2022. That EDI package is as follows: Hong, S.D., K.E. Gonzales, C.R. See, and R.D. Yanai. 2021. MELNHE: Foliar Chemistry 2008-2016 in Bartlett, Hubbard Brook, and Jeffers Brook (12 stands) ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/b23deb8e1ccf1c1413382bf911c6be19 This data package contains the raw images underlying the data reported in a separate data package on stomatal density and length: https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-hbr&identifier=372 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. 

Stomatal density and length were measured on leaves of sugar maple (Acer sacharrum Marsh.) and yellow birch (Betula alleghaniensis Britton.) trees in New Hampshire at the Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook as part of the Multiple Elementation Limitation in Northern Hardwood Ecosystems (MELNHE) study. Leaves were collected in late July and early August in 2021 and 2022 from the tops of dominant and codominant trees using a shotgun. These measurements were made on 3 leaves from each tree. These data correspond with other foliar trait data collected from the same trees in 2021 and 2022. That EDI package is as follows: Hong, S.D., K.E. Gonzales, C.R. See, and R.D. Yanai. 2021. MELNHE: Foliar Chemistry 2008-2016 in Bartlett, Hubbard Brook, and Jeffers Brook (12 stands) ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/b23deb8e1ccf1c1413382bf911c6be19 This data package contains the stomatal density and length derived from the raw images in a separate EDI data package: https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-hbr&identifier=321 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. 

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 by the USDA Forest Service, Northern Research Station. 

In northern hardwood forests, litter decomposition might be affected by nutrient availability, species composition, stand age, or access by decomposers. We investigated these factors at the Bartlett Experimental Forest in New Hampshire. Leaf litter of early and late successional species was collected from four stands that had full factorial nitrogen and phosphorus additions to the soil and were deployed in bags of two mesh sizes (63 µm and 2 mm) in two young and two mature stands. Litter bags were collected three times over the next 2 years, and mass loss was described as an exponential function of time represented by a thermal sum. Litter from young stands had higher initial N and P concentrations and decomposed more quickly than litter from mature stands (p = 0.005), regardless of where it was deployed. Litter decomposed more quickly in fine mesh bags that excluded mesofauna (p < 0.001), which might be explained by the greater rigidity of the large mesh material making poor contact with the soil. Neither nutrient addition (p = 0.94 for N, p = 0.26 for P) nor the age of the stand in which bags were deployed (p = 0.36) had a detectable effect on rates of litter decomposition. 

Although temperate forests are generally thought of as N-limited, resource optimization theory predicts that ecosystem productivity should be co-limited by multiple nutrients. These ideas are represented in the Multi-Element Limitation (MEL) model (Rastetter et al. 2012). To test the patterns of resource limitation predicted by MEL, we are conducting nutrient manipulations in three study sites in New Hampshire: Bartlett Experimental Forest (BEF), Hubbard Brook Experimental Forest (HBEF), and Jeffers Brook in the White Mountain National Forest. We are monitoring stem diameter, leaf area, sap flow, foliar chemistry, leaf litter production and chemistry, foliar nutrient resorption, root biomass and production, mycorrhizal associations, soil respiration, heterotrophic respiration, N and P availability, N mineralization, soil phosphatase activity, soil carbon and nitrogen, nutrient uptake capacity of roots, and mineral weathering. These data can be found in the EDI repository, using the search term "MELNHE" (http://portal.edirepository.org), and through the data catalog on https://hubbardbrook.org, using the same search term. This data package is referenced by the MELNHE datasets, and includes a datatable of site descriptions and a pdf file with the project description, and diagrams of plot configuration. 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.