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Carbon Isotope and Ring Width Measurements from Tree Rings of Selected Canopy Species at Six Sites in the Eastern United States
Forest Water Use Efficiency (WUE) is defined as the ratio of carbon uptake per unit water vapor loss via transpiration. Micrometeorological measurements suggest that forest WUE has dramatically increased over the last two decades, in excess of what would be expected from increases in atmospheric carbon dioxide concentrations. Coinciding with observed trends in forest WUE have been marked decreases in acid deposition throughout much of North America and Europe. There is evidence that acid deposition may impact forest WUE, either by altering the availability of nutrients in forest soils or by directly affecting foliar physiology. Changes in WUE could also lead to changes in stream discharge from forested catchments. The hypothesized response of forests to changing levels of acid deposition is not currently considered in the land surface components of global climate models (GCMs). Since carbon dioxide and water vapor are the two most important greenhouse gases, it is vital to accurately model their land-atmosphere exchange. This research uses a catchment-based approach to investigate the effects of changing acid deposition on forest WUE. Tree ring carbon isotopes reconstruct historical WUE time series within six catchments that have been differentially impacted by acid deposition due to distinctions between their underlying bedrock mineralogy and geological histories. The research also capitalizes on experimental treatments that have altered soil biogeochemistry in paired catchment designs (Bear Brook, ME; Hubbard Brook, NH; and Fernow Experimental Forest, WV). Additional watersheds that vary in underlying bedrock chemistry are also used in this research to examine tree-ring WUE time series as natural experiments along a base-cation gradient. These watersheds include Sleepers River, VT; Hubbard Brook, NH; Cone Pond Watershed, NH; and Shenandoah National Park, VA.
Tree Seed Dispersal in Hemlock Removal Experiment at Harvard Forest 2005
Throughout the northeast, the hemlock woolly adelgid (Adelges tsugae) threatens eastern hemlock (Tsuga canadensis) through direct mortality resulting from infestation followed by defoliation and indirect mortality in the form of pre-emptive logging. The efficacy of regeneration of vegetation following hemlock decline depends upon advance regeneration of seedlings and saplings, seed dispersal, and recruitment. In this study, we investigated (1) whether the basic parameters of height of release and wind velocity affected seed dispersal distance and (2) tested the fit of a basic ballistic model of seed dispersal to empirical data in areas both with and without canopies. We collected empirical data from seed dropping and seed rain experiments at Harvard Forest. Height and wind velocity only affected seed dispersal distance in open areas. Predicted values of dispersal distance generated by the basic ballistic model did not provide a good fit to observed dispersal data. Poor fits of the ballistic model to the data were due to the model’s inability to account for rare, long distance dispersal events. More complex models with additional parameters are necessary to model non-localized seed dispersal.
Sapwood Temperatures in Hemlock Trees at Harvard Forest HEM Tower 1997-1998
Sapwood temperatures in four large hemlocks, 130-200 years old and about 40 to 90 cm basal diameter and 25 to 29 m tall, were measured in order to estimate sapwood respiration in these trees as part of a physiological model for hemlock forest carbon exchange. As expected, sapwood temperature varied most in small branches and least in the main bole of the tree near the ground. An additional finding from these measurements is that sapwood begins to freeze at -1 to -2 degrees C, as shown by a stabilization and in some cases an increase of about 1 degree C in sapwood temperature when air temperature cooled continuously to below this temperature range.
Tree Growth and Coarse Woody Debris in Regenerating Forests at Harvard Forest since 2008
This project is a field-based study to measure sequestration of atmospheric carbon dioxide in a regenerating New England forest. This study established long-term biometric plots suitable for measuring changes in carbon storage through time in three forest stands: an early-20th-century conifer plantation, a naturally regenerating former conifer plantation harvested in the 1990s, and a conifer plantation scheduled for harvest next winter. The first three years of this project determined the initial carbon budget of these forest stands, measured carbon fluxes into and out of these stands, and laid the groundwork for future investigations. Subsequent years will investigate larger-scale questions, such as how successional patterns affect carbon sequestration, and how these patterns change with stand age. The work also addresses how forestry practices influence carbon sequestration, and provide guidance for how forest management could enhance terrestrial carbon uptake in the future.
Nonstructural Carbohydrates in Forest Trees at Harvard Forest 2007-2010
Forest trees accumulate and store surplus nonstructural carbohydrates (NSC) as resources to be used to support future growth. This can be viewed as a conservative investment strategy, providing reserves that the tree can utilize in times of stress. NSC reserves are thus important in the context of forest responses to climate change, and forest ecosystem carbon cycling. At quarterly intervals over a three year period, we have monitored stemwood nonstructural carbohydrate (NSC) reserves of the dominant tree species of New England at three sites along a forest composition gradient: an oak-dominated transition hardwood forest (Harvard Forest), a maple-beech-birch northern hardwood forest (Bartlett Experimental Forest), and a spruce-fir boreal transition forest (Howland Forest). Adding to recent evidence indicating that in mature forest trees the nonstructural carbohydrate pool is surprisingly large, our results suggest that this pool is also highly dynamic, and unexpectedly old. In most species, seasonal dynamics in starch (2-4x higher in the growing season, lower in the dormant season) mirrored those of sugars. This data set contains 3 y of quarterly NSC concentration measurements (stemwood starch and sugars - sucrose, glucose, fructose, raffinose, stachyose - in mg per g OD wood tissue) for red maple, eastern hemlock, and red oak at the Harvard Forest.
Inorganic Nitrogen Pools and Tree Composition in Hemlock Removal Experiment at Harvard Forest 2007-2009
This study assessed how the change in leaf litter input and environmental conditions, from that of hemlock stands to earlier successional deciduous stands, will affect inorganic nitrogen availability at the interface of the mineral soil and LFH horizons. In early October 2007 we exchanged 0.5 x 0.5 m "loaves" of LFH horizons from hemlock and deciduous stands between forest types, while keeping control plots in the original forest stands. Inorganic nitrogen outputs from the litter loaves were monitored for 20 months using ion-exchange resins, removing and replacing the resins three times at 5 - 8 month intervals. Results indicated that there were differences between the control hemlock and deciduous loaves - NO3 and NH4 availability were higher in deciduous stands. However, the transfer of litter loaves from one stand type to another did not reveal changes in nutrient availability due to a shift in habitat. Rather, the methodology of moving litter loaves to a new site caused greater changes in nutrient availability, particularly over the summer months.
Pre-Colonial and Modern Tree Data from Nine Northeastern States 1620-2008
The northeastern United States is a predominately-forested region that, like most of the eastern U.S., has undergone a 400-year history of intense logging, land clearance for agriculture, and natural reforestation. This setting affords the opportunity to address a major ecological question: How similar are today’s forests to those existing prior to European colonization? Working throughout a nine-state region spanning Maine to Pennsylvania, we assembled a comprehensive database of archival land-survey records describing the forests at the time of European colonization. We compared these records to modern forest inventory data and described: (1) the magnitude and attributes of forest compositional change, (2) the geography of change and (3) the relationships between change and environmental factors and historical land use. We found that with few exceptions, notably the American chestnut, the same taxa that made up the pre-colonial forest still comprise the forest today, despite ample opportunities for species invasion and loss. Nonetheless, there have been dramatic shifts in the relative abundance of forest taxa. The magnitude of change is spatially clustered at local scales (less than 125-km) but exhibits little evidence of regional-scale gradients. Compositional change is most strongly associated with the historical extent of agricultural clearing. Throughout the region, there has been a broad ecological shift away from late successional taxa, such as beech and hemlock, in favor of early- and mid-successional taxa, such as red maple and poplar. Additionally, the modern forest composition is more homogeneous and less coupled to local climatic controls.
Forest Inventory for Tree Demography and Carbohydrate Reserves at Harvard Forest 2009-2011
The objective of this study is to establish a network of forest plots spanning the eastern U.S. focused on understanding how regional scale climate patterns affect patterns of tree demography (e.g. growth, mortality, dieback). Within each research site we also aim to understand the landscape-scale variability in demographic rates and how these rates are affected by edaphic variables by aligning plots along primary environmental gradients (elevation, soils, hydrology, fire return interval). The demographic data obtained will also be compared to regional and landscape-scale patterns in carbon reserves in adults and sapling by sampling root and stem concentrations of nonstructural carbohydrates (TNC) and relate these to demographic patterns, life-history traits, and plant C:N ratios. Besides addressing important ecological questions directly, this study is designed to improve the representations of vegetation dynamics and carbohydrate reserves in regional and landscape-scale forest ecosystem models--two of the least data-constrained processes in such models--by parameterizing and validating the modules for these processes in the Ecosystem Demography model (ED v2.1). This data set contains two years of census data for eight mapped plots distributed across Harvard Forest along the aforementioned primary environmental gradients.
Concentration and Age of Nonstructural Carbon Reserves in Two Trees at Harvard Forest 2012
We know surprisingly little about whole-tree nonstructural carbon (NSC; primarily sugars and starch) budgets. Even less well understood is the mixing between recent photosynthetic assimilates (new NSC) and previously stored reserves. And, NSC turnover times are poorly constrained. We characterized the distribution of NSC in the stemwood, branches, and roots of two temperate trees, and we used the continuous label offered by the radiocarbon (14C) bomb spike to estimate the mean age of NSC in different tissues. NSC in branches and outermost stemwood growth rings had the 14C signature of the current growing season. However, NSC in older above- and below-ground tissues was enriched in 14C, indicating that it was produced from older assimilates. Radial patterns of 14C in stemwood NSC showed strong mixing of NSC across the youngest growth rings, with limited.
INTERPNT Software for Mapping Trees Using Distance Measurements
The INTERPNT method can be used to produce accurate maps of trees based solely on tree diameter and tree-to-tree distance measurements. For additional details on the technique please see the published paper (Boose, E. R., E. F. Boose and A. L. Lezberg. 1998. A practical method for mapping trees using distance measurements. Ecology 79: 819-827). Additional information is contained in the documentation that accompanies the program. The Abstract from the paper is reproduced below. "Accurate maps of the locations of trees are useful for many ecological studies but are often difficult to obtain with traditional surveying methods because the trees hinder line of sight measurements. An alternative method, inspired by earlier work of F. Rohlf and J. Archie, is presented. This "Interpoint method" is based solely on tree diameter and tree-to-tree distance measurements. A computer performs the necessary triangulation and detects gross errors. The Interpoint method was used to map trees in seven long-term study plots at the Harvard Forest, ranging from 0.25 ha (200 trees) to 0.80 ha (889 trees). The question of accumulation of error was addressed though a computer simulation designed to model field conditions as closely as possible. The simulation showed that the technique is highly accurate and that errors accumulate quite slowly if measurements are made with reasonable care (e.g., average predicted location errors after 1,000 trees and after 10,000 trees were 9 cm and 15 cm, respectively, for measurement errors comparable to field conditions; similar values were obtained in an independent survey of one of the field plots). The technique requires only measuring tapes, a computer, and two or three field personnel. Previous field experience is not required. The Interpoint method is a good choice for mapping trees where a high level of accuracy is desired, especially where expensive surveying equipment and trained personnel are not available."
Estimating Forest Productivity Using Carbon Isotopes in Tree Rings at Harvard Forest 1992-2010
We investigated relationships between tree-ring δ13C and growth, and flux tower estimates of gross primary productivity (GPP) at Harvard Forest from 1992 to 2010. Seasonal variations of derived photosynthetic isotope discrimination (Δ13C) and leaf intercellular CO2 concentration (ci) showed significant increasing trends for the dominant deciduous and coniferous species. Δ13C was positively correlated to growing-season GPP and is primarily controlled by precipitation and soil moisture indicating that site conditions maintained high stomatal conductance under increasing atmospheric CO2 levels. Increasing Δ13C over the 1992-2010 period is attributed to increasing annual and summer water availability identified at Harvard Forest and across the region. Higher Δ13C is coincident with an enhancement in growth and ecosystem-level net carbon uptake. This work suggests that tree-ring δ13C could serve as a measure of forest GPP and be used to improve the calibration and predictive skill of ecosystem and carbon cycle models.
Ungulate Browsing and Foundation Tree Regeneration in Central New England 2010
Large herbivores are important forest disturbances capable of altering community composition, biodiversity, tree density, successional pathways, and nutrient cycling. The extent to which browsers exert important impacts on forests, however, depends on the intensity and duration of browsing, the palatability and tolerance of the vegetation, available resources to plants, and the scale at which these factors are being investigated. Few studies have examined ungulate impacts at the landscape scale. Since the late-1980s moose have recolonized their pre-historical range in southern New England, joined white-tailed deer to create a potentially important new driver of forest dynamics in the region. Few, if any, studies have looked at combined deer and moose impacts on temperate forests in eastern North America. In the summer of 2010, we initiated a landscape-scale observational study on ungulate habitat use and browsing on foundation tree species (Quercus spp. and Tsuga canadensis) in unlogged forests. Seventy-two forest plots were sampled across several ecoregions in central and western Massachusetts, southern Vermont and New Hampshire and northern Connecticut. Tree seedlings, overstory characteristics, browsing, pellet piles, and shrub densities were sampled; and site attributes such as mean annual temperature and forest fragmentation were examined.
Functional Traits of Selected Tree Species in Harvard Forest, New Hampshire, and Southern Quebec 2015
Increasing evidence suggests that species' phenological responses may predict their performance with warming, but this work has generally ignored whether phenology is correlated with other traits known to drive plant performance. This is perhaps surprising given that interest in functional traits has also increased in recent decades, yet within the functional traits literature there has been an equally limited consideration of phenology, perhaps because robustly estimating it is time-intensive, and simple field estimates will show extreme variation across sites of different latitudes and climate regimes. Here we collected a suite of trait data on the same species for which we collected phenological data (see related dataset HF314, Leaf and Flower Phenology of Woody Plant Species at Harvard Forest and Southern Quebec 2015) to help address this gap. We focused on populations of trees in temperate forests in the Northeast face, which face different environmental conditions across their ranges. This project measured functional traits of trees at two to four sites, to provide a foundation for studies on the relationship between range shift, phenology, and functional traits.
Tree-Associated Fungal and Bacterial Communities at Harvard Forest 2021
Cities are investing in tree-planting initiatives to protect their citizens from climate change-related heat and pollution exposure, yet Boston’s street trees are growing nearly four times as fast and dying twice as young as Massachusetts’ rural forest trees. Our research aims to characterize the belowground variables and microbial community composition that might explain the differences in growth and mortality rates observed between urban and rural trees. In 2021, soil, leaf, and root samples were taken from 25 trees in Harvard Forest to use as a rural comparison to Boston’s street trees and trees in other forests along an urban-to-rural gradient from Boston into Western Massachusetts. At each tree, three 12” deep, 2.4-centimeter radius soil cores were taken within the drip line, and soil cores were divided into the top 6” and lower 6” of soil. Fine roots were picked from each soil core. Six leaf samples were taken from the mid-canopy of each tree, where possible. Soil variables including temperature, moisture, percent organic matter, soluble nitrogen availability, bulk density, and root biomass were measured. Thus far, we have found that urban trees have fewer roots than Harvard Forest trees (F1,252) = 10.88, p = 0.0011), and that urban trees establish more root biomass deeper into the soil than Harvard Forest trees (p = 4.84e-5).
Sap-flux and associated environmental data from ash tree monitoring at four urban parks in St. Paul, Minnesota, USA, from May to November of 2023.
We measured the sap flux density of eighteen ash trees (Fraxinus spp.) of varying health and canopy conditions across four urban parks in the City of St. Paul, MN, USA in summer 2023 with a low-cost, compact data logger system we designed in-house. Although many ash trees in the city have either been killed or removed to control the spread of Emerald Ash Borer, chemical insecticide treatments are available for trees that are in early stages infestation. The trees selected for the research have all been receiving insecticide treatment for a few years, but their health and canopy conditions vary. We also have collocated temperature, soil moisture, and precipitation measurements at the same site for summer 2023.
Minneapolis-St. Paul Urban Tree Inventory
This dataset is a compilation of spatially explicit, species-specific urban tree inventories from across the seven-county Minneapolis-St. Paul (MSP) metropolitan area in Minnesota, U.S.A. The dataset was compiled to examine fine-scale patterns of tree biodiversity across MSP. Existing tree inventories were solicited from all municipalities, counties, park systems, and relevant non-profit organizations in the region for which we were able to find contact information, resulting in inventories from 35 municipalities, one county, one park system, three non-profit organizations and and two prior academic research efforts. The spatial and temporal scope of the inventories varies; for example, the inventories from some municipalities include data from a subset of only street trees at one timepoint, while other municipal inventories were continuously updated datasets with spatially comprehensive data for street trees in addition to some trees in parks and private lands. No inventory was fully comprehensive of all trees in an area. Data are assumed to have been collected between 2012-2022, although the timestamp on each data point is not explicit. Individual inventories were combined into one uniform database.
National Phenology Network tree phenology at Crosby Farm Adaptive Silviculture for Climate Change study, 2021-2025
Phenology is the study of relations between climate and periodic biological phenomena, such as bud break or leaf drop in deciduous trees. Phenology is a leading indicator of climate change, and the response of urban tree species to climate can help inform how to manage for a more resilient, and adaptive urban tree canopy. This dataset contains tree phenology data from the The Mississippi National River and Recreation Area (MNRRA) Urban Affiliate Adaptive Silviculture for Climate Change (ASCC) project located at Crosby Farm Regional Park. This dataset includes Individual Phenometrics, Site Phenomentrics, Status and Intensity, and Magnitude Phenometrics. This data was collected through mobile app submissions to Nature's Notebook and downloaded from the National Phenology Network Observation Portal, filtered by date range 01/01/2021 to 02/26/2024 and for Crosby Farm ASCC. Data Attribution: USA National Phenology Network. 2024. Plant and Animal Phenology Data. Data type: Status & Intensity, Individual Phenometrics, Site Phenometrics, Magnitude Phenometricts. 01/01/2021-02/26/2024 for Region: 45.221627°, -92.554965° (UR); 44.599185°, -93.5712° (LL). USA-NPN, St. Paul, Minnesota, USA. Data set accessed 03/19/2024 at http://doi.org/10.5066/F78S4N1
North Temperate Lakes LTER Northern Highland Lake District Coarse Woody Debris Trees
Coarse woody debris (CWD) is an important, but often neglected, component of lake ecosystems. It is ecologically valuable because it creates littoral habitat complexity but it is susceptible to manipulation by riparian process, in particular removal by property owners. The objective of this study is to determine the spatial scales at which human and environmental factors contribute to coarse woody debris input and output dynamics. Coarse woody debris, boat docks, and riparian trees (with the potential of becoming CWD) around the five lakes of the NTL-LTER site (Trout Lake, Allequash Lake (north basin), Sparkling Lake, Crystal Lake, and Big Muskellunge Lake) were measured in 1996 and 1997. Riparian trees with the potential of becoming CWD were measured in Feb. 1997. Locations were determined by differential GPS (greater than 10 points per tree) and diameters were measured as diameter-at-breast-height (dbh) using a "cruising stick" according to the Scribner 78 scale (Philip 1994). Substantial snow cover made nominal "breast height" approximately 200 cm. The entire shores of Crystal and Sparkling Lakes were sampled. Shorelines on the other lakes were selected to represent developed and undeveloped conditions. Approximately 31 percent% (19/61 km) of the total shoreline of the five lakes was surveyed.
Subalpine tree seed availability and germination at Niwot Ridge, 2015 - ongoing.
These data were collected to assess how seed availability and site limitations affect conifer germination across species distributions. Our study focused on areas above alpine treeline where subalpine tree species must migrate to track movement of suitable climate, but we also included sites in the core and at the lower ecotone of subalpine forests. We monitored seed availability and germination of new seedlings for four subalpine tree species from 2015-present at Niwot Ridge, Colorado, USA. Seed availability was collected in 66-95 seed traps in 14-17 sites (6-12 traps per site; see data for count per site), depending on year. In the lab, seeds were counted by species. In the field, new germinants were counted by species 3-5 weeks after snow disappearance (i.e., peak germination) and again in late September from 2015 to 2018 only. Only one census of new germinants was conducted from 2019 to 2023. New germinants from prior years were censused in subsequent summers.
Tree Mast Production in Pinyon-Juniper-Oak Forests at the Sevilleta National Wildlife Refuge, New Mexico
The purpose of this study is to monitor the fruit production of three common woody tree species that occur on the Sevilleta National Wildlife Refuge (NWR) in New Mexico. We estimate fruit production of two monoecious species, Pinus edulis (pinon pine) and Quercus turbinella (Sonoran scrub oak) and one dioecious species, Juniperus monosperma (one-seed juniper). During August – November, we estimate fruit production for these three species at up to six sites within the Sevilleta NWR. Different protocols are used for each species (see Methods). In addition, the age and/or size of each individual tree was assessed at the beginning of the study, excepting in one site (WM) where fruit counts occurred at the plot, rather than individual tree, scale. For P. edulis and J. monosperma, trees wre binned into categories of young, medium, old, or very old trees. For Q. turbinella, we estimate canopy surface area in m 2
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.