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Deer and Moose Browsing in Hemlock Removal Experiment at Harvard Forest 2008
Hemlock decline in New England is caused by direct and indirect effects of invasion of the hemlock woolly adelgid. Direct damage from the insect is causing gradual mortality of hemlock, and widespread harvesting of hemlock in advance of mortality, in contrast, causes immediate mortality and removal of biomass from the site. Although both processes affect thousands of acres of forest annually we have only a limited understanding of their effects on forest ecosystem function and productivity and the nature of the subsequent forest community. We anticipate that harvesting will yield different consequences than gradual mortality from the insect. Therefore we designed an experiment to simulate these contrasting impacts, by logging or girdling hemlock stands. Results from the experimental treatments will be compared to the changes observed in forests that are being infested by the adelgid, and can also be included in integrated analyses of a suite of large experiments that form a core component of the Harvard Forest LTER program. Deer and moose foraging can play a key role in shaping forest regeneration after disturbance in temperate forest. In 2008, we initiated a browsing survey of woody stems in the Simes hemlock removal experiment plots. There are regular moose sightings in the study area, and moose pellets are commonly found within the plots. Also, extensive browsing of tree regeneration in the logged plots was noted starting in 2007. Sampling of the 8 study plots was completed in Summer 2008. The next sampling is tentatively scheduled for Summer 2013.
Coarse Woody Debris in Hemlock Removal Experiment at Harvard Forest since 2005
The woody detritus survey is designed to measure coarse woody detritus that includes snags, logs, and stumps, and to estimate fine woody detritus which includes smaller pieces of downed wood. To capture both standing and downed wood, we based our survey around two main types of methods, the line intercept method and the fixed radius plot method. Surveys have been completed for 2005, 2007, 2009, 2011, 2013, 2015, 2017, and 2021.
Overstory Vegetation in Hemlock Removal Experiment at Harvard Forest since 2003
Hemlock decline in New England is caused by direct and indirect effects of invasion of the hemlock woolly adelgid. Direct damage from the insect is causing gradual mortality of hemlock. Widespread harvesting of hemlock in advance of mortality, in contrast, causes immediate mortality and removal of biomass from the site. Although both processes affect thousands of acres of forest annually we have only a limited understanding of their effects on forest ecosystem function and productivity and the nature of the subsequent forest community. We anticipate that harvesting will yield different consequences than gradual mortality from the insect. Therefore, we designed an experiment to simulate these contrasting impacts, by logging or girdling hemlock stands. Results from the experimental treatments will be compared to the changes observed in forests that are being infested by adelgid and can also be included in integrated analyses of a suite of large experiments that form a core component of the Harvard Forest LTER program.
Timber Harvesting Field Study in Western Massachusetts 2004-2005
Forest harvesting is one of the most significant disturbances affecting forest plant composition and structure in Western Massachusetts, yet few studies have quantified the effects of harvesting in this region. Massachusetts requires all commercial harvest operations above 87 m3 to file a Forest Cutting Plan (FCP) with the state. We have digitized these FCPs (see McDonald et al. 2006), covering all harvests from 1984 to 2003. Our study area is Massachusetts west of the coastal basin, as defined by Motts and O’Brian (1981). We selected 126 sites for sampling. Two-thirds of the sites (89) were harvested once between 1984 and 2003, and these were selected randomly from the larger FCP database. The remaining one-third of the sites (37) were control sites selected randomly from all unharvested forest in the study area. The boundaries for our field surveys were those filed with the FCP for harvested sites, and were circular for control sites, proportional in size to the mean FCP in the physiographic region (Motts and O'Brien 1981): Connecticut River Valley (10.7 ha), Central Upland (11.3 ha), Berkshire Valley and Taconic Mountains (12.6 ha), and the Western Upland (15.9 ha). Note that our sampled sites were well-dispersed over the study area, and encompassed the variety of past agricultural land-use.
Impacts of Hemlock Harvesting in Central Massachusetts 2003-2009
The recent unimpeded infestation of the hemlock woolly adelgid (HWA; Adelges tsugae) across the northeastern U.S. is driving large-scale hemlock decline and mortality. HWA has already infested over 40% of the towns in Massachusetts and, as a result, many landowners are considering pre-emptively harvesting their eastern hemlock (Tsuga canadensis) stands. To examine the local impacts of this cutting activity, we examined stand and ecosystem dynamics in 10 hemlock-dominated sites on public and private lands where hemlocks were harvested between 1 to12 years ago with nearby uncut forests. Forty-two to ninety-seven percent of hemlock stems and basal area were removed from the harvested sites. Sapling densities of 10,500 to 24,000 stems ha-1 dominated the vegetation at older cuts and consisted primarily of black birch (Betula lenta), red maple (Acer rubrum), and white pine (Pinus strobus). Seedling densities averaged 5 m-2 across sites, peaked at 20 m-2 at 6 to 9 year old sites, and consisted of hemlock, white pine, black birch, and red maple. Additional understory species that were common in cuts sites included various raspberry (Rubus) species, often averaging 30% cover, hay-scented fern (Dennstaedtia punctilobula), and various sedge (Carex) species. Harvesting resulted in soils that were 3 to 5 (deg C) warmer and tended to be drier in recent vs. older cuts. Net nitrogen mineralization rates in organic soils averaged just over 10 kg N ha-1yr-1 in recent cuts and approx. 5 kg N ha-1yr-1 in older cuts. Mineral soil net mineralization rates were lower among all cuts, ranging from 2.1 to 3.5 kg N ha-1yr-1. Nitrification rates were low in both soil horizons at all harvest ages. Recent cuts had much higher nitrogen capture (NH4- + NO3+) on resin bags averaging around 1200 μg N g resin-1 vs. 300 to 600 μg N g resin-1 captured in older cuts. Nitrification rates and nitrate capture on resin bags were lower in Massachusetts sites than those reported on sites with a long history o
Linking Xylem Diameter Variations with Sap Flow Measurements at Harvard Forest 2003-2006
Measurements of variation in the diameter of tree stems provide a rapid response, high resolution tool for detecting changes in water tension inside the xylem. Water movement inside the xylem is caused by changes in the water tension and theoretically, the sap flow rate should be directly proportional to the water tension gradient and, therefore, also linearly linked to the xylem diameter variations. The coefficient of proportionality describes the water conductivity and elasticity of the conducting tissue. Xylem diameter variation measurements could thus provide an alternative approach for estimating sap flow rates, but currently we lack means for calibration. On the other hand, xylem diameter variation measurements could also be used as a tool for studying xylem structure and function. If we knew both the water tension in the xylem and the sap flow rate, xylem conductivity and/or elasticity could be calculated from the slope of their relationship. In this study we measured diurnal xylem diameter variation simultaneously with sap flow rates (Granier-type thermal method) in six deciduous species (Acer rubrum L., Alnus glutinosa Miller, Betula lenta L., Fagus Sylvatica L. Quercus rubra L., and Tilia vulgaris L.) for 7-91 day periods during summers 2003, 2005 and 2006 and analyzed the relationship between these two measurements. We found that in all species xylem diameter variations and sap flow rate were linearly related in daily scale (daily average R 2 = 0.61-0.87) but there was a significant variation in the daily slopes of the linear regressions. The largest variance in the slopes, however, was found between species, which is encouraging for finding a species specific calibration method for measuring sap flow rates using xylem diameter variations. At a daily timescale, xylem diameter variation and sap flow rate were related to each other via a hysteresis loop. The slopes during the morning and afternoon did not differ statistically significantly from each other,
Eastern Redback Salamander Abundance in North Central Massachusetts 2005
Throughout the twentieth century several dominant tree species suffered severe decline in the eastern United States due to non-native pests and pathogens, yet little is known of the effects these losses have on ecosystem processes or associated wildlife populations (Orwig 2002). Eastern hemlock (Tsuga canadensis), an important late-successional tree species, is currently threatened throughout its range by the hemlock woolly adelgid (Adelges tsugae; HWA), an invasive insect pest native to Japan (Orwig and Foster 1998). The unique structure and microenvironment of hemlock-dominated forests create critical landscape level heterogeneity, providing habitat for numerous bird and mammal species several of which are strongly associated with hemlock stands in the Northeast (Yamasaki et al. 2000). The effects of hemlock loss on associated wildlife is largely unknown, but is of particular concern for terrestrial salamanders as they are sensitive to microclimatic conditions that are likely to change as hemlocks decline. In this study, populations of eastern red-backed salamanders (Plethodon cinereus), significant contributors to the overall vertebrate biomass in northeastern forests (Burton and Likens 1975a), are compared in hemlock-dominated and mixed deciduous forest. The objectives of this study was to 1) to determine whether the relative abundance, body condition, and size class structure of P. cinereus populations differ in hemlock-dominated forests versus mixed deciduous forests in north-central Massachusetts. A difference in age-class structure in the two forest types may suggest a difference in survivorship, while differences in body condition are driven by differences in the energy expenditure required to obtain food resources and can lead to differences in reproductive success 2) to evaluate how structure and microenvironment differ and determine which variables best predict the variation in relative abundance and body condition of P. cinereus in the two forest types.
Eastern Redback Salamander Abundance at the Arnold Arboretum 2004-2005
Terrestrial salamanders are significant contributors to the overall vertebrate biomass in a forest (Burton and Likens 1975a). Due to this abundance, they are ecologically important as both predators of soil fauna, and as prey for larger animals such as birds, reptiles, and small mammals (Welsh and Droege 2001). In 1997, the invasive insect pest, hemlock woolly adelgid (Adelges tsugae) or HWA, was discovered on Hemlock Hill at Harvard University’s Arnold Arboretum in Jamaica Plain, Massachusetts. Unfortunately, this infestation has led to the death, decline, and removal of a larger percentage of the eastern hemlock (Tsuga canadensis) trees in this section of the Arboretum. In April 2004, researchers from the Harvard Forest and the Arnold Arboretum began studying the environmental impacts of this disturbance event (HF061). To complement this research twenty-four artificial cover objects (ACOs) were installed in three plots on Hemlock Hill in the summer of 2004 to monitor the relative abundance of eastern red-backed salamanders (Plethodon cinereus) and any other herpetofauna encountered. The timing of the installation permitted an analysis of the effects of a logging treatment conducted in the winter of 2004-2005 on the relative abundance of terrestrial salamanders. Logging had an immediate impact on the relative abundance of eastern red-backed salamanders in both logged plots as seen by an 83 percent decline in the relative abundance of red-backs in plot 1 and a 63 percent decline in plot 2 in the spring following logging versus the fall prior to logging. In the unlogged control plot (plot 3) the relative abundance declined 9 percent in the spring versus the fall. The lower relative abundances in the logged plots were likely due to higher temperatures on the surface of the soil (5.7 deg C) and five centimeters below the soil surface (1.2 deg C), and lower relative humidity on the surface of the soil (3.4%) than in the unlogged plot. By Fall 2005, the relative abundanc
Litterfall, Biomass and Productivity in CRUI Land Use Project at Harvard Forest 1996-1997
Prior agricultural land use often plays an important role in the present condition of forests. This research was conducted to find any productivity differences among previously plowed, pastured, and woodlot sites. There are six sites, two from each of the land use types. With this research we wanted to estimate the productivity for each of the six stands and test the hypothesis that rates of annual aboveground biomass and annual litter fall in recovering forests would decline in the order woodlot - pastured - plowed. Twenty-five trees, of various diameters and species, were cored at each site. The cores were analyzed and the radial growth was calculated for the most recent 5 and 10 year intervals. Biomass increments were also calculated for the same time span using published allometric equations. Aboveground woody productivity was calculated for diameter classes within species and semi-log relationships of productivity per diameter were used to calculate the productivity of all trees in the stand that were not cored. Site-specific and species-specific equations were used. Litter fall was estimated by collecting litter from ten traps each in the six stands. Litter was sorted by species and reported on a dry matter basis. Red oaks and red maples were the major contributors of biomass and litter fall in all six of the stands, accounting for about seventy percent of the total aboveground biomass. Although woodlots had higher total biomass there was not a significant difference in productivity across the six sites. The range of productivity including both litter fall and aboveground woody production was from 7524-9014 Kg/ha. This fell into the range for temperate forests according to results published by the International Biological Program. Production per unit biomass was greater in the plowed stand and least in the woodlots.
Tree Canopy Leaf Area Index in CRUI Land Use Project at Harvard Forest 1997
Numerous variables related to land use disturbance and recovery processes can influence forest composition and structure. We’ve measured differences in forest communities in six sites that were formerly plowed, pastured, or continuously forested woodlots in Prospect Hill. None of the sites had noticeable canopy gap disturbance at the time of the measurements. Leaf area index (LAI) was measured with an LAI-2000 plant canopy analyzer (Li-Cor, Inc., Lincoln, NE) at all 77 edge and interior intersection points in the 30 m x 50 m permanent plot (7 columns x 11 rows) in 5 of our 6 land use sites. Under-canopy measurements were made in each site over 25-30 minutes during midday hours (11:00-2:30 EST) on overcast days near solstice (June 13, 18). The under-canopy readings were contrasted with an open-sky measurement taken in an open field near the Harvard Forest headquarters just before beginning data collection in each site. LAI averaged 3.98 and ranged from 2.28 to 5.93 across all sites. W1 had the highest site-level mean (4.62) and maximum (5.93) LAI while S2 had the lowest values (mean = 3.41, max = 4.55). The woodlot also showed the greatest spatial variation as measured by C.V., while plow #1 showed the least variation.
Canopy Sky Factors in CRUI Land Use Project at Harvard Forest 1998
Hemispherical photos were taken at 35 interior grid corners in each land use site’s 30 m x 50 m permanent plot on uniformly overcast days during summer 1998. A Canon A-1 35 mm camera with a 7.5 mm lens was mounted on a tripod, positioned so the film plane was 0.5 m above ground, oriented N-S with a compass, and leveled. Ektachrome 100 slide film was used. Two exposures were made for each location. The slides were processed and digitized in jpeg format by Kodak, Inc. at a resolution of 1536 x 1024 dpi. The jpeg images were screened for nearground obstructions. Fifteen of the 35 photo locations per site were used in subsequent analysis. Hemiview software (v. 2.0, Delta-T Devices Ltd., Cambridge, UK) was used to process the images and calculate indirect, direct, and global (= indirect + direct) sky factors for each sample location, plus the proportion of global sky factor represented by direct beam radiation. Several images spanning a wide range of canopy density were used to develop protocols for setting optimal thresholds in converting from color to black and white images. Each B/W image was then analyzed at three threshold levels, the optimum level plus 5 threshold units (~ 2.5%) above and below the optimum. The results were averaged across the three threshold levels to provide one set of sky factor data per sample location. Above-canopy incident radiation was calculated daily for the June-September growing season based on (1) latitude and longitude, (2) average atmospheric transmission, and (3) monthly averages for fractions of the day in diffuse radiation due to cloud cover for the Harvard Forest area. Data for 2 and 3 above were provided by researchers at the State University of New York at Albany. Below-canopy radiation was estimated daily across half-hour intervals as the sum of diffuse and direct beam components. Sky factors were then calculated from the above- and below-canopy radiation values and averaged both monthly and across the growing season.
Herbaceous Species in CRUI Land Use Project at Harvard Forest 1996
Forests recovering from agricultural legacies differ in many ways that influence the landscape distribution, local abundance, and dispersion of herbaceous populations, as well as patterns of species associations within the herbaceous stratum. We recorded the presence/absence of 10 herbaceous species on a 1 x 1 m resolution in a 30 x 50 m permanent plot grid in six land use legacy sites (2 plowed, 2 pastured, 2 permanent woodlot) in summer 1996 to test predictions about herbaceous species abundance, richness, dispersion patterns, patterns of association, and their relationships to forest structure, microclimates, and soil resources. The 10 species chosen differed in several ways (evergreen vs. deciduous, stature, clonal architecture, affinity for disturbed vs. undisturbed forests) that allowed us to probe the impacts of prior disturbance and current resource patterns (light, water, nutrients) on the spatial patterns of individual species and species associations.
Mapped Trees in CRUI Land Use Project at Harvard Forest 1996-2006
Numerous variables related to land use disturbance and recovery processes influence forest composition, structure, and growth. We measured forest communities in six sites that were formerly plowed, pastured, or continuously forested woodlots in Prospect Hill to test predictions about species composition, stand structure, and productivity in response to agricultural land use legacies. A permanent 30 x 50 m plot gridded in 5 x 5 m sub-plots was established in each of the 6 sites. All trees at least 2.5 cm DBH (diameter at breast height, 1.3 m) were mapped visually in the field, marked with an aluminum tag, and their DBH recorded in summer 1996. Individual boles of multi-stemmed trees were measured separately and a composite single DBH was calculated. Standing dead trees were also mapped and their DBH recorded as well. The 1996 data were used to determine above ground woody biomass using allometric equations for individual trees. The permanent plots were re-surveyed ten years later in fall 2006. The status of each tree mapped in 1996 was recorded (alive, dead standing, dead fallen, forked) and DBH’s were re-measured. Additional trees that grew across the 2.5 cm DBH threshold during the ten-year period were mapped and their DBH’s measured. Composite diameters and above ground woody biomass were determined for forked trees as in 1996. The 2006 re-measurements were used to analyze changes in species composition, stand structure (density, diameter distribution), and mortality patterns among species and size classes, and to calculate net changes in above ground woody biomass across the ten-year period.
Microclimate in CRUI Land Use Project at Harvard Forest 1997
Understory microenvironmental patterns are strongly influenced by both the forest community and substrate, which are in turn affected by site factors, disturbance history and recovery processes. We measured ground-level microclimates across the growing season as part of a multi-faceted study of soil-plant-atmosphere interactions in sites with different agricultural land-use legacies (formerly plowed, formerly pastured, permanent woodlots) in Prospect Hill. A permanent 30 x 50 m plot was established in each of six sites (2 per land use category) and gridded into 5 x 5 m sub-plots. Fifteen microclimate stations were used to measure photosynthetic photon flux (PPF, umol m-2 s-1, LI-190 quantum sensor, Li-Cor, Inc), soil temperature (107B thermistor, Campbell Scientific, Logan, Utah), and air temperature (107 thermistor, Campbell Scientific, Logan, Utah) at 5 locations each in three sites simultaneously. PPF and air temperature were measured at 50 cm, while soil temperature was measured 5 cm. The central sample station was located in the center (sub-plot D6) of the 30 x 50 m grid and four additional stations were positioned 10 m from the central station in the cardinal directions. In addition to the variables described above, relative humidity (%, 207 air temperature/relative humidity probe, Campbell Scientific, Logan, Utah) was measured at 50 cm at the central station. All sensors were connected to a Campbell Scientific 23X datalogger and sampled continuously every 10 sec and averaged every 10 minutes for 5 days at a time. The stations were switched between two sets of sites (P1-S2-W2 followed by P2-S1-W1) at the end of every week, so the data record for any one site includes alternate weeks. Measurements were made during April through September, 1997. The data archived here are daily means per variable per station. Missing records are due to inclement weather, while blank fields represent occasional sensor or datalogger connection problems.
Photosynthetic Light Response Curves in CRUI Land Use Project at Harvard Forest 1998
Ambient CO2 concentrations in terrestrial ecosystems vary substantially on several spatial and temporal scales as numerous soil, plant, and atmospheric processes respond to irradiance, temperature, moisture and wind. There is one widespread microhabitat in terrestrial ecosystems, the nearground zone, in which CO2 is naturally enhanced above average background levels. CO2 produced by soil respiration diffuses through the litter and boundary layers and dissipates fairly rapidly into the overlying bulk air. However, a marked vertical profile of nearground enriched CO2 (hereafter NEC) is usually present in the first 0-50 cm above ground. The degree of enrichment varies primarily with soil respiration rate and turbulent mixing, secondarily with photosynthesis by plants in the herbaceous stratum, and usually shows marked diel and seasonal variation. References to this CO2 "subsidy" and its effects on plants have occurred occasionally in the literature since 1939, but there have been few detailed studies of either the nearground profile or plant responses in the field, particularly for species that consistently occupy the nearground stratum. Considerable research over the last twenty years in both controlled and field environments has shown that co-occurring plant species may respond differently to artificially elevated CO2. But in contrast to light, temperature, water, and nutrients, plant community ecologists have generally not considered CO2 among the factors that regulate species’ distribution and abundance, except indirectly as it may affect water balance. We have documented differences in forest composition (woody and herbaceous), soil characteristics, microclimates, and nearground CO2 levels among six sites that were formerly plowed, pastured, or continuously forested woodlots in Prospect Hill. We selected three perennial herbaceous species (Aralia nudicaulis, wild sarsaparilla; Clintonia borealis, blue-bead lily; Medeola virginiana, Indian cucumber root) and two do
Massachusetts Historical Landcover and Census Data 1640-1999
An appreciation of historical landuse and its effects is crucial when interpreting the structure, composition, and spatial characteristics of modern forests. The Harvard Forest has compiled many different historical data sources in an ongoing effort to understand how anthropogenic disturbances have shaped our modern landscapes. Estimates of town land use and land cover were gathered from a variety of sources, including tax valuations (1801-1860) and state agricultural census records (1865-1905). Data prior to 1801 rarely cover the entire state and are excluded from these datasets. Data on forest structure are available for several time periods, including 1885 and 1895 (Agricultural Censuses) and 1916-1920s (State Forester’s reports).
Herbaceous Stratum Sunfleck Regimes in CRUI Land Use Project at Harvard Forest 1998
Numerous variables related to land use disturbance and recovery processes can influence forest understory irradiance regimes. In addition to season-long measurements of herbaceous stratum microclimates (data archived separately), we explored the degree to which differences in forest community composition and structure generate differences in near-ground sunfleck regimes in our six land use sites (2 plowed, 2 pastured, 2 permanent woodlot). Considerable research has shown that photosynthetic responses to fluctuating irradiance cannot be predicted accurately from steady-state gas-exchange measurements, and that sunflecks may account for both a large fraction of total daily photon fluence and net carbon assimilation by plants in the herbaceous stratum of moist forests. We measured clear-day irradiance patterns to test predictions about how sunfleck frequency, duration, and brightness should vary across the three land-use legacies. We also wished to document sunfleck regimes as part of a companion study on photosynthetic responses by herb and tree species to sunflecks. Twenty-three quantum sensors (Li-190, Li-Cor, Inc., Lincoln, NE) were placed at regularly-spaced interior intersection points across the 30 m x 50 m permanent plot grid in each land use site. The sensors were mounted on stakes 50 cm above ground, leveled, and attached to a Campbell Scientific CR23X datalogger. Photosynthetic photon flux (PPF) values were recorded at all 23 microsites every 6 seconds for 3.5-4.5 hours in the morning (8:00-11:30+ a.m. EST) on one clear day per site in July and August 1998. Using custom software and a sunfleck definition threshold of 100 umol m-2 s-1, sunfleck events were extracted for each microsite across the sampling period and the following were calculated for each fleck event: number of fleck events per hour, sunfleck duration (sec), duration of the shade period prior to the sunfleck (sec), mean PPF across the sunfleck event, and peak PPF during the sunfleck. Descrtipti
Tree Seedlings in CRUI Land Use Project at Harvard Forest 1996
Forests recovering from agricultural legacies differ in many ways that influence tree seed dispersal and seedling establishment patterns. We recorded the number of seedlings (less than 0.5 m tall) of all tree species on a 1 x 1 m resolution across six land use legacy sites (2 plowed, 2 pastured, 2 permanent woodlot) in summer 1996 to test several predictions about seedling abundance, diversity, and dispersion patterns, and their relationships to forest structure, microclimates, and soil resources.
Herbaceous Community Composition in CRUI Land Use Project at Harvard Forest 1996
Patterns of vascular plant species richness were investigated in six land use legacy sites (2 formerly plowed, 2 formerly pastured, and 2 permanent woodlot) in Prospect Hill to test predictions about the effects of disturbance, light and soil resources, and forest floor environmental heterogeneity on community composition. The occurrence of vascular taxa was recorded in each of the 60 5 m x 5 m contiguous plots within the 30 m x 50 m permanently gridded study plot in each land use legacy site in June 1996. Identification was made to species in most cases. Woodlots showed higher average species richness at the site level (53) than either pastured (52 species) or plowed (49) sites. However woodlots also show greater spatial variation in richness at the 5 m x 5 m resolution than either the plowed or pastured sites (in that order) as represented by the range, standard deviation, and coefficient of variation. Seasonally-averaged light levels at 50 cm are approximately twice as high in the plowed and pastured sites as in the woodlots, but the woodlots show significantly greater soil organic matter, carbon, nitrogen and water-holding capacity than the post-agricultural sites. These results suggest that soil resources may be more important than light in fostering higher herbaceous stratum richness. However, woodlot richness is also affected by the presence of taxa that are slow to re-colonize heavily disturbed sites (e.g., Epigaea repens) and to distinctive microsites that are less common in the plowed or pastured sites in the Harvard Forest system (e.g., exposed boulders). The greater spatial variation in woodlot richness is strongly influenced by both substrate diversity and by scattered hemlock trees, which substantially depress the herb stratum in localized patches.
Hydrocarbon Concentrations at Harvard Forest EMS Tower 1992-2001
Hydrocarbons are products of incomplete combustion and also emitted by vegetation. Hydrocarbons are important precursors for photochemical ozone formation. A system to quantify concentrations of several low-molecular weight hydrocarbons was installed at the EMS tower in the summer of 1992. The measurements were intended to help resolve questions about the potential reactivity in rural New England atmosphere and identify and quantify biogenic hydrocarbon emissions.
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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.