Northeastern States Research Cooperative

High-resolution LiDAR data (flown summer 2009) were acquired for the Hubbard Brook Experimental Forest in New Hampshire. Researchers collected ground-based measures of forest canopy structure, forest health and productivity, and insect and bird diversity and abundance on 36 50-meter-radius plots throughout Hubbard Brook during summer of 2012. Tree measurements included: percent tree crown and understory closure, yearly tree growth, and leaf nutrient assessment, among other measures. Researchers collected branch clippings and bird counts to estimate insect and bird abundance and diversity. They then assessed relationships between four LiDAR categories of forest canopy structure and the ground-based measurements.

To document biological responses to a changing world, researchers, in a previous NSRC study, set up a “PhenoCam” using networked digital cameras, or webcams, at 12 research sites to monitor tree canopy phenology across New England, upstate New York, and adjacent Canada. Researchers use camera images to track phenology of canopy leaf development and senescence using computer modeling and image analysis. In this project, researchers used camera data, ground observations of leaf phenology, and measurements of forest productivity to answer basic questions about how phenology controls year-to-year variability in productivity across sites. On the PhenoCam webpage, images and long-term data on seasonal patterns of phenology and productivity are available, in near-real-time.

In the early 1930s and repeated in 1984, scientists measured soil pH and calcium levels, as well as vegetation, on more than 60 plots across the Adirondack Mountains. From 2004 to 2006, NSRC researchers repeated the 1984 vegetation and soil studies on 54 of the plots. For the time period between 1930 and 2006, researchers discovered a 50% depletion of plant available soil calcium in organic and upper mineral soil horizons in spruce-fir, northern hardwood, and pine forests. In spruce-fir plots, there was 35% reduction in live red spruce basal area between 1984 and 2004, and in the northern hardwood plots, a significant reduction in sugar maple sapling density. Both of these species are known to be adversely affected by low soil calcium levels.

NSRC researchers compared abundance and impacts of insect and disease pests between traditional management (90-100% sugar maple) and ecological management (25% of the basal area non-sugar maple). At nine sites (three each in USDA plant cold hardiness zones 3, 4, and 5), researchers quantified pear thrips, maple leafcutter, sugar maple borer, maple trumpet skeletonizer, maple anthracnose, and eutypella canker incidence. Researchers estimated stand health based on tree crown transparency ratings. They determined carbon sequestration using a USDA carbon calculation tool. Researchers also surveyed sugarmakers' attitudes towards non-traditional sugarbush management. Increased tree species diversity in sugarbushes using ecological management significantly reduced presence and impact of sugar maple insect and disease pests. Differences were similar across cold hardiness zones and sites but not always by year due to normal yearly fluctuations in pest populations.

Researchers observed a dramatic decline in maple growth rates across the Adirondack region since the 1980s. Growth declines were consistent for most populations, with 3 of 4 trees experiencing a downward trajectory in growth despite differences in stand age and soil fertility. The period of growth decline coincided with a period of rapid warming in the Adirondacks, but researchers found that the growth responses of sugar maple to changes in temperature and precipitation were complex and changing over time. Defoliation events also have contributed to reduced growth during this period. These factors will shape the future of sugar maple growth and health in the Northern Forest, and should be considered in the management of this economically and ecologically significant species in the region.

To assess the role of site nutrition in sugar maple decline, NSRC researchers evaluated soil and foliar nutrients and tree diameter growth and crown health of sugar maple trees in 14 forest stands in Vermont. The stands represented a range in calcium availability based on bedrock geology. Of all the nutrients tested, only calcium and aluminum appeared to be directly linked to tree growth and health. Healthier stands had higher levels of soil calcium. Trees with more branch dieback had low foliar calcium and high foliar aluminum. Average annual tree growth during the decade prior to testing was lower for trees in stands with low foliar calcium and high foliar aluminum. Although the 14 stands differed widely in average tree age, site history, and site characteristics such as elevation and drainage, relationships of foliar calcium and aluminum to stand growth and health were consistent.

The decline and even extermination of species of native giant silk moths is a critical conservation concern. Although no single cause is likely responsible for the threat of silk moths, an exotic parasitic fly, Compsilura concinnata, introduced from Europe more than a century ago to control gypsy moth and other invasive tussock moths, is implicated. NSRC researchers will investigate effects of forest structure by deploying “sentinel” larvae of two species of silk moth at intervals over a gradient of oak density and retrieving them after set time periods to assess parasitism. They will evaluate predation by birds and wasps over the same forest gradient using both living caterpillars and “dummy” caterpillars. Finally, they will use local and landscape gypsy moth population density estimates, coupled with forest inventory data, to assemble a computer risk model for silk moth attack by C. concinnata.

Researchers tested the response of proteolytic enzymes to manipulations of temperature, protein and nitrogen availability, and root abundance. They also examined whether these responses were influenced by presence of tree species that differ in their associations with soil chemistry and mycorrhizal fungi. This research was conducted in single tree species plots dominated by arbuscular mycorrhizal (fungus penetrates root cells) associated trees, sugar maple and white ash, or ectomycorrhizal (fungus forms sheath on outside of root tips) associated trees, eastern hemlock and American beech. The plots were located at the Harvard Forest in Massachusetts and the Pisgah State Park in New Hampshire.

Red spruce winter injury, associated with red spruce decline in the Northern Forest, results from needle freezing that can lead to crown thinning and eventual tree mortality. We set out to measure impacts of this injury on long-term carbon storage in red spruce trees. We collected tree stem increment cores from 10-15 dominant red spruce trees in 30 forest plots in Vermont, New Hampshire, and Massachusetts. From the cores, we measured annual tree diameter growth and, in combination with growth equations and USDA Forest Service Forest Inventory and Analysis (FIA) data on red spruce populations, estimated impacts on aboveground carbon storage for red spruce across the region. We found that needle loss from winter injury reduced red spruce growth for three or more years following the 2003 winter injury event. Cumulative loss for red spruce trees across the region was substantial. Importantly however, trees injured in 2003 experienced a surprising growth rebound since 2007.

Investigators studied the interaction between beech bark disease and forest composition and soils by locating 180 stands in the Catskills and 111 stands in the White Mountains where a canopy beech tree has died and the canopy gap had subsequently been filled. Researchers measured which species filled the gap, the vegetation within and surrounding the plot, and the chemistry of the soil in the plot.

Climate change may bring increased frequency and severity of droughts to the Northern Forest region, which is adapted to humid, temperate conditions. Understanding impacts of drought is critical to ensuring effective forest management and adaptation to climate change. NSRC researchers will create a regional network of scientists and diverse stakeholders, called “Northern Forest DroughtNet,” charged with improving scientific and public understanding of how the Northern Forest responds to drought. NSRC researchers will conduct a field experiment at the Hubbard Brook Experimental Forest in New Hampshire to assess the impact of drought on nutrient, water, and carbon dynamics of a Northern Forest ecosystem. They will compare findings with impacts of two other climate change stressors: soil warming and frost events. Researchers will then disseminate information about effects of changing precipitation patterns on Northern Forest ecosystems to diverse audiences

Forest health in the northeast is of increasing concern due to climate change and anthropogenic pressures. In order to monitor canopy condition across the region, this study uses remote sensing images, which can be used to assess the crown condition of forests over long time periods and large areas. A forest health rating based on canopy “greenness”, photosynthetic capacity, canopy density and water content was applied to Landsat TM5 satellite imagery to quantify yearly forest health from 1984 to 2009, as well as changes and trends in health over that time period.

NSRC researchers investigated relationships among nonnative invasive plants, soil drainage, tree canopy openness, and harvest type and intensity in a mixed conifer forest on the Penobscot Experimental Forest in Maine. Researchers studied 20 forest stands, managed using various long-term silvicultural treatments (including no harvest), and 2 additional unmanaged stands on former agricultural sites. They measured density and percent cover of woody plants up to two feet tall, herbaceous plants, mosses, liverworts, and lichens. Percent canopy openness was determined from digital photographs, and drainage was determined from soil pits.

Using methods like those used to make snow at ski areas, researchers successfully created ice glaze on tree branches (remarkably similar to conditions during the Northeast’s 1998 Ice Storm) over a large northern hardwood forest area. This novel experimental tool will allow scientists to study controlled icing events of different intensity and frequency in different forest types. Researchers also held a workshop with ecosystem scientists, climatologists, physical scientists, computer modelers, social scientists, and industry experts to define the state-of- knowledge on ice storms and examine the nature and extent of these storms in the Northeast. In addition, they developed machine-learning algorithms which allow computer models to identify unique ice storm climatology in past weather systems to better predict ice storms in the future.

NSRC researchers will test if the release of parasitoid wasps that attack and kill EAB eggs or larvae, in already established release study areas in New York State, is an effective means to slow mortality of large ash trees, sustain health of ash saplings and seedlings, and promote regeneration of ash stands over time.

Researchers sought to determine the impact of commercial thinning practices on defoliation recovery by examining the ability of red spruce and balsam fir to recover from defoliation by storing non-structural carbohydrates (NSC's) used for foliar growth and secondary defensive compounds such as lignins and tannins.

NSRC researchers determined rates of total atmospheric deposition on sites within Class I wilderness areas of the Northeast and assessed the nitrogen saturation status (point at which full capacity for nitrogen is reached) of watersheds in these areas.

Regional assessments of forest health and productivity require a strong, region-wide understanding of ranges in chemical nutrient concentrations in the foliage of the region’s forest tree species. NSRC researchers requested foliar chemistry data from 122 scientists. They created a database of data from 25 research projects located in approximately 13 states in the northeastern United States. The database now contains foliar chemistry data from 10,000 trees. Currently, there are 294 registered users of the online database. The database is a searchable resource that provides foliar chemistry data for most eastern forest tree species. In addition, the website provides cumulative frequency distributions of the foliar chemistry for each tree species and chemical element represented in the database. Data can be submitted to the database by registering on the website.

NSRC researchers identified eastern white pine provenances (seed sources) with enhanced adaptation to climate change pressures and carbon sequestration potential throughout the portion of the tree’s native distribution from Wisconsin to Maine and Ontario and Quebec. Researchers evaluated provenances grown in long-term plantations established in the 1960s. Using computer climate models and data collected from the plantations, researchers predicted effects of climate change on growth, productivity, and wood properties of existing white pine forests; estimated carbon sequestration potential of white pine under new climate regimes; and quantified the tree’s genetic variation in climatic response and adaptation, among other study objectives.

Calcium is an important soil nutrient in healthy forests, but interactions with acid rain cause elements, such as aluminum, to interfere with calcium uptake by plants. Calcium-to-aluminum ratio in foliage and soil has been shown to be a predictor of tree health and is used in critical loads assessments to determine impacts of air pollution. Most studies have been done on greenhouse seedlings and have questionable application to mature forests. Another element, manganese, has also been shown to interfere with nutrient uptake. NSRC researchers investigated these ratios in mature forest trees. They measured chemistry of soil, soil water, and foliage of sugar maple, yellow birch, white ash, and black cherry in 56 hardwood forest plots from Pennsylvania to New Hampshire. Researchers assessed tree health by rating tree canopies for dieback, transparency, and overall vigor. They measured stem diameter growth with increment cores.

Researchers use forms of nitrogen as tracers to track nitrogen transformation in forest soils using intensive time-course sampling. This will help researchers identify pathways in the retention of nitrogen, including mycorrhizal fungi tissues, which are likely an important control in plant and soil nitrogen stocks but are rarely observed under field conditions. A second part to this study is a lab experiment aimed at assessing the effects of manganese limitation on leaf litter decay in soils exposed to long term nitrogen addition.

Using a large collection of red spruce (Picea rubens) tree cores, we assessed the relationship between climate, acid deposition, and other environmental data and tree growth.

Investigation of the impact of beech thickets on local biodiversity.

Establish an experimental design that will evaluate and monitor the effects of a range of silvicultural treatements having the potential to minimize ecological impacts and, in some cases, enhance ecological and biodiversity values, thereby sustaining both timber yield and ecosystem functioning. 1. Evaluate the relative ability of silvicultural alternatives to achieve desirable forest management outcomes. 2. Evaluate the operational effectiveness and economic tradeoffs of alternate silvicultural systems, including those designed to enhance structural complexity. 3. Determine the effects of forest management alternatives on selected elements of biological diversity and ecological processes. 4. Test the ability of silvicultural manipulations to accelerate the development of late-successional structural and compositional characteristics in northern hardwood forests. 5. Provide an experimental framework for collaborative research on relevant ecological, sociological and economic dimensions.

Assessment of changes in forest canopy health over time by the use of canopy photography. Establish an archivable image of stand condition to use as a baseline for future comparisons. Since a baseline has been created in past years, photography will be taken only if other surveys indicate tree stress or damage is occuring, and results will be compared to baseline established.

The Forest Health Monitoring Program was established in 1991 as a joint effort between the Vermont Department of Forests, Parks and Recreation (FPR) and the Vermont Monitoring Cooperative (VMC) (as of March 2017 renamed to Forest Ecosystem Monitoring Cooperative (FEMC)) to monitor the condition of a range of tree species in Vermont. Plot design follows the structure set by the National Forest Health Monitoring Program with additional metrics added to reflect improvements in monitoring technologies and additions to monitoring objectives.

CASTNET is a national monitoring network established to assess trends in pollutant concentrations, atmospheric deposition, and ecological effects due to changes in air pollutant emissions. Regional CASTNET dry deposition chemistry data from New York and northern New England are archived here.

Year-round daily monitoring of wet deposition as part of a national AIRMoN network of intensive precipitation monitoring and research sites. Provide atmospheric deposition data for research and monitoring in the Lake Champlain Basin in cooperation with NOAA and the Lake Champlain Research Consortium.

Determine compliance with 8-hour National Ambient Air Quality Standard (0.070ppm)

Year-round monitoring of atmospheric mercury deposition in wet deposition, aerosol (particulate-bound) and vapor (gaseous elemental) phases. The study is part of an integrated program of research and monitoring on atmospheric deposition in the Lake Champlain Basin coordinated over time with NOAA, University of Michigan Air Quality Lab, the Lake Champlain Research Consortium, the Mercury Deposition Network and the Atmospheric Mercury Network.

Broad goal is to better understand mechanisms controlling foliar ion exchange (foliar leaching and uptake) in forest canopies.

Monitor chemistry of cloudwater at the summit of Mount Mansfield.

Annual measurement of sugar maple forest stands to determine tree condition, trends and possible causes of sugar maple decline. Assess the variation in within-season timing of measurements, using same plot design as in the National Forest Health Monitoring Program (NFHM). Initially part of a cooperative monitoring program with other states and Canada, since 2002 Vermont has measured these plots independently for internal use. NAMP is primarily an overstory/forest health monitoring program but they have collected regeneration data beginning in 1998.

Determine the variability in crown ratings as a function of observation time within a 10 week sampling period. Assess the variation in within-season timing of measurements, using same plot design as in the National Forest Health Monitoring Program (NFHM).

Determine the current health of Vermont's hardwood forests using aerial photography and ground surveys.

Determine concentrations and composition of fine aerosols (PM-2.5) of relevance to light scattering, light absorption, human health and biological effects. Data available for use in conjunction with other biological, physical and chemical variables in trend and relationship assessments.

Monitor bruce spanworm

To assess winter injury severity to red spruce (Picea rubens) trees after winter injury event in 2003

This project measures atmospheric mercury fractions which contribute to dry and total mercury deposition. Proctor Maple Research Center and VMC participate in a network of sites collecting concentrations of atmospheric mercury species from automated, continuous measuring systems coordinated by the National Atmospheric Deposition Program.

This project is a 50-year monitoring effort to examine the long-term effects of broad-scale environmental changes--particularly changes in climate, air quality, soil health, and vegetation, in the Green Mountain National Forests.

The Environmental Monitoring and Management Alliance (EMMA) is examining the effects of deer overabundance on forest regeneration at seven upland oak forest sites centered in the Hudson Valley. These data, coupled with deer management programs, will allow us to both assess the impact deer are having on the survival of native species and evaluate the effectiveness of various deer management strategies across the region.

The Vermont Air Quality and Climate Division (AQCD) operates three monitoring sites for ambient air toxics. These are located in Burlington, Rutland and Underhill. Samplers at the sites are operated on a 1-in-12 day (Burlington, Rutland) or 1-in-6 day sample schedule (Underhill). The Underhill site is part of the EPA National Air Toxics Trend Station (NATTS) network. The Burlington and Rutland air toxics monitoring sites are part of the VT AQCD air toxics network. The air toxic sample collection and analysis program includes volatile organic compounds (VOC) and carbonyl compounds at all sites. The NATTS - Underhill site includes sampling and analysis for PM10 metals and polyaromatic hydrocarbons (PAH) compounds.

Root starch analysis can be used to indicate the impact of defoliation on tree health. Root starch analyses in stands defoliated by forest tent caterpillar were conducted in 2004-2007 and in 2016.

Initially this project was part of the National Forest Health Monitoring Program, a collaboration between State forestry agencies, the US Forest Service, and State & Private Foresters. The Ozone Biodindicator Lead for the Forest Service was Dr. Gretchen Smith from UMass Amherst. Our role in Vermont was to be trained by Gretchen, then collect data on cumulative ozone injury during the “ozone window” usually the end of July – early August, before fall color change. If symptoms were found, vouchers were sent to Gretchen for verification. Regional data were gathered and reported by the Forest Service. Vermont also included summary results in annual Conditions Reports.

Rapid mortality of red pine (Pinus resinosa) forests has been noted throughout New England, with several factors likely contributing to this widespread forest decline, most notably the exotic red pine scale (Matsucoccus matsumurae syn: M. resinosae). In symptomatic sites, tree mortality has been observed within a few years of outward symptom expression and has occurred uniformly and completely across entire red pine stands. Our project is evaluating the health of red pine plantations and natural forests throughout New England.

This is a field-based study of intermediate wind disturbance (i.e., blowdown) effects on forest structure, composition, and carbon dynamics. Under Professor William Keeton's supervision, field crews collected data at four sites at multiple points in time. One of the primary outcomes is a journal article in Ecological Applications.

Compare patterns of increasing soil mercury concentrations with elevation on four mountains across the Northern Forest (Whiteface Mountain, NY; Mount Mansfield, VT; Mount Washington, NH; Saddleback Mountain, ME; assess the factors driving formation of biological mercury hotspots in these habitats.

Researchers used a long-term record of red spruce winter injury in a New Hampshire plantation and conducted analyses with local weather data to determine which environmental factors helped account for injury, and how much this injury affects tree carbon storage

Researchers assessed condition of sugar maple trees in 47 previously monitored stands, and produced hazard-rating tables to help land managers predict which stands would be more vulnerable to decline following defoliation events.

NSRC researchers created an on-line, interactive database for storing and sharing soil chemistry data and maps of the northeastern United States and eastern Canada. The database assists in promoting collaboration among soil researchers, identifying missing data and monitoring needs, and assessing response of ecosystems to disturbance and change.

NSRC researchers conducted three projects on development and application of critical loads to forest and aquatic ecosystems in the Northeast and beyond. Researchers used a computer model to determine critical loads of air pollutants for lake/watershed ecosystems in the Adirondack region of New York. They then applied the model to a watershed at the Hubbard Brook Experimental Forest in New Hampshire to examine how changing climate influences the values of critical loads. Researchers also developed critical loads for effects of atmospheric nitrogen deposition on different ecosystems across the United States.