Jane R Foster

US Forest Service | FS · Southern Research Station

Defoliation outbreaks are biological disturbances that alter tree growth and mortality in temperate forests. Trees respond to defoliation in many ways; some recover rapidly, while others decline gradually or die. Functional traits such as xylem anatomy, growth phenology or non-structural carbohydrate (NSC) storage could explain these responses, but...

As global temperatures rise, variation in annual climate is also changing, with unknown consequences for forest biomes. Growing forests have the ability to capture atmospheric CO2 and thereby slow rising CO2 concentrations. Forests’ ongoing ability to sequester C depends on how tree communities respond to changes in climate variation. Much of what...

Ecotones are transition zones that form, in forests, where distinct forest types meet across a climatic gradient. In mountains, ecotones are compressed and act as potential harbingers of species shifts that accompany climate change. As the climate warms in New England, USA, high elevation boreal forests are expected to recede upslope, with northern...

Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality mo...

Spring phenology in temperate forest ecosystems is responding in diverse ways to global climate change, with unknown consequences for insect disturbances that affect forest productivity. Adaptive forest management that anticipates changes in insect disturbance regimes requires an understanding of the mechanistic links between climate and disturbanc...

It is often logistically impractical to measure forest defoliation events in the field due to seasonal variability in larval feeding phenology (e.g., start, peak, and end) in any given year. As such, field data collections are either incomplete or at coarse temporal resolutions, both of which result in inaccurate estimation of annual defoliation (f...

Recent expansion in data sharing has created unprecedented opportunities to explore structure–function linkages in ecosystems across spatial and temporal scales. However, characteristics of the same data product, such as resolution, can change over time or spatial locations, as protocols are adapted to new technology or conditions, which may impact...

Cold‐air pooling is a global phenomenon that frequently sustains low temperatures in sheltered, low‐lying depressions and valleys and drives other key environmental conditions, such as soil temperature, soil moisture, vapor pressure deficit, frost frequency, and winter dynamics. Local climate patterns in areas prone to cold‐air pooling are partly d...

Spruce–fir (Picea–Abies) forests of the North American Acadian Forest Region are at risk of disappearing from the northeastern United States and Canada due to climate change. Species distribution models (SDMs) have been used to predict changes in this critical transitional ecosystem in the past, but none have addressed how seasonal patterns of temp...

Recent expansion in data sharing has created unprecedented opportunities to explore structure-function linkages in ecosystems across spatial and temporal scales. However, characteristics of the same data product, such as resolution, can change over time or spatial locations, as protocols are adapted to new technology or conditions, which may impact...

Lianas are found in virtually all tropical forests and have strong impacts on the forest carbon cycle by slowing tree growth, increasing tree mortality and arresting forest succession. In a few local studies, ecologists have successfully differentiated lianas from trees using various remote sensing platforms including satellite images. This demonst...

Aim Populations of cold‐adapted species at the trailing edges of geographic ranges are particularly vulnerable to the negative effects of climate change from the combination of exposure to warm temperatures and high sensitivity to heat. Many of these species are predicted to decline under future climate scenarios, but they could persist if they can...

Global change represents the greatest challenge facing forest managers today. The uncertainty and variability of potential future impacts of shifting climatic and disturbance regimes has led resource managers to seek out alternative approaches to sustain the long-term delivery of forest ecosystem services. We use a spatially explicit forest landsca...

The monitoring of tree range dynamics has emerged as an important component of adaptive responses of forest management to global change scenarios such as extreme precipitation events and/or invasive species. Comparisons between the locations of adults versus seedlings of individual tree species using contemporary forest inventories is one tool wide...

Interactions among disturbances are seldom quantified, and how they will be affected by climate change is even more uncertain. In this study, we sought to better understand how interactions among disturbances shift under climate change by applying a process‐based landscape disturbance and succession model (LANDIS‐II) to project disturbance regimes...

In the eastern United States, American chestnut (Castanea dentata) was historically a major component of forest communities, but was functionally extirpated in the early 20th century by an introduced pathogen, chestnut blight (Cryphonectria parasitica). Because chestnut is fast-growing, long-lived, and resistant to decay, restoration of American ch...

Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics-changes in forest stand composition, density, size and age str...

Tree growth rings are applied in forest ecology to understand the relationship between climate and forest growth. To this end, individual trees considered sensitive to climate are sampled and the average effects of climate over a sample period are estimated. Forests are dynamic systems, the structure, composition, and health of which evolve over ti...

Defoliation outbreaks are biological disturbances that alter tree growth and mortality in temperate forests. Trees respond to defoliation in many ways; some recover rapidly, while others decline gradually or die. These differences may arise from species functional traits that constrain growth such as xylem anatomy, growth phenology or non-structura...

Climate change is projected to affect the integrity of forested ecosystems worldwide. One forest type expected to be severely impacted is the eastern spruce-fir forest, because it is already at the extreme elevational and latitudinal limits of its range within the northern United States. Large-scale bioclimactic models predict declining habitat sui...

This report documents the results of a four year research project to assess and map vegetation communities of Shenandoah National Park. The project was a collaborative effort between Shenandoah National Park, the US Geological Survey-Leetown Science Center, the Virginia Department of Conservation and Recreation-Division of Natural Heritage, the Uni...

Background/Question/Methods Tree biomass growth results from physiological processes that are sensitive to annual variations in temperature, precipitation and potential evapotranspiration. Dendrochronological analyses aimed at past climate reconstructions often employ standardization techniques that magnify the signal of tree growth variance that...

Forest insects cause defoliation disturbances with complex spatial dynamics. These are difficult to measure but critical for models of disturbance risk that inform forest management. Understanding of spatial dynamics has lagged behind other disturbance processes because traditional defoliation sketch map data often suffered from inadequate precisio...

Background/Question/Methods Understanding how woody biomass production changes as trees and forests age is critical for models of forest dynamics and carbon sequestration. The most frequently cited stand-level models of woody biomass change report a rapid increase in biomass accumulation that peaks around canopy closure, and declines to a constan...

Defoliation by insect herbivores can be a persistent disturbance affecting ecosystem functioning. We developed an approach to map canopy defoliation due to gypsy moth based on site differences in Landsat vegetation index values between non-defoliation and defoliation dates. Using field data from two study areas in the U.S. central Appalachians and...

Eruptive forest Lepidoptera defoliate millions of hectares annually in North America (Haack and Byler 1993), suppressing growth and weakening or killing host trees (Davidson et al. 1999), altering nutrient dynamics and affecting competition among forest species (Muzika 1999). Defoliation outbreaks are recurring, large-scale disturbances that influe...

This research sought to predict the potential short- and long-term effects of insect defoliation and disturbance interactions on above-ground forest carbon dynamics in eastern North American forests. I integrated forest inventory data with remote sensing analyses to help determine the spatial processes that drive outbreaks of hardwood defoliators,...

Background/Question/Methods Defoliation outbreaks are recurring, large-scale disturbances that influence the productivity and composition of temperate forests over long time-scales. We simulated defoliation outbreaks with a new extension for the forest disturbance and succession model, Landis-II, to better understand the long-term consequences of d...

In a recent article, McMahon et al. (1) examined forest-plot biomass accumulation across a range of stands in the mid-Atlantic United States and suggest that climate change and trends in atmospheric CO2 explain an increase in forest growth. To show this increase, they fit a simple model to live above-ground forest biomass (AGB) as a function of sta...

We assess and predict the interactive effects of gypsy moth defoliation, fire management, and climate change on carbon uptake, forest productivity, species composition, and tree mortality in the New Jersey Pine Barrens. This effort will combine carbon flux measurements, a forest landscape disturbance model, and field monitoring data. We will determ...

Background/Question/Methods Defoliation outbreaks of forest canopies are biological disturbances that preferentially affect growth and mortality rates of host species, producing short and long-term changes in forest productivity, competition and composition. Tree and stand level response to defoliation varies from rapid recovery to abrupt mortali...

Woody lianas are critical to tropical forest dynamics because of their strong influence on forest regeneration, disturbance ecology, and biodiversity. Recent studies synthesizing plot data from the tropics indicate that lianas are increasing in both abundance and importance in tropical forests. Moreover, lianas exhibit competitive advantages over t...

1] Ephemeral disturbances, such as non-lethal insect defoliations and crown damage from meteorological events, can significantly affect the delivery of ecosystem services by helping maintain nitrogen (N) limitation in temperate forest ecosystems. However, the impacts of these disturbances are difficult to observe across the broad-scales at which th...

Earth Observing 1 (EO-1) Hyperion and Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) imagery were used to predict canopy nitrogen (N) concentration for mixed oak forests of Green Ridge State Forest in Maryland. Nitrogen concentration was estimated for 27 ground plots using leaf samples of the dominant tree species from each plot that were...

We used 32 Radarsat SAR images collected between 1996 and 2001 over the Roanoke River floodplain, North Carolina (USA), to assess the utility of C-HH Radarsat SAR for operationally mapping flooding beneath forest canopies. Our objective was to test the sensitivity of standard-beam Radarsat to flooded forests under leaf-on and leaf-off conditions, a...

We used classification and regression trees (CART) to map forest composition with Hyperion and AVIRIS in the Central Appalachian Mountains. Imagery from both sensors exhibited strong topographic effects, with AVIRIS also having a view-angle dependent brightness gradient across the image swath. A DEM-based empirical adjustment to reflectance levels...

1] The hydrology of riparian wetlands worldwide has been altered extensively owing to the construction and operation of dams. We developed a model for the Roanoke River floodplain (United States) to simulate flood extent and duration based on a power law correlation between inundation area A, as mapped from synthetic aperture radar (SAR) imagery, a...

An increasing interest in the ability of tropical forests to sequester large amounts of carbon has pushed scientists to look for new ways to acquire accurate estimates of biomass and other forest structural attributes over large, remote areas. We used hyperspectral images acquired in the fall of 2001 from the Hyperion imaging spectrometer to predic...

Of the many promising applications of imaging spectroscopy in forest ecosystems is the possibility of mapping species composition and distribution with greater accuracy than is possible using standard multispectral data. In areas with complex forest composition, vegetation mapping with hyperspectral imagery requires methodological approaches that c...

In this report, we use several tools to document recent large scale trends in Middle East hydrology. Four interelated aspects are investigated: 1) upland snow cover in the Zagros and Taurus mountains, 2) runoff and discharge in the Tigris, Euphrates and other rivers, 3) rainfed agriculture in the Fertile Crescent and 4) irrigated agriculture using...

We describe a variety of satellite-derived datasets and their application to understanding changes in the landscape of southwest Asia, including regional climatology, natural vegetation, and the expansion and intensification of agricultural production. We demonstrate the effectiveness of several remote sensing tools in gauging environmental change...

Hyperspectral imagery from EO-1 Hyperion and AVIRIS were used in conjunction with continuous forest inventory (CFI) data to map detailed forest composition in the state forests of Western Maryland. We developed a hierarchical vegetation classification that conformed to the National Vegetation Classification Standard (NVCS) at the Alliance level and...