Scientific Basis for Regionalization
Research at the Harvard Forest LTER covers a range of spatial scales from
regional (~1000 km) to subregional (~100 km) to landscape (~10 km) to
site (~1 km); (Figure 1). Many projects span
more than one spatial scale (Table 1). Study
areas are described in more detail below.
Table 1. Spatial Scales and Research Approaches of Harvard Forest Studies
||0 - 1870 m
||30 - 610 m
||190 - 425 m
||280 - 425 m
| Hurricane Modeling
| Ecosystem Modeling
| Vegetation Surveys
| Soil Surveys
| Atmosphere Exchange
| Hurricane Pulldown
| Nitrogen Saturation
| Soil Warming
| Organic Matter
| Controlled Environment
| Atmospheric Deposition
| Water Management
| Forest Management
| Land Protection
| Land Use Planning
New England Region
The New England region (120,000 km2) is geologically and topographically
varied. Highlands are typically 200 m to >500 m a.s.l. whereas lowlands
occur below 200 m and mountainous areas reach above 1000 m. Physiography
is bedrock controlled. Highlands consist of Paleozoic granites, gneisses,
and schists. Lowlands are formed in eroded Paleozoic and Mesozoic
sedimentary and metamorphic rock and include the primary carbonate-rich
rocks in the region.
Regional climatic gradients associated with latitude, distance from the
coast, and elevation produce considerable variation in vegetation and
natural disturbance. The importance of tropical windstorms and fire is
thought to decrease from southeastern coastal areas to the northwest
and inland. Major forest types include: Central Hardwoods-Hemlock,
Transition Hardwoods-White Pine-Hemlock, Northern Hardwoods-Hemlock-White
Pine, and Spruce-Fir-Northern Hardwoods.
Due to broad similarity in vegetation, natural disturbance regimes and
cultural history across this region, most of our regional LTER studies
focus on the New England states excluding northern Maine. However, for
purposes of examining very broad-scale phenomena (e.g., atmospheric
transport and deposition of pollutants; tropical storm meteorology) or
comparison of forest dynamics across major environmental or cultural
gradients, this study region is occasionally expanded to include the
Adirondack region of New York or adjacent mid-Atlantic states.
North Central Massachusetts Subregion
The 40-township subregion (3,150 km2) largely occupies the Central
Upland (200 m - 400 m a.s.l.), a rugged physiographic area characterized
by north-south ridges. To the east and west are lowlands of low-to-moderate
relief (25 m - 150 m a.s.l.). Climatic gradients of temperature and
length of growing season parallel physiography and are responsible for
subtle variation in forest composition. The predominant Transition
Hardwoods-White Pine-Hemlock Forest includes oak, red maple, birch,
white pine, and hemlock. However, the Connecticut Valley Lowland supports
many southern or coastal species and higher elevations of the Upland
contain species of the Northern Hardwoods-Spruce Forest. The presence
of nutrient demanding species in the Lowland suggests a fertility
gradient associated with bedrock.
Historical patterns of settlement and land-use activity follow the
physiography. The Lowlands were settled earlier than the Central Upland
and agriculture has remained important in these fertile areas.
Reforestation after agricultural abandonment has been most complete in
the Central Upland, with ~70% of the modern landscape supporting second
growth forests. Several urban areas occur within the subregion, and
suburbanization is increasing throughout.
Petersham (9844 ha) is characteristic of the Central Uplands region.
Elevation ranges from 160 m to 400 m, with local relief less than 60 m.
Topography is bedrock controlled with gneisses and schists overlain by
shallow till deposits (0-10 m) in the uplands and glaciofluvial sediments
in lowland drainages. Soils are acidic, coarse-textured loams and sands
locally underlain by a dense, impermeable hardpan. Good agricultural
soils are restricted to the main ridge crests comprising approximately
20% of the township, whereas over 40% of the area is considered unsuitable
for agriculture. Land clearing for agriculture peaked in the mid-19th
century followed by natural reforestation. The township is currently
Prospect Hill Tract, Harvard Forest
The Prospect Hill Tract (337 ha) forms the northern, highest portion of
the major ridge in Petersham. Elevation ranges from 270 m to 420 m.
Variability in relief, depth to bedrock, and presence of a fragipan
create a highly dissected pattern of soil drainage. The annual
temperature is 8.5oC, the frost-free season averages five months, and
the annual precipitation is 105 cm with 150 cm of snow.
The area is dominated by mixed oak-white pine-red maple forests on the
uplands and hemlock and spruce in low lying areas. With the exception
of a 31-ha woodlot, the tract was cleared in the 18th and 19th Centuries
for pasture (72%) and tillage (18%). Upon agricultural abandonment,
cleared areas reforested naturally or were planted with conifers,
whereas the woodlot developed into a mature hemlock stand.
Examples of Current Research:
Land-use History as Long-term,
Broad-scale Disturbance: Regional Forest Dynamics in
Central New England
D. Foster, G. Motzkin, J. Fuller, B. Slater
Human land-use activities differ from natural disturbance processes and
may elicit novel biotic responses and disrupt existing biotic:environmental
relationships. The widespread prevalence of land-use requires that human
activity be addressed as a fundamental ecological process and that lessons
from investigations of land-use history be applied to the conservation
and management of forested landscapes. Changes in the intensity of land-use
and extent of forest cover in New England over the past 3 centuries provide
the opportunity to evaluate the nature of forest response and reorganization
to such broad-scale disturbance. Using a range of archival data and modern
studies, we assessed historical changes in forest vegetation and land-use
from the Colonial period (early 17th C) to the present across a 5000 km2
area in central Massachusetts (Figure 2) in
order to evaluate the effects of this novel disturbance regime on the
structure, composition and pattern of vegetation and its relationship to
regional climatic gradients.
Cultural history in the region following European settlement in the 17th
and 18th C has involved a gradual and continual increase in the human
population with a pronounced change through time from a dispersed agrarian
population to a progressively urbanized and suburbanized population as
large-scale industry increased in the mid 19th C
(Figure 3). Rapid deforestation for
agriculture led to a landscape dominated by open fields and scattered
woodlots in the mid 19th C when the land was very intensively used.
Concomitant with the opening of agricultural lands in the mid-west and
industrialization in the east, farmland was abandoned in New England and
reverted naturally back to forest, a process that has continued to the
present (Figure 4). The major objectives of
this study and related paleoecological research across the same region
(Fuller et al. 1997) are to determine the impact of this changing
intensity of land-use on regional vegetation patterns and to compare the
forest composition during the pre-settlement period and today.
At the time of European settlement the distribution of tree taxa and
forest assemblages showed pronounced regional variation and corresponded
strongly to climate gradients, especially variation in growing degree
days (Figure 5;
Table 2). The dominance of hemlock and
northern hardwoods (maple, beech, birch) in the cooler Central Uplands
and oak, chestnut and hickory at lower elevations in the Connecticut
Valley and Eastern Lowlands is consistent with the regional distribution
of these taxa and suggests a strong climatic control over broad-scale
vegetation patterns. We infer that intensive natural or aboriginal
disturbance appears to have been minimal in the uplands, whereas
infrequent surface fires in the lowlands may have maintained the
abundance of central hardwoods and restricted the abundance of hemlock,
beech and sugar maple in these areas.
Table2. Results of regressions of township positions on the first two
DCA axes versus climate calculated as average, maximum or forest-weighted
growing degree days for the township.
Significance levels include * < .05, *** < .001.
| Average GDD
| Maximum GDD
| Average GDD
| Maximum GDD
| Forest Weighted GDD
The modern vegetation is compositionally distinct from Colonial vegetation,
exhibits little regional variation in the distribution of tree taxa or
forest assemblages defined by tree taxa, and shows little relationship
to broad climatic gradients (Figure 6). The
homogenization of the vegetation, disruption of vegetation:environment
relationships, and formation of novel assemblages appear to be the result
of (1) a massive, novel disturbance regime; (2) ongoing low intensity
human and natural disturbance throughout the reforestation period to
the present; (3) permanent changes in some aspects of the biotic and
abiotic environment; and (4) a relatively short period for forest
recovery (100-150 years). These factors have maintained the regional
abundance of shade intolerant and moderately tolerant taxa (e.g., birch,
maple, oak, pine) and restricted the spread and increase of shade-tolerant,
long-lived taxa such as hemlock and beech. These results raise the
possibility that historical land-use has similarly altered
vegetation:environment relationships across broader geographic regions
and should be considered in all contemporary studies of global change.
Publications and Presentations
Foster, D. Integration of long-term studies into the analysis and
management of modern landscapes. Plenary Talk, International Association
for Landscape Ecology, Duke University, March 16, 1997.
Foster, D. Ecosystem response to human disturbance - integrating
approaches and results across scales. Synthesis in Ecology: Applications,
Opportunities, and Challenges. National Center for Ecological Analysis
and Synthesis. November 18-20, 1996.
Foster, D. 1995. Land-use history and four hundred years of vegetation
change in New England. In B. L. Turner (ed.), Principles, Patterns and
Processes of Land Use Change: Some Legacies of the Columbian Encounter.
SCOPE Publication. John Wiley and Sons, New York. pp. 253-319.
Foster, D. 1993. Land-use history and transformations of the forest
landscape of central New England. Pages 91-110 in S. T. A. Pickett and
M. McDonnell (eds.), Humans as Components of Ecosystems: Subtle Human
Effects and the Ecology of Populated Areas. Springer-Verlag, New York.
Foster, D., G. Motzkin, and B. Slater. 1998. Land-use history as
long-term broad-scale disturbance: regional forest dynamics in Central
New England. Ecosystems 1:96-119.
Fuller, J., D. Foster, J. McLachlan and N. Drake. 1998. Impact of
human activity on regional forest composition and dynamics in Central
New England. Ecosystems 1:76-95.
Motzkin, G., D. Foster, A. Allen, J. Harrod and R. Boone. 1996.
Controlling site to evaluate history: vegetation patterns of a New England
sand plain. Ecological Monographs 66:345-365.
Motzkin, G., W. Patterson and D. Foster. In review. A regional-historical
perspective on uncommon plant communities: Pitch Pine-Scrub Oak in the
Connecticut River Valley of Massachusetts. Journal of Ecology.
PnET: A Simple, Lumped Parameter Model
of Forest Biogeochemistry for Regional Applications
J. Aber, W. Currie, C. Driscoll, E. Farrell, C. Federer, C. Goodale,
M. Goulden, J. Jenkins, D. Kicklighter, R. Lathrop, G. Lovett,
M. Martin, S. McNulty, J. Melillo, S. Ollinger, K. Postek, P. Reich,
We first discussed our approach for the Harvard Forest's contribution
to regional studies at the LTER All-Scientists meeting in 1990. Working
out from the heart of New England, and working with the Harvard Forest
LTER theme of natural versus human disturbance, we chose the New York/New
England region as the target area. This region encompasses a wide range
of climatic zones and forest types, as well as significant gradients in
pollutant deposition. We developed an approach (Aber et al. 1993) which
combined a high resolution GIS with statistical models to summarize
important climate drivers and a simple, lumped parameter model to predict
water, carbon and nitrogen dynamics across the region. All of the
components of this systems are now in place and have been used to derive
site-level and region-wide estimates of forest NPP and water yield under
current conditions and those predicted for the next century.
For the New England/New York regional GIS, a 30 arc-second
(approximately 1 km.) digital elevation model
(DEM, Figure 7) was obtained from the USGS,
and a 1 km. land use/land cover (LULC) map
(Figure 8) was derived from AVHRR
satellite data that identifies current vegetation as hardwood,
spruce-fir, pine and mixed forest types (Lathrop and Bognar,
Rutgers University). In the absence of a successfully-validated
soil WHC coverage (Lathrop et al. 1994), we have used a regional mean
value of 12 cm. Mean monthly climate values are determined as
functions of latitude, longitude and elevation, using a statistical
climate model developed for the region in combination with the DEM
(e.g. temperature Figure 9,
precipitation Figure 10; Ollinger et al. 1995).
Existing data on wet deposition and atmospheric concentrations of dry
deposition components were used to derive regional patterns in
deposition of all major ions (e.g. nitrogen
Figure 11, sulfur
Figure 12; Ollinger et al. 1993, 199 ). In
concert with the development of the regional GIS we began to work on
a new forest ecosystem model which would summarize accepted
physiological controls on water, C and N dynamics in as simple a
structure as possible, requiring only those inputs which could be
defined within a regional GIS. The result of this effort to date
is PnET, a nested
series of lumped-parameter models of carbon, nitrogen and water
fluxes in temperate and boreal forest ecosystems
(Figure 13). The different versions of
PnET are modular and build out from simplest to most complex.
Algorithms such as photosynthesis which are common to all versions are
identical between versions. Increasing complexity occurs by
layering additional algorithms, representing additional processes,
over the core processes in simpler or included versions.
PnET-Day uses foliar mass, specific leaf weight, foliar N concentration,
temperature and radiation flux to predict daily gross and net
photosynthesis of whole forest canopies, and has been validated against
daily summaries of eddy correlation carbon balance measurements from the
Harvard Forest (Aber et al. 1996). PnET-II adds carbon allocation and
respiration terms, as well as a full water balance to predict NPP,
transpiration and runoff. An empirical soil respiration terms allows
prediction of total ecosystem carbon balance under ambient conditions.
This version has been validated against annual NPP and monthly water
yield data from the Harvard Forest and Hubbard Brook ecosystems and is
used to predict the combined effects of climate change and increased
atmospheric CO2 on these processes (Aber et al. 1995). An earlier
version (Aber and Federer 1992) was also validated against data from
10 additional forest types across North America, and a recent
modification has extended the model to predict effects of
tropospheric ozone concentrations (Ollinger et al. 1997).
PnET-CN adds compartments for woody biomass and soil organic matter,
as well as algorithms for biomass turnover and litter and soil
decomposition to allow calculation of complete carbon and nitrogen
cycles. This version maintains the predictions for NPP and water
balance used for validation in PnET-II, and also compares well
with field data in predicting total annual, mean seasonal, and actual
time series rates of nitrate loss in streams (Aber et al. 1997a, 1997b).
An additional version of the model (PnET-BGC) is under development.
This uses multiple element limitations on NPP and element concentrations
in all pools to calculate cycling rates for all elements. This version
has been combined with the soil chemistry model CHESS (Santore and
Driscoll, Syracuse University) and used to predict stream and soil
chemistry (Postek et al. 1995). Both the PnET-CN and PnET/CHESS
versions represent significant collaborative efforts with Dr. Charles
Driscoll and other cooperators from the Hubbard Brook LTER site.
For regional productivity and water balances, PnET has been run for
each pixel of the 1 km resolution GIS data base. Predicted outputs
include annual net ecosystem production
(Figure 14), net primary production, wood
production and water yield (Figure 15).
Regional validation of water yield predictions have been carried out
using data summarized from gauged watersheds (Ollinger et al. 1997,
Bishop et al. 1997). Initial assessments of climate change effects
were made by Aber et al. (1995). Interactions with O3 have been
addressed by Ollinger et al. (1996, 1997). Impacts of N deposition
have been discussed relative to the ability of forest ecosystems to
retain and cycle N under undisturbed (Aber et al. 1997a) and
manipulated (Aber et al. 1997b) conditions. PnET has been used in
other settings as well. A methodology similar to that described here
has been used to develop soil and climate data planes, and to run
PnET regionally to predict potential forest productivity under
current and double CO2 conditions for Ireland, a country where
afforestation is occurring rapidly (Goodale et al. 1997a,b). At the
other extreme in spatial coverage, PnET has been used in conjunction
with estimates of canopy chemistry obtained by high resolution remote
sensing for the Prospect Hill tract at Harvard Forest (Martin and Aber
1996, 1997). Applications to sites in Japan, France and the Czech
republic have been carried out and manuscripts are submitted or in
Aber, J.D. and C.A. Federer. 1992. A generalized, lumped-parameter model
of photosynthesis, evapotranspiration and net primary production in
temperate and boreal forest ecosystems. Oecologia 92:463-474.
Aber, J.D. and C.T. Driscoll. In review. Effects of land use, climate
variation and N deposition on N cycling and C storage in northern
hardwood forests. Global Biogeochemical Cycles.
Aber, J.D., C.T. Driscoll, C.A. Federer, R. Lathrop, G. Lovett,
J.M. Melillo, P. Steudler and J. Vogelmann. 1993. A strategy for
the regional analysis of the effects of physical and chemical climate
change on biogeochemical cycles in northeastern (U.S.) forests.
Ecological Modeling 67:37-47.
Aber, J.D., P.B. Reich and M.l. Goulden. 1996. Extrapolating leaf CO2
exchange to the canopy: a generalized model of forest photosynthesis
validated by eddy correlation. Oecologia 106:257-265.
Aber, J.D., S.V. Ollinger, C.A. Federer and C. Driscoll. In press.
Modeling nitrogen saturation in forest ecosystems in response to land
use and atmospheric deposition. Ecological Modelling.
Aber, J.D., S.V. Ollinger, C.A. Federer, P.B. Reich, M.L. Goulden,
D.W. Kicklighter, J.M. Melillo and R.G. Lathrop, Jr. 1995. Predicting
the effects of climate change on water yield and forest production in
the Northeastern U.S. Climate Research 5:207-222.
Bishop, G.D., M.R. Church, J.D. Aber, R.P. Neilson, S.V. Ollinger and
C. Daley. In review. A comparison of mapped estimates of long-term
runoff in the northeastern United States. Journal of Hydrology.
Goodale, C.L., J.D. Aber and E.P. Farrell. In review. Applying an
uncalibrated, physiologically based model of forest productivity to
Ireland. Climate Research.
Goodale, C.L., J.D. Aber and S.V. Ollinger. Mapping monthly
precipitation, temperature and solar radiation for Ireland with
polynomial regression and a digitial elevation model. Climate Research.
Lathrop, R.G., J.D. Aber and J.A. Bognar. 1995. Spatial variability of
digital soil maps and its impact on regional ecosystem modeling.
Ecological Modeling 82:1-10.
Martin, M.E. and J.D. Aber. Estimating canopy characteristics as inputs
for models of forest carbon exchange by high spectral resolution remote
sensing. IN: Gholz, H.G., K. Nakane and H. Shimoda (eds.) The use of
remote sensing in the modeling of forest productivity. Kluwer Academic,
Dordrecht, The Netherlands, pp 61-72.
Martin, M.E. and J.D. Aber. 1997. Estimation of forest canopy lignin
and nitrogen concentration and ecosystem processes by high spectral
resolution remote sensing. Ecological Applications 7:431-443.
Ollinger, S.V., J.D. Aber and C.A Federer. In review. Estimating
regional forest productivity and water yield using and ecosystem model
linked to a GIS. Landscape Ecology.
Ollinger, S.V., J.D. Aber and P.B. Reich. Simulating ozone effects on
forest productivity: interactions between leaf,- canopy- and stand-level
processes. Ecological Applications.
Ollinger, S.V., J.D. Aber, C.A. Federer, G.M. Lovett and J.M. Ellis.
1995. Modeling physical and chemical climatic variables across the
northeastern U.S. for a geographic information system. U.S.D.A. U.S.
Forest Service General Technical Report NE-191. 30p.
Ollinger, S.V., J.D. Aber, G.M. Lovett, S.E. Millham, R.G. Lathrop and
J.M. Ellis. 1993. A spatial model of atmospheric deposition for the
northeastern U.S. Ecological Applications 3:459-4.
Postek, K.M., C.T. Driscoll, J.D. Aber and R.C. Santore. 1995.
Application of PnET-CN/CHESS to a spruce stand in Solling, Germany.
Ecological Modeling 83:163-1.
Landscape and Regional Impacts of Hurricanes
in New England and Puerto Rico
E. Boose, K. Chamberlin, M. Serrano, D. Foster
This project is studying the long-term hurricane disturbance regimes of
New England and Puerto Rico with a focus on the Harvard Forest (central
Massachusetts) and the Luquillo Experimental Forest (LEF; northeastern
Puerto Rico), two LTER sites with very different climate, topography,
forest vegetation, and land-use history. Our approach combines historical
research with computer modeling to reconstruct the impacts of past
hurricanes at spatial scales ranging from site (~1 km) to landscape
(~10 km) to regional (> 100 km).
For each hurricane, reports of actual wind damage to trees, buildings,
and other property are collected and indexed by town to create a database
for each storm. Primary sources are newspapers for recent centuries and
personal diaries and chronicles for earlier storms. Each report is
assigned a Fujita scale (F-scale) value using the classification scheme
proposed by T. Fujita for assessing wind damage in tornadoes and hurricanes.
A map of actual wind damage for each hurricane is then created by using
the maximum F-scale value for each town in the database (e.g. Hurricane
Bob, Figure 16; Boose et al. 1997).
Regional wind conditions and wind damage are reconstructed for each storm
using a simple meteorological model (HURRECON; Boose et al. 1997,
Boose et al. 1994). The model utilizes data on the track, size, and
intensity of a hurricane to reconstruct wind conditions at specific sites
and regional gradients of wind speed and direction during a storm. The
model can also predict damage on the Fujita scale using the correlations
between peak wind speed and damage proposed by Fujita. In historical
reconstructions the model provides informed estimates for sites lacking
The HURRECON model is parameterized for each region through detailed
studies of recent hurricanes. All reconstructions are tested by
comparing model results with available wind and damage data
(e.g. Hurricane Bob, Figure 17). Input data
for Atlantic hurricanes since 1886 are derived from the NOAA HURDAT
database. For earlier hurricanes, storm tracks and maximum wind
speeds are estimated from observed peak wind directions, observed
storm surges, and the regional patterns of observed wind damage.
Composite maps of long-term regional impacts are created by compiling
the results of individual hurricane reconstructions.
At a landscape scale, local topography may create complex patterns of
exposure to damaging winds. These topographic effects are estimated
with a simple model of topographic exposure to wind
Boose et al. 1994). Wherever possible model results are compared with
actual maps of landscape-level damage.
Results to date for New England show strong gradients across the region
from southeast (CT, RI, and southeastern MA coastlines) to northwest
(northern VT, NH, and ME) both in maximum intensity and in frequency
of hurricanes of a given intensity. These gradients resulted from the
consistent direction of the storm tracks, the shape of the coastline,
and the tendency for hurricanes to weaken rapidly over land or over
cold ocean water. Twenty-six hurricanes were reconstructed for the
period 1620-1885, and 36 hurricanes for the period 1886-1996. Average
return intervals for F0 damage (defoliation, branch break, occasional
blowdowns) ranged from 5 to 110 years; average return intervals for F1
damage (isolated blowdowns) ranged from 10 years to none in 110 years;
and average return intervals for F2 damage (extensive blowdowns) ranged
from 95 years to none in 375 years (Figure 18).
Hurricane impacts at individual sites appeared to be clustered in time,
with significant differences over relatively short distances (e.g. 100 km
between Petersham, MA and Providence, RI, Figure 19).
In Petersham (central Massachusetts) most of the landscape was
apparently subject to F2 damage during the historical period, with
small areas in protected valleys experiencing only F1 damage
The approach developed in this project can be used to study the impacts
of past hurricanes in any part of the world where good historical records
survive. Results can be combined with evidence of other past disturbances
(e.g. fire, disease, human land-use) to build a more complete picture of
long-term forest disturbance regimes for a particular region.
Preliminary results for Puerto Rico also show gradients across the island
from southeast to northwest in hurricane frequency and intensity, though
all areas were subject to repeated damage from hurricane winds. Both
frequency and intensity were significantly greater than in New England:
preliminary estimates for 71 hurricanes during the period 1886-1996 showed
average return intervals in the LEF of 11 years for F1 damage, 22 years
for F2 damage (Figure 21), and 111 years for F3
damage. Hurricane impacts at individual sites appeared to be clustered
in time, with significant differences over relatively short distances
(e.g. 150 km between the LEF and Mayaguez,
Figure 22). In the LEF, landscape-level damage
during this 111 year period was dominated by F3 winds from the NE and E
during the 1928 hurricane, with lesser damage (F2) on southwestern
slopes and scattered pockets of minor damage (F1) or no damage in deep
valleys or ravines (view toward south, Figure 23;
view toward north, Figure 24. Future work will
examine the major hurricanes of the earlier historical period, 1508-1885.
Boose, E. R., K. E. Chamberlin and D. R. Foster. 1997. Reconstructing
historical hurricanes in New England. Pp. 388-389 in Preprints of 22nd
Conference on Hurricanes and Tropical Meteorology, American Meteorological
Society, Boston, MA.
Boose, E. R., D. R. Foster, and M. Fluet. 1994. Hurricanes impacts to
tropical and temperate forest landscapes. Ecological Monographs 64: 369-400.
Foster, D. R., M. Fluet and E. R. Boose. In review. Human or natural
disturbance: landscape-scale dynamics of the tropical forests of Puerto
Rico. Ecological Applications.
Foster, D. R. and E. R. Boose. 1995. Hurricane disturbance regimes in
temperate and tropical forest ecosystems. Pp. 305-339 in Wind and Trees.
M. P. Coutts, ed. Cambridge University Press.
Foster, D. R. and E. R. Boose. 1992. Patterns of forest damage resulting
from catastrophic wind in central New England, U.S.A. Journal of
Ecology 80: 79-98.
Foster, D. R. 1988. Disturbance history, community organization and
vegetation dynamics of the old-growth Pisgah Forest, south-western New
Hampshire, U.S.A. Journal of Ecology 76: 105-134.
Foster, D. R. 1988. Species and stand response to catastrophic wind in
central New England, U.S.A. Journal of Ecology 76: 135-151.
Regionalization studies at the Harvard Forest LTER have been supported
by funds from the following sources:
Bermuda Biological Station for Research
Dept. of Energy - National Institute for Global Environmental Change
Environmental Protection Agency
A. W. Mellon Foundation
National Aeronautics and Space Administration
National Biological Service (LUHNA)
National Science Foundation - Ecosystems Studies
National Science Foundation - Long-term Studies
National Science Foundation - Research Experience for Undergraduates
U.S. Forest Service