9^th Annual Harvard Forest Summer Research Program

15 August 2001

• Introduction to Harvard Forest
• Summer Research Program
• Symposium Program
• Abstracts
• Seminars and Workshops
• Summer Research Assistants
• Mentors and Participants
• Personnel at the Harvard Forest

INTRODUCTION TO THE HARVARD FOREST

Since its establishment in 1907 the Harvard Forest has served as a center for research and education in forest biology. Through the years researchers have focussed on silviculture and forest management, soils and the development of forest site concepts, the biology of temperate and tropical trees, forest ecology, forest economics, landscape history, conservation biology and ecosystem dynamics. Today, this legacy of research and education continues as faculty, staff, and students seek to understand historical and modern changes in the forests of New England and beyond resulting from human and natural disturbance processes, and to apply this information to the conservation, management, and appreciation of natural ecosystems. This activity is epitomized by the Harvard Forest Long Term Ecological Research (HF LTER) program, which was established in 1988 through funding by the National Science Foundation (NSF).

Physically, the Harvard Forest is comprised of approximately 3000 acres of land in the north-central Massachusetts town of Petersham that include mixed hardwood and conifer forests, ponds, extensive spruce and maple swamps, fields and diverse plantations. Additional land holdings include the 25-acre Pisgah Forest in southwestern New Hampshire (located in the 5000-acre Pisgah State Park), a virgin forest of white pine and hemlock that was 300 years old when it blew down in the 1938 Hurricane; the 100-acre Matthews Plantation in Hamilton, Massachusetts, which is largely comprised of plantations and upland forest; and the 90-acre Tall Timbers Forest in Royalston, Massachusetts. In Petersham a complex of buildings that includes Shaler Hall, the Fisher Museum, and the John G. Torrey Laboratories provide office and laboratory space, computer and greenhouse facilities, and a lecture room for seminars and conferences. Nine additional houses provide accommodations for staff, visiting researchers, and students. Extensive records, including long-term data sets, historical information, original field notes, maps, photographic collections and electronic data are maintained in the Harvard Forest Archives.

Administratively, the Harvard Forest is a department of the Faculty of Arts and Sciences (FAS) of Harvard University. The Harvard Forest administers the Graduate Program in Forestry that awards a Masters degree in Forest Science and faculty at the Forest offer courses through the Department of Organismic and Evolutionary Biology (OEB), the Kennedy School of Government (KSG), and the Freshman Seminar Program. Close association is also maintained with the Department of Earth and Planetary Sciences (EPS), the School of Public Health (SPH), and the Graduate School of Design (GSD) at Harvard and with the Department of Natural Resource Conservation at the University of Massachusetts, the Ecosystems Center of the Marine Biological Laboratory at Woods Hole, and the Complex Systems Research Center at the University of New Hampshire.

The staff and visiting faculty of approximately 50 work collaboratively to achieve the research, educational and management objectives of the Harvard Forest. A management group comprised of the Director, Administrator, Coordinator of the Fisher Museum, and Forest Manager meets monthly to discuss current activities and to plan future programs. Regular meetings with the HF LTER science team, weekly research seminars and lab discussions, and an annual ecology symposium provide for an infusion of outside perspectives. The four-member Woods Crew and Forest Manager undertake forest management and physical plant activities. The Coordinator of the Fisher Museum oversees many educational and outreach programs.

Funding for the Harvard Forest is derived from endowments and FAS, whereas major research support comes primarily from the National Science Foundation, Department of Energy (National Institute for Global Environmental Change), U.S. Department of Agriculture, NASA, and the Andrew W. Mellon Foundation. Our summer Program for Student Research is supported by the National Science Foundation, the A. W. Mellon Foundation, and the R. T. Fisher Fund.

Summer Research Program

The Harvard Forest Summer Student Research program, coordinated by Edythe Ellin and assisted by Sarah Laubscher, attracted a diverse group of students to receive training in scientific investigations, and experience in long-term ecological research. Students work closely with faculty and scientists, and many conduct their own independent studies. The program includes weekly seminars from resident and visiting scientists, discussions on career issues in science (e.g., career decisions, ethics in science), and field exercises on soils, land-use history, and plant identification. An annual field trip is made to the Institute of Ecosystem Studies (Milbrook, NY) to participate in a Forum on Careers in Ecology. At the Annual Summer Student Research Symposium students present major results of their work.

NINTH ANNUAL HARVARD FOREST SUMMER STUDENT SYMPOSIUM
15 AUGUST 2001
HARVARD FOREST – FISHER MUSEUM

TIME	EVENT	SPEAKER
9:00 AM	COFFEE	XXXXXXXXXXXXXXXXXX
9:30	INTRODUCTION	David Foster
9:45	Thirty-Two Years of Population Change in A Hardwood Stand at Harvard Forest, Petersham, MA	Kristin Wilson
10:00	Vegetation Dynamics Associated with Long-Term HWA Infestation in Southern CT	Kathleen Theoharides
10:15	Foliar Carbon and Nitrogen Dynamics in Hemlock Woolly Adelgid Infested Stands	Spencer Meyer
10:30	Hemlock Woolly Adelgid and Avian Communities	Morgan Tingley
10:45	Changes in Land Protection Patterns in the North Quabbin Region, Massachusetts	Susan Italiano
11:00	COFFEE BREAK	XXXXXXXXXXXXXXXXXX
11:15	Maple Leaves Sip Whereas Oak Leaves Chug: A Tale Of Two Designs	Peter Cowan/Truus Thomas
11:45	Long-Term Patterns In Tree Growth: A Comparison In Methodologies	Julia Silvis
12:00 PM	A Comparison Of Stocks Of Coarse Woody Debris Before And After A Selective Harvest	Bridgid Curry
12:15	LUNCH	XXXXXXXXXXXXXXXXXX
1:30	Effects of Soil Moisture on Methane Oxidation Rates in the Harvard Forest	Linda Jane Wan
1:45	Effects of Nitrogen Deposition on Soil Respiration in the Harvard Forest	Christian Arabia
2:00	Spatial Heterogeneity & Wind Effects on Soil Respiration Methodology	Rosa Navarro
2:15	The New Soil Warming Site: History And Recent Carbon Storage of A Mixed Hardwood Stand	Caitlin Dwyer-Huppert
2:30	CONCLUDING REMARKS	David Foster
5:30	BARBECUE	XXXXXXXXXXXXXXXXXX

Effects of N Deposition on Soil Respiration in the Harvard Forest

Chris Arabia

Prior studies have shown that long-term N deposition in temperate forest ecosystems results in decreased productivity and ground-level vegetation, and an increased mortality rate among tree species. All of these factors can affect the rates of soil respiration through changes in root respiration, decomposition and inputs of carbon to the soil. This study was based at the Harvard Forest Chronic N Experiment, where 13+ years of N addition (+50 and +150 kg N Ha-1 yr-1) on coniferous and deciduous forest have degraded canopy structure and understory growth in treated sites. Recent data have shown that the sites with N treatment exhibit lower rates of soil respiration than untreated, control sites (Fig. 1a).

The two primary factors controlling rates of soil respiration have been shown to be root respiration and microbial decomposition. This experiment investigates the role of microbial decomposition on soil respiration rates by isolating the soil from the roots.

Soil cores were taken at each site and incubated in sealed jars at field moisture over a period of 3 hours. Gas samples were taken from the jars at times 0, 60, 120 and 180 min., and analyzed for changing CO2 concentration. Trends in average CO2 fluxes for each plot (Fig. 1b) were similar to those observed from soil respiration sampling in the field. By showing a similar trend between the soil incubation and field respiration rates, the data suggests that nitrogen deposition within the Chronic N Experiment has affected the rate of microbial decomposition, which has led to an observed decrease in CO2 production and flux in the treated sites.

A Comparison of Coarse Woody Debris Stocks Before and After a Selective Harvest

Bridgid Curry

Harvesting is a human disturbance that significantly impacts the carbon cycle in forests by affecting soil and vegetation, altering the quantity of dead wood, creating space for recruitment into the stand, and increasing the available light. A selective harvest on an 80-acre tract of land adjacent to Harvard Forest provided an opportunity to study changes in carbon stocks, uptake, and respiration with harvest. A pre-harvest survey found that 8.78 MgC/ha was stored in coarse woody debris (CWD). Data collected following harvest showed that the CWD pool increased to 13.23 MgC/ha. Carbon in the form of logs increased from 3.78 MgC/ha to 9.92 MgC/ha and carbon in stumps increased from 0.25 MgC/ha to 1.21 MgC/ha. Prior to the harvest, there was 4.76 MgC/ha in the form of snags that was reduced to 2.10 MgC/ha (Fig. 1). The reduction in snag biomass resulted from both direct removal during harvest and secondary damage to snags which created logs. Continued monitoring of soil respiration, tree growth, CWD decomposition, and leaf litter in the harvest plots will determine the long-term impact on the carbon cycle.

The New Soil Warming Site: History and Recent Carbon Storage of a Mixed Hardwood Stand

Caitlin Dwyer-Huppert

Land history and tree growth recorded in annual rings give us greater understanding of potential research sites. Preparations for the new soil warming plot at Harvard Forest, Petersham, MA include investigation of these subjects. The site, located in the northernmost compartment (I) of the Slab City Tract was pastured in the 19th C and managed as a pine stand by Harvard Forest after its 1908 acquisition. The 1938 Hurricane destroyed the site and salvage operations followed. Oak and red maple were the dominant colonizers of the blowdown. Questions regarding the relative carbon storage of the tree species and factors influencing their growth rates will be important for interpreting the effects of increases of temperature on tree growth. Increment cores allow us to estimate the carbon accumulation in the above ground woody biomass of the tree species and study their relative growth rates. Annual carbon storage from 1990-2000 was estimated for hardwood species in the new soil-warming plot. Growth rings of four sets of trees were measured: 25 each of red oak (Quercus rubra), red maple (Acer rubrum), and white ash (Fraxinus Americana), and 18 of yellow birch (Betula alleghaniensis) and published allometric equations were used to estimate yearly biomass additions based on tree ring width. The growth was then transformed to amount of carbon fixed (kg/tree/yr).

The red oak is the most dominant species in the stand, accumulating biomass faster than the other hardwood species and thus fixing the highest proportion of carbon (Fig.1). Carbon storage trends of 1990-2000 for each species depict a decline for ash, red maple, and yellow birch while red oak continue to store carbon at a steady rate. This indicates competition favoring red oak. How will the trees respond as increased temperatures affect soil nutrient dynamics? Dendrochronological studies based on increment cores document long-term trends in tree growth and carbon fixation. Coupled with climate records they may add to our understanding of the effects of global warming on the carbon cycle.

Raup, H. M. and C. E. Reynold. 1941. The History of Land Use in the Harvard Forest. Harvard Forest Bulletin No. 20. Harvard Forest, Petersham, MA.

Tritton, L. M. and J. W. Hornbeck. 1982. Biomass Equations for Major Tree Species of the Northeast. USDA For. Serv. Gen. Tech. Rep. NE-69. p. 9-26.

Changes in Land Protection Patterns in the North Quabbin Region, Massachusetts

Susan Italiano

The loss of open space to residential, commercial and industrial development has accelerated over the last decade. Spurred by the threat of rampant development, private, municipal, state and federal organizations and agencies are making efforts to protect open space. With the effort of over 25 government and private land protection agencies in the North Quabbin Region (NQR), Massachusetts, conservation planning and design is possible. Alisa Golodetz developed a comprehensive database of the NQR, capturing the spatial placement of parcels with associated attribute data including ownership, protection level and acquisition date (Golodetz and Foster 1997). Continuing with Golodetz's methodology, updated spatial information was collected and transferred to USGS topographic quads. Patterns in conservation revealed a greater than 10% increase in land protection. Acquisition patterns suggested state funding has also been a major contributor to protected open space as state agencies continue to represent the largest conservation force. Fee ownership was found to be the leading acquisition type with conservation restrictions and the Agriculture Preservation Restriction program following respectively. Maintaining a spatial database of conservation activity will allow agencies and organizations to recognize gaps where open space protection efforts might be concentrated. Filling in these gaps will promote landscape level management for connectivity, expansion of the interior forest and protection and promotion of biodiversity, recreation and water quality.

Golodetz, A. and D. Foster. 1997. History and importance of land use and protection in the North Quabbin Region of Massachusetts (USA). Conservation Biology 11:227-235.

Foliar Carbon and Nitrogen Dynamics in Hemlock Woolly Adelgid Infested Stands

Spencer Meyer

Hemlock Woolly Adelgid (Adelges tsugae) depletes eastern hemlock (Tsuga Canadensis) nutrients through its stylet, rather than defoliating like most herbivores do. The ensuing ecosystem stress is a major concern as stand dynamics change. Shade-tolerant hemlock stands convert to mixed-hardwood stands with long-term HWA infestation.

At eight sites of varying infestation in Connecticut and two control sites in Massachusetts, hemlock foliage was sampled for chemical analysis. Where it was a major constituent, black birch (Betula lenta, hemlock’s primary successor) foliage was also sampled. Hemlock foliage was separated by age class, yielding subsamples of foliage from 1999 and 2000. Current year growth was excluded. All foliage was analyzed for C and N on a Fison CHN Analyzer.

No significant differences between age classes were witnessed. Uninfested sites averaged 1.39% N and 48.47% C, while infested sites showed 1.31% N and 48.41% C. Birch foliage had nearly double the amount of foliar N, at 2.69% and 50.22% C (Fig.1). Soil from the same sites collected in 1998 (Orwig et al., unpublished) show 1.18 and 1.27% N (infested and uninfested, respectively) and 27.70 and 34.54% C (Fig. 2). Smaller pools of C and N in both foliage and soil suggest greater nutrient mobility in the infested sites. The birch foliage results show significantly higher concentrations of C and N, indicating an increase in nutrient availability at sites with few living hemlocks.

Further chemical analysis of both foliage and soil is needed to better understand ecosystem changes of HWA infestation. Study of lignin concentrations and decomposition rates will help to qualify nutrient mobility. Current data shows nutrient availability change in HWA infested ecosystems. However, the specific biogeochemical effects of the adelgid on hemlock are not yet known.

Wind Effects On Soil Respiration Measurement Methodology

Rosa Navarro

Soil respiration, which includes both root and microbial respiration, is one of the largest and most important fluxes of carbon in terrestrial ecosystems. Soil respiration occurring within the soil and litter layers is measured directly using an IRGA (infrared gas analyzer). A chamber top is placed over a 10” PVC collar set in the soil surface, and the soil respiration rate is derived from the increase of CO2 concentration in the sealed chamber, of known volume, over a 5 minute sampling period.

Though this chamber-based methodology of measuring soil respiration and other trace gas emissions from soils has been used for many decades, there are some concerns regarding possible artifacts and biases, which may result in over or under estimation of flux rates. Examples of chamber artifacts are pressure differences between the inside and outside of the chamber, spatial and temporal variation, and the effects of wind. The lattermost, and its effect on CO2 flux, is the chamber artifact, which was explored further in this experiment.

Soil respiration was measured under four different wind intensities (created by a 20” box fan with 3 level settings): no fan-natural wind (<0.2 m/s), low (~0.8 m/s), medium (~1.95 m/s), and high (~2.8 m/s). The fan was placed 1 m from the collar. Wind speed was measured using an anemometer, which stood 30 cm above ground right next to the collar. Sampling was conducted in the morning hours, on two consecutive days, near the EMS (Ecological Monitoring System) tower at Harvard Forest.

No relationship between different wind speed and mean CO2 flux was observed (Fig. 1). In conclusion, studies thus far have not provoked a consistent bias in flux measurements with altering wind speeds. Further studies will include randomizing wind speed order of measurement; allowing more time (with no wind) between measurements; as well as placing the fan at different angles towards the collar.

Long-Term Patterns In Tree Growth

Julia Silvis

Tree ring variations record long-term patterns of forest growth and can be used to reconstruct forest responses to past weather and disturbance events. Tree cross-sectional pieces were cut during a 2001 selective harvest on a tract of private land south of the EMS tower at Harvard Forest. The growth rings were measured and above-ground woody increment (AGWI) estimated for 16 trees across 5 species (Fig. 1). The annual diameter increment ranged from 0.22 mm, found in a maple (Acer rubrum) to 18.54 mm, found in an oak (Quercus rubra). By species, maples had the smallest annual mean increment (2.79 mm), and oaks one of the largest (4.76 mm). The oldest trees in the survey were a 1832 hemlock (Tsuga Canadensis) and 1839 beech (Fagus grandifolia); the youngest tree sampled was a birch (Betula papyrifera) from 1950. A cohort dating from the 1870s represented 7 of the 16 trees in the sample. Deviations from the long-term mean AGWI could be correlated with annual precipitation trends (Fig. 2), disturbance events and land use changes. The 2001 selective harvest altered the species distribution and stand composition by preferentially removing larger trees, most specifically oak. The sprouting tendencies and current distribution of beech will likely result in a significant species biomass shift with the future stand development. This baseline history provides a context for understanding and quantifying the impact of this selective harvest on the carbon exchange.

Vegetation Dynamics Associated With Long – Term HWA Infestation In Southern Connecticut Hemlock Stands

Kathleen Theoharides

Hemlock Woolly Adelgid (HWA; Adelges tsugae), an introduced pest from Japan, has moved up the East Coast through the range of the eastern hemlock (Tsuga Canadensis) since 1950. HWA can severely reduce or eliminate this important late successional species and create subsequent changes in the unique ecosystem associated with the hemlock. Eight sites in southern Connecticut were monitored to assess long-term patterns of decline and mortality of overstory hemlock and the associated changes in understory vegetation resulting from HWA. Tree mortality has increased at each site during the last six years. Canopy gaps created by HWA damage allowed more light to penetrate to the forest floor, resulting in a rapid understory response. The sites with the most HWA damage experienced the most significant understory response involving, but not limited to, black birch (Betula lenta), red maple (Acer rubrum), sugar maple (A. saccharum), and oak seedlings (Quercus spp.). Opportunistic shrub and herb species such as grape vine (Vitis spp.) and raspberry (Rubus spp.), bittersweet (Celastrus spp.) and fern also responded to increased light. In sites containing invasive species such as Japanese stilt grass (Microstegium vimineum), Japanese barberry (Berberis thunbergii) and Asiatic bittersweet (Celastrus orbiculatus), the occurrence of plots containing these species increased significantly in the last few years, suggesting that hemlock mortality and the altered ecosystem create a more favorable setting for these plants. Hemlock seedlings were scarce within the sampled stands, in part due to HWA damage, suggesting that regeneration of hemlock in damaged stands is not likely. This study provides a unique opportunity to study the impact of the removal of a dominant forest species on ecosystem structure and composition.

The Effects of Adelgid-induced Changes in Eastern Hemlock Forests on Bird Communities

Morgan W. Tingley

With the anticipated decline of the eastern hemlock (Tsuga Canadensis) due to infestations of hemlock woolly adelgid (HWA, Adelges tsugae), there is concern about how this structural change to Eastern forests will affect wildlife - specifically avifauna. In this project – a continuation of work from June and July 2000 - I conducted bird surveys at 40 points in 12 hemlock-dominated stands in central Connecticut. Point counts of bird vocalizations and sightings lasted 10 minutes and used a fixed 50 m radius, following the BBIRD standard. Two survey replicates were completed between June 6 and July 4, 2001. Individual points were classified by hemlock mortality level and vegetation structure (Table 1) in order to differentiate between high hemlock mortality areas with aggressive Betula lenta re-growth (Hi-B), and those with high mortality but less re-growth due to an intact canopy of broadleaf species (Hi-A). In general, high mortality level points held higher diversity than undamaged hemlock stands. The addition of the 2001 high count data, averaged with the 2000 data, clarified many trends in individual species, showing either rapid growth or decline with the changing forests (Fig. 1). Of all the species negatively affected by hemlock demise, the black-throated green warbler (Dendroica virens) has consistently shown the greatest change (94% decline from Low to Hi-B). Species positively affected include woodpeckers and edge or gap-associated species. Several species were specifically abundant in the temporal habitat of the Hi-B areas, including the regionally scarce Hooded Warbler (Wilsonia citrina). Ultimate effects on bird populations will be determined by adaptability of species to the new growth of deciduous hardwoods.

Maple Leaves Sip Whereas Oak Leaves Chug: A Tale Of Two Designs

Truus Thomas and Peter Cowan

We studied the leaf hydraulic design of sun and shade leaves of several species of Harvard Forest trees. This presentation focuses on Acer saccharum and Quercus rubra, ecologically distinct species. Although the two species can occupy similar habitat at maturity, during establishment A. saccharum tolerates deeper shade, while Q. rubra grows faster and, rooting more deeply, tolerates stronger drought. We determined leaf hydraulic and stomatal conductances (Kleaf and g respectively), stomatal density, leaf mass per area (LMA), and pressure-volume curves, which provide parameters such as turgor loss point (TLP) and leaf capacitance near TLP (CTLP), indicating water storage. We expanded our study of leaf vascular design by cutting the different leaf vein orders and measuring effects on transpiration. Strong differences were found in each feature. Q. rubra leaves move water faster than A. saccharum leaves, with more than triple the Kleaf and g (Fig. 1A and B), and a significantly higher stomatal density (456 vs 291 per mm2). The greater drought tolerance of Q. rubra is reflected in its lower TLP (-2.1 vs –1.6 MPa), arising in part from a more rigid leaf, of higher LMA (50 vs 35 g/m2). Q. rubra leaves survive extensive cuts to the vasculature that kill A. saccharum leaves. However, Q. rubra has a lower water storage capacity than A. saccharum (CTLP values 3.2 vs 5.7 % water MPa-1). Such differences in leaf hydraulic design are potentially very important in determining species’ relative performances in overall resource-use and growth, and their distinct ecological roles.

The Effect of Soil Moisture on Methane Oxidation in the O and A Horizons of Harvard Forest Soils

Linda Jane Wan

Methanotrophs are responsible for between 3% and 9% of the total consumption of atmospheric CH4, the principal terrestrial biological sink. To better evaluate how future climatic changes will alter the terrestrial CH4 sink, we need to examine the processes influencing CH4 flux under field conditions. In order to study soil moisture’s effect on methanotrophic activity, we manipulated soil water content (SWC). To compare the methanotrophic activity with respect to individual soil horizons at varying water contents, 5 soil samples were taken from the L, F, H, and A Horizons, respectively. Subsamples of all soils were dried at 105° C for 24 hours to determine SWC. Various water contents were adjusted by adding water or air-drying at ambient temperature. After one week of equilibration, samples were incubated for 9 hr in air-tight glass jars. CH4 concentrations were analyzed on the GC at intervals varying from 0.5 hour to 9.5 hr. Utilizing non-linear regression analyses, we ascertained the relationship between CH4 oxidation rates and soil moisture. Incubations have demonstrated no CH4 oxidation or production in the L-, F-, and H-horizons. However, there is a logarithmically decreasing CH4 concentration from ambient down to 50 ppb in the A-horizon over time (Fig. 1). As CH4 oxidation occurs primarily in the A-horizon, the CH4 oxidation rate was quantified in terms of SWC. As indicated by Fig. 2, the relationship between SWC and CH4 oxidation rate is curvilinear and increases to an optimum point of approximately 0.3 g H2O g-1 soil and begins to decrease exponentially. Overall, Harvard Forest soils exhibit an extremely strong CH4 oxidation rate, one of the strongest sinks ever documented. This is caused by the soil’s unique texture, propitious to higher CH4 diffusivity, and consequently results in higher uptake. SWC affects CH4 oxidation through gas diffusivity in the soil. At higher SWC there is lower gas diffusivity while there is higher gas diffusivity at lower SWC; at very dry SWC, methanotrophs are limited by water stress. In such temperate forests as Harvard Forest, soil moisture is a dominant factor in regulating CH4 oxidation rates.

Thirty-two Years of Population Change in a Hardwood Stand at Harvard Forest, Petersham, MA

Kristin Wilson

Permanent plot studies documenting forest change over a large area and extensive period of time are extremely valuable. This study, established by Walter Lyford over a 7.13 acre area at Harvard Forest in the 1960s, includes detailed spatial features, including trees and a damage boundary from the 1938 hurricane (Fig. 1). The objectives of this study were to continue the 32-year study and to determine whether the effects of the 1938 hurricane are still evident, in terms of forest stand structure and species composition. In summer 2001, we measured condition, canopy class, and dbh of live trees. For dead trees, condition, decay class, ~dbh, bole length, and orientation were measured. New trees >=2 inches were added; most new trees were mapped using triangulation (Boose et al. 1998). All of Walter Lyford’s original, hand-drawn maps were digitized into GIS format. Since 1969, the entire site has decreased in stem density as basal area has increased. Overall stem densities are higher in the hurricane area. Both areas show a decrease in stem density with a much more rapid decrease in the hurricane area. Basal areas are higher outside of the hurricane area; however, both areas show an increase in basal area with a slightly more rapid increase in the hurricane area. Red maple and birches appear to be the most important species in the hurricane area, while oaks appear most important outside (Fig. 2). Densities of wind thrown trees are much higher inside the hurricane area than outside (Table 1). The trends in the hurricane area seem consistent for a stand in an earlier stage of development; however, alternate explanations such as slightly differing land use histories or differences in soil moisture are possible. In conclusion, there are persistent differences between the severely affected hurricane area and the rest of the site.

Boose, E. R., E. F. Boose, and A. L. Lezberg. 1998. A practical method for mapping trees using distance measurements. Ecology 79: 819-827.

2001 STUDENT SUMMER PROGRAM SEMINARS AND WORKSHOPS

FOWARDING ADDRESSES – SUMMER STUDENTS 2001

Chris Arabia, Allegheny College
Box 1676
Allegheny College
Meadville, PA 16335
arabiac@allegheny.edu

Tricia Burgoyne, University of Wisconsin
N79 W5289 Bywater Lane
Cedarburg, WI 53012
tburgoyne@hotmail.com

Peter Cowan, Kalamazoo College
10827 N. 12th Street
Plainwell, MI 49080
K98pc02@kzoo.edu

Bridgid Curry, University of Notre Dame
10827 Bulla Road, Apt. C
South Bend, IN 46637
bcurry@nd.edu

Caitlin Dwyer-Huppert, Clark University
35 Clement Street, Apt. #1
Worcestor, MA 01610
cdwyerhuppert@yahoo.com

Susan Italiano, Gettysburg College
1078 Gettysburg College
Gettysburg, PA 17325
italsu02@gettysburg.edu

Lynda Joudrey , University of New Hampshire
3F Bass Street
Newmarket, NH 03857l
lyndust@hotmail.com

Spencer Meyer, Dartmouth College
HB 3250
Hanover, NH 03755
srm@dartmouth.edu

Rosa Navarro, Stanford University
15837 Londelius Street
North Hills, CA 91343
Rnavarro@stanford.edu

Julia Silvis, Harvard University
420 Mather Mail Center
Cambridge, MA 02138
jsilvis@fas.harvard.edu

Katie Theoharides, Dartmouth College
Hinman Box 2844
Hanover, NH 03755
kathleen.a.theoharides@dartmouth.edu

Truus Thomas, Benedict College
P.O. Box 351
Thomson, GA 30824
truusandrew@hotmail.com

Morgan Tingley, Harvard University
31 Elliot Street
Exeter, NH 03833
mtingley@fas.harvard.edu

Linda Jane Wan, University of Pennsylvania
409 Sansom West
Box 115
3650 Chesnut St., Philadelphia, PA 19104
ljanewan@hotmail.com

Kristin Wilson, Middlebury College
MC Box 3608
Middlebury College
Middlebury, VT 05753
kwilson@middlebury.edu

Sarah Laubscher
85 North Whitney Street
Amherst, MA 01002
srl124@hotmail.com

HARVARD FOREST SUMMER PROGRAM 2001
MENTORS AND PARTICIPANTS

David Foster and Audrey Barker-Plotkin
Harvard Forest
Kristin Wilson

David Orwig and Richard Cobb
Harvard Forest
Spencer Meyer
Kathleen Theoharides
Morgan Tingley

David Foster, Glenn Motzkin, and Dana McDonald
Harvard Forest (on Long Island and coastal New England)
Tricia Burgoyne
Lynda Joudrey

David Kittredge and Andrew O. Finley
Harvard Forest and UMass. - Amherst
Susan Italiano

PERSONNEL AT THE HARVARD FOREST 2000-2001