Report on LIDET Workshop
March 23-25th, 1996
Sevilleta Field Station
Compiled by M. E. Harmon
I.
Over view
A
two day workshop was held at the Sevilleta Field Station to discuss the
analysis of data being collected as part of the LIDET (Long-term Intersite
Decomposition Experiment Team) project.
The meeting started with a series of progress reports on the status
data, preliminary analyses of key data sets, and concluded with a briefing on
the CIDET experiment being conducted in Canada. The rest of the meeting was devoted to planning the analysis and
publication of the existing data.
II. General Points of Agreement
Several
general points were agreed to by the participants:
A. All the data that is currently available (or
that can be brought on line by early summer) will be used in the analyses
proposed at the workshop.
B. Participants are free to publish using data from their own site. There
were few plans to do this, however, this option is always open to
individual sites.
C. The venues for publication will be two fold:
1) a general overview paper for Nature that describes the major conclusions and
2) a set of papers to be published
jointly in Ecological Applications or Ecology. If the papers are not accepted as a set, then individual
manuscripts will be submitted by the subcommittees drafting the papers.
D. Drafts of the manuscripts will be produced
by the authors by October 1, 1996.
These will be reviewed by an Editoral Committee (H. Gholz , M. Harmon,
D. Wedin) to check for consistency, overlaps or gaps in coverage, etc. The overall goal will to be able to send in
draft manuscripts with the renewal proposal that will be submitted December 15,
1996.
E. Authorship on the papers will be determined
by the level of participation. An
exception will be the manuscript submitted to Nature which will be a LIDET
authored piece. A tenative lead author
for each of the other manuscripts was assigned at the workshop and potential co-authors
signed up on topics of interest. The
number authors and order of authorship of each manuscript is to be determined
by the subcommittee writing the manuscript.
F. The participants agreed to several data
related tasks to help the overall analysis:
1)
The first will be to check the data they recieved at the workshop for possible
outliers. The primary data set to examine is the TD2309.* file
which contains the mass loss data. The
deadline for completing this screening of the raw data is May 1, 1996. Return all comments concerning outliers and suspecious data points
to Mark Harmon. The plan is to have the
corrected data available by May 15, 1996.
2) The second task will be to contact the
appropriate person at their site to compile and send climatic data to Bill
Parton. The minimum data required will be long-term averages for
mean monthly air temperature, mean monthly minimum air temperature, mean
monthly maximum temperature, and mean precipitation. If at all possible, the participants should compile and send data
for the period during which the litter was decomposing. If available, soil temperature data would
also be helpful. The deadline for sending these data to Bill Parton is June 1,
1996.
3) Data on soil characteritics including soil
texture (including fraction in coarse fragments) and soil depth to the nearest
5 cm are also required to estimate moisture balances. Finally, estimates of
leaf area index for the sites where incubations were conducted are needed. This would include not only the range in
leaf area typical for these sites, but the period (starting and ending months)
that leaf cover occurs. The deadline for sending these data to Bill Parton is
June 1, 1996.
G. A LIDET specific mailing list was created by
the LTER Network Office. To use this
mailing list mail send a message to LIDET@lternet. edu. This is “private line” so to speak, so feel
free to be frank during communications.
Just don’t go over the top!
III. Outlines of the Manuscripts
A.
Nature Manuscript
All
the participants contributed to the general discussion and outlining of the
Nature manuscript.
Working
Title: Broad-scale patterns of litter
decomposition: implications for stable soil organic matter formation.
Authorship:
LIDET
INTRODUCTION
*The main hook is the
critical importance of the decomposition process in the global C
cycle/balance....decomposition as a control of ecosystem functioning.
*Aber and Melillo's "plant to humus (SOM)
continuum". This is an emphasis on long-term patterns.
Can we predict the amount of plant C that is
"stabilized"?
Are there climates that are
more favorable for "stabilization"?
Are there species more prone to forming stabilized material?
*Testing substrate quality
and climate control (Meentemeyer paradigm) on decomposition. This is emphasis on short-term patterns in
the first 2 years.
*Refer to previous
experience with process models-a la Moorhead et al. manuscript.
*Possible hook on the
potential effects of biodiversity and climate change. Is litter quality (i.e. species differences) critical relative to
incremental climate change? (Problem:
we didn't address interspecific differences vs intraspecific plasticity in
tissue chemistry).
SECTION A
* The big question is litter
quality vs climate control on short-term decomposition and long-term (stable
pool formation) decomposition.
*Is it really true that all
litters converge on a similar amount of "stable" pool (Aber's initial
15-20% hypothesis). This is a major
unanswered question. Examples of Swedish and Rothemstead studies as possibly having
contrasting results. Note: Bill Parton
can you send us all the reference for the Swedish study? I think you mentioned this during the
discussion. If it wasn’t you then some
who recalls please let litterbag cnetral know.
SECTION B
* Review and discuss
adequacy of existing empirical models: Aber, Taylor, Meetemeyer, Melillo
*Lignin & AET, C/N
ratios, Lignin/N, LCI - note most of
these models really deal with the first year or two. Are they adequate for long-term representation?
*Do process models give
similar results as empirical models?
SECTION C
*Generating the response
surface of climate vs substrate quality:
INDEPENDENT VARIABLES
CLIMATE
AET
Defact (CENTURY
and others)
cooling
degree days
degree
days
SUBSTRATE QUALITY
lignin,
N, P, Carbon, LCI
DEPENDENT VARIABLES
Decomposition rate-constant K
(ash free, one value for whole time period for each standard litter type at
each site. N = ca.250)
The "two K model"
- incorporating a "stable" pool for sites and litters for which
decomposition has progressed to an advanced degree. Compare single and compound exponential models (and others?)
N<250
SECTION D - WRAP UP
*Surprises, unexpected
results, are there patterns in the outliers and residuals?
*After construction of the
above empirical model using the K values, how well can we predict the
decomposition values for the Wild Cards.
N= ca. 150.
*Speculation on the
importance of detrital pathway (vs herbivory?), or shifts in species
composition (exotics) in controlling ecosystem functioning.
* Do we learn something new
in long-term vs short-term studies?; single site vs multisite?; single biome vs
multi-biome? Do we need 28 sites?
B. Other Manuscripts
All
the partcipants contributed ideas for potential topics for manuscripts that
would be submitted as a set to Ecological Applications or Ecology. A total of 16 topics were suggested and
discussed. The participants were then
asked to cast 3 votes for the projects they were most interested in seeing
develop into manuscripts. The topics
with 3 or more votes were then discussed by subcommittees that developed
preliminary outlines describing the primary questions, methods, data
requirements, and other considerations.
Topics that recieved less than 3 votes were to be pursued by the
individuals that were still interested
(identified if existance known). These
manuscripts may be included in the joint set or submitted individually
depending on the predilections of the authors.
The following topics were discussed.
The potential authors, based on a sign up sheet, are listed with the
first name being the lead author.
Those LIDET members that were not able to attend the workshop, should
feel free to sign up by sending an email message to Mark Harmon. Topics without outlines are those for which
outlines were not recieved in time for this report. They will be included as they become available.
Working
Group Reports
Working Group 1- Five-year
Stable Fraction
Potential
Authors: Morris, Burke, Currie, Edmonds, Hart, McClellan, Schaefer, Wedin,
Zedler.
Working
Title: “The contribution of site-specific variables and litter quality to
the
refractory component of litter”
I.
Introduction
A. Carbon storage in soils is a major
component of the global carbon budget.
Positive or negative feedback between climate and soil carbon storage
may have important implications for climate
change.
B. Freshly produced plant litter consists of
labile and refractory fractions. The
refractory component enters the pool of relatively stable soil carbon. Include here some literature review about
what we know about this.
C. Our objective is to determine the
relative sensitivity of the refractory component of litter to site-specific
variables (soil and climate) and litter quality (species differences). We have adopted an operational or functional
definition of refractory carbon rather
than a chemical definition. Our
definition
of refractory organic matter is that fraction of litter that remains after five
years of in situ decomposition corrected for interannual variation.
II.
Methods
A. How we estimate the fraction of refractory
organic matter that remains after years (usually five) of decay. There is going to be some trial and error
before the method is established, but the group felt that a 1st approach would
be to fit a single exponential with a positive asymptote using non-linear
parameter
estimation
(SAS proc model).
B. Statistics- simple correlation and
multiple linear regression, ANOVA
III.
Results
A. ANOVA results- what shows up in the matrix
of dependent variables as contributing significantly to the differences in
refractory organic matter remaining?
B. Mean refractory fraction remaining by
species across sites (separate above and below- maybe segregate salt marsh
sites on the basis that the electron acceptor differs). Table or Fig 1
C. Correlations of mean refractory fraction
remaining (by spp) with initial lignin and N (also LCI and
lignin:cellulose). Fig. 2
D. Correlations with climate variables (AET,
Temp, PPT, cooling degree days?)
E. Correlations with soil variables (Avail.
N, %C in soil, etc.)
IV.
Discussion
A. What is the relative importance of these
variables? What are the major controls?
B. what is the relative importance of roots
and leaves?
C. Are there implications for the global
carbon cycle? climate change scenarios?
Working Group 2- Above-
versus Below-ground Rates of Decomposition
Potential
Authors: Gholz, Hart, Wedin
Working title: "Above-
and below-ground C and N dynamics during decomposition"
The approach for the paper
is to compare above and belowground litter decomposition for two species (Pinus
sp - somewhat mixed species) and Drypetes glauca (a high litter quality
tropical species) across the LIDET sites.
These four litter types contain two of our poorest and two of our
highest litter quality types.
The data to be used are
initial litter quality, mass loss data at all sites, and litter %N during
decomp for these four litter types
KEY QUESTIONS:
Q1 Do decomposition rates differ significantly above- and below-ground
and does this difference vary across the LIDET network (i.e. as a function of
climate and ecosystem type)? Is there
an interaction with litter quality (Pinus vs Drypetes)
Q2 Does the rate of N immobilization for a given litter type
differ significantly above and belowground and does this difference vary across
the LIDET network?
Methods:
The estimation of
exponential decay rates for each of the 4 x 28 sites will be straightfoward
once the data sets are cleaned up. Does
fitting separate above and below models significantly improve on a decay model
(probably the model from the synthesis paper) that simply incorporates litter
quality and macroclimate (probably AET)?
Logical ecosystem comparisons are deciduous forest, coniferous forest
and grassland.
Do we need microclimate data
for this? At the least, we should know
whether the litter bag locations at each LIDET site are open, forested, or
partially shaded. We will probably
pursue more site level data as patterns start to fall out of the data.
The N dyamics data should be
available this summer. A starting
approach to analysis will be to fit Aber and Melillo's equation (% original
mass remaining vs %N in remaining material) to each litter type at each
site. The slopes and intercepts of
these equations have been described as the "N factor" and the "N
equivalent" and describe the N immobilization potential and dynamics
during decomposition. These results will
be used to compare N dyamics above and below ground, and across climates and
ecosystem types.
Relation to other papers:
*to a large degree, the data
for Q1 will already have been analyzed for the synthesis paper, but the above
vs below questions will not have been addressed. Bill Parton's summary AET and climate data will be probably be
used over again here. The effect of
ecosystem type will probably not have been addressed in the syntheses paper
however.
*the N
immobilization/mineralization dynamics during decomposition will be driven by
site N availability as much as litter quality.
The results here should be relevant to the soils group which is
comparing various estimates of N availability at the LIDET sites (including the
resin bags, lab incubations, and site-collected data). Based on the litter N dynamics, we should
end up with an independent estimate of site N availability. The relationship of this paper and the soils
paper will need more discussion.
Working Group 3-Cation
Dynamics
Potential
Authors: Baron, Blair, Harmon
Outline
to be developed at later date.
Working Group 4- Native
versus Exotic Species
Potential
Authors: McClellan, Clinton, Edmonds, Harmon, Schaefer.
Basic
Question: For species with the same substrate quality is there a difference between
the rates of decomposition for a native versus a exotic (non-native species)?
There
is some evidence that importing exotic litter onto a site leads to lower
decomposition rates than expected on a chemical basis. This means decomposers can “tell” the difference.
Methods
There
are 2 possible ways to test for this effect.
1. Check to see if the standard litter supplied
from a site deviates from the relationship predicted from the non-native
litters. This test would involve the
sites that supplied the litter.
2. Check to see if the substrate relationship
developed using LIDET species (excluding
any species from that site) is the same as for that developed for native
species. Adjustments need to be made
for any differences in climate or
location differences. Data should be
available from Andrews, Bonanza Creek, Cedar
Creek, Coweeta, Juneau, Luquillo, Olympics.
Other sites welcome to join in the fun.
Basically there is a need to have enough spread in litter substrate
quality that curves can be dceveloped for both sets of species.
Working Group 5- Wood
Decomposition (Non-dowel Wood)
Potential
Authors: Harmon, Blair, Clinton, Nadelhoffer, Trofymow
Major
Question: How does the decomposition of small natural pieces of wood compare to
that extrapolated from fine litter studies?
The low nitrogen and high lignin content of woody substrates is used to
explain their low decomposition rates.
Probably true to some extent, but what happens if one extrapolates the
relationship between litter quality and decomposition rates from fine litter to
small woody litter?
General
Approach: for each site with woody litter decompositon data develope a
relationship between indices of fine litter
quality and decomposition of the LIDET litters. Then use the chemistry of the small wood (<5 cm diameter) and
these relationships to predict the amount of decomposition expected. Compare this to the observed rates of
decomposition.
Expectation:
The extrapolated decomposition rates will underestimate the actual amount of
decomposition. This is because wood
decomposers can deal with a nitrogen depleted environment better than litter
decomposers. Also, lignin is the
preferred substrate of a large set of wood decomposers. This means they may not be subject to the
same set of limitations (or at least to the same degreee).
Possible
Data Sets:
Andrews-
Harmon data on 10 years of decomposition; Douglas-fir, silver fir, western
hemlock, western redceadr; 1 and 2 cm diameter
Bonanza
Creek-Yarie data on 10 years of decomposition; balsam poplar, birch, aspen
Coweeta-Crossely
and Mattson 1-5 years of decomposition; several hardwood species including
chestnut oak and tulip poplar
Harvard
Forest-McClaugherty study with 5 years of data; red pine and sugar maple
Hubbard
Brook-Gosz data on twigs, Fahey et al. small woody roots
Puerto
Morelos-Harmon 4 years of data on 6 species of tropical hardwoods. Local leaf litter decomposition data may
exist (Dennis Whigham contact).
Prediction
of initial chemistry. Will use NIR to
predict chemistry in short-term. Over
long-term wet chemical analysis would be preferred.
Working Group 6-Soil N &
C Dynamics
Potential
Authors: Burke, Baron, Blair, Hart, McClellan, Parton,
Seastedt, Wedin
Working
Title: “ The effects of environmental nitrogen availability on rates and
patterns
of surface and buried litter decay”
Questions
The
literature indicates that environmental nitrogen availability (e.g., inorganic
N in bulk precipitation, fertilizer or from mineralization; but not initial N
concentration) may have positive, neutral or negative effects on decomposition.
We propose to address the following questions with the LIDET database:
1)
Is the first component of decomposition (the labile fraction or decay observed
the first season) stimulated by the presence of environmental nitrogen?
2)
Is the subsequent rate of decay inhibited by the presence of environmental
nitrogen?
Addressing
the first question is complicated by interaction effects with other
environmental variables. We do not
choose to directly address this question.
However, we will attempt to address the second question in a manner that
does not completely distinguish between a positive result for questions 1 and 2
and a positive result for question 2, alone.
The following approach is suggested:
Mass
loss observed between years four and five, expressed as percent of initial mass
decay, will be divided by the decay observed during the first year of mass loss
expressed in similar fashion. This
fraction will be expressed as a function of various indices of environmental
nitrogen availability measured across the
LIDET
gradient.
A
second approach will be to fit models to a two-component exponential decay
model. In practice, the second
component will be created by using percent of initial mass in years 2-5,
finding an initial percentage for this component, then fitting the first decay
curve [examples are numerous: Seastedt and Tate (1981) comes to mind]. The ratio of second component to first
component decay rates will then be regressed against environmental nitrogen.
proposed
procedure for analysis:
1)
all litter
2)
aboveground only (likely to be less effected by soil conditions)
3)
belowground only (likely to be strongly affected by soil
conditions)
Working
Group 8- Climate Variability (annual versus seasonal)
Potential
Authors: Parton? Any others?
Outline
to be developed.
Working Group 9- Larger
Ecosystem Context
Potential
Authors: Currie, Baron, Burke, Gholz, Hart, Kaye, Morris, Nadelhoffer
Working
Title: “Implications of LIDET data for
ecosystem level functioning”
Begin
with results of working group topic #1:
k values and asymptotes for each litter x site combination
Data: Attempt to flesh out additional data from
sites:
CO2 efflux from soils (Currie will
contact individual site personnell)
soil C stocks (published literature;
site contacts can help identify publications)
litter inputs: aboveground (easy);
belowground or ratio to above/below (harder to get).
Climate drivers from selected sites,
for modeling (aquire from Climate Central as needed)
Questions:
Focus on C cycle at ecosystem
level.
What are differences between natural
functioning within biomes?
E.g.,
turnover rate of recalcitrant fraction of SOM.
Identify
amounts of “functionally refractory” material produced in each type of system.
Identify
feedbacks between litter quality / site “quality” (as evidenced by decomp rate)
Relate
production (independent estimates) to decomp rates
What are sensitivities within each
biome, of C cycling, to changes in litter or changes in climate?
How robust are our results, to
changes in the assumption of steady-state?
Methodology:
1.
Lump individual sites into
terrestrial biomes: grassland, desert, temperate forest, boreal forest, tundra.
2.
Lump litter into broad
quality classifications, based on initial litter chemistry. The idea is that for studying natural
ecosystem functioning in each biome, we need native litter and its decay, but LIDET
data are sparse for native litters at their natural sites, so we will match
non-native litters with similar litter quality broadly defined.
3.
Identify a single site
within each biome for which more detailed data can be obtained, for more
detailed study, potentially with a process model.
Working
Group 10- Effect of mesh Size on Decomposition Rates
Potential
Authors: Harmon, Halstead, Moorhead, Nadelhoffer, Schaefer,
Note:
this will be developed as a small manuscript that will go in as a note or some
other short communication.
Author
list based on the sites that recieved large and small mesh bags. Ohers with interest and or data are
welcome!
Working Group 11-Within
versus Between Site Variability
Potential
Authors: Hart, Blum, Kaye, Kratz
no
outline recieved
Working Group 12/15-
Grasslands & Low AET Sites
Potential
Authors: Seastedt, Blair, Blum, Burke, Yarie, Zedler
Maximum
variation in global patterns of soil carbon storage are observed at relatively
low AET values (Meentemeyer et al 1985). Many low AET systems can be dominated
by either grasses or woody
forms,
depending upon the seasonality of precipitation, fire frequency and other
biotic and abiotic constraints. Under conditions where these multiple plant
life forms exist (here, simplified to "woody" vs "nonwoody"
ecosystems), does decomposition exhibit different patterns for different
ecosystem types?
Specifically,
is decomposition more efficient under woody vegetation than under graminoid
vegetation? (or, is carbon sequestration greater in soils of graminoid systems?)
Test: Graph decay constants against cumulative
AET. Use an analysis of covariance to
see if "woody" and "nonwoody" are significant variables
affecting the slope of this relationship. (Note, if vegetation type affects
overall decay, but not the slope of the cumulative AET curve, then only
intercepts would be
different,
which suggests some other interpretation is warranted.)
Procedure:
a)
all litter
b)
surface litter (not expected to show relationship. If a vegetation effect is
identified, we hypothesize that this is the vegetation's affect on microclimate
affecting the pattern.)
c)
buried litter (expected to show relationship, as "factors affecting carbon
stabilization" are suggested to be higher in nonwoody systems).
Working Group 13-Tropical
Site Comparison
Potential
Authors: Schaefer, Molina, Nadkarni, Sollins, Wright
Doug
Schaefer will be contacting the sites involved in this comparison. No outline as of yet.
Working
Group 14-Marsh and Wet Sites:Terminal Electron Acceptor Influence on Decomposition
Potential
Authors: Blum, Morris
Note:
these two authors will proceed on own, enlisting help as needed.
IV. Other Manuscripts
A. Bill Parton will be developing an analysis
of the dowel data with emphasis on effect of environment on decomposition. Hopefully this could be included in the set of manuscripts
described above.
B. Daryl Moorhead is completing a manuscript on
predicting the first 2 years of decomposition for two endpoint species at 4 endpoint
sites.
C. Sandy
Halstead and Eldor Paul are using wheat straw as a standard substrate and
comparing its decomposition in differing environments. This will be coupled with data from other
broad-scale studies. A presentation
will be made this summer and hopefully a manuscript could be published.
D. Daryl Moorhead would like to analyze the
first year of decomposition data in detail.
The outline for this paper was presented to the group during the
workshop.
V. Workshop Participants
Note
that names marked with a * were LIDET members unable to attend the
workshop. Their names are included for
future reference. All names without an
email address listed can be reached via LTERNET. tyoe the full last name, then the first initial, then
lternet.edu (e.g., Jill Baron is
baronj@lternet.edu).
Jill Baron
NREL
Colorado State Univ.
Fort Collins, CO 80523
phone: 970‑491‑1968
fax: 970‑491‑1965
John Blair
Division of Biology
Kansas State University
Manhatten, KS 66506
phone: 913‑532‑7065
fax: 913‑532‑6653
Linda K. Blum
Dept. Environ. Sci.
University of Virginia
Charlottesville, VA 22903
phone: 804‑924‑0560
fax: 804‑982‑2137
Ingrid Burke
NREL
Colorado State University
Fort Collins, CO 80523
phone: 970 491‑1620
fax: 970‑491‑2156
Barry Clinton
Coweeta Hydrol. Lab
999 Coweeta Lab Rd.
Otto, NC 28763
phone: 704‑524‑2128
fax: 704‑369‑6768
email: bclinton@sparc.ecology.uga.edu
Bill Currie
The Ecosystem Center
Woods Hole MA 02543
phone: 508‑540‑3705 ext 7705
fax: 508‑540‑6902
wcurrie@lupine.mbl.edu
Robert Edmonds
Coll. For. Res. AR10
University of Washington
Seattle, WA 98195
phone: 206‑685‑0953
fax: 206‑685‑7295
email: bobe@u.washington.edu
*Tim Fahey
Department of Natural Resources
Fernow Hall
Cornell Univesity
Ithaca, NY 14853
Henry Gholz
Department of Forestry
University of Florida
Gainesville FL 32611
hlg@nerm.nerdc.ufl.edu
phone: 352‑846‑0889
fax:
*Tom Gower
Department of Forestry
University of Wisconsin
1630 Linden Drive
Madison, WI
53706
phone:
608-262-0532
fax:
608-262-9922
Mark Harmon
Department of Forest Science
Oregon State University
Corvallis, OR
97331
phone:
541-750-7333
fax:
541-737-1393
Sandy Halstead
Kellogg Biological Station
Hickory Corners, MI 49060
phone: 616-671-2512
fax:616-671-2351
Steve Hart
School of Forestry
N. Arizona University
Flagstaff, AZ 86011‑4098
phone: 602‑523‑6637
fax: 602‑523‑1080
email:sch@alpine.for.nau.edu
Timothy Kratz
Trout Lake Station
University of Wisconsin
Boulder Junction, WI 54512
phone: 715-356-9494
fax: 715-356-6866
Mike McClellan
Forestry Sci. Lab
2770 Sherwood Lane
Juneau, AK 99802
phone: 907‑586‑8811
fax: 907‑907‑586‑7848
email: mmcclell@ptialaska.net
Sandra Molina
Departmento de Biologia
Pontificia Univesidad Catolica de Puerto Rico
Suite 970
2250 Avenida has Americas
Ponce, Puerto Rico 00731-6382
phone: 809‑841‑2000 ext 641 or 289
fax: 809‑840‑4295
email:do not have email address
Daryl Moorhead
Department of Biology
Texas Tech University
Lubbock, TX 79409‑3131
phone: 806‑742‑1158
fax: 806‑742‑2963
Jim Morris
Baruch Institute
Univ. S. Carolina
Columbia, SC 29208
phone: 803‑777‑3948
fax: 803‑777‑4002
email:
morris@cls.biology.sc.edu
Knute Nadelhoffer
The Ecosystem Center
Woods Hole MA 02543
phone: 508‑548‑3705 ext 476
fax: 508‑457‑1548
*Nalini Nadkarni
MS LAb II
The Evergreen State College
Olympia, WA 98505-
phone: 206-866-6000
fax: 206-866-6823
email: nadkann@elwha.evergreen.edu
Bill Parton
NREL
Colorado State Univ
Fort Collins, CO 80523
phone: 970‑491‑1987
fax: 970‑491‑1965
*Eldor A. Paul
Crop and Soil Science
Michagan State University
East Lansing, MI 48824
phone: 517-353-0262
fax: 517-353-5174
Douglas Schaefer
Terrestrial Ecology Division
PO Box 363682
San Juan, PR 00936‑3682
phone: 809‑767‑0350
fax: 809‑758‑0815
Tim Seastedt
INSTARR Box 450
University of Colorado
Boulder, CO 80309‑0450
phone: 970‑492‑6302
fax: 970‑492‑6388
*Phil Sollins
Department of Forest Science
Oregon State University
Corvallis, OR
97331
phone:
541-737-6582
fax:
541-737-1393
Tony Trofymow
Pacific Forestry Centre
506 West Burnside Road
Victoria, BC V8Z 1M5
phone: 604-363-0677
fax:
604-363-0797
email: ttrofymow@a1.pfc.forestry.ca
Carl White
Department of Biology
University of New Mexico
Albuquerque, NM
87131
phone: 505-277-8689
fax: 505-277-0304
John Yarie
Forest Soils Lab
University of Alaska
Fairbanks, AK 99775
phone: 303‑491‑8293
fax:
Dave Wedin
Department of Botany
University of Toronto
Toronto, Ontario
M5S 3B2
phone: 416‑978‑5807
fax: 416‑978‑5878
*Joseph Wright
Smithonian Tropical Research Center
Unit 0948
APO AA, FL 34002-0948
phone: 507-27-6022 (Panama)
fax: 507-32-5978 (Panama)
email: stri.tivoli.wrightj@ic.si.edu
Paul Zedler
Biology Department
San Diego State Univ.
San Diego, CA 92182
phone: 619‑594‑6328
fax: 619‑594‑5676
email: pzedler%sunstroke@sdsu.edu