science Plan for the Long-Term Site Productivity Research Program
USDA
Forest Service, Pacific Northwest Research Station,
Portland, Or
The LTSP Basic Research
Program, Science Review Board:
F. Herbert Bormann (Yale
Univ.) Robert J. Naiman (Univ. Wash.)
Dale W. Cole (Univ. WA) Chadwick D. Oliver (Univ. WA)
Kermit
Cromack, Jr. (OR St. Univ.) Dave
Perry (OR St. Univ.)
Dean DeBell (PNW) Jim
Sedell (PNW)
Rich Everett (PNW) Phil
Sollins (OR St. Univ.)
Jerry F.
Franklin (PNW) Frederick
J. Swanson (PNW)
John C.
Gordon (Yale Univ.) Robert
F. Tarrant (OR St. Univ.)
Ross Kiester (PNW) Arthur
R. Tiedemann (PNW)
J.P. Kimmins
(Univ. BC) Fiorenzo
Ugolini (Univ. WA)
Jack Lattin (OR St. Univ.) Keith
Van Cleve (Univ. ak)
Susan N.
Little (PNW) Richard
H. Waring (OR St. Univ.)
Randy Molina (PNW)
Writing COMMITTEE: B. T. Bormann (PNW), J. C. Gordon, R. H.
Waring, P. Sollins,
D. A. Perry, S.
Little, and R. F. Tarrant.
Signed 1991
__________________
Bernard T Bormann
Program Leader, Basic
__________________
Susan N. Little
Program Leader, Applied
__________________
C. W. Philpot
Station Director, PNW
SUMMARY
This
document is the initial science plan of the PNW Station Long-term Site
Productivity (LTSP) Research Program.
This plan also seeks to integrate the basic and applied components of
the PNW LTSP Research Program.
Background, justification, goals, and administrative structure of the
combined Program are presented in more detail in the Program Charter. A more detailed applied research plan will
follow later this year to address how management tools for assessing and
ameliorating productivity losses will be developed.
LTSP
is one of several important new research initiatives in the Pacific Northwest
Research Station. In some sense, all of
these initiatives seek to better understand ecosystem sustainability. Among the overlapping initiatives are Global
Climate Change, New Perspectives in Forestry, Forest Health, Consortium for
Social Values in Forestry, Biodiversity, and Cumulative Watershed Effects. The Station also plans to expand basic
research on ecological processes and land-water interactions.
The
LTSP Program seeks to fill two niches in this research environment: (a) to
increase our ability to evaluate the effects of current and future stand
management practices and ecological processes and (b) to use the perspective of
sustained ecosystem productivity to foster integrated research. A primary focus on integration in the LTSP
Program results from slow progress in previous site productivity research
because of, we believe, ineffective
integration. To achieve these goals, we
propose to:
• Develop an approach where direction and design of research
will follow from a conceptual model, not from current or envisioned management
practices, not from existing models, and not from processes
out-of-context;
• Develop a conceptual model that, in its simplest form, says
that all major productivity drivers must be evaluated simultaneously even if
this means assessing some factors at a less detailed level;
• Apply new predictive models that are compatible with this
conceptual model and that can be tested in process studies and in long term
experiments;
• Support predictive modeling, retrospective studies, and
short- and long- term experiments that can be used to continually re-evaluate
and modify our conceptual model; and
• Incorporate perspectives from other ongoing research
initiatives, where possible, in experimental designs and conceptual and
predictive models.
The
ultimate desired outcome is to increase managers' confidence in predicting the
consequences of major decisions and to increase public confidence that
"best practices" are being used on the land.
introduction
Public
concern over management policies on federal forest land reflects in part our
narrowness of focus in Forestry.
Forestry research and management have traditionally concentrated on the
production or protection of one product or amenity in a limited geographic area
and time scale. A broader demand on
National Forests has emerged that calls for a change in research and
management. The overall need was
recognized in the Multiple-use Sustained-yield (MUSY) Act of 1960 with its goal
of achieving and maintaining a high level of production for various renewable
resources "without impairment of the productivity of the land". Other federal legislation, including the
NFMA (1976) and NEPA (1969), builds on this sustainability concept.
Whether
current management strategies have succeeded in meeting these objectives has
been called into question. To attain
the original goals of the MUSY Act, the LTSP Program has evolved new ways of
organizing and conducting research.
SCOPE
AND FOCUS OF THE BASIC RESEARCH PROGRAM
This
Program first and foremost seeks to identify critical linkages between
physical, chemical, and ecological processes operating in all forested
ecosystems. Once identified, the key
linkages will be quantified under a range of conditions. Predictive models will be employed to assess
selected management systems. The
overall validity of the predictive models, their underlying assumptions, and
the effects of various management practices will be evaluated across a range of
conditions and over a long period of time.
The
idea of naturalness and normal stability in ecosystems are assumptions being
questioned. We have learned that
productivity can fluctuate greatly in relatively undisturbed systems due to
changes in flora, fauna, and soils. We
also recognize that few ecosystems are in equilibrium with present climate, and
that no system within the earth's atmosphere is outside the influence of human
activities. The question arises as to
whether or not the currently observed rates of production can be sustained
under any management scheme? Can they
be substantially increased? The answers
lie in understanding how a multitude of changes might alter the state and
function of future forest ecosystems.
In
searching for common properties of all ecosystems, we start with vegetation,
the foundation of all food chains from microbial to human. Ultimately, plant production is limited by
the amount of solar radiation absorbed throughout the growing season. How effectively the radiation is captured
through photosynthesis and then transformed into biomass determines the plant,
animal, microbial, and detrital composition of the ecosystem. A tangible index of reduced productive
capacity is a pronounced reduction in photosynthetically-active radiation (PAR)
actually absorbed by vegetation throughout the growing season.
Even
in death, plant products are important because they may become residues that
store and release water, carbon, and nutrients. All ecosystems contain animals and microbes that speed the
cycling of minerals, transform organic matter, and alter plant species
composition. Animals and microbes may
play important roles in soil fertility and speeding or retarding soil
development (e.g., nutrient cycling by detrital feeders, N2-fixers,and denitrifiers; soil mixing by earthworms;
increased weathering by microbes).
Change
is constant in all ecosystems, but is most dramatic following episodic
disturbances such as harvesting, fire, or windthrow. It appears that many species within the ecosystem are well
adapted to disturbances that have been part of their historical norm. But we must address what happens when the
spatial pattern, magnitude, or frequency of disturbance is significantly
altered. Changes in disturbance regime,
for example, could result in exclusion of early or late successional species
(plants, animals, & microbes), net loss of organic matter and nutrients,
and increased incidence of insect pests or disease. Conversely, many forests appear to decline if not periodically
disturbed. How often and how extensive
must disturbance be to assure recycling and renewal? Quantifying the extent that organisms are adapted to a variety of
disturbances also is an important task.
Finally,
and importantly, we must evaluate the long-term social and economic consequences
of various management options. This is
a difficult challenge because management objectives and constraints are likely
to change as the supply of and demand for forest products and values change. Whether economic and social returns can be
maintained or increased depends in no small measure on improved understanding
of forest ecosystems.
Admittedly,
some products and values, such as endangered species or aesthetic qualities,
may be difficult to relate well to established measures of biological productivity. These must be considered in the broader
Programs such as New Perspectives in Forestry and the Consortium for Social
Values in Forestry. New Perspectives
and LTSP will be closely integrated by selecting common research sites,
exchanging ideas, and collective modeling.
LTSP Program approach
The
Program seeks to improve our ability to predict site-specific LTSP effects
under changing management, environment, and biotic composition. To achieve this, we propose an integrated
research approach (Figure 1). Direction
and design of research will follow from the conceptual model---not from current
or envisioned management practices, existing models, or concepts of processes taken out-of-context. The Program will sponsor research and develop models to better understand
ecosystem function. We will continually
search for simplification and generality as new methods and insights
emerge. Both conceptual and predictive
models will be tested in the near-term and over extensive periods.
Figure 1. Information flow in the PNW Station LTSP
Program.
Most
short- and long- term experimentation will occur on six to eight
"Integrated Research Sites" distributed widely on National Forests in
Oregon, Washington, and Alaska. These
sites will be chosen to be representative of "general" forest land;
land not given a single-use designation by the Forest (wilderness, riparian,
spotted owl habitat areas, pine martin, viewsheds, etc..). These are lands the Forest Service expects
to be managing for multiple-use over the next 50 years. Research will be tied across sites through
research design and consistent methodology (minimum measurements,
documentation, data and sample storage, and quality control).
We are
building a strong partnership with land managers, especially the National
Forest System and the Bureau of Land Management, to facilitate installation of
sites and eventual application of research results.
We
have designed the Integrated Research Sites to allow small-scale process-level
research to be linked with measurement of stand-level responses. We seek to increase integration by (1)
having a common conceptual model that integrates a wide variety of biological
disciplines; (2) having much of the work done on common sites with a common
design; (3) supporting scientists committed to integration; and (4) developing
close links with other related programs.
Conceptual model
Our
conceptual model strives to: (1) forge an integrated approach; (2) further
develop the concept of sustainability; (3) guide formation of predictive
models; (4) identify important research areas; and (5) help link with other
research programs and models.
In its simplest form, our
conceptual model is that long-term site
productivity is the product of changes in the complex interaction between the
biotic assemblage and abiotic environmental factors (Fig. 2). Activity of the biotic assemblage is
ultimately controlled by its aggregate genetic composition (within and between
species). Support for this model rests
on the observation that living systems modify their environment, and thus, to a
large extent, affect their own production and production of future
assemblages.
Figure
2. The LTSP conceptual model: mechanisms of change in biotic-environment
interactions (potential mechanisms are listed in Table 1; environmental
variables and biotic fluxes are listed in Appendix 2)
Mechanisms
of change will be explored in retrospective studies and short- and long-term
experiments. We place initial emphasis
on management-driven mechanisms (e.g., changes in species composition, initial
changes in environment) as well as intrinsic ecological mechanisms (e.g.,
succession, soil development, senescence, ...).
Stand-level
measures of physiology of forest ecosystems will be used to explore constraints
on the rates of basic processes. We
also seek a small set of measures that encompass the net effect of the many
interactive ecosystem functions (Appendix 2).
For example, animals and microbes make up a critical part of the biota and
their physiological status may be as important to assess as that of vegetation
(e.g., CO2
flux from the soil
is greatly affected by roots, microbes, and animals through processes such as
soil mixing, spore dispersal, and decomposition).
Management
and ecological mechanisms that alter the biotic-environment complex are the
primary driving force for short- and long- term changes in productivity. It follows implicitly (1) that specific
management practices can sustain production in some environments for some
assemblages but not in others; (2) that long-term site productivity can be
altered by manipulating the biota, and; (3) that interpretations and
predictions apply over a restricted range where the biota and environment are
well specified.
Defining LTSP
Foresters
have traditionally sought to index site productivity using the height growth
patterns of dominant crop trees. A new
vision of site productivity is needed because of increasing concern of the sustainability
of entire ecosystems, greater emphasis on non-crop-tree products and values,
and the potential for large changes in climate and management practices. As the LTSP Program develops, we expect to
continually refine our definitions of productivity.
Our
definition of forest productivity encompasses the view that the
forest can provide a wide variety of benefits to society. Thus, forest productivity is the rate of
production of specific products (e.g., timber, recreation, clean water, fisheries, wildlife...)
and resource values (e.g., aesthetically pleasing
landscapes, biodiversity, healthy wildlife populations, wilderness,...). Developing a single measure or index of
forest productivity based on a specific product or resource value has obvious limitations,
especially with shifting management objectives.
We
propose to use actual ecosystem productivity, the measured rate of accumulation of organic
matter in the ecosystem, as an integrative index of forest productivity. We also extend this concept to the
redistribution of organic matter into (1) a wide range of specific products,
(2) living plants, animals, and microbes, and (3) detrital pools (heartwood,
standing dead trees, large woody debris, and various forms of litter and humus
in soil horizons). The change in the
rate of accumulation of organic matter over multiple rotations or generations,
is the ultimate means of evaluating changes in long-term ecosystem
productivity.
We
recognize that individual measures of ecosystem productivity are insufficient
by themselves to assess "sustainability" of managed or unmanaged
ecosystems. Even trends in ecosystem
productivity may not be sufficient to address some aspects of sustainability. Additional indicators of sustainability will
be sought by the Program.
We
define potential ecosystem productivity to be a theoretical maximum
ecosystem productivity based on optimum rates of biologically controlled fluxes
and specified environmental variables.
The difference between actual and potential ecosystem productivity gives
us insight into the relative limitations of local biota and, conversely, in
other situations the relative limitations of the environment. This difference may also represent an
investment in the productivity of subsequent biotic assemblages in anticipation
of unknown future conditions (e.g., genetic and structural diversity and
process redundancies related to past ecosystem history).
The
primary output of LTSP models will be future ecosystem productivity. Models are needed to predict future productivity of ecosystems
because of the complex interaction of mechanisms, biota, and environment over
long time periods.
Models to predict future productivity
Modeling
future productivity is a challenging, yet critical task. Most current predictive models suffer from
inadequate information and untested assumptions. It is also often difficult to understand embedded assumptions in
or confirm predictions from these models.
We propose an alternative modeling approach based on further refinement
of our conceptual model to predict long-term changes in ecosystem productivity
and distribution of organic matter and imply effects on production of specific
products and resource values (Fig. 3).
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓LTSP predictive models▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
▓ ┌─────────────────────────────────────────┐ ▓
▓INPUT │Initial site-specific
biotic/environment │ ▓
▓ │ conditions; management objectives │ ▓
▓ └──────────────────┬──────────────────────┘ ▓
▓ ┌──────────────────v──────────────────────┐ ▓
▓MECH │
Imposed or projected mechanisms of
│<──┐ ▓
▓models │
change in biotic-environment complex
│<─┐│ construc- ▓
▓ └──────────────────┬──────────────────────┘<┐││
tion ▓
▓ ┌──────────────────v──────────────────────┬─┘││ and ▓
▓BXE │
Biotic-Environment interactions model
│<─│┤
testing ▓
▓models └──────────────────┬──────────────────────┘<┐││ ▓
▓ ┌──────────────────V──────────────────────┐ │││ ▓
▓OUTPUT │
Change in ecosystem productivity, C
├─┘││ ▓
▓ │
distribution implications for specific ├──┘│ ▓
▓ │
product production and resource values │ │ ▓
▓ └──────────────────┬──────────────────────┘
│ ▓
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓│▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓│▓▓▓▓▓▓▓▓▓▓▓▓
│ │
┌─────────────────────────v────────────────────────┐ │
│Other non-LTSP models (Programs): │
│
│landscape-level disturbance models, C-channelling │ │
│models (New Perspectives); global C balance │ │
│(Climate Change);
social implications (Social ├─┘
│Consortium); defining forest health (Forest Health│
│Program); evaluating functional biodiversity │
│(Biodiversity Team); Soil porosity-organic matter │
│interactions (USFS National long-term soil │
│productivity study) │
└──────────────────────────────────────────────────┘
Figure
3. Initial ideas on LTSP predictive
models and their relation to other models.
Initially,
we propose to model the effects of sets of management practices and ecological
processes as mechanisms that change the biotic-environment complex. Mechanism-induced changes in the
biotic-environment complex would be detected by measuring biotic and
environment variables that affect key processes (Appendix 2). By evaluating these relationships over a
broad range of practices, biotic assemblages, and environments, we expect to
develop relationships that are generally applicable throughout the region.
To
allow extrapolation across regions, quantitative functions of models must have
mechanistic plausibility and be easily verified. We accept the basic premise that it is easier to measure large
changes in small quantities (e.g., the rate of a process) rather than small
changes in large quantities (e.g., changes in pool size of carbon or nitrogen).
The initial biotic-environment
interaction model focuses on the flux and storage of carbon products controlled
by linkage to a small set of all-encompassing variables that describe net
function of the ecosystem.
Mechanisms
that could bring about changes in the biotic-environment complex are quite
numerous (Table 1). A model of all of
these mechanisms and their interactions would seem to attempt to explain nearly
all forest biology. This appears to be
beyond our abilities at this time.
Table
1. Mechanisms thought to alter the
biotic-environment complex over time:
Management: planting, weeding, thinning, harvesting, slashburning, timing and
magnitude of nutrient and Carbon removal, fertilization, compaction, erosion,
grazing, hunting, pesticides, introduced plants and animals, predator
control...
Climatic: CO2 enrichment, air pollution, temperature, precipitation,
drought, fire, windstorms, ...
Genetic: evolution, extinction, species migration, exotic species
introductions, reproductive processes,...
Ecological: stand development, succession, plant-animal interaction (e.g.,
herbivores altering plant succession), plant-microbe interactions (e.g.,
diseases, symbiotic N2-fixation), denitrification, redundancy,
resiliency,...
Soil: deposition of new parent material, soil development, water and wind
erosion, net loss of nutrients by harvesting or fire, compaction, soil mixing
by windthrow or animals, rooting depth, deep leaching,...
Initial focus and links to other programs and models
The
LTSP Program appears best adapted to studying the biotic-environment complex
and a limited set of mechanisms. We
propose to study mechanisms that have a high potential for long-term effects,
that have important stand-level components, and that can be altered by
management practice or intrinsic ecological processes (e.g., succession, soil
development, climate change, stand development, plant-animal-microbe
interactions).
The
LTSP Program investigations will be largely limited to stand and sub-stand
spatial scales for three reasons: (1) we believe that we need to explore a wide
range of treatments that would not be possible in larger scale experiments; (2)
areas with uniform soil large enough for replicated long-term experiments may
not be available at larger than stand-levels; and (3) integration of processes
and ecosystem responses will be most efficient at the stand level due to
existing measurement techniques and logistics.
Possible
linkages with other research efforts can be best demonstrated as an exchange of
information (Fig. 3). For example,
General Circulation modelers acting through the PNW Global Climate Change
Program could identify a range of likely shifts in climate variables to feed
into LTSP biotic-environment, mechanism, and potential productivity models. Conversely, the LTSP Program and other PNW
Programs will be able to provide information on changes in C capture and
distribution that could be used to feed into or test climate models.
Given
the complicated effects of management and changing environments on the
biotic-environment complex, any outside efforts to explain mechanisms of change
at any spatial or temporal scale will be eagerly followed. Such work will be especially valuable if it
can suggest hypotheses that can be tested in stand-level experiments. Existing ecological process models could be
evaluated with the biotic-environment interactions model.
We
suggest the desirability of evaluating both upland and riparian sites because:
(1) we would then be better able to tie in with land-water interface research,
and evaluate specific products such as fisheries; (2) processes rates and
mechanisms of change may be very different; and (3) riparian-upland
interactions may greatly affect important mechanisms of change. Most of our National Forest System and
Bureau of Land Management partners, however, want Integrated Research Sites to
be on upland sites. We will explore the
possibility of associated studies in riparian areas adjacent to selected upland
sites.
Research direction
Four
main areas of research are now envisioned: (1) further development of
conceptual and predictive models; (2) short-term experiments; (3) retrospective
studies; and (4) long-term experiments.
Most short- and long-term experiments will be established on Integrated
Research Sites. Retrospective research
will be carried out within broad geographic limits.
Conceptual and predictive model development
Further
development is needed before the conceptual model can serve to direct research
and shape predictive models. We will form
a modeling team to pursue model definition and development during fiscal year
1991 (Table 2). After the
conceptual/predictive models take form, we expect considerable effort will be
required to develop cost-effective and accurate sampling techniques. Some computer simulation models are already
available to predict water and nutrient, PAR, and gross primary
productivity. New techniques and
synthesis of existing ideas and technology will be needed to better measure
belowground biotic activity, determine nutrient supplying potential of soil
horizons, and gauge potential rooting depth.
Emphasis will be given to evaluating spatial patterns and
variability. The LTSP Program will seek
to test methodology in conjunction with other ongoing programs supported by
NASA, NSF (LTER), and EPA.
Table
2. Objectives for the LTSP modeling
team for 1991.
1. Further develop the LTSP conceptual
model, including definitions and examples of sustainable and
non-sustainable ecosystems;
2. Propose a detailed modeling strategy
and analyze its feasibility;
3. Explore modeling linkages with other
Programs and existing models;
4. Propose a list of mechanisms to be
evaluated in short-term experiments on all Integrated Research Sites;
5. Propose pre-treatment measurements
for short- and long- term experiments;
6. Identify development needs for key
methods;
7. Publish a manuscript that describes
our conceptual model.
Short-term experiments
The
primary role for short-term (<10 yr), small-scale (<0.1 ha) experiments
will be to construct and initially test models developed by the modeling
team. A major purpose of short-term
experiments is to measure actual ecosystem productivity and C distribution and
relate this to predictor variables. To
induce differences in ecosystem productivity and C distribution in short-term
experiments, treatments will have to be extreme, or soils will have to be
homogenized to overcome natural variability.
Short-term
experiments will take place on all of the widely dispersed Integrated Research
Sites. For example, biotic composition
could be altered by excluding large herbivores or by shifting the composition
of plant, microbe, or less mobile animal populations. The environment might be altered, for example, by redistributing
soil organic matter, varying large woody debris, or burning slash. We can even
envision the possibility of carrying out common-soil or bioassay experiments
across Integrated Research Sites.
Assessing changes in the rates of key processes and establishing the
biotic-environment interactions will improve our understanding of ecosystem
function.
A
second role for short-term experiments is to test major constituents of the
treatments in long-term experiments such as role of individual plant species and
the exclusion of large herbivores.
Retrospective Research
In
many existing long-term studies, treatments established with single-discipline
objectives have resulted in large ecosystem changes. We have the opportunity to re-evaluate treatments as changes in
the biotic-environment complex.
Examples of studies include species trials, herbicide experiments,
growth and yield studies, animal exclosures, tree genetic trials, and
slashburning studies.
Existing
managed stands and natural disturbances may allow us to make comparisons of
ecosystems with different mechanisms of change in the biotic-environment
complex. Examples of these
opportunities include past management activities, primary and secondary
succession chronosequences, wildfire, and windthrows.
We
need new methods to reconstruct disturbance history, and previous biotic
composition and environments. For
example, concentrations of nutrients and various isotopes in tree rings may
give insights into changes in the biotic-environment complex. Detailed stem sectioning may reveal
frequency of windstorms, or some types of insect attacks. Palynology might be used to evaluate a wide
variety of longer-term changes. These
methods are needed in retrospective studies and to establish baseline
information in long-term experiments.
Retrospective
studies will provide information that will be both useful by itself and useful
in predictive models. For this reason,
the Program will initiate some stand-alone retrospective projects in FY 1991. A retrospective study team (Sollins, Waring,
Oliver, Tiedemann), formed in FY 1990, is developing guidelines for this
research.
Long-term experiments
The
conceptual model serves as a framework for designing site-specific treatments
to be installed in long-term (100 year+), large scale (15-30 acre; Fig. 4)
experiments at Integrated Research Sites.
A set of treatments has been designed by the PNW LTSP Integrated
Research Site team (Appendix 3) in conjunction with the development of this plan. Two series of long-term experiments will be
carried out to look at the influence of: (I) different assemblages of biota and
(II) manipulating the initial environmental conditions on subsequent
productivity . In both cases, we will
begin with existing, relatively even-aged, and uniform stands developed
following natural disturbances. This
approach minimizes the influence of previous management practices including
planting, site preparation, and harvest removals and the influence of
cumulative legacies in old-growth stands.
Figure 4. Idealized layout for long-term experiments
on Integrated Research sites (numbers represent year of entry following study
inititation).
In
the series I experiment, we evaluate the general idea that the biotic
assemblage has a large long-term, sustained impact on its environment and thus
greatly affects its own productivity and that of subsequent assemblages. We also recognize that one of the principal
effects of most current management is to greatly shorten early and late successional
stages, relative to natural successional patterns. For these reasons, we have decided to vary biota by manipulating
successional patterns in four contrasting ways (Table 3). Specific hypotheses are being developed in
the Integrated Research Site plan.
Table
3. Series I core long-term experiments
at all Integrated Research Sites (manipulating succession):
1.1: A prescription to accentuate
early seral species throughout most of the rotation. This would most likely be achieved through very wide initial
spacing, thinning, or pruning of crop trees and repeated thinning to maintain
large gaps in the canopy.
1.2: A prescription to establish
and maintain crop trees (probably mostly conifers) with a closed canopy over
most of the rotation. This would
involve intensive weeding of early successional species as much as possible and
harvesting before late successional species become established. Frequent light thinning of crop trees would
be carried out to capture mortality and minimize production of large woody
debris.
1.3: A prescription to accentuate late-successional species and stand
structures leading to uneven-aged management.
Single tree or group selection, planting, and other strategies will be
employed to attract and retain late-successional plant, animal, and microbial
species, in uneven-aged stands with high species and structural diversity. A constant proportion of trees will be
harvested (substitute for rotation) periodically to capture some net production
and promote late-successional species.
1.4: Unmanipulated succession.
This treatment could be described as a "no extraction"
option. Stands would be allowed to
progress through all phases of succession without human interference, either
forward in time, or after simulating natural disturbances. This treatment might be considered as a
benchmark for the other three. Thorough
evaluation of existing stands before installing treatments and potential productivity
models will allow additional benchmarks.
Series
II treatments center around the idea that detritus pools are one of the more
dynamic aspects of the environment and that changes in detritus are likely to
affect subsequent biotic assemblages (Table 4). The cumulative effects of previous biotic assemblages and
management activities such as harvesting and burning are expected to alter
detritus pools such as standing dead vegetation, large woody debris, litter,
and organic matter in soil horizons.
The distribution, quality, and amount of detritus is closely tied to the
biotic-environmental complex (e.g., nutrient cycling, soil structure, rooting
depth, secondary producers,...). The
treatments are designed to look at the extremes of removal and addition of key
detrital components hypothesized to control subsequent productivity.
Table
4. Series II core long-term experiments
at all Integrated Research Sites (manipulating detritus):
2.1: Remove key detritus
constituents and follow with silvicultural treatments that drain detritus from
the site. Key constituents will be
identified as those thought to be most closely linked to environmental factors
that limit productivity in that site.
2.2:
Augmentation of the same detritus constituents followed by
silvicultural treatments designed to build and maintain excessively high levels
of detritus.
General research guidelines
Guidelines
are needed to ensure that research activities meet the LTSP Program
objectives. Of primary importance is
the connection with our conceptual model by assessing mechanisms of change as
well as the biotic-environment complex.
We will invest in cooperative studies to link with other research
programs as a means to obtain the broadest possible understanding.
FUNDING MECHANISMS
It
is the policy of the Program to support competitive funding where it is
responsive to Program needs and not burdensome to the program and supported
scientists. Competitive funds will be
available in clearly defined research areas (retrospective studies and
short-term experiments). Preliminary
proposals (<5-pages) will be requested.
A committee will choose two promising proposals in each research area
and return them to the author(s) for completion of a more detailed
proposal. One of the two proposals will
be assured funding. This policy also
means that some exploratory studies and modeling efforts, deemed of key
importance, will not be funded competitively.
Ongoing and planned studies of this type are: (1) further development of
the conceptual and predictive models and, (2) the Existing Studies Project to
develop guidelines for retrospective research.
Table
5. Condensed five-year plan (see
Charter for more detail)
FY
1990 BASIC RESEARCH:
Write overall research plan and obtain wide review to identify science direction
(this document).
Develop guidelines for LTSP retrospective research; initiate pilot study on
integrating ecosystem processes (Existing Studies Project).
FY 1990 APPLIED RESEARCH:
Form research team for Integrated Research Sites and develop fundamental
direction for common approach across sites (IRS plan; see appendix 3).
Locate Integrated Research Sites using criteria developed by consensus of
researchers and cooperators.
Review and evaluate existing data bases.
FY 1991
BASIC RESEARCH:
Support activities of the model team (including publishing of conceptual model;
see Table 2).
Continue pilot retrospective study.
Initiate a competitive grant program to support stand-alone retrospective and
short-term research.
FY 1991
APPLIED RESEARCH:
Integrated sites: establish all sites in Region 6 as far as laying out
boundaries, recognizing sites in Forest GIS data bases and other records as
appropriate. Begin initial surveys and
monitoring on at least three sites.
Satellite sites: identify potential site locations and interested landowners;
develop individual agreements; determine type of activities to be done on
satellites that are in common with Integrated Research Sites.
Supporting studies: Formalize research plan for supporting studies. Initiate at least one supporting study.
Table
5 (cont'd)
FY 1992 BASIC RESEARCH:
Continue modeling and stand-alone retrospective, and short-term research under
base and competitive funding.
Begin short-term, retrospective, and methods studies to build predictive models.
FY 1992 APPLIED RESEARCH:
Integrated sites: begin initial surveys and monitoring on remainder of
sites. Write prototype contract for
treatment application(s). Schedule
initial treatment for first three sites for FY 1993.
Satellite sites and supporting studies: establish sites; initiate field studies
most likely on ameliorative measures for soil disturbance and relationship of
ameliorative measures for root rot abatement to productivity.
FY 1993 BASIC RESEARCH:
Continue modeling, retrospective, and short-term research under base and
competitive funding.
FY
1993 APPLIED RESEARCH:
Integrated sites: implement initial treatments on first three sites. Schedule
initial treatment for remainder for FY 1994.
Satellite sites and supporting studies: Complete pre-treatment monitoring;
schedule initial treatment for following year.
FY 1994 BASIC RESEARCH:
Continue modeling, retrospective, and short-term research under base and
competitive funding.
Continue basic research on Integrated Sites (first year of post-treatment
response).
FY 1994 APPLIED RESEARCH:
Integrated sites: Implement initial treatments on remaining sites. Intensive
post-treatment work on all sites.
Satellite sites and supporting studies: Implement treatments on followed by
intensive post-treatment follow-up.
FY 1995 BASIC RESEARCH:
Continue modeling, retrospective, and short-term research under base and
competitive funding.
Synthesize program research with a major workshop and published proceedings.
FY 1995 APPLIED RESEARCH:
Integrated sites: Intensive post-treatment follow-up. Draft IRS update. Begin
using IRS sites as demonstration sites.
Satellite sites: Intensive post-treatment follow-up; quality check on approach;
re-visit agreements.
APPENDICES
Appendix 1.
Technical Reviewers.
D. Botkin (ecol. modeling) R.
Nielson (ecol. modeling)
Univ. Calif., Santa Barbara EPA,
Corvallis, OR
C. Binkley (economics) R.
Powers (soils/silv.)
Univ. British Columbia PSW,
Redding, CA
Vancouver, B.C.
T. Chapin (plant ecology) B.N.
Richards (soil biology)
Univ. Calif., Berkeley Univ.
Armidale, Australia
R. Clark (forest sociology) R.
Sidle (hydrology)
PNW, Seattle, WA INT,
Logan UT
K. Connaughton (economics) W.
Swank (ecosystem ecol.)
PNW, Portland, OR SE,
Otto, NC
R. Curtis (mensuration) A.
Stage (mensuration)
PNW, Olympia, WA INT,
Moscow, ID
W. Farr (mensuration) E.
Stone (soils)
PNW, Juneau, AK Univ.
Florida
Gainsville,
FL
T. Ledig (genetics) T.
Terry (soils)
PSW, Berkeley, CA Weyerhaeuser
Co.
Centralia,
WA
G. Likens (ecosystem ecol.) J.
Trappe (soil biology)
Inst. for Ecosystem Studies, Oregon
State Univ., Corvallis, OR
Millbrook, NY
C. Maser (wildlife ecol.) G.
Woodwell (ecosystem ecol.)
EPA, Reno, NV Woods
Hole Research Center
Woods
Hole, MA
Appendix
2. Proposed flux measurements
(controlled by biotic composition) and environmental variables based on
divisions in Figure 2. Note that change
in these variables will be used in models to predict potential productivity, future
ecosystem productivity, and future organic matter distribution.
A. C balance:
1. Leaf area index (LAI) and
duration of seasonal display from direct measurement or remote sensing as a as
a
reference for estimating maximum
gross primary production (GPP);
2. Respiration (Rs) rates of both
aboveground (vegetation) and belowground (litter, mineral soil, and roots
combined) as a means to estimate
the net primary productivity (NPP) component of GPP;
B. Nutrient balance:
1. Change in nutrient availability
(estimates of annual mineralization rates, nutrient uptake by vegetation,
and return in litter);
2. Shifts in the extent and intensity
of root and microbial activity as determined by distribution and evidence of
biotic activity (soil enzymes,
soil aggregates, xylem sap mineral balance,)
3. Leakiness of the system as measured
by nitrate in the groundwater, sediment transport, and denitrification;
C. Water balance:
1. Constraints on evaporation and
transpiration as measured by remote sensing (surface temp. vs. greenness
index), natural abundance of C
isotopes, or direct measures of transpiration?;
2. Changes in water infiltration,
retention, or watertable related to changes in soil structure, organic matter
amount and quality (e.g., coarse
woody debris vs humus), or vegetative uptake;
D. Climate:
1. Amount and seasonal distribution
of photosynthetically-active solar radiation (PAR) directly measured or
from satellite sensors;
2. Temperature fluctuations directly
measured, interpolated from NOAA data, or possibly inferred historically
from the hydrogen isotopic ratio
in cellulose of annual rings;
3. Atmospheric composition including
pollutant loading from direct measurement or modeled from NADP and
other databases.
E. Potential nutrient supply:
1. Atmospheric deposition of
nutrients from direct measurement or modeled from NADP and other databases;
2. Weathering of primary minerals
across many time scales throughout the potential rooting zone as
determined by total content of
the parent material, and from a series of sequential extractions;
3. Potential for long-term nutrient
immobilization and release of secondary minerals in soil horizons;
4. Measured soil nutrient losses from
water and wind erosion;
F. Potential water supply:
1. Rain and cloud water deposition
from direct measurement or modeled from NOAA and other databases;
2. Infiltration, retention, and
drainage;
Appendix 3.
The PNW Station Integrated Research Site Team:
Susan Little PNW Jim
Boyle OSU Trish
Wurtz PNW
Bernard Bormann PNW Bill
Farr PNW Darlene
Zabowski PNW
Larry Bednar PNW Connie
Harrington PNW John
Zasada PNW
Mike Amaranthus R6 Art
Tiedemann PNW Mike
McClellan PNW
Mike Castellano PNW