An Ecological Approach for the Inventory, Analysis,
and Monitoring of Forests in the United States
USDA Forest Service Research
Forest Inventory and Analysis Program,
ECOFIA Steering Group, ***DRAFT COPY***
March 24, 1994
PURPOSE
The need for forest inventory information from a broad, ecosystem
perspective has been addressed in documents such as "A Blueprint for FIA
[Forest Inventory and Analysis] Research and Vision for the Future" (USDA
Forest Service 1993) and the "Report of the Blue Ribbon Panel on FIA" (American
Forests Council 1993). This paper outlines an initiative to provide national
direction for improving the U.S. Department of Agriculture, Forest Service
Research, Forest Inventory and Analysis Program's responsiveness for taking an
ecological approach for the inventory, analysis, and monitoring of all forested
lands. This national direction will improve consistency and coordination among
FIA units and related efforts. The adoption of ecosystem management as a
guiding philosophy by the Forest Service (Kessler et al. 1992, Overbay 1992)
and the broader forestry community provides a strong basis for this
initiative. The objectives of this paper are to:
- 1. Review FIA's current role in ecosystem inventory, analysis, and
monitoring;
- 2. Outline a rationale and conceptual framework for determining the
future
ecological inventory, analysis, and monitoring role of FIA; and
- 3. Determine an action plan for implementing an ecological approach
for the
national FIA program.
GUIDING PRINCIPLES
Adopt an Ecosystem Perspective
The essence of this initiative is a paradigm shift from viewing the FIA
program as one that focuses on specific commodity resources (e.g., timber) to
one that considers the composition, structure, and function of the vegetation
components of forest ecosystems. While FIA has been gradually moving from a
forest product to a multi-resource focus for the last 10-15 years (see Rudis
1991), it is time to accelerate to an even more holistic approach. An
inventory strategy that places primary emphasis on the forest's ecological
components and relationships will yield information usable in a variety of
ways for a wide array of values--including but not limited to various
resources and commodities.
Stay Flexible
Because ecosystems are dynamic, complex, and poorly understood, movement
towards ecological analysis is an on-going, adaptive process. We advocate a
flexible approach that continually reassesses information needs, incorporates
other disciplinary perspectives, and responds to new scientific information and
society's changing values. Such an approach involves measuring basic forest
attributes that underlie ecosystem processes.
Build on Strengths and Emphasize Coordination
Demands for new and complex kinds of information to support ecosystem
analysis and management are overwhelming, and the array of possible approaches
is immense. Tight budgets and concurrent efforts by other agencies and
organizations dictates that FIA develop an ecologically-based inventory system
that builds on our established strengths and emphasizes coordination with
related inventory and monitoring efforts.
CURRENT ROLE
Historically, FIA has emphasized the inventory, classification, and
analysis of existing vegetation within physical and social contexts (see USDA
Forest Service 1992 for an overview of the FIA program). With more than
one-half century of experience, the FIA program has built on strengths to
establish its niche within the environmental science community. Some existing
FIA strengths that will guide future efforts are:
- 1. Experience and expertise in measuring and characterizing existing
vegetation;
- 2. Temporal data characterizing forest vegetation and its dynamics that
span
several decades;
- 3. Vegetation data (from field measurements) representing a variety of
spatial
scales and all ownerships. Examples of these scales include ecosystem
scales from subsection to domain (ECOMAP 1993) and political scales from
county to nation;
- 4. An established infrastructure (staffing, facilities, funding) for all
phases of inventory, including data collection, processing, analysis, and
dissemination;
- 5. A national network of permanent plots (now being re-established
over all
National Forest System lands and extended to reserved area, e.g., parks and
wilderness) that are geo-referenced, allowing linkages to other
spatially-registered data; and
- 6. Statistically rigorous sampling designs with national standards.
FUTURE DIRECTION
Taking an ecological approach will require successive refinement and
reliance on a strategy of adaptive management. While general guidance has been
provided by Congress through legislation, priorities will be modified by FIA's
partners. Forest industry, cooperators, research institutions, National Forest
System planners, and other stakeholders constitute the FIA program support
base. As the system evolves, active encouragement, support, and involvement of
nontraditional natural resource and environmental disciplines and organizations
will extend FIA's support base toward ecosystem analysis and its concomitant
priorities.
Information Needs and Implementation Plan
Information needs for an ecological approach must guide the implementation
of this initiative. Identification of ecosystem information needs will
require input from, and coordination with, many other sources. Many
ecosystem-related activities are on-going at a regional level with individual
FIA units. There are several topics that are currently being addressed by one
or more FIA units and that could or should be addressed nationally. In
addition to internal efforts, other efforts outside of FIA are on-going and
their methods and findings need to be incorporated into the FIA program.
Implementation will be considered in three phases. Each phase requires
successively greater levels of commitment by FIA and its partners as additional
techniques research, data collection, and analyses are developed.
- Phase 1. Identify ecosystem information needs currently being addressed
by all
FIA units and partners and standardize them nationally.
- Phase 2. Identify ecosystem information needs currently being addressed
by one
or more FIA units or partners that should be standardized
nationally.
- Phase 3. Identify ecosystem information needs not currently addressed
by the
FIA program or partners that should be developed nationally.
Following are examples of ecological issues that FIA is well-positioned and
qualified to address nationally. All of these issues can be characterized in
terms of amount, spatial and temporal distribution, and interactions at
multiple scales.
- 1. Biodiversity across several levels of organization, from species to
landscape;
- 2. Landscape patterns demonstrating the impact that humans have on
forested
ecosystems, such as fragmentation and land use dynamics;
- 3. Structure and dynamics of community- or stand-level forest
vegetation, such
as attributes of forest regeneration and vegetation life-form
profiles;
- 4. Extent and distribution of seral stages including late-successional
forests;
- 5. Woody biomass and carbon storage;
- 6. Snag and down woody material characteristics and density;
- 7. Riparian forests and forested wetlands;
- 8. Forest health and productivity; and
- 9. Ecological assessment of all
lands dominated by tree cover (including
timberland, parks, wilderness, woodland, and urban tree land) for all
ownerships in the United States.
Since ecosystems are so complex, it helps to use a simplifying model to
adequately characterize them. One developed by Franklin et al. (1981)
identifies three primary attributes of ecosystems: composition, structure, and
function. Composition has to do with the identification of various elements in
the system, and includes species lists and diversity measures. Structure is
the physical organization or pattern of a system, and includes the size and
distribution patterns of vegetation or stands. Function involves various
processes, such as disturbances, succession, and land use transitions. Noss
(1990) took these attributes and simplified them further by organizational
states. Using this model, examples of biological, social, and physical
elements of forest ecosystems that could be addressed by FIA are displayed in
Table 1. Similar presentation of such data and
analyses could provide the
framework for ecological assessments of the nation's forests.
Research and Development Needs
Research plays an essential role in all phases of implementing an
ecological approach to inventory and monitoring. Coordination among FIA units,
cooperation with other research institutions, and support of allied natural
resource agencies and nongovernmental organizations are key elements for all
FIA research activities. A greater proportion of FIA resources should be
devoted to research and development in the future. FIA should become a
recognized authority in techniques for broad-scale inventory and analysis of
forest vegetation composition, structure, and processes. The following areas
of research deserve high priority.
Sample Design.
Sample design strongly influences FIA's
ability to provide
relevant information for ecological analyses. Currently, FIA units employ an
extensive, photo-based sample design of all land and a field sample of forests
from a random or systematic grid of permanent plots. Research activities
should be undertaken that consider the possible need for different plot designs
for ecosystem analysis; stratification and classification approaches that are
ecosystem-based; multi-phase designs that combine spatially explicit data with
field plot data; strategies for horizontal "edge-matching" of various
sample-based inventories to provide complete geographical coverage; and
approaches for aggregating and disaggregating information, and quantifying
errors across spatial and temporal scales.
Vegetation Measurement and Classification.
We need to
identify efficient and
repeatable methods for measuring and quantifying composition, structure, and
function of all forest vegetation. New systems for classifying existing
vegetation that are ecosystem-based rather than forest product commodity-based
should be developed and implemented.
Spatial Analysis and Modeling.
Techniques are needed
for characterizing
landscape patterns and their dynamics using GIS modeling, remote sensing, and
spatial statistics. Research on more efficient and effective ways to combine
map-based and sample-based data is another critical need.
Standards for Ecosystem Inventories.
Identification and
implementation of national data standards
are needed to improve the utility of FIA data
for ecosystem analyses.
Biodiversity Assessment.
Development of a conceptual
framework, sampling
methods, data elements or indicators, and analytical approaches to evaluate
biodiversity is a major step needed for ecosystem management and ecological
analyses.
Forested Riparian Zones and Wetlands.
Development of
sampling designs and
analytical methods for regional assessments of streamside forests and other
forested wetland communities are needed to provide basic descriptions of these
valuable ecosystems.
Human Dimensions.
Humans comprise an integral
component of forest ecosystems,
and we need inventory data and analyses to better assess the interactions
between human and natural systems. Examples include status and condition of
rare and endangered habitats, extent of harvest disturbance, human community
development in forested areas, tree and forest community establishment in human
communities, ownership impacts on landscape fragmentation, and land use
transition probabilities over various temporal scales.
ECOFIA Steering Committee
March
1994:
DG Email addresses are below.
Example Internet version for Roger Conner is:
FSWA/S=r.conner/ou=S29A@mhs.attmail.com
Roger Conner SE-FIA (R.CONNER:S29A) 704-257-4359
Will McWilliams NE-FIA (W.MCWILLIAMS:S24A) 610-975-4050
Renee O'Brien INT-FIA (R.OBRIEN:S22L02A) 801-625-5371
Janet Ohmann PNW (J.OHMANN:S26L07A) 503-321-5859
Doug Powell, Chair WO-FIA (D.POWELL:W01C) 202-205-1724
Vic Rudis SO-FIA (V.RUDIS:S30L01A) 601-338-3109
Tom Schmidt NC-FIA (T.SCHMIDT:S23A) 612-649-5131
LITERATURE CITED
American Forest Council. 1992. Report of the blue ribbon panel on forest
inventory and analysis. Presented to U.S. Department of Agriculture,
Forest Service Chief Robertson on October 10, 1992. Washington, D.C.
9 p.
ECOMAP. 1993. National hierarchical framework of ecological units.
Washington, D.C. U.S. Department of Agriculture, Forest Service. 19
p.
Franklin, J.F., K. Cromack, Jr., W. Denison, A. McKee, C. Maser, J. Sedell,
F. Swanson, and G. Juday. 1981. Ecological characteristics of old-growth
Douglas-fir forests. USDA Forest Service General Technical Report
PNW-118. Pacific Northwest Forest and Range Experiment Station, Portland,
OR. 48 p.
Kessler, Winifred B., Hal Salwasser, Charles W. Cartwright, Jr., and James A.
Caplan. 1992. New perspectives for sustainable natural resources
management. Ecological Applications 2(3): 221-225.
Noss, Reed F. 1990. Indicators for monitoring biodiversity: a hierarchical
approach. Conservation Biology 4:355-364.
Overbay, James C. 1992. Ecosystem management. In: Proceedings of a national
workshop: Taking An Ecological Approach To Management, April 27-30, 1992,
Salt Lake City, UT. USDA Forest Service Watershed and Air Management
WO-WSA-3, Washington, DC. p. 3-15.
Rudis, Victor A. 1991. Wildlife habitat, range, recreation, hydrology, and
related research using forest inventory and analysis surveys: a 12-year
compendium. U.S. Department of Agriculture, Forest Service, Southern
Forest Experiment Station GTR SO-84. New Orleans, LA. 61 p.
USDA Forest Service. 1992. Forest Service resource inventories: an overview.
Forest Inventory, Economics, and Recreation Research, Washington, DC.
39 p.
USDA Forest Service. 1993. A blueprint for forest inventory and analysis
research and vision for the future. U.S. Department of Agriculture, Forest
Service, Forest Inventory, Economics, and Recreation Research Program Aid
No. 1512. Washington, D.C. 20 p.
TABLE 1.
Examples of elements
for forest vegetation inventory and analysis at
three organization levels by ecosystem component.
Lower level elements are aggregatable to
higher levels of organization.
Level of Ecological Organization and Ecosystem Component
Region/Landscape
Composition:
- Earth cover and land use proportion
- Species ranges
- Forest owner characteristics
Structure:
- Earth cover and land use characteristics
- Successional patterns
- Patterns of ecotones, edges, patch size, connectivity, and
juxtaposition
Process/Function
- Disturbance: extent and frequency
- Earth cover and land use change
- Patch dynamics
- Species migration
- Biotic, social, and economic sustainability
Community/Stand
Composition
- Forest type
- Species diversity
- Habitat type/plant association indicators
- Endemic vs exotic species
- Vegetation life forms
- Slope, aspect, etc.
- Mast tree abundance
- Softwood/hardwood volume
Structure
- Stand diameter, size, or seral class
- Stand density and age
- Snags and downed woody characteristics
- Successional stage, including old growth
- Forest condition, size, and shape
- Canopy height diversity
- Gap patterns
Process/Function
- Potential and actual productivity
- Disturbance, e.g., harvesting, prescribed and natural
fire, grazing.
- Stand dynamics, e.g., regeneration, growth, mortality,
succession.
- Sustainability
- Forest health
Species/Population
Composition
- Species abundance, e.g., number, density, biomass
- Frequency
- Importance
Structure
- Tree diameter distribution
- Tree architecture, e.g., crown size, shape
Process/Function
- Tree history, e.g., survivor growth, ingrowth,
mortality, cull increment, removal
- Tree vigor, health, and productivity
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Modified for WWW February 17, 1995 by
V.Rudis.