LONG-TERM ECOSYSTEM PRODUCTIVITY (LTEP) PROGRAM

GOVERNING RESEARCH PLAN

FOR THE INTEGRATED RESEARCH SITES

Prepared by

Susan Little, Bernard Bormann, Larry Bednar,

Trish Wurtz, John Zasada, Mike McClellan,

Lauri Shainsky, James Boyle, Mike Castellano

Mike Amaranthus, Connie Harrington,

Darlene Zabowski, and Mike Geist

This version of the research plan was updated from the original plan signed in 1992. The update reflects a changed program name (previously long-term site productivity), actual research sites selected, newer figures, and makes minor editorial corrections. Other changes to the study are not included in this update (B. Bormann, April 2, 2000).

RESEARCH PLAN FOR THE LTEP INTEGRATED RESEARCH SITES

Introduction

The USDA Forest Service, USDI Bureau of Land Management, and other stewards of the land have been charged with the challenge of maintaining forest productivity for current and future generations. Forest productivity is the ability of the land to provide a combination of resource values such as fiber, water, air, quality experiences and biological diversity. Long-term ecosystem productivity is the capacity of the site to support forest ecosystems over generations of humans and trees, as measured against some defined reference. Our desire to maintain long-term ecosystem productivity, and the legal mandate to do so, includes a desire to maintain options for future use as well as the sustained production of the current mix of forest products and intangible resources. In this research plan we will refer to potential productivity—approximated by gross primary productivity derived from models, and referenced by indices of soil quality and genetic potential—and to the net and cumulative production of specific products and forest attributes such as net primary productivity, wood volume, nesting sites, forage, and species diversity.

Long-term ecosystem productivity is determined by the cumulative interaction of soil, biota, climate, natural disturbance, and human activity. Two recent proceedings capture current knowledge of productivity and have references for specific topics (Perry and others 1989; Gessel and others 1990). Nearly all forestry research contributes in some manner to our understanding of ecosystems and the management of forests. However, most research to date has focused on short-term responses of individual components of ecosystems to individual events and manipulations. Thus, a fragmented body of knowledge has evolved in which research methods and language are specialized by discipline and individual disciplines are pursued at different locations and scales. Although some individual processes and responses are adequately understood, integration and synthesis are difficult at best.

The focus for the research proposed here was derived from discussions within a broad community of people interested in long-term ecosystem productivity (see Appendix I). The authors developed specific objectives, hypotheses, and design in response to the community's input. Two primary mechanisms by which forest management may influence long-term productivity were identified and form the basis for the two basic questions posed by this research plan:

· Does altering the pattern of succession through species manipulations influence long-term ecosystem productivity? and,

· Does the amount, timing, and distribution of organic matter left on-site influence long-term ecosystem productivity?

The integrated research sites are being established as a network of long-term research sites to address these as well as other questions that are truly long-term and complex, and demand that research disciplines integrate in concept, in application, and in analyses. The research sites will provide a setting for continual observation, discussion, and involvement across disciplines, management, and interested publics. Research on these sites will be conducted in a 200-year context, allowing for several generations of crop trees. In order to provide for the needs of land managers in the near future—prior to completion of long-term studies—research from these sites will contribute to conceptual and numerical modeling of long-term processes and responses on a continuing basis. Our desire is to provide a legacy of integrated information on productivity and to provide a context for basic research that will result in more efficient research and more successful incorporation of results into models.

The integrated research sites are the cornerstone of a broader LTEP Program, led by the USDA Forest Service Pacific Northwest Research Station in cooperation with Pacific Northwest and Alaska Regions and with the USDI Bureau of Land Management, Oregon State Office. Research under the Program includes research on belowground processes, retrospective, and chronosequence research on ecosystem productivity, modeling long-term productivity to evaluate consequences of management decisions, and investigations on the effects of specific management practices on long-term ecosystem productivity.

Background

Net Primary Productivity

Sustainable forest productivity is the ability of the land to produce a wide array of products and values on a perpetual basis within broad environmental limits. Thus, the most appropriate measure of forest production is likely be an index which integrates across this array and quantifies values and resources such as timber, grazing, wildlife, fisheries, water, visually attractive landscapes, recreation, microbes, biodiversity, habitat and other ecosystem properties. Ideally, measures of sustainability would be derived from changes in overall production over long time periods, independent of changes in environmental limits. However, overall production is often not quantifiable because of widely varying units of measure, and changes in climate. Thus, surrogate measures of sustainability are needed that closely relate to the production of as many products and values as possible and at the same time can be directly measured. The LTEP Program will use total ecosystem production-- net primary production (Npp)—and components of Npp as the principal surrogate measure of long-term ecosystem productivity. We do not, however, preclude use or development of other surrogate measures.

Components of Npp form the basis for the conceptual model that drives and will be driven by the research proposed here (fig. 1). Primary producers or autotrophs (plants) capture light energy through photosynthesis. Gross productivity (Gpp) is the cumulative dry matter added to the ecosystem through photosynthesis. Npp is Gpp minus the dry mass lost during maintenance and growth respiration (R_a):

Gpp=Npp + R_a. [1]

Changes in net storage of carbon resulting from additions or losses are defined as net ecosystem production (NEP). Losses of carbon other than R_a result primarily from the respiration of heterotrophs (R_h). Heterotrophs are animals and non-photosynthetic microbes and plants that depend on the energy fixed in organic molecules during photosynthesis by autotrophs.

Npp= NEP + R_h [2]

NEP is defined as change in storage of carbon in all forms during a defined period and include changes in carbon content in plant, animal, and microbial biomass, and changes in detritus—all dead organic matter such as soil humus, litter, and downed logs. Further divisions of changes in biomass are useful, such as stem and forage production. These are often the type of production managers are most concerned with.

Figure 1. Net primary production and its relation to net ecosystem production, respiration, and the production of ecosystem goods (such as wood products) and services (such as changes in soil organic matter).

Measurement of Npp can be problematic, mostly because of difficulties in quantifying belowground and detritus production, as well as other outputs or losses. Our approach follows that of Bormann and Gordon (1989), which focuses on three principal components of Npp: soil respiration; changes in soil organic matter; and changes in aboveground biomass.

Succession, Management, and Implications For Long-Term Productivity

Change is a fundamental characteristic of forest ecosystems. The rate and nature of change is a function of species composition (including plants, animals, soil organisms, fungi and other biota), site conditions, and the frequency and severity of disturbance in a given ecosystem. Succession is the sequence of change in biotic communities that occupy an area. Succession involves numerous processes by which species influence the physical environment and replace one another over time (Connell and Slatyer 1977, Bormann and Likens 1979, Kimmins 1987, Oliver and Larson 1990).

The mechanisms of succession in biotic communities are complex; numerous mechanisms and pathways exist for a given site's progression from one set of species (or "sere") to another. Although seres are often described only in terms of the primary producers, i.e., plants, changes in plant composition can cause changes in other species (e.g., animals, soil organisms, and others). Conversely, animals and other organisms may be a major cause of change in the composition of the primary producers. Forest succession can be either autogenic, whereby organisms make changes in the site which favor the development of other species, or allogenic, whereby geologic or climatic processes cause changes in the physical environment which lead to changes in the biota (Kimmins 1987, Oliver and Larson 1990).

In this research plan, we are concerned with secondary succession, the progression of plant communities that occur following disturbances such as fire, windthrow, and timber harvesting. Secondary succession is distinguished from primary succession in that the former occurs on sites that have some level of soil development and previously supported vegetation. The species composing the forest vegetation that develops following disturbance fall into one of several categories (Kimmins 1987, Halpern 1988, 1989, Oliver and Larson 1990). Residual species occurred in vegetative form before disturbance and some portion of the plant survived the disturbance. These species can rapidly dominate a site and in extreme cases prevent the establishment of species which otherwise may have dominated later succession. Examples of these species developing from roots and rhizomes are Rubus spp., Populus tremuloides, Vaccinium spp., and Galtheria shallon. Others develop from basal sprouting Acer spp., Corylus, Salix spp., and Arbutus menziesii. A final group can develop by layering, one of the best examples of this is Acer circinatum. Invader species become established from seeds entering the area from adjacent stands. Species of all of growth forms (trees, shrubs and herbs) can be part of this group. They can all establish at the same time; dominance is determined by growth rate and longevity. Examples of these species are Epilobium spp., Senecio spp., Alnus spp., Betula, many of the commercial conifers, and Salix spp. Another group of species are represented in the buried seed pool. These species may or may not be present on the site in vegetative form prior to disturbance. The classic examples are species that occur in the early successional flora but are only present in seed form in later successional stages. Following disturbance, seeds germinate and the species are present for several to many years depending on life form and growth characteristics. Some of the best examples are Ceanothus spp, but other examples are various Rubus spp., Geranium sp, Corydalus sp. and Sambucus spp. Knowledge of how different species recolonize disturbed sites will aid us in prescribing means of achieving the different seral treatments.

Three proposed mechanisms that determine the relationship among dominant species (and less obvious but important species such as nonvascular plants, soil flora, and soil fauna) and the pathways of succession include facilitation, tolerance, and inhibition (Connell and Slatyer 1977, Kimmins 1987). Facilitation occurs when individual species modify the environment in such a way that it becomes more suitable for the invasion of other species than for its own regeneration. Tolerance occurs when the environment is satisfactory for the establishment of any of the potential invading species, and species dominance is based mainly on which species happen to arrive first, their growth form, rate of growth, longevity, and the physiological ability to tolerate the current environmental conditions. Inhibition occurs when species modify the environment in such a way that prevents the recruitment of other species or significantly prolongs the recruitment period. These processes are not mutually exclusive and may all occur simultaneously on the same site. The importance of each will be determined by species composition, disturbance regime, and growth and reproductive characteristics of the species involved.

Successional patterns following disturbances such as harvesting or wildfire are known to varying degrees in Alaska, Oregon and Washington (see for example Stewart 1978, Van Cleve and Viereck 1981, Franklin and Hemstrom 1981, Foote 1983, Alaback 1984, Kimmins 1987, Halpern 1988, 1989, Oliver and Larson 1990). Most research to date has focused primarily on changes in species composition and cover of trees and associated vascular plants. Some studies have dealt with nonvascular species and microorganisms. However there is little information on the relationship of changes among different trophic levels as a result of forest management activities.

Forest management practices often result in shortening or eliminating some parts of the successional sequence. For example, use of herbicides or site preparation techniques in combination with planting favored timber species can result in a reduced duration of early seral species. As a result, the influence of some species is eliminated or reduced. The long-term impacts of practices that alter succession are not known in detail. The importance of some individual species whose tenure on a site is often shortened is known to some extent. The potential detrimental effect of the elimination of species such as alder and Ceanothus, which fix nitrogen, can be assessed in a general way. However, there is little information on the role of other non-crop species in determining long-term ecosystem productivity or the effects of eliminating or reducing their time of occupancy.

Forest management in the Pacific Northwest is evolving, particularly with respect to harvesting strategies. Past approaches used narrowly defined methods and blanket prescriptions. Now, case-by-case evaluations are made which seek to achieve landscape objectives as well as efficient production of timber. This evolution is leading to more partial cutting, uneven-aged management, and retention of individual trees or groups in an even-aged setting (e.g., Eubanks 1989). Some of the products and values tangible at the landscape-scale depend more on species composition, distribution, and stand structure than on achieving maximum growth of selected tree species. Thus, there is a need to understand the impact of management practices at the stand-scale in ways that relate to landscape-scale questions. In order to assess the effects of harvesting and other management practices on productivity, we need to be able to relate changes to easily identifiable states or stages of forest development. Forest successional development provides a framework for such assessments. This plan seeks to use this framework to examine the consequences of directed forest successional development and associated links of ecosystem structure and function, as they relate to productivity on various spatial and temporal scales.

Organic Matter and Long-term Ecosystem Productivity

Organic matter (OM) is any and all material on a site, living and dead, containing carbon compounds derived from living organisms, including specific components, such as the forest floor, soil organic matter, and downed woody debris. Total ecosystem OM may be divided into categories defined by structure or function. Structurally, OM may be usefully divided into foliage, branches, stems, roots, standing dead, forest floor (including down logs and branches), soil organic matter (SOM), dissolved OM, volatilized OM, and animal biomass. Many functional definitions are possible also, with OM divided into photosynthetic, respiring, and detrital components or into categories based on relative OM recalcitrance, expressed as half-life or turnover time. A structural approach will be used in the design and implementation of this study.

Organic matter has multiple functions in forest ecosystems that may determine forest productivity, including as a primary reservoir of nutrients, essential to plant and animal growth; as the energy source for heterotrophs; and as a structural material that functions as habitat (e.g., snags, down logs) and that creates soil horizons and aggregate structures that buffer ecosystems against physical forces. Examples of buffering activity include organic horizons that protect soil from erosion, plant canopies that moderate wind speed and radiative heating or cooling, and coarse woody debris on steep slopes and in stream channels that reduces the erosive power of flowing water. Perry and others (1989) provide discussions on the role of organic matter in forest productivity in general, and Jurgenson and others (1990) discuss organic-matter issues pertinent to the forests of the Inland Northwest.

Research in the last 20 years on management effects on organic matter has concentrated on two main areas: comparing bole-only and bole-and-crown harvesting; and evaluating the effect of site preparation, primarily fire, on surface organic matter pools (S.U.N.Y. 1979; Ballard and Gessel 1983; Perry and others 1989; Gessel and others 1990; Walstad and others 1990). Both areas of research were motivated primarily by a concern for nutrient capital. Methods typically compared nutrient capital in pre-treatment sites with that removed during the management activity. Long-term effects have been predicted by comparing management losses to natural inputs of nutrients and through models of nutrient cycling (Kimmins and Sollins 1990). Ecological research on contributions of individual species to litter, decomposition, and below-ground processes have also been conducted, but seldom on the same sites as the harvesting research. Direct evidence of long-term impacts from intensive harvesting is weak, primarily due to the lack of long-term, controlled experiments (see Powers and others 1990 for synopsis of multi-generational studies and Dyck and Cole 1990 for a discussion of research needs).

Harvesting and site preparation are the major ways by which forest management practices may influence site organic matter. Current National Forest plans have standards and guidelines for retention of large woody debris and protection of forest floor. The intent of these standards is to protect long-term productivity. Economic trends have altered how harvests are conducted, with more reliance on whole-tree yarding and more complete utilization of individual trees than in the past. The question now is not whether to whole-tree or bole-only harvest, but how much material is to be left on site either as felled trees, or as specified pieces of residue classified by length, diameter or quality. Research is needed to compare organic matter inputs to the forest floor (and subsequently to the soil) as a result of harvesting in even-aged and uneven-aged settings. This research will be most fruitful if combined with studies of the different contributions of species groups to forest floor and soil through annual litterfall and turnover between harvests.

Objectives

The research discussed in this plan has two primary objectives:

A. To examine how potential and realized productivity are affected by the pathway along which succession is directed by management practices. All sites are capable of supporting a variety of forest conditions at any point in a seral sequence. These forest conditions can be described in terms of the species present, their vertical and horizontal distribution and abundance, amount of non-living organic matter, microclimate regimes, general state of health, as well as in terms of relative position of that site to others across the landscape. This research is designed to examine how conditions produced by directing the aboveground plant component of an ecosystem to a particular successional state or "sere" can affect subsequent ecosystem development and productivity. Forest conditions can be altered by management practices that affect composition by removal of species, addition of species, conversion of organic matter to different forms, and change soil physical and chemical properties. This research will focus on three distinct strategies for directing or arresting succession towards forest conditions that may have distinct differences in ecosystem production. These treatments include: (1) incorporating an abundance of early seral species into even-aged management of conifer crop species; (2) directing site resources exclusively to mid-successional conifer crop species to the exclusion of other seral stages; and (3) emphasizing late-seral species and forest structure along with the management of the crop species (fig. 1). A fourth treatment will be an unmanipulated stand, left untended throughout the duration. The crop species will be consistent across treatments within a site, but will not necessarily be consistent across sites.

B. To examine how altering the amount of periodic inputs of organic matter to the forest floor can influence long-term ecosystem productivity. The importance of organic matter will be examined by directly manipulating aboveground organic matter, primarily through the cutting and removal or retention of whole plants. Treatments will be defined as proportion of aboveground biomass to be left in a felled condition after each harvest. Hence, the stand-scale treatments will address the aspects of managing quantity of organic matter (fig. 2). Small-scale studies on these sites will look at issues of quality of organic matter, particularly as it relates to decomposition rates of different sized material, contributions of individual species to annual litterfall and soil-organic-matter quality.

Figure 2. The generalized experimental design for the LTEP integrated research sites. Note that the unmanaged control treatments is not shown, the Olympic Peninsula site has a mid organic matter treatment as well, and that the Oregon Coast Range site includes 10 to 30 residual trees per acre on early and mid treatments.

Hypotheses

The hypotheses listed below represent the central issues to be addressed by the research team through the implementation of this research plan. The primary null hypotheses target four broad categories: net primary productivity, biodiversity, soil organic matter, and soil physical properties. Within each category, alternative hypotheses are proposed, some of which include underlying mechanisms. Some of these hypotheses are stated in a testable form and will be directly addressed by the design. In other cases, small-scale manipulative studies will be needed to test proposed hypotheses, particularly the more mechanistic ones. Hypotheses will be tested within and between sites. Ideally, the ultimate test of most hypotheses concerning long-term ecosystem productivity would be an on-site bioassay of crop production after 200 years of subjecting each site to its array of treatments. In the meantime, the hypotheses will tested from periodic assessments of net and cumulative production, gross primary productivity, biodiversity, and soil attributes. We will be inviting other scientists to explore related hypotheses as an ongoing process, and will allocate space within the units to do so.

Net primary productivity

We will focus on three aspects of net primary productivity (Npp):

C. Annual Npp (Npp yr^-1)—the Npp accumulated over a year. This can be a measured accumulation for one year, or an average derived from total accumulation over a measurement period divided by the years in that period.

D. Cumulative Npp (SNpp)—the Npp accumulated from the initiation of the experiment to some reference point in time; and

E. The function of annual Npp over time.

For both annual and cumulative Npp indices, we will chose mid-rotation as our primary reference point in time. Mid-rotation is site-specific and defined as the halfway point through the rotation length, as determined by local foresters at the time of treatment prescription. However, we will continually monitor Npp and explore treatment differences throughout the experiment.

Null Hypothesis I: Net primary production (Npp yr^-1 and SNpp) at mid-rotation and the shape of the Npp yr^-1 function over time will be the same for all treatments—for all species compositions and OM manipulations—and will not differ from that of the unmanipulated stand.

Alternatives:

1. Within an organic matter treatment, there will be differences in Npp between the different seral treatments. These differences in Npp yr^-1 and SNpp should be evident by mid-rotation.

2. Although annual Npp at mid-rotation will be the same between all treatments, the cumulative Npp will differ: the early seral treatment will have the highest SNpp, and the natural stand will have the lowest SNpp.

3. Year of attainment of maximum Npp yr^-1 will differ between treatments: the natural stand will begin at its maximum Npp yr^-1; the late seral treatment will achieve its maximum Npp yr^-1 by mid-rotation of the first introduced cohort; the mid-seral treatment will achieve its maximum Npp yr^-1 at the end of the first rotation; and the early seral treatment will continue to increase its Npp yr^-1 throughout the second rotation.

4. Organic matter treatments will alter Npp yr^-1, SNpp, and the Npp yr^-1function.

Null Hypothesis II: The proportional allocation of production between ecosystem components is the same for all treatments.

Alternatives:

1. There will be differences between treatments in the proportion of total Npp allocated to bolewood of the crop species. For a given organic matter treatment, this effect is expected to be measurable at the end of the first rotation. The mid-seral treatment is expected to have the greatest proportion of Npp devoted to bolewood, followed by the late seral treatment, then the early seral treatment. The natural stand is expected to have the smallest proportion of Npp allocated to bolewood at the end of the first rotation. These trends should continue through the second rotation. We expect that the early seral treatment will devote a larger portion of Npp to reproduction and annual litterfall. The natural stand will be approaching a relatively stable level of bolewood, and will be devoting a greater proportion of Npp to annual litterfall than the other treatments. The late seral treatment will fall between the mid-seral treatment and the natural stand.

2. Differences between the organic matter treatments in proportional allocation of Npp may not be expressed until the second rotation. Differences in proportional allocation of Npp are expected to be due primarily to differences in decomposition and nutrient uptake.

3. The proportion of Npp devoted to heterotrophic respiration (R_h/Npp) will be higher in treatments with more species diversity due to enhanced diversity of litter quality and associated microbial populations, and greater allocation of resources to reproduction than to structure.

4. The proportion of Npp devoted to autotrophic respiration (R_a/Npp) is expected to be higher in systems stressed by availability of water or nutrients or by pests and pathogens. Which treatments are more stressed than others will differ between sites.

5. The ratio of new heterotrophic respiration to old heterotrophic respiration (R_h-new/ R_h-old) is expected to be the same between the early- and mid-seral treatments, but greater in the late seral treatment and in the natural stand.

6. It is likely that species composition and OM treatments will interact to influence Npp yr^-1, SNpp, allocation of Npp components, and the function of Npp over time. Each plant species present will have a unique effect on the physical and chemical environment, which will influence the diversity of microbial populations present, OM conversions, and subsequent Npp. In addition, OM treatments are likely to influence the presence and abundance of species colonizing the units by creating differential substrate microenvironments for germination. Persistence, dominance, and production by the species present may also be affected by OM levels through differences in nutrient cycling and soil temperature and moisture regimes, and potential herbivore habitat.

Biodiversity

Biodiversity in the context of this plan refers to the diversity of species present within a treated plot.

Null Hypothesis I: There will be no differences in aboveground and below-ground species composition between treatments.

Alternatives:

1. Seral treatments, by definition, impose differences in aboveground plant species. We expect that there will be differences between seral treatments in the kind and abundance of insect, mammalian, and bird species utilizing the treatment units. These differences will be apparent within the first 10 years after initial entry, and are expected to decrease late in the first rotation, but increase during the second rotation. The causes of these differences will be changes in the diversity of potential habitat and food supply.

2. Low OM treatments will reduce diversity of belowground species. This effect is expected to be measurable within 10 years after first entry because of differences in soil surface temperature, quality of forest floor and inputs to the soil organic matter.

3. The abundance and diversity of rodent populations will increase with increasing surface organic matter because of increasing diversity of habitat.

4. Organic matter treatments will influence the plant biodiversity by creating different patterns in substrate and environment for germination.

Interactions between biodiversity and Npp

Null Hypothesis I: Changes in biodiversity of plant species composition will not result in changes in Npp amongst treatments.

Alternatives:

1. Increased plant species diversity will result in higher annual and cumulative Npp. Increased plant species diversity will result in greater utilization of site resources through divergent patterns between species in resource partitioning. It will also enhance Npp by increasing the diversity of soil microbial species that will improve utilization of belowground resources. In the more diverse treatments, SNpp will increase with time most rapidly and early in the rotation, and plateau sooner than the less diverse treatments.

2. More diverse treatments will have higher Npp yr^-1 and SNpp because they are more resilient to perturbations such as disease and insect outbreaks, and climate change.

Soil organic matter

Null Hypothesis I: The amount and distribution of soil organic matter will not differ between treatments.

Alternatives:

1. The organic matter manipulations will influence soil organic matter. The amount of soil organic matter will be greater in those treatments having greater retention of aboveground OM.

2. Species composition will alter soil organic matter. The amount of soil organic matter will be greater in the late seral treatments and the natural stands because of greater large woody debris and uninterrupted litterfall contributed by late seral species.

Null Hypothesis II: The chemical and structural composition of soil organic matter will not differ between treatments.

Alternative:

1. Early seral species will contribute greater amounts of leaf litter to the soil organic matter pool, while later seral species may contribute greater amounts of large woody debris. Decomposition and incorporation of surface OM into the soil profile will be influenced by the effects of different species and forest floor on soil temperature and moisture, and by their associated microbial species.

Null Hypothesis III: Soil development (depth and quality of individual horizons) will not differ between treatments.

Alternatives:

1. Species composition will influence soil development through effects on the microclimate and evaporative demand. Species composition will also affect soil development through their differential biological activity: leaf litter and woody debris fall; root growth and below-ground OM input; root exudation, nutrient uptake and ion exchange; plant species-specific microbial associations and their influence on the biochemistry of the soil.

2. Organic matter treatment will influence the soil development by creating different initial SOM inputs. OM treatments are expected to interact with species composition treatments to influence soil development. Plant and microbial species will interact to influence both each other and their environment, thus affecting the soil profile development.

Soil physical properties

Null Hypothesis I: The mean and variance of soil bulk density (and porosity, water holding capacity, aeration) will not differ between treatments after initial entry and at subsequent measurements through the second rotation.

Alternatives:

1. The change in quality of OM inputs, amounts, and SOM distribution between treatments will alter soil physical properties directly and through change in the activity of soil microbes. For the early seral treatment, soil bulk density will decrease over the first rotation due to increased SOM and quality of litter. Soil bulk density will increase in the mid-seral treatment during the first rotation because of a decline in SOM.

2. In areas disturbed by treatment, there will be treatment differences in the rates of recovery of soil bulk density and porosity, due to differences in amounts and quality of organic matter inputs to the soil and subsequent effects on soil biology.

Methods

Integrated Research Site Locations

A network of five stand-alone experimental, integrated research sites will be established in Washington and Oregon (fig. 3). These sites are representative of the soils and forest types most likely to remain under management in the Pacific Northwest for resource outputs, including timber. Individual sites are described in Table 1. These sites are large enough to accommodate four replications of 7 to ten treatments applied at the stand-scale (8 ha).

Figure 3. Integrated research sites

Philosophy of Approach

No single research design can efficiently provide for research needs pertinent to all forest productivity questions. This research plan describes an approach to investigating questions tangible at the stand-scale (2 hectares) and smaller. The design described here will permit the quantifying and comparing measures of resources tangible at larger scales but will not allow direct comparisons of populations that have larger home ranges. Opportunistic use of natural events, such as insect outbreaks and wildfire, may provide some insights for landscape-scale questions.
Table 1. Description of LTEP integrated research sites (updated 4-2-2000)

Coastal Siskiyou
Location	Pistol River drainage, west and south of Gold Beach, Oregon
Manager	Chetco Ranger District, Siskiyou National Forest
Soils	Sedimentary rock parent material
Species	Douglas-fir, tanoak, and knobcone pine
Elev./topog.	800 to 1100 m; undissected slopes
Age	80 to 100 years old
Past History	Stand replacement following hot wildfires, few surviving residuals
Pathogens	Little evidence of pathogens
Oregon Cascades
Location	Isolation Block, south of Vida and HJ Andrews Experimental Forest
Manager	Blue River District, Willamette National Forest
Soils	Volcanic gravelly loam/loam, relatively homogeneous
Species	Douglas-fir, hemlock, red cedar with alder/maple in draws
Elev./topog.	About 700 m; undissected slopes
Age	About 80 years old
Past History	Stand replacement following hot wildfires with variable survival of residuals
Pathogens	Little evidence of pathogens
Oregon Coast Range
Location	North and east of Hebo, Oregon
Manager	Hebo Ranger District, Siuslaw National Forest (North Coast AMA)
Soils	Tyee sandstone and basalt, highly eroded following fire
Species	Douglas-fir with scattered Sitka spruce and red alder
Elev./topog.	About 400 m; gentle slopes for the Coast Range
Age	About 70 years old
Past History	Early plantation (possibly off-site stock) following a series of hot fires
Pathogens	Little root rot, wind-snaps, possible history of Swiss needlecast
Washington Cascades
Location	East of Mt. Rainier
Manager	Naches Ranger District, Wenatchee National Forest
Soils	Volcanic parent materials
Species	Douglas-fir with mixed conifers
Elev./topog.	About 1000 m; gentle terrain
Age	Uncertain
Past History	Hot wildfire
Pathogens	Little evidence of pathogens
Olympic Peninsula
Location	Near Sappho, Washington
Manager	Washington Department of Natural Resources
Soils	Outwash till with thick forest floor
Species	Douglas-fir, hemlock, and spruce with scattered hardwoods
Elev./topog.	100 m; large outwash deposits along the Sol Duc River
Age	About 70 years
Past History	Railroad logged; blowdown prevalent from previous stand
Pathogens	Mistletoe, some rot pockets

No single measure of production is adequate to assess forest productivity. A suite of measures and indices will be followed on these sites over time. Particular attention will be given to measures of primary production (plants) and the soils supporting that production. Assessments of quality and temporal and spatial distribution will be a part of all measures of production.

The following features are expected to facilitate integration of research results and activities:

· Research will guide as well as be guided by, the development of conceptual models which provide a common framework and language;

· Treatment prescriptions will be written in the context of local productivity concepts developed by interdisciplinary teams;

· Small-scale, manipulative research on key processes and interactions will be conducted within the context of the stand-scale treatments;

· Consistent methods for describing and analyzing ecosystem components and processes will be encouraged;

· Quality assurance will be an integral part of the program (QA plan to be appended); and

· Data will be accessible through a common database.

Overview of Experimental Design

A split-plot design will be used for each integrated research site. Seral treatments will be applied to whole plots, and organic matter treatments will be applied to subplots. Whole plot treatments will be assigned in a randomized complete block design, generally with four blocks per site. This design is chosen primarily to minimize buffer areas by locating similar seral treatments on adjacent subplots. Other advantages include increased sensitivity to differences in organic matter treatments (expected to be smaller in magnitude than differences between seral treatments), and reduced number of timber sales required to impose treatments (which should result in greater economy and ease of execution of treatments).

Individual seral treatments will be applied on at least 18 or 24 ha areas, including 50-m buffers (fig. 4). These areas with common seral treatments will be divided into two or three subplots for application of organic-matter treatments. Within subplots, 2-ha mensuration plots will be established for monitoring stand-level effects (fig. 5). Destructive sampling other than soil sampling will not be permitted in the mensuration plots. Separate destructive sampling zones for trees and other ecosystem components will be delineated from the onset, and dedicated to sampling at prescribed time intervals to allow opportunities for future scientists. Other areas will be reserved for small-plot investigations of varying duration. We anticipate space limitations on some of our sites and may not be able to provide space for small-scale investigations on all blocks. At least one complete replication per research site will have such space reserved.

All foot and wheel traffic on plots will be confined to designated trails in order to protect the long-term integrity of the site. As much as possible, common transects and plots will be used to assess and sample the various ecosystem components and processes. Measurement crews will cover as many aspects as possible in one visit in order to reduce traffic impacts. There will be opportunities during treatment application (harvest) to remove whole shrubs and trees for more thorough stem, biomass, and chemical analyses. Within the destructive sampling zones, priority will be given to investigations that add to inference from mensuration plot. The majority of small-scale plots will be reserved for future generations of scientists in order to provide some incentive for continued scientific support of these sites.

Preliminary Site Assessment

A preliminary assessment of sites will be conducted prior to actual establishment of plot boundaries. This evaluation will include mapping soil and vegetation from ground and aerial assessments. This will include use of both high-altitude photography and video imagery obtained from low-level overflights with ultra-light aircraft. Presence of significant insect populations, diseases, or other influences of a spotty nature will be noted. The presence of Threatened, Endangered, or Sensitive species will also be heeded. This work is intended to ensure definition of blocks and plot boundaries that are consistent with the goals of the research.

Spatial correlations will be examined at each site by placement of transects on representative areas. Correlograms and spectral density estimates will be estimated and will be used subsequently to aid in development of more detailed sampling plans. Later sampling (post-treatment sampling, for instance) may be preceded by additional examinations of spatial correlations when changes are expected. Length and orientation of transects and measurement interval will be chosen to reveal information about spatial correlations at distances and directions expected to have important influence.

Plot Establishment

Treatment units will be blocked along variables locally considered to have the most significant influence on productivity of the site. Most likely, these will include soil differences, aspect, stand age and history, drainage, and local climate. Blocks will not be constrained to be contiguous, but may occur in separate drainages.

Figure 4. Layout of part of one of three blocks at the Coastal Siskiyou site.

A locational grid will be established on each whole plot. A 25- x 25-m grid would seem appropriate, but this choice may be modified to meet site-specific needs. All distances will be measured as horizontal distance to reduce relocation error and to facilitate integration with geographic information systems and aerial and remote sensing technologies. Compass declination used in plot layout will be recorded on forms and noted on corner stakes.

Whole plot and subplot corners will be monumented with 2-m labeled metal stakes. Mensuration plot corners will be monumented with 1.5-m labeled PVC irrigation pipe. Small-scale plot corners and grid intersections within the mensuration plots will be monumented with cedar stakes. Each whole plot will be signed, corners re-established, and cedar stakes replaced with more permanent PVC markers after application of treatments.

Figure 5. Example layout of the 2-ha mensuration plot, with 25-m grid points, for the late-seral, low-OM treatment on one block of the Siskiyou LTEP integrated research site experiment. Space outside the mensuration plot is available for destructive sampling and small-plot studies.

Travel corridors will be established on each subplot prior to treatment application. In addition to these formally delineated corridors, it is expected that lines between momumented points of the plot locational grid will attract traffic. Plots and measurements sensitive to such traffic will therefore generally be placed off the lines of the locational grid.

Soil and vegetation maps will be upgraded after establishment of the locational grid. This mapping is expected to exhibit greater precision and detail than the maps created during preliminary assessments.

Vegetation surveys

Following plot establishment, a variety of permanent and non-permanent vegetation survey plots will be established both within and outside of the mensuration plot. In the mensuration plots, every tree and sapling of 2 m in height or more will be tagged and measured, and a subset will be cored. Tree locations will be mapped in reference to the whole plot location grid (table 2). Descriptions of canopy structure will be developed, including maps of the type developed by Halle and others (1978) and Oliver and Larsen (1990). These maps show stand cross-sections illustrating spatial relationships among tree crowns and how individual trees interact to create the canopy structure. Fish-eye photography and other techniques will be used to measure understory light conditions as related to overstory condition. Representative trees from all crown classes will be selected for bole growth analysis as a part of treatment. Tree nutrient content will also be determined from these selected trees.

Table 2. Minimum measures for integrated research sites

Subject	Measure	Approach
Trees >2m height	Location DBH Height Cores (pre-treatment)	Census Census Census Sampled
Canopy	Maps of structure	Sampled
Shrubs	% cover by species # stems by species	Sampled Sampled
Understory	Vegetation map by strata % cover by species	Census Sampled
Residue	Species End DOB and length in plot Decay class	Sampled Sampled Sampled
Soil	Soil map Depth of horizons Particle size distribution Bulk density Soil chemistry Soil biota Seed bank	Census Sampled Sampled Sampled Sampled Sampled Sampled
Large mammals	Vegetation utilization Pellet counts Activity locations	Sampled Sampled Sampled
Small mammals	Population estimates Activity surveys Activity locations	Sampled Sampled Sampled
Birds	Population composition	Sampled
Insects	Species composition	Sampled
Diseases	Presence/absence Infection center locations	Census Census
Weather	Daily weather records	One station per site

Nested plots will be established to quantify understory vegetation. Site-specific sizes for each of these plots will be determined by examination of relationships between plot size and variation of the statistics of interest on site. In the smallest plots, percent cover of mosses and small herbs will be estimated. In larger plots, percent cover and number of woody stems larger than 2-m in height will be determined for shrub and tree species. Herbaceous components of the understory will be described in terms of their spatial distribution and its relation to other vegetation strata. If possible, the bud bank of these species will be assessed and its response to harvesting and future stand development will be followed. Biomass will be examined over several growing seasons to estimate annual variation in this component of the vegetation. Residue will be assessed on the largest plot. Species, decay class, length, and end diameters within plot boundaries will be recorded. Some individual shrubs and logs will be marked and identified for repeated measurements.

If the forest type warrants it, a lightweight, portable platform will be used to allow researchers to work directly above the nested vegetation plots without trampling them. Trampling of plots will also be limited by use of sampling with replacement as outlined below. Only very minor collections of soil and plant tissue will be allowed within the mensuration plots.

A complimentary series of nested vegetation plots will be established in the destructive zones outside the mensuration plots. These will be used for development of site-specific assessments of chemical content and equations for estimating biomass of above- and below-ground components.

A series of permanent photopoints will be established within the mensuration plots, and their locations noted in reference to the established mapping grid (the permanent nested vegetation plots will be a part of this group of photopoints). At least seven photos will be taken from each photopoint periodically during the course of the experiment: a photo of 1 m2 of forest floor taken a short, known distance and direction away from the photopoint, a photo of 4 m2 of forest floor taken from the top of a step ladder at the same location, a photo taken horizontally in each of the four cardinal directions from the photopoint, and a photo taken straight up from the photopoint to document the forest canopy. A fisheye lens would be used for this last photo. Photographs will be taken at each of the photopoints periodically during the course of the experiment.

Location of nested vegetation plots. Because comparisons of changes with time are of concern, survey plots used in pre-treatment surveys will be surveyed post-treatment. Location of plots during pre-treatment surveys therefore must consider needs expected of later surveys. Several concerns related to later sampling influence pretreatment sampling plans, and must be taken into account before pre-treatment plots can be located.

Sample plots will be located on a grid. The use of a grid offers several advantages including ease of relocation, favorable qualities towards the use of geostatistical techniques, and reasonable statistical properties (Haynes 1948, Milne 1959, Matern 1960, Cochran 1977). Because lines on the site locational grids are likely to be frequently traveled by researchers in post-treatment work, the sampling grid will be offset from the locational grid. Spatial correlation revealed by early pre-treatment assessments, expected later changes, and examination of adjacent areas with characteristics similar to those expected on plots will be used to modify the spacing of this sampling grid where necessary. Changes in spacing of the sampling grid may also require changes in monumentation of the locational grid to avoid traffic impacts.

Comparisons over time generally are more precise if the same plots are used repeatedly, but a great many remeasurments may eventually result in trampling and unrepresentative assessments. A compromise will be sought by use of partial replacement of sample plots at each sampling cycle. This limits the number of survey repetitions on a given plot, while still providing some repeated measurement of plots through time.

Further advantage will be offered by more precise specification of the way in which plots will be relocated at replacement. Changes with time are more precise when the same plots are used because values taken from the same experimental unit at different times are positively correlated. Many measures of interest in the present study are expected to show positive spatial correlations at small distances. Comparisons of two closely located plots measured at different times can therefore be expected to have some of the same advantages as remeasurement of the same plot. Partial plot replacement will therefore use new locations that are close to the previous locations. This technique will also preserve some of the advantages that argue for use of a grid of plot locations--sampling performed in this way will result in relatively small distortions of the sampling grid.

In each mensuration plot, the following plan will be used to determine plot locations. Within the mensuration plot four rectangular potential plot locations will described within each square of the locational grid (fig. 5). These will be arrayed in a 2 x 2 square pattern around the center of the grid square, with sides of the plots parallel to the sides of the grid square. These potential locations will be labeled according to the direction they lie from the center of the grid square. All grid squares on the mensuration plot will therefore have similar arrays of potential locations. One of these directions will be randomly selected. All grid squares will use this location during pre-treatment survey and during the first post-treatment survey. A systematic sample of these locations will be designated as permanent and will be used throughout the study. All other plots will be subject to replacement by new plots at each survey. Partial replacement will begin at the second post-treatment survey. At this time, half the non-permanent plot locations will be randomly selected and moved clockwise to the next potential plot location within the same grid square. At the next survey, the remaining half will be moved in the same fashion. This method of replacement will be repeated for all subsequent surveys, unless unforeseen developments argue against it. Seven surveys can be repeated in this way before the first location is used again.

Soil Description

Because destructive sampling will be limited on the mensuration plot, much of the soil description will be obtained from representative areas outside this plot. There will be a tendency for researchers with soils and vegetation orientations to work in distinctly different fashions during this study. Coordinated effort will be encouraged during sampling efforts. Of specific importance will be attempts to question the relationships between trees and associated vegetation distribution and the physical, chemical and biotic properties of the soil. The following activities will be undertaken to describe soil characteristics:

· Permanent soil pits will be established outside the mensuration plot for pre-treatment description and future demonstration of the soil profile.

· Standard soil physical properties such as particle size distribution, bulk density, soil structure, and others will be used to characterize current conditions. Information on vertical and horizontal variability of these properties will be necessary to fully assess preharvest conditions.

· Soil organic matter and nitrogen will be sampled by horizon using soil cores. Soil sampling will be done in close association with the nested vegetation plots. For deep horizons, some subdivision will be necessary. Available nutrient levels will be pursued where feasible.

· Soil respiration will be measured at the nested vegetation plots using portable infra-red gas analyzers. Methods are being developed to standardize and test approaches to measuring soil respiration. The contribution of below-ground autotrophic respiration to total soil respiration will be estimated through controlled environment studies.

· Belowground census of fauna and flora will be needed prior to treatment, the year of treatment, and the following five years. Population levels will be assessed for those species thought to be critical for productivity.

· Preharvest samples of organic and surface soil layers will be taken at selected nested vegetation plots to assess the composition, quantity, and spatial distribution of species comprising the current seed bank in order to provide some insight into ecosystem and stand development. This sampling will be part of the soil sampling process.

Animal Populations

Due to the relatively small size of the treatment areas in this study, work with animal populations will be limited. Large mammals, such as deer and elk, have home ranges that are larger than the treatment units proposed in this study. Units in this study will be on the same spatial scale as most of the home ranges of smaller mammals such as mountain beavers and various microtines, however. Birds offer yet another situation.

The following actions will be undertaken as a minimum effort to document the relationship of proposed treatments with animal populations:

· For large mammals, their preharvest utilization of the site will be determined by estimating browsing activity. Presence in the stand will be determined by making pellet counts. 2. For small mammals, trapping surveys will determine the species composition and distribution on the site. This work will be conducted over several years to follow annual variation in populations. Live trapping could provide an index of displacement following harvesting. The presence of mountain beavers is evident from their burrowing activities and heavy utilization of vegetation within their burrowing area. Mapping areas of observable activity prior to harvesting and observing post-treatment changes offers another potential route to assess the relationships between treatment and animal population dynamics. 3. Bird populations will be censused before and after treatment applications to determine the general changes resulting from treatments.

Insects and Diseases

The following activities will be undertaken in efforts to assess the relationship between insects, diseases, and imposed treatments:

· Insect populations will be monitored in only the most general way prior to harvest. Species composition of the insects on the site will be determined. Soil insects will most likely receive more attention that other insects because of this study's emphasis on soil description. 2. The presence and distribution of tree diseases will be determined as part of the pre-treatment surveys. For root rots, the location of infection centers permanently identified.

Climatic Information

Each integrated research site will have at least one weather station at a representative on-site location. Within-treatment monitoring of the microclimate will be invited and pursued by scientists outside the research site team as part of the analysis of processes and mechanisms underlying observed changes in productivity.

Sample Archiving

Samples of various types will be archived for later use. Vegetative samples will be archived for use in monitoring genetic changes associated with treatments. Other samples will provide standards and calibration materials by which results of future assay techniques can be meaningfully related to earlier results.

Treatment Definitions

Seral Treatments

The seral treatments proposed for this study are intended to result in significantly different successional states, as reflected by species composition, organic matter distribution, and forest structure. In defining treatments, we hope to achieve the essence of three distinctive successional patterns as simply as possible. Some conventions across treatments are necessary. These include:

· Rotation length for crop trees will be defined in the local Forest Plan, and will be consistent across manipulated treatments, but may differ across sites.

· Relative amounts of material remaining after harvest defining the OM treatments will be proportioned among aboveground components relative to pre-harvest distributions.

· Harvest methods will be chosen that cause minimal disturbance to soil and residual stems. Harvest systems will be the best feasible for individual sites.

· Site preparation methods causing minimal disturbance to soil and residual stems will be chosen. Also, consideration will be given to minimum preparation methods needed to achieve desired regeneration.

· Reforestation will include planting of seedlings from local seed source of desired species at a spacing determined as more than adequate to achieve treatment. Once established, stands will be thinned to prescribed density.

· Stand tending (thinning and pruning, primarily) will be minimal, and only that needed to achieve desired treatments.

Taking these conventions into account, seral treatments will be defined as follows:

· Even-aged management of crop trees with incorporation of early seral species and curtailing late successional stages. Early seral species present on more than 50% of the unit, evenly distributed, for half of each rotation, with crown closure achieved at two-thirds through the rotation. This treatment would involve even-aged management of crop trees, wide spacing of crop-tree seedlings, maintenance of gaps in canopy through thinning, and maintenance of other preferred conditions for early seral species.

· Devotion of site to even-aged management of crop trees to the exclusion of early and late seral species. Maintain closed canopy of crop trees over at least 80% of the rotation. Early successional stages will be shortened through aggressive site preparation, vegetation control, and close spacing of crop trees. Thinning and pruning would be conducted to assure maximum production of bolewood.

· Uneven-aged management of crop trees with inclusion of late seral species and structure. Cohorts of the crop species in seral treatments 1 and 2 would be maintained through group selection. Group size could vary but minimum size would depend on limits for target species regeneration and early growth. Within harvested groups, individual trees and shrubs might be left over successive rotations, again, within requirements of target species. Under this concept, stands would include 3-6 cohorts, each group having a variety of ages/species within, but would consist primarily of target species of a single age.

· Allow a natural progression of species from the initial, undisturbed state through the duration of the study. This treatment would involve no management activity.

Site-specific prescriptions for achieving these treatments will be developed by multi-disciplinary teams. These teams will consider local influences (such as that of local fauna on productivity and the influence of these treatments on faunal species) as part of the prescription process. Prescriptions will be written in a 200-year context.

The species encouraged in seral treatments 1 and 3 will be selected based on local experience. Both these treatments may require planting or artificial seeding to insure the presence of desired species. It may also be necessary to reduce the presence of some species by a variety of control techniques. The actual implementation of the treatments will draw heavily on the experience of Forest and District silviculturists and others with local experience.

Organic Matter Treatments

Three OM treatment levels are planned: high, medium, and low retention. The high and low OM treatments will bracket the widest range consistent with attainment of the seral treatment objectives. Low OM treatments will be achieved through whole-tree harvesting. However, the structural needs of the late-seral treatment may dictate some minimum level of retained OM for low OM treatments to provide the large live trees, snags, and down logs that characterize this seral stage. Residual OM at the medium treatment level will approximate the mean of the high and low treatments. The high OM treatment will be defined as the maximum that could be left while still successfully promoting early-seral vegetation in seral treatment 1. The light requirements for germination of early-seral species may require lower OM levels in the high OM treatments than might otherwise be selected. Only mechanical removal methods will be used to manipulate OM; fire will not be used to consume OM.

Treatments will retain organic matter from individual species and components in amounts that are proportional to their contribution to the total aboveground biomass at the time of harvest. This includes foliage, branches, stems, standing dead and down logs, and branches of all vegetative species. Roots, forest floor (excluding down logs and branches), soil organic matter, dissolved OM, volatile OM, and animal biomass will not be manipulated directly. Roots will be retained because removal is difficult without ground-based heavy equipment and significant soil disturbance--soils on all plots would need to be disturbed equally. Actual amounts of OM removed will be defined on a site-by-site basis. At each research site, the standing crop of OM in each category will be measured prior to every treatment application.

Treatment description

Application of treatments will be documented in considerable detail for each subplot and whole plot treated. Descriptions will include site weather conditions, prescriptions, equipment used, disturbance due to treatment, and post-treatment distribution of organic matter.

Analyses

General Approaches

Retrospective analyses of representative trees from all crown classes will be conducted to examine the development of trees on the sites and how their growth has varied over time. Analysis of cores taken from trees on the mensuration plots will also contribute to an understanding of stand growth. From this analysis, mean and periodic growth of trees within the stand will be described, providing a comparison for future productivity. Tree nutrient content will also be determined from these trees.

A similar analysis of the woody component of the understory will be undertaken to more fully understand the dynamics of the understory and their relationship to conifer development. This information will be used to develop relationships between stem characteristics and total and annual biomass production.

The above-mentioned growth analysis will be assisted by comparison of on-site climate with nearby areas. When nearby areas have reliable weather records, it may be possible to make useful inferences about site climatic history using this off-site data.

Attempts will be made to use the stand and understory vegetation maps of mensurational plots to relate post-harvest growth of vegetation to the spatial distribution of vegetation prior to treatment.

Descriptive techniques will be used at all stages of data collection and analysis. Histograms, box-plots, and the like will be used to examine the distribution of statistics of interest across entire sites as well as within blocks, treatments, and vegetative strata. Data will be checked for spatial correlations that might affect sampling designs or later statistical analyses.

Statistical Analysis of Plot-level Information

When appropriate univariate measures can be developed, ANOVA may be used to test hypotheses. ANOVA will be applied only after descriptive examinations have been completed and indicate that the data to be suitable for ANOVA. The data will likely require transformation in many cases. One relatively simple model that might be used for a single research site is:

y_ijk = µ + b_i + t_j + (bt)_ij + E_ij + gk(_j) + (bg)_ik(j) + e_ik(j) [3]

where y_ijk represents a subplot response, µ represents overall mean response, b_i represents block effect, t_j represents seral-treatment effect, (bt)_ij represents the interaction between block and seral treatment, E_ij represents whole plot error, gk(_j) represents the effect of OM treatment, (bg)_ik(j) represents the interaction of block and OM treatment, and e_ik(j) represents subplot error.

This model states OM treatment to be nested under seral treatment, not crossed. Nesting is appropriate if OM treatment definitions will not extend across seral treatments. Although the proportion of organic matter to be retained on site will most likely be consistent across seral treatments, the absolute amounts will vary. If definition of OM treatments were consistent across seral treatments, the model would need to be modified accordingly.

If only one replicate per block is installed, no exact estimate of either whole plot error or subplot error will be available. It is usual in such a case to assume higher order interactions to be zero. This assumption is justified by the recognition that higher order interactions are usually smaller in magnitude than lower order interactions. If any terms are to be assumed zero, and if no other information to guide a choice is available, the high order interactions are the most sensible choice. If that assumption is correct, mean squares for those interactions are unbiased estimates of error. If this assumption is in error, these estimates contain components due to both error and interaction, and are biased towards values in excess of the true error. F tests developed using those estimates in the denominator will be correspondingly biased towards low values - acceptance of hypotheses of no treatment differences.

Due to space limitation at sites, it is probable that the interactions between block and seral treatment, and between block and OM treatment will be assumed to be equal to zero. If treatment differences for either set of treatments vary from block to block, a different approach must be developed. Because of this, the need for simultaneous application of treatments within all blocks is accentuated. Simultaneous application of treatments will reduce chances of confounding effects of seasonal differences.

It should be noted that analysis based on this model provides conclusions specific to the treatment factors and responses represented. Deeper questions about mechanisms that might account for the observed data are not addressed. That information must be obtained by other approaches, including on-site, small-scale experiments. A complex and interacting set of mechanisms might show great changes without overall change in productivity as tested by a model such as the one stated above.

An extension of this model for use with data from several sites is:

y_hijk = µ + s_h + b_i + t_j + (sb)_hi + (st)_hj + (bt)_ij + E_ij + gk_(hj) + (bg)_ik(hj) + e_ik(hj). [4]

The model parameters are used as in the previous model, with the addition of s_h to represent site effects, (sb)_hi to represent interactions between site and block, and (st)_hj to represent interactions between site and seral treatment.

Note that subplot effects (the second line on right-hand side of the model) are now nested under site and seral treatment combinations. This nesting is appropriate if seral treatments are expected to vary from site to site. Such nesting is appropriate if a treatment cannot be adequately represented by reference to the treatment alone, but also must include knowledge of the site to give a complete representation. It should also be noted that although all treatments will be implemented on each site within a given year, all sites will not be treated the same year. This means that site will be confounded with year of treatment implementation.

The multi-site model represented above requires the same assumption of zero interactions as the single-site model discussed previously. The desirability of simultaneous application of treatments on all blocks within a site also holds. In addition, differences in timing of treatment applications between sites will result in confounding of effects of site. This may be especially true in early years, when climatic differences between years may result in different rates of establishment and growth of various species. Site differences are expected to be much larger in magnitude than seasonal differences, however, so this confounding is not expected to present major difficulties.

It is likely that more complex models which include one or more important covariates will be frequently used. The models presented here are likely more simple than those that will be applied later.

Authorizing Documentation, Responsibilities, and Reporting

The Program Charter authorizes establishing and maintaining these sites. Each site will need a detailed operation plan, will need to be identified in the Forest Plan or addendum to the Plan as part of the monitoring network, and will need to be recognized on all geographic records (TRI, GIS).

A scientist on the research team will serve as coordinator for an individual site, serving as the primary liaison with the hosting forest, and as the "gate keeper" for research activities on that site. The team will develop a common research approach across all sites, with treatments tailored to the individual sites. All six members will work in some capacity on all six sites. On-site research activities will be coordinated with forest personnel. Funding of research activities will be through a combination of Program funds and participating research programs.

Each of the hosting Forests for the integrated research sites will have a site manager who will coordinate Forest activities by overseeing installation of treatments and data collection for monitoring variables, and contracts and budgeting for site activities; and who will coordinate research and management activities with respect to the Forest Plan, Forest timber sale program, and corporate information systems (TRI, GIS). This coordination role will likely be a full-time responsibility for the first 3 years.

Region 6 funding of LTEP integrated research site activities will be coordinated by the Regional Office and will subsequently be allocated to the hosting Forests. Costs of implementing treatments that contribute to forest targets will be born by the Forest.

Responsibility for site establishment, treatment implementation, and site maintenance reside with the Forest. The hosting Forest is in the best position to accomplish these needs. Treatments will contribute to accomplishment of Forest targets. Boundary survey and marking is part of timber sale process. The Forest should be cognizant of site location and needs at all times in order to efficiently plan target achievements and to be alert to any special considerations when establishing future targets.

Pre- and post-treatment and periodic surveys will be part of the forest-monitoring program. Detailed response information is needed to evaluate the usefulness of monitoring techniques and guidelines. Measurements and samples to be taken include inventory of existing vegetation, vegetation establishment and growth, dead material, and soil conditions. Because this work will assist in evaluating the effectiveness of monitoring standards and guidelines for all forests, the cost of doing work should be born at the Regional level. The actual doing of the work will be done by the host Forest or contracted to research, or to a private firm or interest group. A team of specialists from all cooperating landowners could share some of the work. Research will help establish the standards and protocols for these inventories, and facilitate technical training and/or contracting.

Documentation in the planning process and NEPA concerns will be addressed in the individual operation plans for individual sites. The NEPA documentation for each site will address concerns for all treatments anticipated over a 50 year period. The Program will work with the hosting Forests in developing this documentation. This Research Plan and appended standards and guidelines will be used to write Forest-specific addendums to the Forest Plans.

Cooperators include Bureau of Land Management, Bureau of Indian Affairs, other federal and state agencies, private industry, tribal councils, and local interest groups. The BLM will play a major role, including financial and technical assistance, participation in developing research questions and approach, contracts for individual studies or research and monitoring activities, and cooperative participation on the ground to accomplish research and monitoring goals. We have interest and commitment from other cooperators for each of these roles as well.

Duration and Cost

This Research Plan is the guiding document for all integrated research sites. It is hoped that these sites will be maintained indefinitely. The Research Plan will be reviewed every 5 years with the Long-Term Ecosystem Productivity Charter to assess the need for additions or updates.

The total research appropriated funds needed for these sites, exclusive of Program overhead, will be $1 MM annually in the first 5 years. Long-term monitoring and additional studies are likely to require $500 M per annum. Establishment and maintenance of the integrated research sites will be largely supported by participating management agencies, who may also contribute to research efforts directly or indirectly.

Coordination With Other Efforts

Coordination with NFS and BLM related activities will be promoted through active participation in the Integrated Research Team and on the LTEP Program coordinating committee by staff specialists. Coordination with several concurrent research programs will facilitate the sharing of ideas, data protocol and data, and assisting in joint syntheses. Direct cooperation will be sought with the following:

Coastal Oregon Productivity Enhancement Coop: The Integrated Research Site on the Siuslaw National Forest will be the COPE site for reforestation research.

Long Term Ecosystem Productivity Program will provide Global Climate Change with vegetation and soil process response to climate.

We hope also to be part of the Forest Health monitoring network, both within the Forest Service national program and with the EPA EMAP Program.

Links with many of the above programs will come from having members in common, including COPE, New Perspectives, and Forest Health and Productivity in a Changing Atmospheric Environment. The LTEP Program will take advantage of existing research sites for much of its research not directly involved in the integrated research sites. Work already in progress on the H.J. Andrews Exp. Forest LTER site will provide some groundwork and guidance to the Program in terms of fruitful hypotheses to test and sampling designs in complex ecosystems.

Coordination with other research efforts will be through scientific exchange, sharing of research ideas, methods, and protocols, and by facilitating the inclusion of research on integrated research sites that initiates under these other programs.

Environmental Impacts

Treatments will reflect management practices. Their implementation will require standard environmental analyses, timber sale contracts, service contracts, etc. Small-scale investigations will be imposed to determine process-level responses and thresholds. These treatments typically fall under the categorical exclusion for research with regard to environmental analyses.

Environmental analyses of forest management activities will be aided by program research. By the very nature of the subject, the environmental consequences of individual and collective activities on research sites will not be known. Some of the treatments and on the ground activities will be typical of standard practices and will be covered by the environmental analyses conducted by the local management agency. Lead scientists will assist in the environmental analyses for research requiring adverse treatments unfamiliar to the participating office.

Timeline For Research Accomplishments

FY 1991: Establish all sites in Region 6: layout boundaries, recognize sites in Forest GIS data bases and other records as appropriate. Begin timber sale planning. Write Forest Plan addendums. Begin initial surveys and monitoring on at least three sites.

FY 1992: 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.

FY 1993: Implement initial treatments on at least three sites. Schedule treatment for remainder for FY 1994.

FY 1994: Implement initial treatments on remaining sites. Intensive post-treatment work on all sites.

FY 1995: Integrated sites: Intensive post-treatment follow-up. Draft LTEP integrated research site update. Begin using RESEARCH sites as demonstration sites.

Literature Cited

Alaback, P. 1984. Secondary succession following logging in the Sitka spruce-western hemlock forests of southeast Alaska: Implications for wildlife management. USDA Forest Service Gen. Tech. Report PNW-173. 26 p.

Ballard, R. and S.P. Gessel (eds). 1983. I.U.F.R.O. Symposium on forest Site and continuous productivity. Seattle, WA 22-28 August 1983. Portland, OR: USDA Forest Service Pacific Northwest Res. Sta. Gen. Tech. Rep. PNW-163.

Bormann, B.T. and J.C. Gordon. 1989. Can intensively managed forest ecosystems be self-sufficient in nitrogen? For. Ecol. and Mgt. 29:95-103.

Bormann, F.H. and G.E. Likens. 1979. Pattern and process in a forested ecosystem. Springer-Verlag, New York. 253 p.

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