INTRODUCTION

Over the past twenty years, forested watersheds of the Blue Mountains in northeastern Oregon have been subjected to increasing damage by drought, fire, insects, and diseases. Forest health restoration in these ecosystems has become a priority for affected federal and state agencies, and private landowners.

In the summer of 1992, an interdisciplinary team of 14 resource specialists from the Mt. Hood and Gifford Pinchot National Forests were sent to the Blue Mountain area to accomplish two main objectives for the North Fork John Day River Basin.

- To develop an ecologically-based prioritization of watersheds for restoration to facilitate budget development and activity planning for the next five years.

- To develop a list of effective restoration activities to implement in priority watersheds.

WATERSHED PRIORITIZATION

The North Fork John Day River (NFJD) Basin project encompasses approximately 913,000 acres, 60% of which is administered by the Umatilla National Forest. The basin is composed of 20 watersheds, and over 100 subwatersheds. Effective fire suppression since the mid-1900's has resulted in an alteration of many ecosystem structures and processes once molded by relatively high fire frequencies. Recently, a significant amount of the area has experienced extensive tree mortality as a result of insect epidemics and drought.

To prioritize watersheds for restoration we used a landscape analysis approach developed by Diaz and Apostol (1992), in concert with an ecosystem analysis approach adapted from the Northern Region of the Forest Service (USDA Forest Service 1992a). Landscape analysis provided the framework for understanding ecosystem structure and function at the landscape level, while the SES approach incorporated the natural range of variability of ecosystems as a baseline for comparison with current conditions. By understanding the ecological conditions and processes of the basin relative to natural ranges, watersheds could be prioritized based on their divergence from natural conditions.

Ecosystem structure at the landscape scale was described by determining the types of patches, matrix, corridors and patterns which make up the NFJD basin landscape. Landscape structures included park-like ponderosa pine stands with a high component of fir, live or dead late seral fir stands, riparian corridors, dense ponderosa pine or lodgepole pine stands of low vigor, grasslands with invading juniper, meadows, and early seral stands, among others.

We determined ecosystem function by describing "flow phenomena", or those things that use or move through the landscape, and the functions each landscape element performed for each flow. Flow phenomena included such things as water, sediment, fish, fire, elk, deer, livestock, insects, and large woody debris. Landscape structures (patches, matrix, corridors, pattern) could perform one or more of five main functions for each flow: resource capture (e.g. migration, photosynthesis), resource production (e.g. plant growth, reproduction), resource cycling (e.g. transport, local migration), resource storage, or resource output (e.g. migration, erosion). For example, a riparian corridor may function in the production or cycling (travelway) of elk and deer, in the storage of water, or in the production and cycling of fish.

We determined that management priorities at this scale of planning would emphasize ecological processes and their interrelationships with management activities. Hence, the team evaluated complex interactions between current conditions, natural ranges of variability, natural successional processes, and human-caused disturbances.

Natural ranges of variability of key ecosystem elements in the basin had been determined previously by a Regional panel of specialists using the SES approach (USDA Forest Service 1992b). Natural ranges of variability provide a baseline for comparisons with current distribution of seral stages, patch types/shapes/sizes, rates of ecosystem change and stand structures for a specific area. At finer planning scales, managers must decide on desired future conditions relative to "natural" conditions, within the context of social and economic concerns.

Essentially, management priorities for the NFJD project were determined by the following steps.

- Comparing current conditions to natural ranges of variability and evaluating which ecosystem elements were farthest from "natural."

- Identifying where current management activities (human-caused disturbances) were working in concert with, or against natural successional processes.

- Evaluating where treatment would provide the greatest return overall. Restoration activities applied in one patch type may affect restoration of other patch types, hence allowing for the evaluation of relative net landscape level benefits for any particular treatment (eg. returning ponderosa pine stands "invaded" by fir due to fire suppression to an open park-like condition would increase forage availability, possibly decreasing grazing pressure on riparian corridors, thus improving riparian conditions).

- Calculating which watersheds had the greatest amount of those patch types that provided the greatest landscape level net benefits when treated. It was assumed that treatment would emphasize a desire to move them toward their natural ranges of variability (eg. reducing available fuels, restoring the open condition of park-like stands, increasing riparian shrub cover, etc.).

After determining watershed restoration priorities, information gathered on natural successional processes, and their interrelationships with human-caused disturbances were used to list effective tools, or activites to meet management objectives in priority watersheds.

SUMMARY

By understanding landscape structure and function, natural successional processes and their interaction with human-caused disturbances, natural ranges of variability of ecosystem elements, and interactions between ecosystem elements and their management, ecologically-based management priorities can be developed. Landscape analyses, and approaches similar to SES can also be applied to determine ecologically sound management objectives. Accurate, site-specific data on natural variability of ecosystems, and ecosystem and landscape processes and functions is needed to develop a foundation for ecologically sound objective-setting and activity planning.

Literature Cited

Diaz, N. and D. Apostol. 1992. Forest Landscape Analysis and Design - A Process for Developing and Implementing Land Management Objectives for Landscape Patterns. USDA Forest Service, Pacific Northwest Region, Portland, OR, R6-ECO-TP-043-92.

USDA Forest Service. 1992a. Our Approach to Sustaining Ecological Systems. Northern Region. R-1SES_92_02. March 1992 Edition, Desk Reference.

USDA Forest Service. 1992b. Restoring Ecosystems in the Blue Mountains. A Report to the Regional Forester and the Forest Supervisors of the Blue Mountain Forests. Pacific Northwest Region. Portland, OR. July 1992.