Applying Ecological Principles to Management of the U.S. National Forests

Summary

The U.S. National Forest System is a diverse and unique resource that must be managed within the context of competing and shifting social expectations. The policies under which the system operates have changed over the century, along with the values society places on wood production, wilderness protection, recreation, and biodiversity conservation. Proposals for major changes in the management of the National Forests are once again being debated. The consensus among forest ecologists is that all forests, despite their complexity and variability, should be managed as ecosystems. Sustainable forest management practices must be based on an understanding of how natural forest ecosystems work.

We have identified major ecological considerations that should be incorporated in sound forest management policy and their potential impacts on current practice:

• Maintenance of soil quality and nutrient stocks that hold the key to current and future forest productivity may necessitate adjusting timber harvest rates and leaving more large woody debris on cutover sites.

• Protection of water quality and yield and prevention of flooding and landslides call for greater attention to the negative impacts of logging roads and the value of undisturbed buffer zones along streams and rivers.

• Conservation of forest biodiversity will often require reducing forest fragmentation by clearcuts and roads, avoiding harvest in vulnerable areas such as hardwood or old growth stands and riparian zones, and restoring natural structural complexity to cutover sites.

• Planning at the landscape level is needed to address ecological concerns such as biodiversity, water flows, and forest fragmentation. Repeated overcutting of National Forests lands in the past has been linked to lack of planning at the landscape scale.

• Increasing pressures on forests due to human population growth and global change oblige land managers to be alert for climate-related stresses as well as damage from ground-level ozone, acid rain, and acidification of soils and watersheds.

This panel also analyzed the ecological assumptions, both explicit and implicit, that underlie a number of current proposals for changes in National Forest management. Key assumptions in some of these proposals are unsupported or directly contradicted by current knowledge of forest ecology. We are confident that:

• Despite natural disturbance and successional change, forest reserves are much more likely to sustain the full biological diversity of forests than lands managed primarily for timber production.

• No evidence supports the view that natural forests or reserves are more vulnerable to disturbances such as wildfire, windthrow, and pests than intensively managed forests. Indeed, there is evidence natural systems may be more resistant in many cases.

• Traditional beliefs that timber harvesting can duplicate and fully substitute for the ecological effects of natural disturbance are incorrect, although newer techniques such as retaining trees and large woody debris on harvest sites can more closely mimic natural processes.

• There is no scientific basis for asserting that silvicultural practices can create forests that are ecologically equivalent to natural old-growth forests, although we can certainly use our understanding of forest ecology to help restore managed forests to more natural conditions.

• Proposals to ban all timber harvesting on National Forests would leave managers without a valuable tool that can be used selectively to restore early successional habitat, reduce fuel loads, and contain pest and pathogen outbreaks in some forests.

Creativity is needed in designing forest management policies for the future, but simple solutions are almost never adequate for sustaining a complex system that must fulfill diverse expectations. Sustainable management policies must make full use of current ecological knowledge. The goal of our policy efforts today should be to design forest management practices that assure the value of our forest resources for future generations.