Needed modifications to the hundred-year old silvicultural treatments: managing for diverse and resilient forests

Background/Question/Methods

The presently available silvicultural tools have been highly effective in achieving the results asked of silviculturists. Until only a few decades ago, forest management goals were primarily sustainable production of timber. More recently, they also included improvement of habitat for game species, rare and endangered species, and soil and watershed protection, among others. However, the dominant practices require some modifications for a number of reasons: 1) they do not necessarily provide suitable conditions for many of the diverse organisms that are part of the forest ecosystem; 2) forest resilience needs to be improved due to the rapidly changing climate conditions whose impacts on forest ecosystems are largely unknown; 3) forests worldwide have to continue to provide more products and services and to more people in the absence of net increase in forested area.

Results/Conclusions

Theoretical work and results from the few research projects testing modifications to silvicultural treatments suggest to: 1) increase species diversity. Examples of methods to achieve this include retaining rare species and controlling their competitors, extending the retention period for some trees to allow natural regeneration, leaving enough individuals to allow cross-pollination to maintain genetic diversity, planting rare species with consideration of their natural spatial pattern of distribution; 2) increase diversity of structures. Findings from studies recommend variable-retention harvesting to retain dense and sparse patches, large and small trees, standing dead trees, trees with cavities, down woody debris, understory species; 3) extend rotation length, at the very least by leaving some remnants; 4) accelerate development of desired attributes. Specific suggestions are production of old-growth characteristics by increasing growth rates of selected trees, creating snags, producing down woody debris, scarring to provide entry point for decay to create decadent trees and cavities, and production of seeds of key tree species sooner by controlling their competition; 5) incorporate risk and uncertainty into the choice of silvicultural treatments and their implementation. A remaining major obstacle for implementation is that most modifications would cost the landowner.