Upland Forest Restoration

Techniques Used

Variable Density Thinning

Trees are thinned to create patchy distributions that mimic natural disturbance patterns.

The intent of variable density thinning is very different from standard commercial thinning. Commercial thinning aims to maximize growth of fewer individual trees to produce high quality timber. This may be achieved through even spacing between the larger trees and reducing variability in the stand to produce a predictable timber volume and quality. Often the stand is managed as a monoculture of a single dominant tree species.

The intent of variable density thinning is to create greater variability in density and spacing between trees to diversify forest structure, species composition, and development. Variable size patches may be thinned to different spacing, from dense, crowded areas to widely spaced trees that more closely resemble naturally developing forests and natural disturbance patterns.

Variable stand density creates patches of dense, shaded areas and patches where more light reaches the herb and shrub layers of the forest. In this way more habitat niches are created that supports more wildlife species and higher numbers of individuals than uniform forests. Variable tree spacing can also allow less common tree species (such as big-leaf maples) to thrive along side the dominant conifers.

Creating Canopy Gaps, Snags, and Logs

Snags created by topping are used extensively by foraging pileated woodpeckers.

In addition to small canopy gaps that are created during variable density thinning, we also create larger canopy gaps to introduce less shade tolerant species (such as big leaf maple and western white pine) and stimulate herb and shrub growth. Large snags and logs, which are typical in old forests and are critical wildlife habitat, are often missing from commercially thinned forests.

Snags are created by topping or wounding large standing trees, alone or in clusters. Large trees cut during thinning may be left on the forest floor to provide long lasting habitat for insects, amphibians, and small mammals. Snags and logs are usually created where a small number of trees is released or selectively thinned, or where small canopy gaps can be created through a cluster of snags and logs.

Restoration Planting

Planting is the primary tool we use to increase plant species diversity. We generally plant native trees and shrubs, but may plant forbs, grasses, lichen, and fungi, if necessary, to restore the entire complement of native species.