Riparian Thinning

Tree growth rates in conifer-dominated riparian forests in the CRMW are often low due to competition among trees for light, water, and nutrients. In addition, dense conifer stands have reduced understory development and simple vertical structure, both of which result in reduced habitat value for wildlife. 

Thinning in conifer-dominated stands increases tree growth rates, so that they will provide functional LWD (large woody debris) sooner and be more effective at shading streams. Thinning also allows more understory plants to grow and gives the stand greater structural complexity.

In stands younger than 40 years, which are primarily in the upper CRMW, restoration thinning in streamside areas is being implemented in association with more extensive upland restoration thinning treatment units. We are experimenting with the thinning prescriptions in riparian areas in order to find a good balance between tree growth response to thinning and maintaining bank stability. If trees are thinned too widely, it can potentially compromise stream bank stability.

In stands older than 40 years, ecological thinning has been implemented on a very limited basis to date but is being considered more extensively. By thinning trees directly into the stream, there is also some immediate benefit from the addition of LWD.

Taylor Creek

Taylor Creek riparian forest before thinning.

Taylor Creek

Taylor Creek riparian forest after thinning.