State Trust Lands Habitat Conservation Plan
Silviculture
Silviculture is the science of growing trees and forests. The techniques used to grow healthy trees are similar to those used by gardeners at home:
1) Start by planting healthy, vigorous seedlings grown from the best seed source for the elevation and other conditions of the planting area
2) Make sure the young trees aren’t choked out by weeds,
3) Periodically thin the trees to allow each tree enough space for good development.
In forests, the spacing of the trees affects not just tree development, but also the kind of wildlife habitat that develops. If the trees are too close for too long, their crowns will become very dense and shade out understory plants that are important to wildlife. When forests are thinned, more light reaches the understory, allowing other plants to flourish that are important as food and shelter. Thinning also allows the remaining trees to grow faster, so they more quickly reach the large sizes needed by some wildlife that nest in tree cavities or on large branches.
DNR uses silviculture to ensure that our forested trust lands are growing in ways that will meet the needs of future generations. Valuable trees are grown to provide revenue to build the state’s public schools and universities and other state institutions. Important wildlife habitat is grown to support the wide variety of plants and animals found in Washington.
To protect valuable habitats, the Trust Lands Habitat Conservation Plan (HCP) guides silvicultural treatments around sensitive areas such as streams, wetlands, and uncommon habitat types such as old-growth forests. The HCP also specifies that live trees, fallen logs and standing dead trees be left as a part of every timber sale design, to ensure that the new growing stand will have these structures for continued wildlife use as the stand matures.
When trees are young, most silvicultural work is done through work contracts, which can be found on DNR’s Silvicultural Contracts page. When trees are large enough to have commercial value, silvicultural work like thinning can be accomplished through our Timber Sales program.