Did you know that over 100 species of mammals, birds and amphibians depend on down logs to meet at least some of their habitat needs? The updated Forest Practices Illustrated—an overview of forest practices rules that the Washington State Department of Natural Resources (DNR) enforces—requires landowners to leave some live trees after a harvest, in addition to preserving certain features, such as down logs, to provide habitat for current and future wildlife. Reptiles, insects, and a variety of plants also use dead trees (snags) and down logs for habitat.
Habitat needs of amphibians, mammals and birds include nesting, overwintering sites, dens, roosting, foraging and food storage—all can be found in a down log. Some birds, such as sapsuckers and woodpeckers, excavate their own nests in standing dead or dying trees. Other birds occupy abandoned nests or natural tree cavities. Most cavity-nesting birds eat large quantities of insects each year. There is evidence that these birds eat so many insects that they help keep down the populations of tree killing insects, such as bark beetles. Dead, dying, live but deformed, and live trees are an important part of a healthy forest.
Squirrels and other small mammals use dying and dead trees as foraging sites, storing winter food supplies, and for roosting and denning. Bats use loose bark and hollow tree trunks for roosting. Numerous insects use dead trees as over-wintering sites; some eat portions of dead trees, contributing to the decomposition process, and all are part of the diet for many types of birds.
See more about the minimum amount of trees and down logs left for habitat and other important forestry rules in the updated Forest Practices Illustrated. This free download is an overview of rules DNR enforces on 13 million acres of state and private forestlands in Washington state to protect streams, wetlands, clean water, habitat and public resources, such as highways, utilities and built structures.