Gathering winter firewood or felling dead trees may be a necessary chore, but it’s best to avoid fallen or snag trees (still upright and decomposing naturally) because they are home to woodland and backyard wildlife.

Many types of birds, including woodpeckers, chickadees, bluebirds, nuthatches, owls, wrens and tree swallows and small mammals like raccoons, squirrels, opossums and porcupines use the cavities and crevices for shelter, food (in some cases, dining on congregating invertebrates like millipedes, beetles, spiders, worms and ants), mating, nesting and resting.

The U.S. Forest Service says that some 1,200 forms of flora, including mosses, lichens and fungi, rely on dead, dying or rotted-hollow trees and serve to refresh habitat by returning vital nutrients to the soil via the nitrogen cycle. Decaying logs on the forest floor also act as “nurse logs” for new seedlings.

Likewise, it’s good to respect brush piles of mainly fallen limbs and sticks. “These are wonderful hiding places for squirrels, rabbits and chipmunks,” reports Woodrow Nelson, a vice president with the nonprofit Arbor Day Foundation (ArborDay.org), in Lincoln, Nebraska, which serves to plant, nurture and celebrate trees.

It’s best to identify existing and future snags prior to gathering firewood or timber to spare their accidental destruction. Long-dead trees are fairly easy to spot, with their bony limbs bereft of leaves. Snags-to-be require more review. Look for signs of disease or misshapen form: bracket fungi, rotting branch stubs, beetles, carpenter ants or broken main limbs.

Nelson further advises, “Proper pruning can turn around a tree’s health.” He encourages consulting with a local certified arborist or the foundation’s Backyard Woods program.

Keeping one or more snags in a yard can create wildlife refuges. According to the National Wildlife Federation (nwf.org), hardwood trees tend to make better nesting habitats, while softer woods are more suited for food foraging. As long as the wood is kept a reasonable distance from a home, termites and other pests won’t find their way between the two dwellings.