Woodpeckers busily create cavities in hard snags. When these snags become too soft the woodpeckers find more suitable hard snags. Other insectivorous birds, like chickadees, titmice, and nuthatches, occupy the woodpecker cavities in the soft snags. A healthy population of insectivorous birds and bats can help protect forests from damaging insects like bark beetles. If the cycle is disrupted in any one place, the entire ecosystem will suffer.
Snags are a boon for backyard wildlife fanciers.
While only a few animals may actually reside in the wildlife high-rise, dozens more will visit. Raptors such as hawks and owls like the vista provided by the exposed perches of snags. Flycatchers also enjoy the 360-degree view provided by snags. They will often launch numerous sorties on unsuspecting insects, returning time after time to the same perch. Of course, no one is suggesting that you leave dead trees on your property if they are obvious hazards.