The mountainsides of insect-damaged and dead trees in Eastern Washington sadden any tree lover, But a dead tree in your backyard can become home to birds, bees and mammals providing hours of viewing enjoyment.

A windstorm broke off one of our hemlock trees about 15 feet above the ground several years ago at our Shoreline home. We cleaned up the downed portion of the tree and collected the firewood, but decided to leave the snag standing.

The woodpeckers found it first, pounding holes into it and clearing the way for other creatures. Then the flickers nested in the top of it, occasionally poking their heads out of the holes in the trunk. A swarm of bees visited, and now the squirrels have the run of this now hollow column with its bark falling away. A young volunteer hemlock growing between the snag's exposed roots will eventually take the place of this once towering giant.

An arborist recommended last year that we cut the top out of another wind-damaged tree in our yard and leave an "environmental snag," which we did.

Last week, when we heard the familiar knock, knock, knock we went looking for it on the old snag but found instead a pileated woodpecker (in photo) starting work on the new home for birds, bees and beasts in our yard.

If you have a candidate for an "environmental snag," -- that would be a dead, dying or damaged tree -- check with an arborist to make sure it won't be "contagious" to your other trees, but consider leaving something behind not only for your viewing pleasure but for the wildlife, too.

Photo: A pileated woodpecker works on a snag in Shoreline.