Some of the most valuable trees in the woods are the dead ones.

Now, that is relative to who assigns the value. If you are talking in terms of timber sales, no. Dead trees are not significant to one concerned with selling or buying board-footage for lumber.

Dead standing and fallen trees, however, are an essential ecological feature. The living things in the forest are in part dependent on the dead and dying trees.

Wildlife, everything from the largest mammals, birds, reptiles, amphibians and down to the smallest insects and arachnids, need trees that are way beyond their green prime. We might mistake dead snags, gnarly, dying trees or even fallen, rotting logs as eyesores or trash of the woodlot. Nature knows better.

By our seemingly logical way of thinking, we might assume that a robust forest is filled with live trees with a minimum of decomposing junk in the understory. That’s sort of the view of one whose purpose is to manage a forest purely for timber harvest.

A wildlife biologist, an ecologist or even a forester whose goal is conservation and not commercial harvest might see it much differently. Most expert sources see a sign of a healthy, unmanaged forest in a significant presence of dead trees, both standing and fallen in varying states of decomposition.

We are not talking a tree farm here. Wildlife can utilize timber that is heavily manipulated for harvest, certainly, but the benefits from a forest that allows more wild, random process — like lingering dead trees — are much greater for the wild community.

How so? Well, ornithologists confirm that about 45% of North American bird species are dependent on dead trees for some part of their life cycle. Dozens of bird species must have dead or dying trees in which to nest, and if there is no nesting, those birds cannot reproduce there.

Our wood ducks flirted with extinction because wetlands with nesting cavities in dead trees became so scarce. It took man-made nesting boxes as replacement to turn the corner for them.

Think woodpeckers. They hollow out a space in decaying wood of a dead snag or dying tree. Those cavities serve various woodpeckers for nesting, and outside of the nesting season, solo woodpeckers will roost in the same digs.

But other cavity-nesting birds use the same woodpecker holes. Those arboreal apartments might by occupied by creatures other than birds, too. Some of the small ones might serve flying squirrels. As the cavities are expanded, maybe larger birds and/or mammals take advantage.

Dead and dying trees, besides shelter, are food collectors. The ants, caterpillars, spiders and scads of other insects and arachnids that are found on and in various stages of decomposing wood are a buffet for birds. There is food on live trees, sure, but the groceries are all over and throughout trees that are in various stages of breakdown and rot.

The bugs themselves for their own existence must have this decomposing wood from dead trees. The insects and arachnids drawn there then serve as a baseline for the food chain of all the larger critters in the woods.

The bugs do some of their best work down on the ground with fallen wood. Insects are required in the ticky-tacky labor to break down trees into the mulchy stuff that eventually rejoins, enrichens and nourishes the living soil beneath it all. That is how trees and their users recycle themselves and their habitat.

While that decomposing wood is on the forest floor, it is a food magnet, shelter and day to day cover for all manner of wildlife.

Toppled tree trunks on the ground, depending on their size, can house all sorts of animals as denning sites. In our woods, check the contents of a hollow log at the appropriate time of day and you might find a raccoon, ’possum, skunk, bobcat, weasel, mice, gray fox, hibernating snakes, chipmunks — who knows? A cavity in a downed tree is a housing unit, and when there is a vacancy, any of a number of new tenants might move in.

Around decomposing wood, around the logs and rotting stumps, the loosening materials form their own habitats. Rodents, amphibians and reptiles like salamanders, frogs and box turtles are buried down in that stuff right now, sheltering from the cold season.

The cavities in standing dead and even just damaged trees are in high demand.

Gray and fox squirrels are guaranteed to check out and occupy every tree hollow or crevice that they can. Some of these serve as squirrel dens for years.

You see those leaf nests that squirrels build?

Those are the runover squirrels, the ones that could not find their own tree cavities.

If they are of substantial size, cavities often are claimed by raccoons, ’possums or larger birds of prey.

One place I hunted had a big snag of an oak tree that had broken off about eight feet above the ground.

A great horned owl lived in the tall, hollowed out stump. I saw him chase away a buck deer that got too close to his roosting place. For sure, no squirrels got to use that cavity.

Hollow trees could provide den room, even hibernation quarters for bats. The loosening bark on dead trees is prime overhanging shelter for roosting bats.

For all they provide, trees are a valuable wild resource, dead or alive.

Steve Vantreese, a freelance outdoors writer, can be contacted at outdoors@paducahsun.com.