Tree snags are a home for wildlife

Thursday, May 21, 2015

BY KENNETH SETZER
As published in the Miami Herald, 5/21/15.

In my endless pursuit of doing less yardwork, I’ve realized our obsession with neatness and order causes a lot of work and wastes huge amounts of precious resources. Here’s one more task you can skip.

A large and messy tree in my yard ruins everything under it with its biannual leaf drop and the thousands of flowers and seedpods that follow. It’s an invasive tree, but at 30 feet tall or more, it’s not something I can remove myself.

The day I hire an arborist to remove it, I might propose leaving the stump in place, maybe seven feet or more of it. It’s got to be less expensive — tree stumps don’t come out without a struggle. And there are other niceties that come along with leaving the stump in place.

Dead trees or stumps are known as “snags.” You might not see a dead tree or stump in a landscape and think “that’s a healthy thing for the environment,” but it is. Dead trees are a vital part of the cycle of life; in some ways they can be more useful to wildlife than living trees.


An immature eastern screech owl checks out what's going on outside.

Observing snags at Fairchild has shown me how much life they harbor. Many birds nest inside old snags. One particular dead palm tree has holes running up the trunk like entrances to apartments. One of the higher apartments was occupied by eastern screech owls. Such magical little birds — when you see one, you realize why owls play such a role in magic and mythology. Our owls raised young in that dead palm, safe from predators, storms and photographers.

For two years in a row now, red-bellied woodpeckers have occupied a love nest a few stories down from where Mr. and Mrs. Owl lived. Their helpless hatchlings can be heard from outside the tree, constantly squawking for food. The parents make incessant foraging trips and can often be seen bringing grubs, insects and lizards back to the babies.

Bark foragers, particularly this woodpecker, have been proven to consume — with gusto — the destructive emerald ash borer beetle, responsible for the deaths of tens of millions of trees. Woodpeckers have even been shown to recognize and prefer feeding from declining trees, knowing the reason for their waning health may crawl underneath the bark. These omnivorous woodpeckers also depend on trees for cavity nesting.


A macaw takes advantage of a high perch on a dead palm tree.

And it doesn’t need to be vertical. A log left to the elements also does service to the animals, plants and soil. If you are curious, break open a piece of rotting log and observe the life within. You’ll find pillbugs (aka rolly pollies), ants, harvestmen arachnids, mycelial strands of fungi, beetle larvae, centipedes, millipedes and more.

As the snag or stump ages, it will decompose with the help of rain, insects (particularly ants), fungi and other microscopic creatures. Beetle grubs thrive in rotting wood, and these in turn serve as food for yet more birds. Depending on the softness of its wood, it may take many years for the tree to return completely to the soil, but eventually it will. Many times suckers from the dead tree, or dropped seeds, will grow close to the same location, nourished by the breakdown of the tree.

If you need to partially disguise a snag, they make great homes for all kinds of plants, especially epiphytes like tillandsias. ManyNeoregelia bromeliads are happy living on a tree, as are some orchids and even some cacti. You now have an excuse to acquire more plants!


Red bellied woodpecker enters its nest in a tree trunk.

Keep snags a distance from your house to avoid attracting termites, and never leave snags standing where they could fall and harm people or structures.