What’s Missing from Our Urban Forest?

Have you ever found something like this?

Can you tell what this is?

Let’s back off a bit and give you a hint:

Dark inside and lighter outside bark from the same dead tree

Each dark squiggle on the inner bark was chewed by a baby beetle — a bark beetle larva — as it grew from egg to adult. The squiggles that look like spiders or millipedes where chewed by whole families of beetles. If you trace them back to their narrow beginnings, you find where the eggs were laid. Look hard where the widening squiggles end, and you sometimes see the grown-up beetles’ exits.

I think the larger holes that penetrate the bark were made by woodpeckers, but I can’t prove it. I see lots of Hairy and Downy Woodpeckers in the woods where this was found. I’ll bet they do so well is because of this:

The sheets of bark fell off this dead tree, which is still stands among the living.

This narrow strip of Columbus Park woodland is a mix of living trees and dead ones, in all stages of decay. In Oak Park, our houses and streets are set in what some call an “urban forest.” But when I visit a real woods, I can see what’s missing from our neighborhood, and why it’s really not a forest: We don’t have enough dead wood! If you aim binoculars at the living trees around our houses, you can see a few dead branches far above. But Village foresters cut out most dead branches at least once a year. When the remaining dead wood falls, neighbors pile it on street corners, like this:

These branches fell from neighborhood trees. They were piled by the curb, so Village foresters could haul them away.

When I went back a few days later, these branches were gone. But so what? Who would miss them? Well, other families missed the chance to find these burrows:

Pale under-bark burrows left marks on this wood.

And I may have been the only person to spy this evidence of woodpeckers at work:

Woodpeckers made these holes while searching for food or by drumming to claim territory.

And somebody lost a home:

This hollow may have been carved by woodpeckers looking for a place to nest.

Once on the ground, this hollow was lost to woodpeckers — but it could have been a great home for a child’s stuffed animal or doll. And that’s what’s lost to humans when we haul away dead wood. Sticks are prehistoric playthings that work just as well today, for building forts or fairylands, for fighting battles or firing more peaceful imaginations.

When my kids were younger, any fallen branch on our block was fair game, dragged to our backyard. (The front yard wasn’t safe enough — other kids or Village workers stole them.) When the boys lost interest in their projects, I sorted out the elm wood (because some bark beetles can be deadly). Then I piled the rest in a back corner of our yard to shelter small birds from local hawks and cats. Even now a quick look out the window reveals branches rescued while walking home from school. The boys’ collecting instincts persist, even if they won’t follow up with forts.

And what about the trees themselves? Nutrients extracted from the soil leave the neighborhood when branches and mounds of dead leaves are hauled away each fall. Our front-yard elm makes up something by tapping our sewer line — are other trees so lucky? Do they rely on dog pee and ChemLawn for the nutrients they need?

Can living trees maintain themselves without contributions from the dead? I guess our “urban forest” has survived for almost a hundred years — but what about the next hundred, and the next?

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This post was our contribution to Festival of the Trees # 33. If you like trees, be sure to visit this collection of blog posts from around the world.