The fierce derecho winds that tore through the Cedar Rapids area left a curious sight in forests.
Many long dead trees survived the storm, while nearby living healthy ones toppled down or broke off.
There’s an easy explanation.
The number of leaves on a healthy tree varies greatly, but a large oak or maple could easily sport 150,000. These have a combined surface area of several thousand square feet.
Old time ship captains had their crews furl sails during storms to prevent the mast from breaking. Leaves are sails, but trees can’t furl them.
Rain increases tree stress by moistening leaves and increasing their weight. During the derecho, tree trunks and limbs had to withstand enormous wind pressure on heavy wet leaves, while leafless dead trees avoided both stresses. No wonder the derecho felled living trees while sparing nearby dead ones.
The wind didn’t fell all the trees. It stripped branches and leaves from many and left the trunks standing like bare poles. These naked trees may die, but it’s not always necessary to cut them down.
As they gradually decay, dead trees house and feed an amazing diversity of wildlife. For example, bats often prefer roosting in a hollow dead tree to a home’s attic.
“Few items in nature are as valuable to owls as dead trees,” said Karla Bloem, Executive Director of the International Owl Center in Houston, Minn.
Woodpeckers drill into them, creating nesting cavities for chickadees, wrens and many other species. Finally, when the tree topples over, its nutrients decay into humus that helps new tree generations thrive.
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Dead trees are so valuable to the environment that landowners in Germany and Austria can be paid by the government to protect them. There’s a sign in a photo taken by Wolfang Scherzinger, retired Bavarian Forest Zoologist. Coe College Professor of German John Chaimov translated it as follows: “This forest is used in a way that’s close to nature. Here we let nature have old trees and dead wood as habitat for animals and plants.”
Dead and dying trees that present a falling hazard to people, pets, buildings and cars should be removed. However, if they are back in the woods and present no danger, leaving them in place to gradually decay is one of the most effective ways a landowner can help wildlife and enhance forest health.
Rich and Marion Patterson have backgrounds in environmental science and forestry. They co-own Winding Pathways, a consulting business that encouraging people to “Create Wondrous Yards.”