At Natural Lands Trust we have a hazard tree management program overseen by Tom Kershner, arborist and manager of Gwynedd Wildlife Preserve. Each of us monitors potentially hazard trees on the preserves, consulting with Tom as needed. We each received training from Bill Graham at Morris Arboretum on evaluating defects; we also have a few books and Forest Service publications on the subject.
A hazard tree is defined as a tree that has both a defect and a target. The defect could be a cavity of rotted wood or some other sign of potential failure. Or the tree could be dead, something that happens to all trees someday and which results in its eventual return to earth.
But the tree must also have a target to be designated hazardous. Standing dead trees in the forest are good wildlife trees, providing dens for animals and insects for birds, and we leave them for the habitat they create. But a dead tree that might fall in the road is a problem.
So each hazard tree is rated 1 - 4 and each target is rated 1 - 3 (for example, a bench is a much higher target than a trail; public roads are all #3's). We remove all seven's and sixes and evaulate fives case-by-case. Some fives and fours we leave standing but monitor twice each year.
I keep track of the hazard trees I monitor in a database. It tells me that we have removed 49 trees (from a couple miles of road frontage) at Crow's Nest in the last ten years. (There were a few other small ones that did not warrant the paperwork.)
Some trees I take down myself. Other that pose a greater challenge Tom helps me with. And those near wires we hire a full-time arborist to prune or remove (see photo above).
Going into this year we had only six trees I was monitoring, down from 30 a few years ago. But nine trees were found newly dead this year along Hopewell Road, and all of them made the list. For most of them I think it was the natural process of forest maturing that killed them—there isn't room or resources for every tree to make it to full size. But all of them were near the telephone wires and Hopewell Road, so we hired local arborist Norm Koontz of Chesapeake Tree Care, who used his bucket truck to reach over the wires and remove the hazards.
Some of the removed trees are left in the woods to rot and return nutrients to the forest. Where there isn't enough room for that we cut some up for firewood and if necessary chip the branches for mulch for the trails. We've even gotten a few beams for the barn from sound wood in these trees. And when a storm comes there is less cleanup because we have already removed some of what might have fallen.
