EUREKA, Calif. — Timber companies here on California's North Coast have seen their fortunes sink in an era of tight environmental regulations, foreign competition and tree-dwelling protesters. But the biggest threat of all may come from within the forests themselves: black bears that feed off the young trees.
The problem is not a new one; foresters have been battling it for decades. Yet the situation is getting worse, and timber producers say it's because they are planting fast-growing trees that the bears find appetizing.
"We're actually creating habitat for them," said Steve Horner, a silviculturist, or forest scientist, with Pacific Lumber Co. "We're creating salad bars for these bears."
During late spring, when the animals are coming out of hibernation, they rip the bark off redwoods and Douglas firs, then scrape their teeth over the sweet cambium layer underneath.
The bears choose the young trees, those about 15 to 25 years old, because they taste sweet and their bark is easy to rip off, wildlife biologists say.
With the advent of large-scale logging, timber producers began creating vast areas of these young trees, thinned to encourage growth of the healthiest ones.
"You go into old-growth parks, or you go into other stands that are not being managed as aggressively, and you don't see bear damage occurring in them," said Greg Giusti, a forest advisor for the University of California Cooperative Extension in Ukiah.
"There's a direct relationship between thinning activities -- trying to maximize growth on the trees -- and the behavioral response in the bears to begin feeding on the trees," he said.
Giusti, who began studying the issue nearly 20 years ago, said bears probably don't get much nutrition from the trees. It's just that, in late spring, their other favorite foods, such as berries and acorns, are not available.
"They're simply filling their bellies with wood fiber, trying to feel full," Giusti said. "They have literally nothing else to eat."
The effect on timber can be devastating. Sometimes a bear may only "taste" a tree, then move on. At other times, it will tear off the bark all the way around the trunk. Those trees die because the sap cannot travel up the trunk.
Even a single gouge in a tree can reduce its sales value because the wound can invite infestation or rot, Horner said.
