SUNNYTemp: 63 °F
Wind: CLM at 0 mph
Thursday, September 18, 2003
|
SUNNY Temp: 63 °F Wind: CLM at 0 mph Thursday, September 18, 2003 |
|
|
 |
|
|
Study: Birds flee thinned areasBy BILL VARBLEMail Tribune A new study of forest thinning has found fewer bird species in thinned areas. Stewart Janes, an ornithologist at Southern Oregon University, studied two Bureau of Land Management plots near Williams, totaling about 30 acres, that were thinned in the spring and summer of 1996. Many birds declined. The species suffering the most were red-breasted nuthatches, chestnut-backed chickadees, Pacific- slope flycatchers and hermit warblers. The birds are associated with late-succession forests. None is on the federal Endangered Species list.
"I would not have predicted this," he said. He said the results were noteworthy at a time of proposals to increase logging. "I think it’s directly applicable to the kind of forestry practices they’re talking about now," he said. Among breeding populations — nesting birds in the spring and summer — both individual numbers and number of species declined on a north-facing site after the harvest. At the other site — a south-facing one — there was no decline. Among birds present in the winter, the number of species declined on the south-facing site. Overall, two-thirds of the breeding species and 59 percent of wintering species had changes in abundance after the timber harvesting. There were winners and losers. Terrestrial foragers and birds that drill trees for food tended to increase. Bark gleaners and flycatchers decreased. Species with the greatest increases were house wrens and winter wrens. The numbers of some species did not change until the second year after the timber harvest. Janes surveyed the affected area for breeding and winter bird populations before and after the thinning of small-diameter trees within two 119-year-old stands of Douglas fir. "What people don’t understand is that when you open the canopy, you’re moving the forest to an earlier stage of forest succession," he said. "You’ve lost old-growth species, but you’ve brought in species that like being on the ground. You’re trading." Could the missing birds have simply gone somewhere else? Janes said it’s not that easy. "There is a misperception you can just move individuals," he said. "What happens is they lose the opportunity to breed because other areas are already occupied by territorial individuals." Janes said the survey indicates that more study is needed of the effects of thinning on birds. "My hope is just to lay it out for people," he said. "This is what you can expect. We have to make our choices. "The thing that scares me is the thought of doing such a huge area of treatment (large-scale thinning) without understanding the impacts. We should understand it before we implement it." Reach reporter Bill Varble at 776-4478 or e-mail bvarble@mailtribune.com
Archive: Click to Search  Mail Tribune Home Local News | Sports | Business | Obituaries | Life Opinion - Politics | AP News | Archives | Site Map E Southern Oregon | Classified Copyright © 1997-2003 Mail Tribune. All rights reserved. Privacy Policy | Terms & Conditions Website Feedback |
|
|
   |
||||||||||||||||||||||||||||
|
|  |
||||||||||||||||||||||||||||
|
|
|
||||||||||||||||||||||||||||
