How forest restoration methods affect wildlife

How forest restoration methods affect wildlife

Contributed by Marilyn Miller of Miller Conservation Consulting

Our eyes were glued to the ground sorting through animal tracks. The date was June 17, 2011. Elk tracks, large and small ran in every direction. Then we froze in astonishment—we were looking at a paw print larger than a man’s hand, but lacking claw marks. Cougar! We immediately vowed to keep quiet about it—we were less than a mile from the densely populated Sunriver Resort, and we didn’t want wildlife officials coming out to track and kill this important predator.

My husband Craig and I were studying the effects of an experimental forest project on birds and other wildlife. Named the OZ Research Project, it was designed to determine how different forest restoration methods affected the landscape. The methods included various types of tree removal (such as “group select,” “wide thin,” and “single tree selection”), shrub mowing, controlled burning, and tree planting as well as control areas, where no treatment was conducted.

An example of a snag.

Initially, I vehemently opposed the OZ Project, decrying it as just another excuse to cut trees. The “experiment” would study changes in vegetation, but completely ignore wildlife. If this project was truly meant for restoration, then shouldn’t it include wildlife monitoring? Why was there no provision for leaving or creating snags, a critical component of wildlife habitat? Dr. Stephen Fitzgerald, lead scientist of the study admitted that wildlife monitoring was not in the budget. He told me, “If you want wildlife monitoring, you’re going to have to do it yourself.” So, I agreed to monitor wildlife and he in return agreed to create snags as part of the project.

Craig and I set up points and tracks to study how the project would affect wildlife, with our primary focus on nesting birds. We began recording birds and wildlife in 2008, before the treatments began. Now for the 8th year, we continue to conduct surveys during the bird breeding season. We have been rewarded by a number of surprises and have discovered a lot. We continued to observe fresh mountain lion tracks over a three-week period. We have found fresh elk tracks on every visit. In addition we have found evidence of black bear, coyote, badger, mule deer, Douglas squirrel, golden-mantled ground squirrel, and least chipmunk.

Our biggest surprise came from how the birds responded to the snags that were created. At first I was both amused and dismayed by how they appeared. Trees had randomly been lopped off at about the same height throughout the treatment plots, giving the impression of short telephone poles scattered around the forest. Evidently the woodpeckers didn’t mind how they looked, because by the following summer, they scaled and drilled almost every snag we inspected. A year later, woodpecker holes appeared, and cavity nesting birds were observed using them. Prior to the project, woodpeckers were scarce—including sightings of 3 Hairy Woodpeckers, 2 Northern Flickers, and a Williamson’s Sapsucker in 2008. Following the project, the number and variety of woodpeckers have increased dramatically. In 2015 alone, we sighted Hairy Woodpeckers 10 times, Northern Flicker 4 times, Williamson’s Sapsucker two times, White-headed Woodpecker 3 times, and Black-backed Woodpecker once.

Other bird species showed increases in variety and numbers as well. These increases occurred in the treated areas, but not in the control units. On the other hand, the big wildlife species kept mostly to the denser untreated control areas—including elk, mountain lion, and black bear.

What I have come to understand is that the prescribed treatments add variety (and snags) to an already degraded, logged-over forest that is struggling to regenerate. The control units are not representative of mature old growth forests, but instead a young even-aged, even-spaced monoculture. In the short term, the forest treatments appear to benefit birds. A more important question is how these treated and untreated areas will function a hundred years from now. Of course I won’t be around to know the answer, but I hope future generations can benefit from the knowledge gleaned from these experiments.

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