Date: February 4, 2019
Source: Oregon State University
Twenty-five years into a 100-year federal strategy to protect older forests in the Pacific Northwest, forest losses to wildfire are up and declines in bird populations have not been reversed, new research shows.
The findings, published today in the Proceedings of the National Academy of Sciences, underscore the importance of continuing to prioritize the safeguarding of older forests, the scientists say -- forests characterized by a complex structure that includes multiple canopy layers, large trees, downed wood and snags.
The researchers stress it's vital to remember that upon its adoption in 1994, the Northwest Forest Plan was conceived as a century-long plan, and was not expected to show significant positive impacts on biodiversity for 50 years.
"Trees in the northwestern United States are some of the longest-lived and largest in the world," said Matt Betts of Oregon State University. "Douglas-fir can live to be more than 800 years old and grow to be more than 100 meters tall, so it shouldn't be surprising that it is hard to 'restore' this forest type, and that any plan to do so will take a long time.
"The plan has been one of the most impressive forest conservation strategies in the world, and there is no doubt that it has had a strong positive impact on the conservation of old-growth forests, but our results show that even with these strong conservation measures, bird species living in this system still aren't doing too well."
The NWFP, a series of federal policies put in place at the behest of then President Bill Clinton, encompasses 10 million hectares of land, including national forests, national parks, wilderness areas and Bureau of Land Management parcels, in Oregon, Washington and California.
Betts and OSU research associate Ben Phalan led a collaboration that used region-wide bird surveys, forest data and land ownership maps to gauge the plan's effect on biodiversity so far. Birds are a key indicator of biodiversity.
The researchers examined population trends for 24 widespread bird species for which the Pacific Northwest holds important populations -- some associated with older forests, some with diverse early-seral ecosystems, and some with both.
While there have been other detailed studies of threatened species such as spotted owls and marbled murrelets, this study focused on what populations of more-common birds can tell us about wider forest biodiversity.