The Northwest Forest Plan was a groundbreaking policy to ensure wildlife habitat would not be lost to intensive logging in the western parts of Oregon, Washington and California. Now 25 years in, a new study shows it’s still a good ways off from achieving those goals. The research out of Oregon State University and the U.S. Forest Service examined long-term data on bird species that use different forest types, like old growth and less mature, open-canopy areas referred to as “early seral” forests. Bird populations are closely tied to these specific habitats and can be used by scientists to gauge biodiversity. Unhealthy bird populations often mean overall biodiversity is suffering as well. With the Northwest Forest Plan’s (NWFP) focus on preserving and increasing the acreage of mature forests, researchers expected the birds that use these habitats to increase accordingly. But the data showed bird populations are still declining. “You know we basically looked under the hood to see how things were doing earlier than mid-term, and it turns out that things haven’t recovered as quickly as some of us would have hoped,” said co-author Matt Betts of Oregon State University.

Betts said there could be several reasons for these results. “When we looked at the remote sensing data, we realized that actually we have lost quite a bit of old forests since the beginning of the Northwest Forest Plan,” he said. Severe wildfire is a major culprit for this. For example, the 2002 Biscuit Fire in southwest Oregon burned through a half million acres, largely in wilderness areas. That year, the region covered by the NWFP lost about 100,000 acres — or 156 square miles — of older forest. From 1984 to 2012, mature forest area on federal land declined by 2 percent. Older forests declined by 19 percent on private lands (not covered by the NWFP) during that same time period, affecting the overall availability of the habitat in the region. The research, published in the Proceedings of the National Academy of Sciences, found bird populations linked to early seral forests were declining as well.

Betts said there could be other reasons aside from habitat loss for the bird population declines. One is climate change, the effects of which are still a big unknown. Despite the paper’s findings, Betts cautioned against making any rash or sweeping assessments of the Northwest Forest Plan based on his research. He said the plan was designed to achieve its goals over a 100-year time frame, and his research is based on data from the first 20 years. “ still lots of time for the forest plan to have a positive effect on old-forest biodiversity,” he said. Spotlight On Young Forests Focusing on early seral forest habitat has been a newer trend in ecology. The habitat is important to a variety of species, and there’s been some concern that the NWFP’s emphasis on old growth would lead to less early seral habitat being available.

The new focus has also been popular with the timber industry. Depending on how a forest is managed, a push for early seral habitat could create opportunities for logging on large patches of federal land. Cutting the trees would open up the canopy and encourage the development of complex younger forests. But paper co-author Bob Deal says there could be pitfalls in this approach. “If you’re just saying, ‘We need to create more early seral habitat on federal lands … because there isn’t much there,’ that’s not really the case. And I think it’s probably more important that we maintain that older forest structure and habitat for older-forest-habitat birds and such,” said Deal, who is a research forester with the U.S. Forest Service in the Pacific Northwest. The researchers found that early seral forests haven’t decreased in their overall area across forests governed by the NWFP; the same wildfires that are killing older forests are allowing complex young forests to sprout in their place. This raises the question of whether cutting old growth forests to allow younger forests to grow in their place is really necessary.

The answer is complex. In places like southwest Oregon where the land evolved to burn every 10-15 years, wildfire is taking care of business. But that’s only a portion of the forest area covered by the NWFP. “If you have … areas of federal lands where there’s no fires. And you have not many private lands there, well maybe there is some opportunity to do some different kind of harvesting that would create some higher-quality early seral habitat,” Deal said. The coast range and west side of the Cascades could fit this profile. But even so, the paper authors say land managers should take a good hard look at how they apply this kind of strategy. They say cutting forests that are starting to take on the characteristics of old growth could compromise the goals of the Northwest Forest Plan. The Future Of The Plan This paper comes as the Forest Service is working through a process to revise the Northwest Forest Plan. The plan covers 24 million acres of public land managed between the U.S. Forest Service and the Bureau of Land Management.