In 1994, a large-tree harvest standard known as the “21-inch rule” was applied to land and resource management plans of national forests in eastern Oregon and Washington (hereafter, the “east side”) to halt the loss of large, old, live, and dead trees and old forest patches. These trees and forest patches have distinct ecological, economic, and social values, as reflected in widespread fish and wildlife use, public support for protecting them, and commercial interest in harvesting them, thus they have been the topic of much discussion and debate. At the request of regional Forest Service managers, we review the scientific knowledge accrued since implementation of the 21-inch rule and discuss the rule’s role and relevance to forest planning today. Critical to our review are new findings from the social sciences and their integration with new biophysical and ecological science to form a more holistic understanding of forest ecosystems and the values they provide. We examine how human values associated with old trees and old forests are nuanced and evolving and discuss important social and economic changes relevant to large, old trees and old forests that have occurred across the Pacific Northwest in the past three decades. Major advances also have been realized in landscape and fire ecology, climate and carbon science, and wildlife, fishery, and silviculture sciences related to the role and importance of large and old trees in east-side forests. Key findings show that trees of early-seral species that are older than 150 years contribute important ecological values not present in younger large trees. Other findings come from climate change research, landscape assessments, and fire history studies, which have contributed knowledge about the historical and likely future variability in fire frequency and severity in various forest types, landscape dynamics, and how landscape resilience works. Many forests are now homogenized, with conditions no longer resembling those that existed prior to Euro-American settlement. Disturbance regimes have become more severe in many places, causing widespread ripple effects. The area burned by wildfire will continue to increase under climate change, and disturbance regimes will change further, leading to even broader changes in forest structure and species composition. Moderate or severe fires or fuel treatments, coupled with maintenance burning, may be needed to remove local seed sources and competition from undesirable shade-tolerant trees and help some patches of forest better adapt to fire and climate change. Proactive management can help facilitate some transitions, leading to better outcomes for people, forests, and native species.
Climate change poses a clear danger to salmon and steelhead in the Columbia River basin. Rising water temperatures increasingly limit their ability to migrate, spawn, and successfully produce the next generation of fish.
Steve Wondzell, a research ecologist with the USDA Forest Service’s Pacific Northwest Research Station, conducted a study on the upper Middle Fork of eastern Oregon’s John Day River. By using computer modeling, he and colleagues found that adding shade was the single most effective way to cool the water and preserve habitat for salmon into the future. With enough added shade, they found that future water temperature in the river could be cooler than today, even as air temperatures warm.
Adding sufficient shade involves strategically planting streamside vegetation that will grow tall enough to shield long sections of the river from sunlight. The Forest Service and other federal agencies, the state of Oregon, and the Confederated Tribes of Warm Springs are leading an effort to do just this. They are also working to reconfigure sections of the river that were artificially straightened in the past. Wondzell’s research confirms the importance of coupling riparian planting with those efforts and is helping the different parties involved direct their efforts in a more strategic way.
For decades, federal, state, and nonprofit organizations have been working to restore freshwater habitat for Oregon coastal coho salmon (Oncorhynchus kisutch), a species listed as threatened under the federal Endangered Species Act. Much of the restoration, however, has been done without directly considering the availability and connectivity of seasonally important freshwater habitats.
Research by Rebecca Flitcroft, a research fish biologist with the U.S. Forest Service Pacific Northwest Research Station, and colleagues reveals that connectivity among different types of freshwater habitat is important for coastal coho salmon. In fact, salmon occupancy in rivers or streams over time is best explained by the level of connectivity among habitat used for spawning, summer rearing, and winter refuge. Juvenile fish benefit when they can move easily among these habitat types.
Restoration projects that focus on only individual habitat segments may not result in watershed-scale improvements. Targeted restoration that fills habitat gaps may be more effective when diversity, location, and proximity of seasonally important habitats already present in a watershed are considered.
Resource managers are using these findings to reevaluate how they think about coho salmon habitat, as well as habitat for other species such as trout and beaver.
In conservation paradigms, management actions for umbrella species also benefit co‐occurring species because of overlapping ranges and similar habitat associations. The greater sage‐grouse (Centrocercus urophasianus) is an umbrella species because it occurs across vast sagebrush ecosystems of western North America and is the recipient of extensive habitat conservation and restoration efforts that might benefit sympatric species. Biologists' understanding of how non‐target species might benefit from sage‐grouse conservation is, however, limited. Reptiles, in particular, are of interest in this regard because of their relatively high diversity in shrublands and grasslands where sage‐grouse are found. Using spatial overlap of species distributions, land cover similarity statistics, and a literature review, we quantified which reptile species may benefit from the protection of intact sage‐grouse habitat and which may be affected by recent (since about 1990) habitat restoration actions targeting sage‐grouse. Of 190 reptile species in the United States and Canadian provinces where greater sage‐grouse occur, 70 (37%) occur within the range of the bird. Of these 70 species, about a third (11 snake and 11 lizard species) have >10% of their distribution area within the sage‐grouse range. Land cover similarity indices revealed that 14 of the 22 species (8 snake and 6 lizard species) had relatively similar land cover associations to those of sage‐grouse, suggesting greater potential to be protected under the sage‐grouse conservation umbrella and greater potential to be affected, either positively or negatively, by habitat management actions intended for sage‐grouse. Conversely, the remaining 8 species are less likely to be protected because of less overlap with sage‐grouse habitat and thus uncertain effects of sage‐grouse habitat management actions. Our analyses of treatment databases indicated that from 1990 to 2014 there were at least 6,400 treatments implemented on public land that covered approximately 4 million ha within the range of the sage‐grouse and, of that, >1.5 million ha were intended to at least partially benefit sage‐grouse. Whereas our results suggest that conservation of intact sagebrush vegetation communities could benefit ≥14 reptiles, a greater number than previously estimated, additional research on each species' response to habitat restoration actions is needed to assess broader claims of multitaxa benefits when it comes to manipulative sage‐grouse habitat management. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.