Implications of spatially extensive historical data from surveys for restoring dry forests of Oregon’s eastern Cascades
Abstract. Dry western forests (e.g., ponderosa pine and mixed conifer) were thought to have been historically old and park-like, maintained by low-severity fires, and to have become denser and more prone to high-severity fire. In the Pacific Northwest, early aerial photos (primarily in Washington), showed that dry forests instead had variable-severity fires and forest structure, but more detail is needed. Here I used pre-1900 General Land Office Surveys, with new methods that allow accurate reconstruction of detailed forest structure, to test eight hypotheses about historical structure and fire across about 400,000 ha of dry forests in Oregon’s eastern Cascades. The reconstructions show that only about 13.5% of these forests had low tree density. Forests instead were generally dense (mean ¼ 249 trees/ha), but density varied by a factor of 2–4 across about 25,000-ha areas. Shade-tolerant firs historically were 17% of trees, dominated about 12% of forest area, and were common in forest understories. Understory trees and shrubs dominated on 83.5%, and were dense across 44.8% of forest area. Small trees (10–40 cm dbh) were .50% of trees across 72.3% of forest area. Low-severity fire dominated on only 23.5%, mixed-severity fire on 50.2%, and high-severity fire on 26.2% of forest area. Historical fire included modest-rotation (29–78 years) low-severity and long-rotation (435 years) high-severity fire. Given historical variability in fire and forest structure, an ecological approach to restoration would restore fuels and manage for variable-severity fires, rather than reduce fuels to lower fire risk. Modest reduction in white fir/grand fir and an increase in large snags, down wood, and large trees would enhance recovery from past extensive logging and increase resiliency to future global change. These forests can be maintained by wildland fire use, coupled, near infrastructure, with prescribed fires that mimic historical low-severity fires.
Read or download William Baker’s Ecosphere report here.
These spatially extensive reconstructions of forest structure and fire severity show, for the first time, the substantial spatial heterogeneity in historical dry-forest landscapes that were commonly thought to have been rather uniform.
Variable-severity fires, including substantial high-severity fire, interacted with the variation in environmental setting over long time periods (e.g. Hessburg et al., 2007), to produce these structurally diverse dry-forest landscapes. Common management practices today include extensive, rather uniform reduction in tree density, removal of understorey shrubs and small trees, and other fuel modifications to lower fire severity. Our reconstructions show that these common practices, if widespread, will move most dry forests outside their historical range of variability, rather than restore them, probably with negative consequences for biological diversity (Keane et al., 2009).
Read or download the Global Ecology and Biogeography paper here.
And/or view its synopsis “Text, Lies and Photographs” in poster form here.
Researchers supported by the Joint Fire Science Program (JFSP) are examining the complicated relationship between bark beetles and wildfire . . . Are the beetles setting the stage for larger, more severe wildfires? And are fires bringing on beetle epidemics? Contrary to popular opinion, the answer to both questions seems to be “no.”
. . . The biggest wild card in the fire-beetle relationship is climate. “A warming climate,” says Turner, “is almost certainly why we’re seeing such a big infestation now.” Warmer temperatures bring drought,
which stresses trees and makes them more susceptible to beetles, and warmer winters enable more beetle larvae to survive and breed.
Snowshoe hare tracks bound deep in the snow next to the trail above Krause Creek. They criss-cross it, run along side it and disappear into the trees.
The snow is light and muffles the sound of movement.
It’s the first snowshoe and cross-country ski trip of the season for the Swan Rangers hiking group. Keith Hammer, who started the weekly hiking group in 2005, said they usually are snowshoeing and cross-country skiing by mid- to late December.
“This year, it’s like we’re at least a month late,” Hammer said. “There’s a lot of trails that up to a few days ago were bare.”
Read the full Bigfork Eagle article.
Bigfork Eagle photo by Camillia Lanham
Forest thinning to help prevent or reduce severe wildfire will release more carbon to the atmosphere than any amount saved by successful fire prevention, a new study concludes.
In research just published in Frontiers in Ecology and the Environment, Oregon State University scientists conclude that even in fire-prone forests, it’s necessary to treat about 10 locations to influence fire behavior in one. There are high carbon losses associated with fuel treatment and only modest savings in reducing the severity of fire, they found.
“Some researchers have suggested that various levels of tree removal are consistent with efforts to sequester carbon in forest biomass, and reduce atmospheric carbon dioxide levels,” said John Campbell, an OSU research associate in the Department of Forest Ecosystems and Society. “That may make common sense, but it’s based on unrealistic assumptions and not supported by the science.”
Even if wood removed by thinning is used for biofuels it will not eliminate the concern. Previous studies at OSU have indicated that, in most of western Oregon, use of wood for biofuels will result in a net loss of carbon sequestration for at least 100 years, and probably much longer.
Read the OSU press release here.
Download the research paper here.
ScienceDaily (Nov. 6, 2011) — Whether a species can evolve to survive climate change may depend on the biodiversity of its ecological community, according to a new mathematical model that simulates the effect of climate change on plants and pollinators.
Read the ScienceDaily article.
A huge “migration” of trees has begun across much of the West due to global warming, insect attack, diseases and fire, and many tree species are projected to decline or die out in regions where they have been present for centuries, while others move in and replace them.
Read the full November 3, 2011 Science Daily article.
A mountain bike racer was rammed full-speed by a Red Hartebeest while competing in a race in South Africa’s Albert Falls Dam and Game Reserve. The charge was filmed by a fellow biker working for the race’s sponsor, Max Cluer Sports Marketing.
The biker fortunately survived with whiplash and a concussion. Rhino and buffalo also call the game reserve home.
Check out the ABC News report.
USFS photo of culvert removal in Big Creek.
