Timber revenues from forestland managed by the Washington Department of Natural Resources (DNR) are used to fund public schools, universities, county services and other state projects.
In 2004, the state legislature directed the DNR to inventory the remaining old-growth forest on its land and develop management strategies for its conservation.
"DNR maintains a comprehensive stand inventory of what's growing on our land, but we needed help coming up with an index of characteristics that could be used to define 'old growth'."
- Tami Miketa, Ecosystem Services Manager, DNR
The management of old-growth forests in the Pacific Northwest has been a contentious issue for decades. Lawsuits in the courtroom and protests in forests have made it a frequent front-page news story. Legal costs and delays in timber harvests impact state budgets and regional economies.
Tami Miketa, Ecosystem Services Manager for the DNR, turned to scientists from the Pacific Northwest Research Station, USDA Forest Service, for help. "We have a legislative requirement to map old-growth forest," said Miketa. "DNR maintains a comprehensive stand inventory of what's growing on our land, but we needed help coming up with an index of characteristics that could be used to define 'old growth'."
Coming up with a definition of "old-growth" in drier eastside forests is harder than one might expect, explained Miles Hemstrom, a research ecologist with the Portland Forestry Science Laboratory.
"Washington is divided by the Cascade Range. Forests west of the mountains are wetter, whereas forests to the east are generally drier. This difference in climate leads to different forest types, and means westside and eastside old-growth has different characteristics."
Hemstrom points out that it's not feasible to have field technicians age every tree on the 5.5 million acres the DNR manages.
And size isn't always a determining factor. The old-growth index developed for the eastside included a set of visual attributes, such as the shape of the tree crown and the thickness and size of bark plates on the trunks of ponderosa pine, larch, and Douglas fir. "We hope to get away from hard and fast rules in determining old growth," said Hemstrom. "There is too much variation in tree characteristics. It makes more sense to look at the whole tree, rather than simply its size."
Very aware of the strong feelings around old-growth management, the Forest Service, DNR, and their collaborator from the University of Washington hosted several workshops for stakeholders, including the superintendent of schools, members of the legislature, environmental groups, and the timber industry, to discuss the role of old-growth in the ecosystem and ways to manage it while also managing timber production.
"We hope that with this inclusive process we might arrive at common ground and avoid a lot of the fighting that has happened in the past," said Hemstrom.
It turns out that on the drier eastside of the Cascade Range, managing forest with old-growth characteristics and commercial timber is fairly compatible. "The large, old trees on the eastside are critical to conserve because they take so long to replace and are at risk from fire and drought stresses brought on by the younger trees crowding in below," said Hemstrom. Managing the understory for timber may improve the health of the trees that remain by reducing the competition for water and nutrients. DNR and Forest Service scientists are now preparing management options for the state's eastside old-growth forest.
More info: Rhonda Mazza, rmazza@fs.fed.us
A field technician maps old-growth ponderosa pine on state land in eastern Washington using an index developed by scientists with the Pacific Northwest Research Station. (Click image to enlarge)
