UC Berkeley’s Sagehen Creek Field Station has over 65 years of data on the basin and its denizens, making it a rare place where we can look at long-term processes and ask questions that can’t be answered elsewhere.

Sagehen is interested in understanding the ecological function of the watershed: our efforts to understand wildfire began as a Ph.D. study of the ability of Strategically Placed Land Area Treatments (SPLATs) to disrupt fire behavior.

They do. But wildlife biologists were seriously alarmed at the idea of applying widespread forest treatments designed to address a single issue without thought to their effect on other ecosystem values. As a response to their concerns, SPLATs morphed into the Sagehen Forest Project: a community collaborative to adapt the fire moderating effects of SPLATs to include considerations of other interests, including water quality, wildlife, recreation, logging, management, and more.

What organically emerged was an ecologically-driven prescription driven by “Emphasis Areas”, where pieces of the landscape are considered for their individual topographical characteristics and highest values, rather than treating all acres the same as in the trees-as-crop agricultural model of the past.

For example, steep sunny south-facing slopes are hot and dry. They naturally support fewer trees and fire will rage here far more easily. We know from the scientists that wildlife species of concern like Northern Goshawks, California Spotted Owls and American Martens don’t den on these sunny, hot hillsides, so we thin heavily on these slopes, rather than trying to pointlessly create denning habitat here. Meanwhile, shady north-faces are far less fire-prone, and wildlife likes to den here, so we leave those areas far denser. We also leave the largest trees alone, rather than cherry-picking them for the most valuable lumber. These large trees store more carbon than an equivalent mass of smaller trees, are more ecologically important, and they are far more fire resistant, with thicker bark and fewer low branches to wick fire into the breezy forest crown where it can take off.

You can’t have a fire-resistant forest made up of only small trees…or large trees surrounded by small trees and brush like a funeral pyre. It just doesn’t work that way.

This Emphasis Area approach creates a patchy, heterogeneous forest structure, with meadow openings and dense copses, sun and shade. This structure mimics that found in these forests before European settlers interfered with them.

Patchiness leads to resiliency: if one patch succumbs to fire or beetles, so what? The damage can’t spread like it can when every acre is the same.

The Lake Tahoe West project is now expanding this scientific effort to further understand the effects of this kind of patchy forest prescription.