The Wildlife Professional - Spring 2010 2009

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all been burned by the largest wildfires in each state’s recorded history.

For the USDA Forest Service (USFS), firefighting efforts now consume one-third to one-half of its annual budget. This leaves few funds to pay for fuels treatments, which follow two general approaches. To contain the spread of wildfire, “linear defense zones” are created, where surface and ladder fuels and some overstory trees are removed from strips near homes or along roads or ridge tops. Within this perimeter, the second approach involves strategically placing low-fuel patches in the landscape to act as ‘speed bumps’ that slow the spread and reduce the intensity of wildfire. Fire science models suggest that strategic treatment of 20 to 30 percent of the landscape can significantly reduce wildfire severity (Finney 2001).

Credit: Chris Hamma

Though often effective, these approaches were never designed to address how forests might be ecologically restored or wildlife habitat enhanced. Most of the landscape matrix—some 70 to 80 percent—is untreated and continues in an ‘unhealthy’ condition from decades of fire suppression, leaving important habitat susceptible to high-intensity burns like the Moonlight Fire. In addition, because many fuels projects face legal challenges over potential impacts to threatened and endangered species habitat, agencies often avoid treating such areas.

Credit: Chris Hamma
The Moonlight Fire
burned with different
intensity depending on
how fuels had been
managed. an area
without prior fuels
treatment (top) was left
severely charred and
denuded. in an area
where ladder fuels and
underbrush had been
cleared, some trees
retained leaves and life.

strategy using localized site conditions and landscape position as templates for varying forest treatments.

The Dinkey Creek area in California’s Sierra Nevada range offers a classic case in point. Its mixed-conifer forest provides rare habitat for the threatened Pacific fisher (Martes pennanti pacifica) and contains many summer homes, yet it also has high fuel accumulations. Managers proposed a fuels-treatment project back in the early 1990s, but in November of 2007, after 15 years of proposals and litigation, the project failed to be resolved even after months of mediated conflict resolution.

Using Topography as a Tool Reconstructions of forest landscapes as they would have looked prior to fire suppression have found that forest structure and composition varied with topography at both stand and landscape scales. Within a stand, wetter areas such as seeps, concave pockets, and cold air drainages usually burned less frequently or at lower intensity. Across an entire forest watershed, forest and fuel conditions varied depending on slope position (location in a valley or riparian bottom, at mid-slope, or on an upper slope or ridge top) and aspect (cooler northeastern orientations versus hotter, drier southwestern aspects). Slope and aspect affect fire intensity and frequency.

This case prompted USFS managers in California to
ask several of us at the Pacific Southwest Research
Station to develop a summary of current research
that might inform best management practices in
fire-prone forests (North et al. 2009). Although
the project’s scientists had different expertise, (fire
science, forest ecology, silviculture, and wildlife
biology), their recommendations coalesced around a
common theme: the importance of creating variable
forest structure and fuels conditions for ecological
restoration, forest resilience, and wildlife habitat.
Based on our research, we propose the following
In many Sierran mixed-conifer forests, higher
slopes and more southwesterly aspects generated
pine-dominated, open forests, while valley bottoms
and northeastern aspects had fir-dominated forests
with higher stem density and canopy cover. The
latter, with riparian and cool microsite areas, likely
provided movement and nesting/resting habitat for
several species including some that are now threat-
ened or endangered, such as the fisher.