• Eugene Weekly Loves You!
Share |

Eugene Weekly : Viewpoint : 4.30.09




Seeing the Forest 

Through the trees 

by George Wuerthner

There’s an old cliché that one can’t see the forest for the trees. It is used to describe people who are so focused on details that they fail to see the big picture. Nowhere is this failure to see the forest for the trees more evident than the rush to utilize dead trees for biomass fuels and/or the presumed need to “thin” forests to reduce so called “dangers” and/or “damage” from wildfire and beetle outbreaks.

Dead trees are not a “wasted” resource. An abundance of dead trees, rather than a sign of forest sickness as commonly portrayed, demonstrates that the forest ecosystem is functioning perfectly well. For far too long we have viewed the major agents responsible for creation of substantial qualities of dead trees — beetles and wildfire — as “enemies” of the forest, when in truth, they are the major processes that maintain healthy forest ecosystems. 

Recent research points out the multiple ways that dead trees and down wood are critical to the forest. One estimate suggests that two-thirds of all species depend on dead trees/down wood at some point in their lives.

Dead trees are very important for functioning aquatic ecosystems as well. Trees create structure in streams that shapes stream channels, reduces water velocity and erosion, and provides both food and habitat for many aquatic species, including trout.

Once a tree falls to the ground and gradually molders back into the soil, it provides home to many small insects and invertebrates that are the lifeblood of the forest, that help recycle and produce nutrients important for present and future forest growth. For instance, there are hundreds of species of ground nesting bees that utilize down trees for their home. These bees are major pollinators of flowers and flowering shrubs in the forest. 

Ants are among the most abundant invertebrates in the forest and many live in down trees and snags. Ants play a critical role in the forest, helping to break down wood, aerate soil with their burrows, and protect trees against the onslaught of other insects. One study found that ants killed 85 percent of the tussock moths that attacked Douglas fir, and there are many other examples of how ants protect trees from tree predators. 

A recent review of 1,200 lichen species found that 10 percent were only found on dead trees, and many others prefer dead trees as their prime habitat. Lichens, among other things, are important convertors of atmospheric nitrogen into fixed nitrogen important for plant growth. 

Even the charcoal that results from wildfires burning up trees is important for soil productivity, helping to increase soil nutrients, water-holding capacity, and as a long-term storage mechanism for carbon. 

Several recent studies have concluded that both beetle-killed forests and the burned forests that remain after stand-replacement wildfires have among the highest biodiversity of any habitat type. 

Logging, thinning, biomass removal and other forest management introduce all kinds of negative impacts to the forest ecosystem, from the spread of weeds to soil compaction to alteration of water flow, disturbance to wildlife, creation of new ORV trails and increases in sedimentation, that all lead to the degradation of the forest ecosystem itself. Most of these negative impacts are ignored or glossed over by proponents of thinning and biomass removal. 

 Forest “management” is so focused on trees and wood products that it represents a critical failure to see the forest through the trees. 

George Wuerthner is an ecologist and writer with 34 published books. He will be speaking at 7 pm Wednesday, May 6, at Harris Hall, 8th and Oak, on “Wildfire Hysteria & Forest Biomass Greenwash.”