What Is A Healthy Forest?

I just received a notice from the Custer Gallatin National Forest CGNF) that they plan to do a Fuels and Forest Health Project in Cooke City, Montana.

The Forest Service says the project aims to mitigate wildland fire risks and enhance forest conditions surrounding Cooke City and Silver Gate, Montana. Among the usual claims, the project’s primary objective is to reduce fuels and thus reduce wildfires by “fortifying forest resilience against insects and disease.”

 We continuously hear from the Forest Service and others that logging creates a healthy forest. The main parameters defining a “healthy” forest are low mortality from natural agents like drought, insects, and disease, high-severity blazes, and rapid tree growth.

Of course, foresters define what constitutes a healthy forest, and by happy coincidence, the Industrial Forest Industry supports all the above criteria.

Such a definition demonstrates that most foresters and agency personnel fail to see the forest through the trees. They want green trees that grow fast because that is what the timber industry demands. But that is not what constitutes a healthy forest ecosystem.

The distinction between a “healthy forest” and a healthy forest ecosystem lies in the realization that an ecosystem is more than just green trees. Tree mortality and occasional episodic forest death are crucial components.

Dead trees serve as homes, food, and shelter for a myriad of species, from bacteria and fungi to insects and amphibians, for birds, and even for the largest mammals like bears. This understanding not only enlightens us about the complexity of forest health but also empowers us with a more holistic perspective.

However, when loggers cut down trees it disrupts the forest’s natural balance and significantly reduces carbon storage.

 When they suggest that this is protecting the trees from fire or other calamities, they never count the trees they have killed by thinning as a loss. This should be a cause for concern, as it directly impacts on our fight against climate change.

Logging is not a benign activity. Logging often requires roads, a major vector for spreading exotic weeds like cheatgrass. Logging roads are a chronic source of sedimentation in streams.

Logging activities can disturb sensitive wildlife, forcing them into other areas where they may not have good habitat.

Logging roads provide access to the forest for hunters, recreationalists, and other humans that can further disrupt or disturb wildlife. Logging removes the physical biomass of tree boles, thus reducing the potential habitat for hundreds of species that may depend on dead wood or snags.

While wildfire may increase sediment flows for a few years before soil cover reduces the erodion, Logging roads are chronic, never ending, source of sedimentation impacting aquatic ecosystems.

Removing trees can even influence fisheries since logs falling into a stream provide a significant aquatic habitat for finny residents. But it can also impact more than fish. Studies have shown that more logs in a stream provide more habitat for aquatic insects, providing greater insect activity in the air above streams that birds and bats exploit.

 Removal of a significant portion of the trees may influence the forest’s genetic adaptations by removing individual trees with specific alleles that may provide long-term survival to the forest stand.

For instance, some trees may have a greater resistance to mortality factors like insects, drought, cold, wildfire, and disease.  These adaptations may only manifest if the stand experiences one of these agents. Since one can’t tell which trees have any particular genetic adaptation, logging may reduce the “resilience” of the forest.

Rajora et al. (2000) compared genetic diversity between pre-harvest pristine and post-harvest residual gene pools of two adjacent, old-growth stands of Eastern White Pine in Ontario. The conclusion was that logging reduced genetic diversity in the post-harvest residual gene pools of the two old-growth stands. Also, all of the genetic losses were low-frequency or rare alleles, which may compromise the integrity of locally adapted gene pools and the ability of Eastern White Pine to respond to changing environmental conditions.

Such losses are seldom considered those advocating logging to promote forest “resistance.” Logging reduces the ability of a forest stand to survive.

Logging sanitizes a forest.  Rather than creating a “healthy forest ecosystem,” logging creates a degraded one.