An Earthly Idea: Giant lessons from tiny bugs
August 23, 2014
I was certain that the Dillon Ranger District was wrong about lodgepole pine being the natural climax vegetation for Summit County. So I went to the library to find books on what kinds of trees were in our forests historically. Instead, I found a book that is must reading for anyone that cares about our local forests or the global environment. "Empire of the Beetle" by Andrew Nikiforuk is a real eye-opener.
Our pine-bark-beetle infestation was not that unusual. Nor was it very severe compared with recent ones elsewhere. Canadian author Nikiforuk explains that beetles are among the oldest, most numerous and most diverse organisms (more than 400,000 species) on Earth. They are crucial to decomposition, serious threats to crops and master forest managers. His colorful stories of beetle infestations and the scientists studying them show beetles and the tree death they cause to be part of normal forest ecology.
As implied by the book title, he portrays the beetle-tree relationship (fungi and mites also play key roles) as an almost purposeful system. The beetles manage the forests by killing older, weaker trees, thus allowing young ones to grow. They thereby maintain a diverse-age forest to provide themselves with a replenishing food supply along with homes for their fungi farming. Nikiforuk describes how a wide range of schemes over the years to control such "normal" beetle infestations by poisoning, clear-cutting and other means all failed or made things worse. Where timber companies used infestations as excuses for breakneck clear-cutting, they caused even more catastrophic damage.
Our local forest lesson is that the comparatively mild infestation and tree mortality here in Summit County fits that "normal" mode. Beetle-killed mature lodgepole are making way for young lodgepole and young fir as part of our natural forest succession process. We can be grateful to the infestation as improving forest health, moving from monoculture lodgepole to age- and species-diverse forest. Our infestation was "normal," though, only because we were lucky to have it reach us later than areas to the north and to have the drought break shortly thereafter.
Nikiforuk's global environment lesson, however, is that intense beetle infestations of the last 20 years have not been "normal." In stories from Alaska, British Columbia, the U.S. Southwest and Eastern Canada (a worm instead of a beetle), he points out how climate change can change the beetles' role from forest manager to forest destroyer. Just as drought and high temperatures set the stage for catastrophic fires, they also do so for catastrophic beetle infestations.
Because of climate change, recent beetle infestations have taken on a whole new character. Trees start out weaker from drought and higher temperatures. Winter cold snaps no longer stop infestations. Beetles survive to infest trees a second year along with the next generation of bugs. Or they have two hatches a summer instead of one. With warmer springs, beetles can attack trees earlier in the year when the ground is still frozen. The trees cannot draw up water to produce defensive sap and so are caught at their weakest. The result — tremendous devastation far beyond the "normal" of the past. If catastrophic infestations move north to the boreal forest, the devastation could spread to the whole continent.
Its story format makes "Empire of the Beetle" very readable, but it skips you around a lot in place and time and species. Similarly, both hope from greater scientific understanding and fear of worse devastation to come are scattered throughout. The lessons will still hit you clearly, though, and they are ones we all should learn.
Howard Brown lives near Silverthorne. While he has extensive environmental policy analysis experience at the federal, state and local levels, he attributes his expertise to observing and asking questions while enjoying Summit County's beauty.
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