A fresh perspective on Pine Beetles

Last Thursday at Hallam Lake for the Naturalist Night speaker series, Professor Dan Tinker from the University of Wyoming gave a really illuminating talk about some of the science and research going into the Rocky Mountain Pine Beetle outbreak we are witnessing across the West. Living, working, and learning in Colorado nearly my entire life, I thought I had a decent grasp on most of the science looking at the interactions of Beetles in our forests. Professor Tinker quickly dispelled that little notion of mine.

In one hour, he presented the most scientifically sound overview of the beetle outbreak that I have read or heard about since my undergraduate days. One of the more interesting things about his presentation was that he had a much different message about the beetle epidemic than a lot of the articles we read about in national or local newspapers. His presentation wasn't all doom-and-gloom, in fact, it was quite the opposite. His assertion, which he explained quite well, was that many of the forests which are being hit by the beetles are regenerating with young seedlings and saplings as many of the older trees are being killed. There are lots of younger trees surviving even in the wake of massive die-offs and many of the lodgepole pine forests are going to regenerate within a couple of decades. I have hiked through areas in Grand and Summit county and seen the acres of dead trees but you can't help but noticing the young survivors. These young survivors are going to be the next generation of trees in the forest. The future for our forests isn't truly as bleak as some sources make it out to be.

Professor Tinker used the Yellowstone fires of 1988 as a comparative model for the beetle kill, and it was a powerful example of how resilient many forests are. After the massive fires ran through vast swaths of forest, a couple of years later Prof. Tinker and colleagues witnessed many of the areas recovering quite rapidly with young aspen and lodgepole filling in the vacuum left by the fires. If forests can rebound from a massive fire disturbance then it is likely a pine beetle epidemic isn't going spell the end for our forests. He also presented research looking into the likelihood of a forest fire occurring after the onset of a beetle infestation. Many of the findings suggest the beetle-killed trees don't have a significant impact on increasing the probability of fires starting in a forest. That was new information to me.

Prof. Tinker also brought up the conversation of climate change and beetle infestations. Warmer winters and periods of drought have allowed the more beetles to survive winters than in the past and drought is making it more difficult for trees to fend off swarms of beetles. However, trees have a pretty good defense against beetles (forcing them out with a resinous sap) but the blue-stain fungus that the beetles carry in their jaws is truly responsible for killing many of the trees. The blue-stain fungus moves into the xylem (sapwood) layer of a tree and it basically cuts off the flow of water throughout the tree. The beetles have evolved to carry the blue-stain fungus.

Dan Tinker's presentation reminded me that things are not always as they seem, especially in nature. There are always multiple layers at work in ecology and we must remember to look at nature holistically to grasp the totality of a phenomena like a insect epidemic. Its also important to keep in mind that a system in nature (like a forest) can recover from major disturbances like fire and insect outbreaks.

If your in Aspen, be sure to come by ACES at Hallam Lake on Thursday Nights at 7:30 for Naturalist Nights. Its free and continue through the end of March. Thanks for reading!

~Micah Davis