20 Jun Bark Beetle Identification — DEVA #2
My two main projects include: mapping the Great Basin western bristlecone pine trees along the mountain ranges and digitizing Death Valley’s herbarium. Western bristlecone pines suffer bark beetle attacks, which have rendered these long-lived trees vulnerable to weather conditions. By creating a reliable map of where these trees are in our backcountry, we will be more well-suited to protecting them from changing conditions. The herbarium digitization will allow external researchers to understand plant phenology and diversity from all across time since the 1930s to present day in a far more accessible way as well. It also makes for a good office break from the outdoor heat!
For the most part, however, I have been learning from my mentor, Carolyn Mills, about recognizing the damage done to western bristlecone pine trees, limber pine trees, and pinyon pine trees. We took a day trip to the Panamint Mountains and began looking around in the area.
After reading through some of Carolyn’s notes, she pointed out to me signs of bark beetle infestation—the three symptoms which were more prominent and easier to identify were pitch tubes, exit holes, and packed galleries. I learned that the pitch tubes were the trees’ defense mechanism against boring beetles which attempted to push them out as they dug through the bark. The exit holes signified the end of the beetle’s life stage within the tree, often when the tree had died and the beetles finally emerged. The packed galleries could be seen on trees whose bark had begun to fall off, where intricate designs of the beetles’ burrowing paths can also be seen.
Of course, there are other factors that contribute to tree die off, such as warmer and drier climate, which forces the trees to cut back on funneling energy to vital systems like closing off their stomata in order to preserve water, thus reducing their metabolism rate.
When combining all these factors and more that I have yet to learn, it is clear that the trees in the subalpine region of Death Valley are in dire need of help. It is also the reason why I am all the more passionate about mapping and monitoring these trees for their protection in the coming months.