Fire Ecology and Bark Beetles

Trails in a pine tree built by bark beetles. Photo: Island Press

Many of you may have heard of the beetle infestation that has devastated North American forests over the last decade. It may surprise you that this infestation is directly linked to our mis-management of wildfires over last century.“Fire suppression” was the leading forest-management strategy of the 20th century, where any and all wildfires were treated as unnecessarily destructive and immediately put out. However, by squelching every wildfire, we have effectively allowed wood (fuel) to stockpile, leading to the inevitable, uncontrollable, and devastating series of wildfires that we have been enduring for the past decade. 
We have since learned that wildfires are a critical step in the cycle of a healthy forest system. Native Americans were fully aware of this fact, and used wildfire as a tool to promote the growth of desired plants in subsequent seasons. Without fire, forests become overgrown. Overgrown forests are more susceptible to massive fires since they hold more fuel, and induce drought by increasing competition among plants for a limited water supply. In short, an overgrown forest is a weaker forest. 
Enter: the bark beetle. There are several species of bark beetle that have contributed to the recent infestation and all are native to the southwest. Bark beetles perform the critical ecological duty of sending weakened trees back into the cycle of decomposition, essentially “thinning” the forest of unhealthy trees. However, when the entire forest is weakened through drought (both natural and unnatural), there is no barrier to the beetle’s expansion. So what can we do? We can’t just let every wildfire burn! 
New forest-management tactics have recently been implemented which cater to the needs of both people and forests. In areas farther away from human activity, professionals use “controlled burns” to maintain forest health in a natural way; while near inhabited areas, “ecological thinning” is used to manually clear forests of excess growth. 
Fire ecology is a prime example of how human ingenuity can often fall short of understanding how interconnected our ecosystems can be. There is still so much that we do not know, and hopefully, by being more cautious about how we tamper with our ecosystems, we can avoid such destructive consequences.

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