The California 2070 Project: Bark Beetles in California Forests

The Leaflet is proud to announce “The California 2070 Project”, a brand new regular column where writers from different perspectives and expertise will show you the challenges and opportunities California will face in the next 50 years as our climate changes. With thousands of miles of coastline, millions of acres of fire-prone forests, and some of the most biodiverse regions in the world, California will be uniquely impacted in the next 50 years by climate change, and our lives will change dramatically. But California is also home to 40 million people, the world’s 5th largest economy, and some of the most progressive and innovative policies in the world. Whether it’s a statewide cap-and-trade program, a gas car moratorium, or sweeping conservation programs, California is often on the forefront of environmental protections. We hope to communicate the severity of the problem, but also the excitement and inspiration of the solutions, and show that the Golden State’s best days are still ahead of us. 

Welcome to the California 2070 project.

You walk through the Sierras, and the crisp air on top of the sweet sugar pine scent helps tone down the worries you carry from your day-to-day life. That moment of peaceful bliss comes to a close when you stumble upon acres and acres of burnt trees. Of course, wildfire is a natural stage of succession, the process forests go through to enable regeneration and the recycling of nutrients. Although, you encounter more tree carcasses and notice the same little insect using them as hosts: bark beetles.

Though tiny, the western pine beetle infiltrates a tree’s outer layer, attacks the inner body, and exposes it for parasites and diseases to infect it. The trees are weakened as the beetles interfere with their biosystem. The vascular structures used to transport sugars and vital nutrients gained from photosynthesis stop, and the tree slowly dies.

 The methods trees use to fight off threats start to fail as well. Normally, trees produce sap at the injury site to trap invading parasites. Bark beetles sneakily overcome this defense mechanism by depositing fungi onto the tree bark to prevent the making of said sap.

You decide to walk a bit closer to one tree in particular. With an attentive look, one can see reddish-brown bubbles oozing from the outer crust, and frass, a substance much like fine sawdust, straying around the outside. The beetles have successfully taken this sugar pine as their host. 

Are these bugs to blame for the fire, or are they merely opportunists who have taken advantage of a vulnerable food source? The answer to this question is fairly complex, as both fire and bark beetles feed off each other’s activity. 

There has been a noticeable increase in bark beetle infestations in addition to forest fires. Climate change, the third actor in this ecological dilemma, has increased the extremity and occurrences of droughts worldwide. Without water, trees are more susceptible to dry out and their defensive walls to fall down. Bark beetles benefit from the rising number of potential hosts to feed off of, and their population has grown due to their spreading to surrounding trees and infestation expansion. As temperatures grow warmer, bark beetles will pose more and more of a threat to forests’ wellbeing. 

Most of us do not live in the Sierra Nevada mountains and witness beetles eradicating hundreds of millions of conifers in-person, but the effects of these three complementing components (bark beetles, droughts, and fires) will impact all Californians. As climate change continues to cause warmer winters, the shrinking level of snowpack has led the state’s water supply to be less continuous throughout the year. What makes this problem even more concerning is the decreasing mass of forests as a result of drought and bark beetle infestation. More sunlight is able to hit the snow and melt it faster. Additionally, as trees decay, they will release the carbon they have been carrying with them back into the atmosphere. All of these various factors affect one another, showing how critical it is for us to understand ecological systems and the complexity of nature. 

Whether one lives in a cabin in Yosemite or an apartment in San Diego, these situations that seem to be rippling outwards are nothing to brush off and label as insignificant.  Recently, researchers have been looking into the evolutionary potential of trees in affected areas. That is, the genetic diversity of California’s plant life may provide a way for trees to build a tolerance against bark beetles and warmer temperatures. Scientists have been looking into why some survive and why others fall victim to climate change impacts. It has been theorized that the trees surviving current environmental conditions are less biologically accustomed to Ice Age conditions. “Assisting gene flow” could be a tactic used to expand the already existing plants that have proven more fitted adaptation to rising temperatures.

We want forests to thrive, since they are the natural carbon sinks we desperately need to fight climate change, and serve as shelter for a wide array of species. 

Today, mechanical thinning and prescribed fires are methods used to lower forest density, and bark beetles have difficulty infringing on neighboring life as a result. 

The relationship between bark beetles and trees is still being studied, and the golden ticket to a better-managed forest is yet to be found. A thorough understanding on how bark beetles, droughts, snowfall, and climate change all connect is crucial to improve the health of trees everywhere, and as Californians, we must not take our invaluable forests for granted during this time-sensitive period.