- Since 2011, California has been engaged in the most severe drought on record. Between 2012 and 2015 our states’ snow-pack was nearly non-existent, and the majority of our reservoirs and water supplies were a mere fraction of average capacity. This effected our forests by limiting water intake, and stressed our trees. Stressed trees become ripe for insects, and begin the bark beetle infestation.
- Bark Beetles
- Bark beetles are a natural part of the forests’ ecosystem, and survive at small populations in a healthy forest. They are natures way of thinning the forest when stands become overstocked, similar to wildfire. When trees are healthy, they are able to “pitch-out” the insects, and can sustain an infestation. When trees are drought-stressed, they aren’t able to pitch the insects out. The beetles lay their larva in the cambium layer, blocking the passage of vital nutrients throughout the tree, and eventually results in the death of the tree. Once the larva reach adult stage, they exit the host tree, and colonize into adjacent living trees. That’s why you see these growing blocks of red, dead trees. Stands of trees that are spaced at natural densities, tend to be less water-stressed, and can help fight these bugs. One good way to keep forests at natural densities, is through the use of logging and commercially thinning trees.
- Lack of Industry
- The timber products industry has greatly reduced in pace and scale in the last 30 years. The factors that have contributed to its downsizing are a slight lack of demand, and the large increase and cost of regulation. Add into the equation environmental litigation, and you see lumber mills closing up shop throughout the entire state. Logging is an asset to forest health by thinning forest stands back to natural tree densities. This helps keep the bugs at bay, and wildfire intensities low. Prior to logging, forests were kept at lower densities through natural wildfire events. However, fire regimes have been altered, and no longer burn in a natural state.
- Catastrophic Wildfire
- Our “good intentions” of trying to put out every wildfire for the last 100 years, has put us in a situation where we have greatly altered the natural ecosystem of our forest. Wildfire created a mosaic of diversity in our forests, and helped allow for altering stages of forest growth. Fire would burn at low to moderate intensities, and clear out the underbrush in the forest, while maintaining natural openings and grasslands by burning up the encroaching trees and shrubs. Wildfires now burn at high intensities, and need to be controlled. They are “crowning-out” forest stands with larger trees, and removing portions of the organic material out of the top soil. Not to mention dumping tons of carbon into the atmosphere by the second. Another factor that is contributing to the intensity of wildfire is climate change.
- Climate Change
- Whatever your view on climate change, researchers have seen a climb in average temperature every year in the Sierra Nevada, and project by 2050 that the average temperatures will rise by 7 degrees. Due to this phenomenon, we will see a change in forest composition on the gradient of elevation. Some trees will no longer be able to survive at the elevations they currently reside at (such as the lower elevations of Ponderosa Pine), and others (such as oaks and other hardwoods) will likely begin to establish and thrive at higher elevations. This is likely having an effect on the tree mortality at the lower elevations.
Dying Sierra, How NWTF is Helping to Save Our California Forests
On 11/18/16, the U.S. Forest Service released a statement that they estimated a total of 102 million dead trees in the state of California since 2010. That’s 62 million tree deaths in 2016 alone! This phenomenon is being described by some as one of the most catastrophic events of our lifetimes here in California. Our forests are drastically turning from green, to a drab red, and remaining as lifeless stems.So how did we get here? Here’s a very brief synopsis of some contributing factors: