Natural History Wanderings

Tree Die-Off a Major Fire Concern

Since October 2020, we have seen sudden tree mortality and dieback in many different species of trees, including eucalyptus, acacia, bay, and pine. The most significant Regional Parks impacted are Anthony Chabot, Reinhardt Redwood, and Tilden. So far, we have tracked approximately 1000 acres of tree die-off.

Sudden tree mortality and dieback is a major regional issue given its impacts on wildfire risks. Dead standing trees burn hotter, faster, and have the ability to cast embers far ahead of the original fire – igniting dangerous new fires or spot fires. Additionally, many of the areas impacted are in old eucalyptus groves, which have a very high tree density.

We are developing a plan for addressing the sudden tree dieback and reallocating some existing fire resources within its existing Wildfire Hazard Reduction and Resource Management Plan. However, additional funds are needed to address this problem.

The cause of tree mortality and dieback is not fully known but most likely has a direct correlation to drought caused by climate change. We are also working in partnership with the United States Forest Service (USFS), UC Berkeley, and CAL FIRE to determine the cause.