The combination of extreme multi-year drought and the recent invasion of several new kinds of unusually destructive tree beetles are causing many oaks, sycamores and willow trees in the Santa Monica Mountains to die.

Residents living in the Santa Monica Mountains can help save our trees by becoming more informed about the particularly destructive beetles and what might be done. Here are six steps you can take to help identify infested trees and prevent your trees from being attacked.

1) Watering is critical! Take care of your trees! For information on how often, where and when to water your trees, go to

2) Add mulch under the drip line of your tree canopy. Ask gardeners to leave decomposing fallen leaves under the tree. A layer 3-6 inches deep, that does not directly touch the trunk, is one of the best ways to help your tree thrive. Mulch moderates soil temperatures, increases absorption of water, supports a healthy micro-organism community and provides important nutrients for the tree.

3) Avoid pruning your trees until after the rainy season. Drought stress and recent pruning cuts are a big target for invasive tree pests.

4) If you suspect your tree is infested by these beetles, contact the Eskalen lab. Their website has photographs and further information to help you verify an infestation.

5) Beware of arborists, pest control companies or others who offer to spray, inject or provide other “treatments” to stop these new types of pests. To date, the only way to control these beetles is by removing the whole tree or affected limb, and disposing of the wood properly. Directions on how to properly treat these problems is also found on the Eskalen lab website, and at

6) Become a Detection Detective! The RCDSMM is initiating a citizen science volunteer survey and monitoring project to help document the spread of tree pests. Information on how to build a home-made trap, where to purchase the lures and directions on setting and monitoring your trap is found at This is a really great opportunity for student science projects, homeowners associations and landowners who live near our public open space areas to help scientists track the speed and impacts of the tree pest invasion. It spreads rapidly! Please help out.