Tending Our Stressed Out Trees
Post date: Mar 28, 2016 8:14:51 PM
Just before last Halloween, Governor Brown declared a State of Emergency around tree mortality and, working with the Department of Forestry and the Office of Emergency Services, convened a Tree Mortality Task Force. While the problem is most pronounced in the Sierra Nevada and Tehachapis, even Bonny Doon has areas identified by the task force, for example in the upper reaches of the San Vicente Redwoods both sides of Empire Grade above Pineridge, along Smith Grade, and around Wild Iris Lane. Since I wrote on the subject in January the storm winds have exposed the drought damage to the crowns of of our trees and the storm saturated soil has allowed their weakened root systems to let go. Douglas firs, tanoaks, and madrones seem to have been particularly hard hit.
Despite all the rain we have had so far this year we our area is still abnormally dry. More worrisome, February was 5º warmer; December through February, 2º warmer; and September through February, 3º warmer than the averages for 1949-2005. Hard as it is to picture now, we will soon be back in hard drought.
So what are we to do? First of all, if you have a dead tree within 1.5 times its height of your house, take it down. It poses both a fire and falling risk to your home. If you have any doubt about the tree or your ability to take it down, please consult a tree care professional. We certainly don’t want to cause any unnecessary injuries to either our trees or ourselves. After the next rain, look for hollow in the crotches of your trees that have pooled water. For madrones especially, these are spots where rot will attack and weaken the tree. If there is a sickly branch adjacent to the wet hollow, watch the tree carefully over time and consider removing the branch.
Moving out from your home, look at your woods and ask yourself if you see areas that are densely wooded with small trees, for example weedy young Douglas firs and tanoaks from the recent mast year. When the rains stop, those trees will all be competing for what little moisture remains, and provide an ideal nursery for the conifer loving bark beetles that nearly exterminated our native ponderosa pines after the Martin Fire. Now would be an ideal time to thin those areas while the remaining trees still have abundant soil moisture to strengthen them.
Finally, looking forward to summer, consider that the trees around your garden have probably been long relying on the the watering you give your garden, so think hard before completely cutting off water to your garden. Driving along the tree lined streets closer to town where conservation-minded water district customers stopped watering last year will highlight the perhaps unanticipated consequences. While providing shade, trees are also reducing evaporation from the ground and mitigating the drought.
A healthy forest is a resilient forest and moves us towards becoming a fire adapted community.