And sudden oak death
|Fog bank out at the coast|
|Deciduous Oaks near Saratoga Gap|
According to the most reliable scientific studies, SOD is caused by a pathogen which can be classified as water borne mold called Phytophthora ramorum. The pathogen spreads in the form of spores which are born in the wind or by rain. SOD needs an unwitting host which harbors the disease, but does not die from it. The California Bay (Umbellularia Californica), also called California Bay Laurel, Pepperwood, Spicebush, Oregon Myrtle, and other names, have been discovered to be the primary vehicle to spread the disease if they are located within 15 feet of an oak species. This is why this new project has been initiated to remove bay trees that are within close enough proximity to be a threat to vulnerable heritage oaks. This is not the first project of this kind. This article in SFGate describes a similar project that was carried out last July. The following quote from that article identifies the California Bay as a major culprit in spreading SOD.
"The research showed that bay trees are responsible for the spreading of the disease," said biologist Cindy Roessler, the open space district's senior resource management specialist. "If you have a bay tree within 15 feet of an oak tree, that oak tree has a much higher chance of getting the disease."
The seriousness of the situation can be underscored by the following quote from the same SFGate article.
“Scientists have discovered that California bay laurels are the prime harborers of the microscopic spores, which are dispersed in the wind and rain. Arborists and ecologists are afraid that if the tiny marauders aren't stopped, California's golden hills could be denuded of its signature live oak trees. As it is, experts predict that as many as 90 percent of California's live oaks and black oaks could die within 25 years.”
This MidPen document from their website describes an earlier bay tree removal project from 2008. Here is a quote from that document.
“The California bay tree has been identified as a main transmitter of sudden oak death
because it hosts the pathogen on its leaves, but is not killed by it. Spores of P. ramorum
spread from the California bay tree leaves to nearby oak trees, which develop trunk
cankers and die.”
And I will offer one more quote from an article posted to the UC Davis Integrated Pest Management Program website.
“Research in California forests has shown that the greatest predictor of P. ramorum canker on oak is the presence of California bay laurel (Umbellularia californica). Pathologists believe P. ramorum drips or is blown down onto oak trunks from neighboring bay leaves when it rains. Once on the oak trunk, P. ramorum uses natural openings in the bark to colonize the bark tissues, killing cells and clogging water and nutrient transport vessels.”
I could go on, but the science gets really heavy from here, and that's a little beyond my scope. However, it is clear that there is no equivocation from the scientific community on the bay tree removals as being a logical step in order to help arrest the spread of SOD. For more detailed information you can visit the California Oak Mortality Task Force website. Given all the research data and public announcements that I found, I am actually amazed that I had not been more aware of this connection between the bay trees and SOD. I had to get this off my chest because I love bay trees, and I hate the idea that some of them must be destroyed, but this is indeed war, and I am in full support. If I only had more time I would volunteer my help.
|San Lorenzo Headwaters|
As the trail descended down toward the headwaters of the San Lorenzo River the fog thinned out into intermittent sunshine. This was on of those odd days when the fog was primarily up high. I was having a really great time checking out, and enjoying the sights, sounds, and even the smells of fall until reaching Castle Rock where I encountered a really large group of hikers that were taking a break around the trail camp. I immediately was thinking that I should really try to get out ahead of them just in case this huge mob of humanity was going to take the Trail I wanted. I was planing to use Loghry Woods Trail to get back to Skyline, and I did not want them to wind up becoming a walking, talking, trail blockage for my assent back to the ridge. I’ve had that happen before with large hiking groups, and it’s really annoying when they don’t have any sense of trail etiquette. Plus their noisy clamor scares away all the wildlife. I decided to make use of the pit toilet there as it was the only one around for miles, and then take off. But when I got finished, lo and behold, there they went en masse down the trail, making a huge racket, in the direction of the junction I was planning to use. And sure enough they began making the turn onto Loghry Woods Trail. Incredulous of my luck, I decided to just hang out around the trail camp for about 30 minutes to let them get well ahead, hoping that would be enough that I would not see them again. Quiet time is good I kept telling myself. The ploy worked, and the rest of my hike was just as pleasant as in the morning. Surely there must be a way to keep Castle Rock open. If this park actually closes, that will severely degrade the trail connectivity of this area. You can visit my photoset on flickr to see some pictures, and see a track log on EveryTrail.
Click here to visit the California Oak Mortality Task Force website
Click here to see MidPen's Sudden Oak Death fact sheet
Click here to download a Guide for Recreational Users from the California Oak Mortality Task Force