Not many people outside Northern California and extreme Southwest Oregon have even heard of Sudden Oak Death Syndrome, but around these parts, it's a matter of serious concern. It's an invasive species, first discovered in the U.S. in the Santa Cruz area in the late 1990's by a private landowner who collects Rhododendrons, which the disease can also kill. The disease is best known for killing Tanoak, a highly prevalent species in our area. It can also kill Rhodies and Myrtles, as well as Coastal Live Oak (a relatively rare species) and Black Oak (which aren't found in Curry County). A number of brush species are killed by it, too.
In Tanoaks, it spreads very quickly by wind-blown spores, mostly in the Spring of the year. A typical distance for spores to spread from one Tanoak to another is up to a quarter mile, but it's been known to reach three miles in range. The infection rate for other susceptible species - Rhodies and Myrtles, for example - is dramatically less with distance.
Tanoaks (Notholithocarpus densiflorusa), incidentally, are not true oaks; they're technically members of the Beech family of deciduous trees. There are many other species, including Douglas Fir and Redwoods, as well as White Oaks, which are found a little further inland, that can host the disease, but it does not kill them, and they aren't a factor in spreading it. Alders, another common deciduous species in the Northwest and around here, are also (thankfully) not affected. Here is a very helpful link to a website that shows pictures of all the known affected plants, and what they look like when they're affected: http://www.suddenoakdeath.org/library/photos/plant-symptom-photos.
Here on the southern Oregon coast, we've been hearing and reading about Sudden Oak Death Syndrome for several years. There are a lot of Tanoaks here, and it doesn't require too much imagination to envision a situation in which large areas of Tanoaks die off. This in turn would increase the danger of wildfires in our dry summers for years to come, jeopardizing all the other trees in the forest. Anyone who uses a wood stove or fireplace around here can attest to the fact that Tanoak makes excellent firewood; it burns very hot, so a conflagration in standing dead Tanoaks could be akin to the Perfect Storm of wildfires.
From its beginnings in the Santa Cruz area, Sudden Oak Death Syndrome has since spread to 15 California counties... and to Curry County, Oregon, where we live. It was first discovered in Oregon in 2000 or 2001. One example of how quickly it can spread is a case in the southwest part of our county, near Brookings, on Alder Ridge Road. The first affected trees in this particular area were discovered in 2011, but for reasons of a lack of funding, there was no response; today, just 4 years later, 75-80% of the trees in that area are dead. We certainly hear a lot about funding shortfalls, but can't help feeling that a way could and should have been found to continue the effort to fight the spread of Sudden Oak Death Syndrome without interruption.
Fortunately, funding has now been restored, and an aggressive program is well under way, but in areas around Brookings, the damage has already been done. As part of that aggressive program, we were recently contacted by the Oregon Department of Forestry; an aerial survey had spotted one or more dead or dying trees on our property, and they wanted to examine the trees and determine whether Sudden Oak Death Syndrome was the cause of their demise. We quickly agreed, and we were recently visited by Randy Weise, the regional forester responsible for this program.
We homed in on the first tree pretty easily, about 200 feet of bush whacking off the road. Even though the GPS locations are only approximate, and can be off by 150 feet or so, Randy homed right in on it, and identified it at about 50 feet, a large Tanoak about 16" through. The tree wasn't dead, but was showing signs of stress, and had developed what he identified as Hypoxillon - Small blackish "buttons" that are another common tree disease in our area. Randy used a small hatchet to trim away bark in various places around the base of the tree, looking for the blackish streaks that are a common S.O.D.S. symptom that should be sampled to establish whether Sudden Oak Death Syndrome is the cause. Finding some, he chipped away samples and collected them in a petri dish; he then collected backup samples, to be used in case the first sample was inconclusive. He recorded his findings, then marked the tree with pink flagging tape, and affixed a metal tag at the base of the tree. Job done! Now to find the other tree!
This one was a little more difficult. Supposedly about 400 feet off the nearest road, it was a steep, brushy walk down through the woods nearby. This was a smaller tree, and was dead or nearly so; but trees die of other causes, too, and he suspected that neither of the two trees he examined had the disease. Still, the only way to know for sure is to analyze them in the laboratory. He collected his samples, made his notes and marked the tree.
Lab analysis takes about 3 weeks; if they turn out to be positive, the trees will have to be cut and removed from the forest, along with all the other susceptible trees within 300 feet. They would be burned, or cut up and used as firewood by the landowners (us, in this case), but cannot be transported or sold as firewood to others for fear of spreading the disease.
We felt a bit more comfortable about Sudden Oak Death Syndrome after this experience. The Department of Forestry is vigilant, and Randy certainly knows what he's doing. Funding to support the program appears stable, at least for now. With continued effort - and a little luck - perhaps Sudden Oak Death Syndrome can be stopped before it spreads further. We all hope so!
A Postscript: According to an e-mail from Randy dated November 9, 2015, “the trees are not Sudden Oak Death. They are another phytopthera of which there are a number that naturally occur within the woods. The lab typically does not specify which one it is.” Randy, many thanks for the great news and for working so diligently to protect our forests.
For more information, here are some sources of additional information:
OSU Extension, Curry County, 29390 Ellensburg, Gold Beach, OR 97444
541-247-6672 or 1-800-356-3986
http://extension.oregonstate.edu/curry/
Oregon Department of Forestry
http://egov.oregon.gov/ODF/
USDA Forest Service, Pacific Northwest Region
http://www.fs.usda.gov/goto/r6/fhp
Oregon Department of Agriculture
http://www.oregon.gov/ODA/CID/PLANT_HEALTH/sod_index.shtml
There is also a very helpful flier (Stop the Spread of Sudden Oak Death) available from OSU, and from the Oregon Department of Forestry.
Informational websites about Sudden Oak Death Syndrome:
OSU Extension Service
http://bit.ly/OakDeath
California Oak Mortality Task Force
http://suddenoakdeath.org
USDA Agricultural and Plant Health Inspection Service (APHIS)
http;//www.aphis.usda.gov/plant_health/plant_pest_info/pram/regulations.shtml