‘Tis the season for holiday greenery and plants—poinsettia plants, festive wreaths, holly to decorate the table and mistletoe to hang in the doorway. And, of course, who could forget the staple of Christmas decorations…the tree.

This year, getting a tree may present a challenge for Californians who cross the border into Curry County, Oregon. Whether your family holiday tradition is to fell your own tree, a la Chevy Chase in “National Lampoon’s Christmas Vacation,” or whether you prefer the freshness of a recently-cut tree from Oregon, there are some things to be aware of this year.

Douglas fir trees, one of the most popular Christmas tree varieties, can be infected with Phytophthora ramorum, otherwise known as Sudden Oak Death (SOD). This invasive fungus can affect a variety of plant and tree species with Sudden Oak Death, which causes plants and trees to wither and die. Sudden Oak Death likely spreads through infected plant material, or spore laden rainwater and soil. Moist, cool, windy conditions are thought to spread the pathogen by dispersing spores from the leaves of hosts. Many of California’s plants and trees could be negatively impacted by SOD, so a quarantine has been set at the California-Oregon border.

Trees coming from Curry County, Oregon into California must have one of two things: a sticker showing the tree has passed federal or state inspection and is free of the Sudden Oak Death pathogen, or a U.S. Forest Service permit proving it is from an uninfected area. The United States Department of Agriculture, California Department of Food and Agriculture and the Oregon Department of Agriculture are working together to stop the spread of Sudden Oak Death through Christmas trees.

Most Californians don’t need to worry about where their tree came from or whether is has been declared free of Sudden Oak Death. Trees cut within California do not need inspection, and trees purchased at tree lots have already been certified as free of the pathogen.

If you’re interested in learning more, check out the HungryPests profile on Sudden Oak Death or visit the California Oak Mortality Task Force web site. Have a very happy holiday season!

Helene Wright
California State Plant Health Director
Animal and Plant Health Inspection Service
United States Department of Agriculture