Saturday, July 20, 2013
It has become an epidemic. If you look out your window you can see them everywhere now, rapidly dotting the once-green landscape with their bright orange colors.
For those of you who are confused on the subject, I’m talking about our dying pine trees, not Oregon State fans. If you haven’t noticed yet, take a look out the window and you’ll see mosaics of ponderosa pine trees throughout the valley that are dying as the result of an infestation by the California fivespined ips — a pine engraver beetle that has only recently been found in the area.
Pine beetles tend to attack trees that have been stressed due to drought or wildfire; however, even the ice storm of 2012 and the high winds of the Gorge can weaken trees enough to make them susceptible to infestation. The beetle — which typically attacks the tops of pines where the bark is at its thinnest — bores into the tree and lays eggs that turn into larvae which eventually feed on the living tissue beneath the bark. Within a month of primary infection, a tree will begin to show signs of “top kill:” needle discoloration at the top of the tree that works its way down the stem.
Other signs of infection include beetle bore holes, orange dust at the base of the tree and large amounts of pitch exuding from the bark and bore holes. Healthy stands of trees can withstand the beetle; however, in conditions of stress, tree mortality can be high.
So, what can you do? The most important thing to consider when faced with infection by the CFI is proper tree care and timing. It may be tempting to immediately prune the infected branches; however, this can further weaken the tree during the dry months and provide further fodder for beetles in flight looking for a host.
Pruning and removal of infected trees should be postponed and only occur from mid-October to January, when beetles are dormant and tree stress is low. During the fall and winter months when it is appropriate to prune infected trees, trimmings and slash should be chipped or burned to reduce food for future broods, and bark removed from any material intended for firewood.
While October may seem like a long way off to care for your trees, there are still things that you can do now to help reduce the summer stress on your trees. Watering your trees two to three times per month for an hour during the hottest part of the summer will significantly reduce stress levels and make them more resilient to both the fivespined ips and fire. When watering, be sure to water at least 3 feet away from the trunks of established trees, using a soaker house or bubbler to moisten 2-3 feet below the surface of the soil.
For further questions on the California fivespined ips and how to keep your home safe this fire season, contact the Hood River Fire Services Wildfire Prevention Hotline at 541-436-0655 or firstname.lastname@example.org.
Jon Gehrig is the wildfire prevention coordinator for Hood River County Fire Services.