JULIAN OAK TREE DEATHS INCREASING: LEARN MORE MARCH 8

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Expert Panel to Discuss Oak Borer Beetle Tuesday March 8, 6 p.m. at Julian Library.  Public invited free.

Photo, left:  Gold Spotted Oak Borer

By Jim Madaffer

March 4, 2016 (Julian) -- Suspecting we had dead or dying oak trees on our property in Wynola Estates, my wife and I hired an arborist to inspect and inventory our trees.  The verdict: out of 80 trees, 10 oak trees are dead and must come down – all thanks to the Golden Spotted Oak Borer Beetle, or GSOB.



The oak trees in our mountain paradise are at risk.  The Governor has declared a state of emergency.  What can we do to save our trees?

(Photo, right:  dead oak trees in San Diego County)

If you love our community oak trees, please come to a free expert panel discussion at the Julian Library on Tuesday March 8th at 6 p.m.  You will learn about GSOB and options for saving the oak trees.  Panelists will include Kevin Turner and Jan Gonzales from the University of California at Riverside; Eric Just, Unit Forester from CAL FIRE; and Tom Launder, an ISA Certified Arborist

In researching GSOB, there are many opinions about what can and cannot be done.  Some say nothing can be done – just let the trees die and contain the wood on site to prevent the further spread of GSOB.  Others suggest chemical sprays, tree injections and even herbal teas. 

(Photo, left:  bark staining and bleeding from

Gold-Spotted Oak Borer larval feeding)

The GSOB is a small insect, less than a half inch long and about a 1/16 of an inch wide with a slender, bullet-shaped body.  Primarily black with an iridescent green sheen and six gold-colored spots on their forewings, they are agile flyers. They burrow into the tops of trees and generally work their way down, slowly eating away at the wood, gradually destroying the tree’s ability to absorb water and nutrients from the soil. GSOB typically exit the tree with a “D” shaped hole near the base of the tree.  They tend to attack more mature trees, killing oaks between 50 and 250 years old.

Since its discovery in 2008, GSOB has been found attacking three species of oak trees around San Diego County’s Cleveland National Forest: coast live oak, canyon live oak and California black oak.  GSOB is responsible for the death of over 100,000 oak trees in San Diego County, with the number growing every day.

In 2011, UC Riverside Natural Resources Specialist Tom Scott predicted the Julian area will continue to lose 17 percent of its oak trees each year as a result of GSOB.  At this rate, it won’t be very long until the very trees that contribute to the beauty of our beloved mountains will be decimated. 

Gov. Jerry Brown declared a state of emergency on Oct. 30, 2015 due to the loss of trees in California. 

“A lack of precipitation over the last four years has made trees in many regions of California susceptible to infestations of native bark beetles, which are constrained under normal circumstances by the defense mechanisms of healthy trees,” Gov. Jerry Brown wrote in his declaration.

(Photo, right: exit hole from Gold Spotted Oak Borer)

One of the biggest culprits in the spreading of GSOB is firewood from dead trees killed by GSOB.  Firewood can harbor harmful insects such as GSOB. Moving around infested wood can introduce these pests to new areas where they can take hold and have devastating impacts to trees, our natural resources and local communities. Even wood that looks safe can harbor destructive pests.  For example, female GSOBs lay eggs in the cracks and crevices of oak bark, and the larvae burrow into the cambium of the tree to feed so they may not be visible.

Some signs that your trees may be infested with GSOB include: bark staining or black areas where sap appears to be oozing out, thinning of the top of the tree or crown of the tree, small “D” shaped exit holes in the bark around the trunk of the tree, increased woodpecker damage as they try to eat the beetle larvae in the tree.

If you are interested in learning more about GSOB and what you can do to help prevent the spread of this terrible pest and potentially save your own oak trees, be sure and attend the free panel discussion at the Julian Library on Tuesday, March 8, 2016 at 6 p.m.

 


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