Cam­pus to cut in­fested trees

Los Angeles Times - - THE STATE - By Matt Mor­ri­son

A deadly in­fes­ta­tion of tiny tree-bor­ing bee­tles from Southeast Asia has reached the UC Irvine cam­pus, and school of­fi­cials say that sev­eral hun­dred trees will be re­moved.

In­fested trees have also been iden­ti­fied on sur­round­ing prop­er­ties, in­clud­ing res­i­den­tial neigh­bor­hoods and public ar­eas in Uni­ver­sity Hills. Sci­en­tists are grap­pling with the pest’s spread through­out South­ern Cal­i­for­nia

“It’s a sig­nif­i­cant threat to all of our trees,” said Richard De­mer­jian, UC Irvine’s direc­tor of en­vi­ron­men­tal plan­ning and sus­tain­abil­ity.

Cam­pus groundskeep­ers first no­ticed signs of a se­ri­ous prob­lem in De­cem­ber, and of­fi­cials were able to con­firm wide­spread in­fes­ta­tion early this year. Tiny, tell­tale bore holes in trees are of­ten un­de­tectable un­less the bark is re­moved. It’s es­ti­mated that the pests may have been in­tro­duced at UC Irvine two to three years ear­lier.

The polyphagous shot hole borer, a bee­tle about the size of a sesame seed, was first iden­ti­fied in South­ern Cal­i­for­nia in 2003, with ma­jor in­fes­ta­tions in 2011 in Long Beach and Los An­ge­les. It has now spread to River­side and Or­ange coun­ties and San Diego.

The bee­tle in­fects a wide va­ri­ety of tree species by bor­ing to the core to begin its re­pro­duc­tive cy­cle. A fun­gus se­creted by the bee­tle chokes the pulp and kills or se­ri­ously dam­ages the host tree. Sci­en­tists have traced the bee­tle’s ori­gin to Southeast Asia.

UC Irvine has as­sem­bled a fac­ulty team to work on a man­age­ment strat­egy with ex­perts from the UC Di­vi­sion of Agri­cul­ture and Nat­u­ral Re­sources as well as UC River­side plant pathol­o­gist Akif Eskalen, who first iden­ti­fied the bee­tle fun­gus as the source of dis­ease in the trees. There is no known treat­ment for in­fected trees.

Ac­cord­ing to UC Irvine, of the more than 25,000 trees on cam­pus, about 1,000 have been iden­ti­fied as in­fested. Most will need to be re­moved. At least 16 species have been in­fected, with va­ri­eties of sy­camores a fa­vorite host of the bee­tle.

In an April 15 email to stu­dents and fac­ulty, Vice Chan­cel­lor Wen­dell Brase ex­plained the prob­lem and the de­vel­op­ing plan.

“We re­gret that many large trees will have to be re­moved ... but this is a nec­es­sary step in pro­tect­ing the re­main­ing healthy trees in our ur­ban for­est,” he said in the mes­sage. “Ex­per­i­men­tal treat­ment and pre­ven­tion pro­grams will place a pri­or­ity on sav­ing large ma­ture trees, such as the 40- to 50year-old na­tive sycamore trees in the cen­tral cam­pus.”

The uni­ver­sity will de­velop a pro­gram for plant­ing re­place­ment trees as in­for­ma­tion be­comes avail­able on species that are re­sis­tant to the bee­tle, school of­fi­cials said. Proper dis­posal of the in­fected wood is also un­der ex­am­i­na­tion.

De­mer­jian said sci­en­tists and stu­dents lament that the only course of ac­tion right now is tree re­moval.

“It’s hard to watch so many trees get cut down,” he said, “but peo­ple un­der­stand the ne­ces­sity of this in or­der to man­age the prob­lem.”

Don Leach Daily Pi­lot

UC IRVINE has dis­cov­ered that hun­dreds of its trees, es­pe­cially in Aldrich Park, above, are in­fested with a bee­tle from Southeast Asia and will be cut down.

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