[ Golden Gater Online - March 18, 1997 ]
Corey Grice
Staff writer
Two major biological threats are posing an "imminent danger" to trees at SF State and could kill half the campus pines within a decade, according to a grounds crew official.
Phil Evans, assistant director of Plant Operations, estimates there are 200 Monterey Pines, or pinus radiata, on the 93-acre campus property. An infestation of beetles and a deadly fungus epidemic could leave 85 percent of them infected within five years and as much as half the Monterey Pines dead in only 10 years, Evans said.
"Basically all of our pine trees are in danger," he said. "Especially the Monterey Pines which are a substantial portion of the campus forest."
The first casualty of the epidemic was identified recently when a 35-year-old Monterey Pine was found to be dead near the J. Paul Leonard Library.
"The big pine on the library patio is turning brown on the ends and has been killed," said Evans, who oversees the grounds crew.
The culprit, he said, is the red turpentine bark beetle, Dendrotonus valens which means "tree killer" in Greek -- one of the two main insects that kill pine trees.
"The beetles' role in nature is to pick off the aged and infirm ... and, much like a pack of wolves, naturally select the most weakened trees," Evans said.
The library pine had been debilitated by nearby concrete that has choked it of oxygen for years, Evans said. But at least five other healthier Monterey Pines have also been invaded by the red turpentine beetle.
"Detection is very difficult," he said.
One problem is the attacks are invisible because the beetles bore under the bark and out of sight.
Adult female beetles bore through the bark to lay a colony of eggs. When the larvae hatch they continue to dig into the wood, feasting on the critical cambium layer of the tree. When the cambium, the layer of cells which produces new sapwood, is killed or damaged it prevents new wood from being formed, Evans said.
Another issue is that some scientists speculate the period of drought in California during the late 1980s and early 1990s sufficiently weakened the North Coast's pine population.
The red turpentine beetle is normally the first bark beetle to attack a weakened tree. If the tree does not repel the beetles -- typically by oozing excess pitch -- another type of beetle swoops in.
The Ips Mexicainis beetle, a much smaller insect, but one that swarms in greater numbers, will follow the red turpentine bark beetle infesting the branch tips and "very rapidly kill the tree," Evans said.
Plant Operations plans to remove the dead tree near the library because it is "an open invitation" to the Ips beetles which are most prevalent in mid-March.
"We need to remove (the tree) immediately or it will be a source of many more problems," Evans said.
The campus grounds crew will fell the diseased tree during spring break at a cost of about $3,750, Evans said.
In addition to the meddlesome arthropods, and of greater concern, is a potentially deadly fungus that has been located in the area along Brotherhood Way near SF State.
Evans said Pine Pitch Canker, a type of fungus which affects the tips of pine trees, leaves them looking like a "candelabra of dead branches," eventually killing the infected plant.
The fungus, which has not yet been identified on campus, can wipe out huge numbers of pines in a few years.
"It moves that fast," Evans said. "It's devastating."
Similar attacks, he said, can be seen along I-280 through San Bruno and Millbrae and have afflicted trees in Santa Cruz and Monterey counties.
Evans said there is no known means of control for the fungal epidemic.
The fungus is believed to be transmitted by flying insects when they literally stop to taste the trees, according to David Wood, professor of insect biology at UC Berkeley.
"(Campus pine trees) are going to get pitch canker within one to three years," Wood said. "There's no doubt about it."
Wood is also concerned about the native conifer species -- pines, firs and cedars -- in the neighboring Parkmerced, Harding Park Golf Course and Golden Gate Park areas, but his biggest fear is that the disease will eventually spread toward Lake Tahoe.
"The worst case is if it gets into the Sierra Nevada Ponderosa Pines and Sugar Pines," he said. "That could be serious."
The 12-member campus grounds crew is taking action to save SF State's trees, including fertilizing, pruning and spraying insecticides on the trunks of the trees, but the process is not cheap. Each dose of insecticide costs about $1,000.
"This has had a very significant (financial) impact on our operations," he said. "We are trying to postpone the demise of the pine forest long enough to replant, but the financial and emotional costs are tremendous. Not to mention we are losing an important feature of our landscape."
Jim Cassin, a garden specialist, is protecting the trees on the front line.
Cassin has been pulled off his regular gardening duties to ensure the campus pines are as healthy as possible.
"It's not that bad yet," he said of the bark beetles. "But the first alarm bells are going off ... so we're on extra alert."
Groves near Maloney Field and in the HSS courtyard need particular attention, he said.
Plant Operations is planning "an aggressive replanting effort" that will take two years to complete. Evans estimates the labor of replacing, staking and training between 50 and 100 trees could cost as much as $10,000.
Wood said SF State will likely replant with three Mediterranean species. The Canary Island, Aleppo and Italian Stone pines -- which are not as susceptible to the fungus -- will replace the prevalent Monterey pines, he said.
While the fate of many campus pines may be doomed, Evans remains hopeful for the future.
"We see tremendously rapid growth here on campus which is why you can see such mature trees in only 30 years," he said, noting the ideal climate conditions in the area. "You're going to be aware that we're cutting down trees but it's not going to be an overwhelming disaster."
[ Golden Gater - March 18, 1997 ]