Armed with axes and shovels, Cal Fire personnel headed out on the morning of Sept. 10, to find out what might be killing off a group of trees in a heavily wooded area of Bear Valley.
Officials thought the may have a serious infestation of the dreaded bark beetle, but what they discovered was something natural but just as destructive -- a grove of Jeffery Pines succumbing to black pineleaf scale and a severe case of Armillaria.
The small sucking insects and the fungus were infecting more than a dozen trees situated on a piece of land just off Deertrail Road about 1,000 feet above the valley floor.
"The scales latch onto the pine needles, removing sap and injecting toxic enzymes," said Kim Camilli, a Cal Fire Forest Pest Specialist who traveled from San Luis Obispo to inspect the trees in Bear Valley. "If the infestation is severe enough, it sucks off all the juices from the tree, which can eventually kill it."
Although deadly, Camilli said the scale is not uncommon and infestations are generally localized.
"But if environmental conditions are right," she added. "The dry weather and dust can help the bugs migrate from tree to tree."
Those types of conditions have been known to cause serious outbreaks. However, infestations can reduced by washing down trees with water or by properly timed insecticidal sprays.
Meanwhile, the Armillaria, like other root rots, causes loss of roots and may cause trees to fall over, even when the tree is still carrying green pine needles.
The native fungus was identified by Camilli and Cal Fire Assistant Chief Frank Spandler by a white colored vein of rot growing inside the bark of some of the trees they examined on Tuesday.
Touring the area last month, Spandler said he initially thought Hetrobasidion annosum might be spreading through the soil in the area after he spotted a large decaying tree stump and several surrounding trees that were dead or dying.
Annosum is a parasite and a saprophyte which attacks trees killing them before living in the stumps for up to 50 years or more. It then travels through the roots to other trees.
Experts say that prevention is the best strategy for controlling annosum, such as immediately dosing freshly cut stumps with an industrial grade borax called "Sporax," to prevent the establishment of annosum spores.
And while the two problems identified on Tuesday were not as alarming as originally expected, there 's still cause for concern.
Al Thibodeau, a certified arborist who contracts with the community service district to find and tag dying or dead trees in Bear Valley said, both conditions discovered can severely weaken trees, making them susceptible to bark beetles.
"Because of dry conditions and no natural clearing by fires, this year's beetle infestation is worse than last," he said. "If the tree is healthy they can push the beetles out with sap, if not, they kill it."
According to Thibodeau, there were an estimated 57 trees in Bear Valley as of Sept. 1, that were tagged for beetle infestation.
Those trees will eventfully need to be felled and removed by the property owner at their expense.
However, Thibodeau said there are solutions for those wanting to save their trees, and if not too far gone, a systemic insecticide can cure a dying tree, but it is expensive -- up to $500 per tree -- and it's not guaranteed to work.
"By the time you notice the tree has a problem, the vascular system of the tree is already compromised," he said.
The good news however from last week's discovery, is that Armillaria moves slowly at around one to two meters per year. It then works on a tree for years before it kills and moves on. It can be controlled if caught early, and perhaps the best way to mitigate problems that create an unhealthy forest Cal Fire experts said, is to develop and follow effective forest management techniques, which includes prescribed fires, vegetation management and fuel breaks.
"There is always a healthy amount of disease in the forest," Camilli said. "These little outbreaks that we are seeing would be lessened if we had more forest management. We are doing a lot, but we need to do more."