Pine trees in Lake County are in severe danger and dying by the hundreds according to a forest expert.
“Trees are water stressed,” said Greg Giusti, the University of California Forest Advisor for Lake and Mendocino Counties. “It’s a one-two punch. As the trees become more and more water stressed they become increasingly susceptible to other pest and pathogens that ultimately kill the trees.”
There are a number of different pine species native to Lake County and found growing throughout the hills from Middletown and Cobb Mountain to the northern reaches of the Mendocino National Forest. It is not unusual to see Ponderosa, Knob Cone and Grey — also known as Digger — pines thriving in close proximity to each other.
“Pines are fairly successful in Lake County,” Giusti pointed out. “What is unusual is the fact that species like knob cone and grey pines are incredibly drought resistant. To see these species succumbing is unlike any of the past drought years we saw in the early 1990s and early 2000s”.
The first issue — sustained drought — leads to further problems. As the trees become increasingly water stressed they lose the ability to sustain high sap flows. It’s these sap flows that keep bark beetles from penetrating the trees. As the beetles enter the trees they lay their eggs making more beetles. When the beetles leave the nursery tree they simply fly to the nearest tree and start the whole cycle over again.
After three mild winters beetle numbers are “astronomically high” Giusti said. He added that “there are at least three species of bark beetles that are attacking the pines.”
One species, the 5-spined Ips beetle is no bigger than a grain of rice. “They’re not big, but there are millions of them attacking pines,” Giusti explained.
This is not a Lake County phenomenon. The problem has been identified throughout the pine growing regions of the state. Counties in the Sierra-Nevadas and southern California will be experiencing record level mortality from drought related insect outbreaks, according to Giusti’s analysis.
He added, “As long as the winters are mild, and dry the beetles will thrive and continue to increase in numbers. We are in for a long and bleak summer for these trees.”
While there is little the experts can do to stem the damage to forest pines until the drought ends, Giusti said that landscape trees in a person’s yard can be spared. He recommends a once-a-month deep watering can prevent the beetles from taking over a tree.
“It’s all about maintaining the trees vigor and sap flows,” Giusti said.
