Grass Valley prepares to battle incoming bark beetle infestation |

Grass Valley prepares to battle incoming bark beetle infestation

Union Hill Elementary School students were acting arborists for a couple of days, helping to transplant 200 Ponderosa Pine saplings to help Grass Valley replace local pine trees lost to the bark beetle infestation. Permission slips were sent to their parents to see if they wanted one or more pine tree saplings to take home to plant for themselves.
Elias Funez/ |

Over 250 infected trees were removed from Grass Valley city property last year due to bark beetle infestations, and the city expects that number to grow in 2017.

Bark beetles are attracted to old, diseased or stressed trees, where they lay eggs underneath the bark and eat the cambium layer that carries trees’ nutrients. They also inject a fungus that prevents sap production.

Drought conditions in California have significantly weakened many trees and provided the perfect habitat for the beetles. A healthy tree can secrete resin to kill invading bark beetles, but weakened trees are unable to produce that defensive response.

The U.S. Forest service estimates at least 12.5 million trees have been killed off by beetles in California’s national forests since the statewide drought began.

Grass Valley City Manager Tim Kiser said he wants to put up the best defense, and work proactively against beetles killing off massive numbers of the city’s trees.

“It’s coming our way,” he said.

The Grass Valley Community Reforestation Program was formed in September 2016 to help combat the beetle infestation rapidly moving into Nevada County.

Program officials work with local schools, where they help students plant pine tree seedlings in one-gallon buckets and distribute them amongst the schools’ families. Second graders at Union Hill Elementary planted 200 seedlings on Tuesday. Kiser hopes this strategy will help reforest Grass Valley by planting new trees to replace dead ones.

Dead trees present a huge fire danger, so Nevada County has a designated transfer site where trees cut down due to infestation are transported out of the county and burned by PG&E to create fuel, said Nevada County’s emergency services program manager John Gulserian.

According to an agenda action sheet presented to Grass Valley City Council in September 2016, “Until our area has several years of normal to above average winters to allow trees sufficient nutrients and water to fight off the beetles, our community is faced with the possibility of losing 80 to 90 percent of conifers, similar to other areas in California.”

To contact Staff Writer Matthew Pera, email, or call 530-477-4231.

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