VALLEJO (CBS SF) — The USDA Forest Service announced Monday that an additional 18 million trees, mostly conifers, have died in California since fall 2017.

Federal officials said that over 147 million trees have died across 9.7 million acres of federal, state, local and private lands in California since the drought began in 2010.

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Since 2016, federal, state, and local partners have felled 1.5 million dead trees, primarily those posing the highest hazards to life and property.

“It is encouraging that the rate of mortality slowed in 2018,” said Cal Fire Director Thom Porter. “However, 18 million trees are an indication that the forests of California are still under significant stress. The stress of drought, insects, disease, and prolific wildfire will continue to challenge the resilience of the state’s forests.”

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While the 2016-2017 winter officially ended California’s drought, below-average precipitation recorded in 2017-2018 slowed the recovery of the state’s surviving trees.

Federal officials warned that dead trees continue to pose a significant hazard to people and critical infrastructure, mostly centered on the west side of the southern Sierra Nevada range.

On January 8, during his first full day in office, Governor Gavin Newsom announced his commitment to forest health and called for a five-year, $1 billion forest management plan in his 2019-2020 state budget proposal.

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“California’s forests offer great recreational opportunities and provide significant ecological and economic benefits,” said California Natural Resources Secretary Wade Crowfoot in a news release. “Years of drought and a bark beetle epidemic have caused one of the largest tree die-offs in state history.”