California ecologists and legislators are trying to find a solution for what they have called the largest die-off of Sierra Nevada forests in modern history, a report from The San Francisco Examiner says.

The epidemic of California’s drought and bark beetles killed about 40 million trees since 2010 in Central and Southern Sierra, the report says, and it’s moving North.

Officials have been cutting down the dangerous trees and creating piles across six counties, the report says, but now the debate on how to dispose of them begins.

The state recently purchased 10 20-foot-long air-curtain burners for about $1 million that are designed to burn so hot that little—if any—smoke is produced, but critics still say that a little smoke is too much. Chief Ken Pimott, director of the California Department of Forestry and Fire Protection (CalFire) tells the San Francisco Examiner that using the burner would create less greenhouse gas than if there were massive wildfires, which the burner would prevent.

Gov. Jerry Brown created an emergency order in 2013 stating the trees must be send to biomass plants to be created into energy, the report says, but the state is facing a decrease in biomass plants due to the rising popularity of wind and solar.

Forest Ecologist at the Earth Island Institute’s John Muir Project Chad Hanson says in the report that the myth of dead trees fueling fiercer wildfires is false, and the best solution for the trees is to cut them and leave them to natural decompose on the forest floor.

In the past, the state attempted to gather the trees for lumber but saw issues when the bark beetles would create a fungus that dyed the lumber blue and making it harder to sell, the report says.

Until an agreement for a solution has been made, CalFire plans to start running its air burners 24 hours per day in the fall, the report says.