CALIFORNIA, (KTXL) — 2020 was the most destructive fire season California experienced with the August Complex Fire hitting a record high 1 million acres burned and becoming the state’s first giga-fire.

On Wednesday, CAL FIRE shared a report of the lessons learned from this massive fire that incinerated nearly 1% of the state’s landmass.

One area that has provided a lot of information for the fire agency is the area of the Tehama Mendocino Fuels Reduction Project. 90% of which was burned over by the August Complex Fire.

“Difference among treatments provided an opportunity to observe how treatment prescription may have influenced fire behavior and overstory mortality,” CAL FIRE wrote in the report.

According to a report, 2,500 acres of the planned 4,054 acres had been treated, which methods included:

  • Mastication (or mulching)
  • Manual hand-cut/pile
  • Mechanical cut/pile
  • Mechanical thin/biomass removal

Following the August Complex Fire, it was found that the reduction treatments did influence fire behavior, according to CAL FIRE. In treated areas, crown fires (fire moving from tree-top to tree-top) became surface fires as canopy density was reduced.

One indicator for the effectiveness of given treatments was the mortality of overstory, the top most layer of a tree.

In areas where mulching recently occurred the fire stayed in the up-to-2-foot-deep piles of biomass and killed the roots of trees as the burning material emitted heat and smoldered, according to CAL FIRE.

CAL FIRE said that an area that had been treated four years prior experienced no overstory mortality as the mulched biomass on the surface had time to decompose or had already been burned.

Sections of the forest that had all of its biomass removed experienced minimal mortality, according to CAL FIRE.

“By providing a rare opportunity to compare fuels management practices, this project will help guide biomass management decisions to come,” CAL FIRE continued in their report.

CAL FIRE concluded that if forest managers want to keep their forests standing it is best practice to remove biomass created from fire reduction practices.