Zinke’s statement came just after a visit to the site of the Carr Fire, where a record-setting fire tornado driven by extreme heat and wind amplified devastation on the western edge of Redding in late July.

Last week, the secretary seemed to acknowledge that climate played a role in the fire, though he did not use the words “climate change.”

'I've heard the climate change argument back and forth. This has nothing to do with climate change.' Ryan Zinke

Zinke wrote on Twitter: "Wildfires are burning hotter and more intense due to drier and hotter conditions and due to a buildup of dead and dying timber."

Later, as the Sacramento Bee reported, Zinke also said that, “there’s no doubt the (fire) season is getting longer, the temperatures are getting hotter.”

That much is true. July was the hottest month on record in California, based on more than a century of data. Research has shown that the fire season has gotten longer. And California is still dealing with the effects of the severe drought between 2011 and 2017, which killed trees across California (presumably the "dead and dying timber" that Zinke mentioned).

It's Climate Change

If it’s not clear what, exactly, Zinke thinks is responsible for the hotter, drier conditions and the longer fire seasons, fire and climate scientists, as well as California firefighters, have no difficulty putting a name to it: Climate change. Research has tied both the recent California drought and the area burned in Western U.S. forests to human-caused climate change.

While other factors, like forest management, play a role, too, climate change is a "threat multiplier," wrote climate and fire scientists Daniel Swain, Crystal Kolden, and John Abatzoglou last week.

Zinke’s comments about forest management appear to refer to the increasing density of trees, shrubs, and grasses in many of California’s forests that have resulted from a century of fire suppression policy.

Most fire scientists agree with Zinke that forest management is also a major factor in many of California’s fires. And while some environmental groups oppose forest thinning in the name of habitat protection, some of the biggest conservation groups are among the most vocal supporters of forest management reform.

Earlier this year, Congress passed a bipartisan “fire funding fix” that is designed to free up funds for forest management projects. Prior to its passage, The Nature Conservancy was one of its biggest cheerleaders.

At the state level, Gov. Jerry Brown is also a big supporter, having built $210 million of funding for forest management into the state budget.

Meanwhile, in Washington, the Forest Service is facing budget cuts, and the Joint Fire Science Program, which supports wildfire research, much of it related to forest management, may be eliminated.

Few Trees, Intense Fires

Regardless, forest management is only one driver of fire behavior in California. Though it has played a role in many California forests, cutting down trees won’t make wildfire behavior less extreme everywhere. Many of California’s largest and most destructive fires of the past two years have burned in places where there are few trees to begin with. The vast majority of land burned in the Thomas Fire, now the second-largest fire in California history, was chaparral (sometimes called "brush"), not forest.

Tweeted fire scientist Crystal Kolden:

If you believe that the primary reason fires are getting worse is dead trees in forests, please explain why non-forest fires are also getting worse? (Hint: it starts with "climate" and ends with "change") 🤔 — Dr. Crystal A. Kolden (@pyrogeog) August 6, 2018

And when it comes to fire behavior, Cal Fire Battalion chief Jonathan Cox says that weather is more important than fuel load in the forest.

"If it's hot, if it's windy, that's going to have a much greater impact on the fire behavior, as opposed to the fuel or the topography," says Cox.

Though climate and weather are not the same thing, they go hand-in-hand, with climate change driving shifts in day-to-day weather. Weather is saying, “It’s hot today.” But Zinke’s statement “the temperatures are getting hotter” is a description of a change in climate.

Allie Weill is a fire ecologist at UC Davis, currently serving as a AAAS Fellow at KQED Science. Jon Brooks contributed to this report.