He is best known for his photographic images of nature’s beauty, but these days John Marshall has become quite the advocate for the occasional need of that beauty to be blackened by fire.

That’s why today he’ll be in Olympia, along with The Nature Conservancy’s Reese Lolley, to make a presentation on prescribed-fire smoke management before the state Senate’s Natural Resources Committee.

And it’s why he’ll be at the Yakima Valley Museum at noon Wednesday for a photographic look at Washington forests’ response to that kind of controlled burns — and to uncontrolled wildfire.

“Fire is huge. It affects everything in our ecosystem,” says Marshall, 61, a Wenatchee resident. “If we get it right, it helps us out. If we get it wrong, it’s disastrous.”

That Marshall, known for his evocative “coffee-table” photography books (“Washington Apple Country,” “Washington,” “Portrait of Washington” and “Idaho,” just to name a few), finds himself delving into the realm of land management might seem incongruous.

But it’s in his blood, and his passion for the subject is obvious.

His photographs first came to national attention more than 30 years ago, when his images of the 1980 eruption of Mount St. Helens filled the pages of National Geographic. His interest in forest stewardship, though, had been passed down to him two decades earlier by his father.

The late David B. Marshall is largely credited as the driving force behind the creation of several national wildlife refuges, was the chief biologist for the federal endangered-species program and was so revered among Oregon conservationists that the state’s Wildlife Society named its most prestigious award for him. Following his death in November 2011, The Oregonian ran a lengthy front-page story acknowledging his accomplishments.

“My father really educated me on fire as a kid, and how the Forest Service had it wrong, and how Smokey the Bear was putting out a message that was patently false,” John Marshall says. “I understood when I was 8 years old that this notion that you had to put out every fire was wrong.”

Putting out every wildfire, though, had been federal and state land managers’ policy and priority since 1910, when a series of small wildfires merged into one that ranged from northeast Washington through the Idaho panhandle and into western Montana. It burned some 3 million acres — roughly the size of Connecticut — and killed 87 people, most of them firefighters.

That fire, Marshall says, “completely galvanized the notion that any fires were a bad thing and we had to put them out. Looking backwards, that was a mistake, and now we’re having worse fires than ever. (The policy of absolute fire suppression) has fundamentally changed our forests. They’re loaded with fuels and crowded with small trees.”

The Washington state fire season of 1994, in which nearly 200,000 acres burned between Leavenworth and Chelan, was one of the factors in federal land managers began to revisit their policies, and in recent years the Forest Service has begun reintroducing fire – albeit prescribed and monitored fire – into the landscape, albeit in small doses.

Those doses need to be larger and more frequent, says Marshall, who has chronicled the impacts of those 1994 Chelan County fires and continues to do so. He has been photographing each of 60 burn sites every few years, and next year he’ll take that 20-year history of change and regrowth and turn it into a museum exhibit.

And just as many of those burn areas have come full circle — growth, wildfire, regrowth — so, too, has Marshall. In college, he got his bachelor’s degree in fishery science and his master’s in wildlife resources, figuring to turn his love of the country’s flora and fauna into a career. But then Mount St. Helens kickstarted his photographic career, and only in recent years has he turned his focus to the lessons his father taught him so many years ago.

“I went that (photographic) direction, but have always felt that need to play a role in conservation, and I see that role as educating the public,” Marshall says. “And with my photography, I’ve got a way to do that other people don’t.”

Marshall’s Wednesday presentation at the Yakima Valley Museum, which is sponsored by Humanities Washington, begins at noon. Free and open to the public, it will last for roughly 50 minutes, followed by a question-and-answer period that, Marshall says, will last as long as people have questions they want answered.

“I know it’s people’s lunch hour. I understand that some people won’t be able to stick around and will have to leave,” he says with a smile. “I won’t be offended.”