Remember there were no invasive species to take over because they were not introduced until people from other countries moved here. And only native people lived in what is now America. Read further in the above article and you will see the subtitle European Arrival Brings Disease & Outlawing of Fire
When naturalists like John Muir first entered the Yosemite Valley of California in the 19th century, they marveled at the beauty of what they believed to be a pristine wilderness untouched by human hands. The truth is that the rich diversity and stunning landscapes of places like Yosemite and other natural environments in the United States were intentionally cultivated by Native Americans for thousands of years. And their greatest tool was fire.“Fire was a constant companion, a kind of universal catalyst and technology,” says Stephen Pyne, an emeritus professor at Arizona State University, author and fire historian. Yosemite itself was routinely burned to clear underbrush, open pasture lands, provide nutrient-rich forage for deer, and to support the growth of woodland food crops to feed and sustain what was once a large and thriving Indigenous population. “If you look at the early photographs of Yosemite and you see the great big, majestic stands of oaks, you would be led to believe that those are natural,” says Frank Kanawha Lake, a research ecologist with the USDA Forest Service, wildland firefighter and Karuk descendent. “But those trees are a legacy of Indigenous acorn management. Those are tribal orchards that were managed for thousands of years for acorn production and for the geophytes or ‘Indian potatoes’ that grow beneath them.”
Examples of Native American cultural burning can be found across the American landscape. In the Appalachian forests of the Eastern United States, the dominance of oak and chestnut trees was the product of targeted burning that resulted in vigorous re-sprouting of the desired nut crops. The iconic tall grass prairies of the Midwest were also likely cleared and maintained by Indigenous burning as pastureland for herd animals.
A 1911 federal legislation made it illegal to ignite fires on public forest lands, a hundred years later, though, western science and policymakers are rethinking the subject. Federal forests are now choked with dead leaves, brush, and dense fir trees, a tinderbox for wildfires whirling out of control. Between 1975 and 1985, wildfires burned just over 2,000 acres a year in the Klamath area. In the decade from 2005 to 2015, that number averaged more than 350,000 acres a year.