The EPA shows a large increase in US burn area.
Climate Change Indicators: Wildfires | US EPA
The National Climate Assessment shows the same thing.
Full Report | Fourth National Climate Assessment
They mysteriously forgot to graph all the years before 1983, when burn acreage was much higher.
National Interagency Fire Center
“In the conterminous United States during the preindustrial period (1500- 1800), an average of 145 million acres burned annually. Today only 14 million acres (federal and non-federal) are burned annually by wildland fire from all ignition sources.”
Note, in a spasm of truthful candor, they admit that the ferocity and size of recent fires are due in a large part to the lack of good forest management – not clearing underbrush, nor doing controlled burns, which historically rejuvenated and strengthened vegetation.