The U.S. agency that publishes national statistics on wildfires says data from before 1983 can't be confirmed and shouldn't be compared to more recent numbers.
The figures show a decline in total acreage burned in recent decades compared to the first half of the 20th century. Individual wildfires have decreased in frequency since 1980, but the average area burned per wildfire has doubled since the 1990s. Nine of the ten largest wildfires recorded have occurred since 2000.
The Environmental Protection Agency has monitored wildfires for their "possible impact on climate change," noting many connections between wildfires and climate. The EPA website hasn't been updated past 2015.