“Let’s add humans to the mix…”
Climate and biological factors are hugely important in shaping how wildfires burn, but humans are also important parts of wildfire processes. For 10,000 years, Native Americans started wildfires in the spring and fall to increase food for the grazing wildlife they hunted, and to help prevent large, out of control fires in the summer. In this way, humans were a part of the natural fire ecology. Then, in the mid 18 hundreds European settlement brought landscape level changes that drastically changed the historical patterns of wildfires. Heavy cattle and sheep grazing mowed down the grasses which once acted as quick burning fuels for frequent, low intensity fires. Roads and railroads acted as lengthy firebreaks, further reducing wildfires on the landscape. It was the beginning of a shift away from the frequent, smaller fires that western landscapes evolved with, and toward a new era with increasingly less fire. Dr. Hessburg explains all this in more detail here in his TED talk “Why wildfires have gotten worse-and what we can do about it”.