Climate and Wildfires

Whether or not climate change is a factor in recent destructive wildfires in California and Australia, there is another factor—forest management—that, unlike climate, is within human power to control.

A professor of forestry at a California University wrote in a University publication that “for thousands of years prior to Euro-American settlement, Native American tribes and lightning fires burned as much as 10 to 12 million acres in California every year [five times greater in area than the California fires of 2018] . . .  These fires were typically more benign, burning more often but at lower intensities. The federal government’s focus on fire suppression has resulted in denser forests with more continuous fuel to burn in an intense fire.” [Emphasis added]

The Forest Foundation of Sacramento states on its website that “Prior to European settlement in California . . . generally low-intensity fires  . . . helped to clear the understory, keep the forest canopy open, and as a result guarded against mega fires . . .

“Starting in the early 1900s land managers were successful in controlling many of the fires, but the result was a tremendous build-up of dense brush and overly-stocked forests.

• Historically, our forests have contained 50 – 70 trees per acre, and today our forests have more than 500 – 1,000 trees per acre – increasing the risk of catastrophic wildfire.
• Without natural thinning, forests grew more crowded and shade tolerant trees filled the understory, providing ladder fuels for today’s crown fires that jump to the crown of the trees and spread quickly.

“[W]e can reduce the risk of wildfires with the help of healthy forest management—which includes forest thinning and the removal of excess ‘fuels’ that can feed and increase the size of a fire.”

The author of this Post has an Australian friend who is a professor emeritus of geology and earth science at one of the major universities of Australia. At yearend 2019 he wrote as follows to friends and family about the destructive Australian bushfires of late 2019.

“Previous farming and forest management policy was to have small cold burns in winter to remove the fuel load. This no longer happens because what were previously managed forests in national parks, with harvesting and regular fuel load reduction programs are now isolated overgrown wilderness areas where fire vehicles cannot enter.

“About 50% of fires are deliberately lit, another 35% are from human stupidity (welding, grinding, barbecue, burning off etc. on hot windy days) and the rest are from lightning and embers from existing fires that can travel up to 30 kilometers.

“Local and state governments have restrictions on burning off undergrowth [and] cutting in fire breaks . . . In my own case, I lost a 8 Ha [20 acre] property, fences, outbuildings and a plantation [to fire] on 9th November 2019 . . .

“For years we had been seeking permission for a winter cold small burn to reduce the fuel load and were refused every time. There was a 30-year dead tinder dry fuel load in the adjacent national park . . . [20 years ago] we had burning embers dropping onto our property . . .

“[A]fter this event, I cut in a fire break and cut back the undergrowth. I was fined $7,000 and warned that if I cut back any regrowth over the following decade, I would again be fined but more heavily.

“Temperatures have been far higher in the past (e.g. 1896) . . . Drought has been more intense in the past. Drought is normal in Australia as is flooding rain. Drought makes the forests tinder dry . . . Our drought/rain cycle is also related to the El Nino-La Nina cycles. . . As per usual, we can expect flooding rains after drought. . .

“Previous bushfires have burned out a greater area and more people have died in previous bushfires than at present, especially in [the Black Thursday bushfire of] 1851.

“Native vegetation in Australia contains volatile flammable oils, burns easily and can explode. Some fires ‘crown’ with the burning of volatile gases above the ore canopy followed by a lower level intense fire. Nothing survives a crown fire because of the radiant heat. . .

“Enquiries commonly followed previous catastrophic fires, deaths and property losses. The recommendations are always the same (i.e. manage forests, cut in fire breaks and reduce fuel loads) and every time nothing is done.”