Wildfires — Plant in Place

Tree curling heat occasionally ravages the land; nature is cycles and circles. Hiking in land recently burned by wildfire is brutal. Gone is the canopy which shades you from the blaring summer sun. The remnant spires of trees, some still glistening black and others bleached white, sway ominously above. Gone is the understory which holds the ground in place. Loose soil and ash makes hiking uphill difficult as you kick up a dust cloud with each step. Fallen trees crisscross the trail, obstacles to hop over or crouch under. The wind blowing through the scorched landscape whistles a distant roar like a crowd in an open air arena. The hair rises on your neck at the uncannily human noise, eerie on a deserted trail. By the end you are invariably sunburned and covered in ash.

Sapling curled by heat, shadowing new growth.

The history of wildfires in western North America is a complicated mix of climatic shifts, natural forces, and human intervention. Over millennia, the climate has fluctuated between dry and wet, hot and cold. Generally drying and warming since the last glacial maximum, the landscape we associate with the west is largely fire adapted. Any given area of ponderosa pine (Pinus ponderosa) woodland, a habitat that covers a lot of territory in the west and is influenced by fire, should expect a low to mid-intensity and patchy fire every 15 or so years with more intense fires occurring at longer intervals. These natural fires, started mostly by lightning, helped to sustain the character of the land by removing dead organic matter, thinning the understory, and rejuvenating the soil. This cycle is called ecological succession, a process that applies to almost every habitat across the planet. It is nature’s way to renewing itself.

In addition to natural fires, Native Americans set artificial fire to keep areas of land clear of trees and shrubs. In the west, these fires sustained sun-filled fields where plants like common camas (Camassia quamash), an important food crop, grew in large number. Elk populations were also managed through the use of fire. The excellent food provided by saplings repopulating a recently burned area allowed elk to thrive, and the elk in turn provided food for the people.

As European settlers colonized the west, fire management became an important issue. Policy of the early 1900’s favored the suppression of wildfires. While suppressing fires to save property is logical on its face, human intention was undermined by the complexity of nature. As fires were doused, organic matter built up and left a land unnaturally full of fuel. Clear cut foresting also played a role as mixed aged old growth forests were replaced by thickly populated even-aged forests, a habitat more prone to massive fires. In recent decades full suppression has been replaced by more nuanced policy which allows fires in wild areas to burn naturally while focusing controlling fires near populated areas. The past few years have brought wildfires unnatural in size and intensity. Instead of small and patchy, they are large and scorching. These fires are the result of the management mistakes from the past 200 years compounded by an accelerated warming and drying of the climate which will favor more fire in the future. It is unclear how the combination of more frequent and intense wildfires coupled with climate change and invasive species will affect the rejuvenation of the landscape with which we are familiar.

One way or another, renewal is the next step after destruction and shortly after the fire there is green dotting the char, a sign of the future. The establishment of pioneer species, the same aggressive plants often considered weeds in the garden, are the fragile first steps of a landscape renewing itself. Fireweed (Chamerion angustifolium), yarrow (Achillea millefolium) and their fellow pioneers quickly spring up in the abundant sunlight and thrive in the nutrient infused soil. Fast growing shrubs and trees such as alders (Alnus sp.) and quaking aspen (Populus tremuloides) sprout over the following years. These sun loving plants exploit the growing conditions that fires create, in a sense selfishly opportunistic. Their presence holds and improves the soil, fixes the nitrogen and adds the organic matter that mid- and late-succession plants need to germinate. The shade intolerant pioneers slowly create conditions that will prevent them from remaining. Are they mindlessly overexploiting ideal growing conditions to their own long-term detriment, altruistically creating the conditions for the reestablishment of climax plant species, or else just playing their pre-programmed part in the mechanical system of habitat succession? Nature is complex and mysterious.