I’d spent the morning trekking through a typical northern forest woodland of 100-foot maples, oaks, and poplars tightly knit with wild grapevines. The umbrella of trees was shading me from the midday sun when the forest canopy suddenly opened, and I stepped into a sun-filled gap. I squinted in the sun as I tried to decipher the unique scene. Shrubs no higher than my waist
hugged the ground. Unfamiliar grasses blanketed every inch of the opening.
Why had this tiny grassland emerged within such a dense hardwood forest? I looked for clues. There were four snags, bleached corpse-white and perforated with more holes than a sieve, serviceberry, and miniature oaks. Three maples I guessed to be about 25 years old grew on top of each other at one end of the clearing. A wide beech stretched skyward, a few dead leaves flapping in the breeze, a triangular scar on its trunk. An old oak lay on its side, its exposed rings telling stories of drought, monsoon, and fire.
I was in a forest that I guessed had burned 5 years earlier, and some 30 years before that, too. Now the rejuvenated soil was nursing new trees that would eventually tower overhead. How did I know all this history? Every woodland is like a mystery novel waiting to be read, the evidence gathered and analyzed, the enigma unraveled. The culprit in this case, fire, is easy to identify because it leaves such obvious clues blazed into the landscape. Learn to identify and interpret these clues and a forest becomes an open book, ready to reveal a story.
From ground to crown
The effects of a few types of fires will be most obvious to hikers.
Ground fire: Always caused by lightning, ground fires burn beneath the duff, so you won’t see flames. Keen observation is needed to uncover traces of this kind of burn. Ground fires char mosses and some roots, but rarely harm living plants taller than your ankle.
Surface fire: Caused by controlled burns or unextinguished campfires, surface blazes creep across the land and consume leaf litter and downed branches. These fires actually promote life by baking open sealed cones (called serotinous cones) of ponderosa, lodgepole, jack, and pitch pine, as well as the seedpods of buck-brush, manzanita, golden eardrops, whispering bells, and mountain balm. Once the seeds drop, reproduction begins. A multitude of these fire-dependent plants in one area indicates a recent fire.
Crown fire: With ambient temperatures as high as 20,000°F (almost 95 times the temperature at which water boils), these fires incinerate everythingdead and living plants, seeds, minerals, even soil bacteria. The resulting dark, solidified soil grows nothing for years.