'Field Notes:' The Fruits Of Fire

Jun 10, 2018

Have you ever walked around in a recently burned forest? One of those areas where perhaps last summer you saw flames leaping out or smoke billowing? If not, I urge you to go out and take a look at this unique environment. I had never spent any time in a burned forest until a few years ago. I was immediately impressed with the beauty and abundant life I found in this transformed forest.

Wildflowers abound in recently burned areas. Fire reduces shading by trees and shrubs, allowing understory plants to get the light they need to grow and bloom. Grasses often provide a lush green carpet beneath wild rose, lupine, fireweed, and mariposa lilies, producing a profusion of color. On early summer evenings in recently burned forests, the air may be heavy with the scent of some of these pioneer species.

Plants aren’t the only organisms that benefit from fire in forests. Many insects find the freshly killed trees perfect habitat in which to lay their eggs. The larvae feed on the wood as they grow and mature. Their activities allow fungi to invade the trees and begin to decay the wood.  In cool and dry climates such as Montana’s, there are relatively few microorganisms like bacteria to carry out the decay process. So in this area, fire plays an especially important role in helping break down plant material and return nutrients to the soil in forms that quickly-growing plants can use.

Fire also benefits larger animals. The new plant growth provides ample food for herbivores like deer, elk, and bears. Many birds are attracted by the seeds of flowering plants and by the insects that are so plentiful.  Cavity-nesting birds, such as woodpeckers, nest in holes in trees, and they, in particular, benefit from fire.  Most cavity-nesting birds need the soft wood of dead or dying trees in which to excavate their nest holes, and these are abundant in post-fire forests. So fire both creates critical nesting sites and provides plentiful food for these birds. Other cavity-nesting species like mountain bluebirds, tree swallows, American kestrels, wood ducks, and many others can’t make their own nest holes, so they depend on cavities already created by woodpeckers.

A walk in a burned forest can be an experience full of natural beauty and activity.  You may first hear a tap-tap-tapping which leads you to a standing dead tree, or snag. If you look carefully, you may see a rare black-backed woodpecker searching the bark for insects; she will be difficult to see because her black back blends in well with the charred bark! You can’t help but notice a brilliant mountain bluebird, looking like a piece of the sky that has broken loose as it flows to earth, alighting on a low branch and watching the grass for insects. Young trees usually will be pushing up through the grasses and flowers; their slower growth ensures that the smaller plants have at least a few years of uninterrupted sunlight.

I hope you will take the opportunity to explore some of this unique environment, and find out firsthand the role fire plays in the ecology of Montana’s forests.

"Field Notes" is produced by the Montana Natural History Center.  Thanks to Dr. Richard Hutto for help with this week's program.

(Broadcast: "Field Notes," 6/10/18 and 6/15/18. Listen weekly on the radio, Sundays at 12:55 p.m., Tuesdays at 4:54 p.m., or Fridays at 4:54 p.m.,  or via podcast.)