Prescribed burns part of a healthy forest

Fall is here and smoke is in the air across Western Montana. The smoke we see and smell can come from one or two very intentional actions by forest managers to benefit our forests.

The first is specifically tied to Montana’s Hazard Reduction Law. This law requires forest operators to reduce excess activity fuels, which means branches, needles and unmerchantable material.

This must meet standards set by the Montana Department of Natural Resources and Conservation (DNRC).

This law originated from concerns over the devastating 1910 burn which blackened 3 million of acres across Montana and Idaho.

The Montana Legislature passed the initial law in 1919 with the intent of disposing of activity fuels within a specified time frame.

Today’s burning season and resulting air quality for burning large acreages is rigorously controlled by the Montana/Idaho Airshed Group.

These are acreages managed by DNRC, U.S. Forest Service, Bureau of Land Management, Montana Fish, Wildlife & Parks, various tribes and private companies.

All other burning of slash, fields and irrigation ditches is controlled by individual burning permits which establish restrictions, normally through local fire departments.

The second intentional fire is a prescribed burn which also can achieve compliance with the Montana Hazard Reduction Law.

However, its primary purpose is to restore ecological function through manipulating vegetation.

Next to climate and soil, fire has been the most important single factor affecting our forest landscapes, distribution of forest stands across this landscape and species composition.

Re-establishing fire on the landscape creates mosaics and patchiness which provides for more diversity in species, age and sizes of trees along with much more diverse grass, forb and shrub communities on the forest floor.

This provides diverse wildlife habitat and improved soil productivity with initial increases of nitrogen and long term benefits from charcoal.

So, why do we need to re-establish fire through prescribed burning?

Simply, in Montana we have too many trees (our forests are unnaturally dense), too many in the wrong place (natural meadows, parks and rangelands), the wrong size (small diameter, same height, competing for sunlight and nutrients) and wrong age (similar age classes and uniform stands).

It is necessary to utilize prescribed fire to achieve overall ecosystem function and restore our forests for future resiliency.

Through the use of prescribed fire, we are replacing the current plant communities by initiating disturbance, which causes different plants to grow and adapt over time with a more diverse structure — more resilient to future disturbance.

Active management will result in a more predictable and sustainable outcome.

The use of prescribed fire often involves some hand or mechanical treatment prior to ignition.

The purpose is to reduce unnatural fuel loads and ladder fuels to a point where fire can more naturally carry across the forested landscape and create the desired ecological condition.

For example, overstocked stands that might naturally have a more open character, if not thinned prior to prescribed fire, would most likely carry a crown fire and kill most of the trees in the stand (a stand replacement fire), rather than rejuvenate the forest condition by reducing the encroaching tree species.

Is prescribed fire always predictable in end results?

No. Those of us involved in prescribed fire have had escapes, catch-outs, slop overs or whatever label but not very often.

For example, nationally, the U.S. Forest Service averages around 4,000 prescribed burns per year with only 1 percent escaping and 99 percent successful.

Surprises do happen with changing weather, wind and fuel conditions.

Therefore, experience is irreplaceable in increasing the odds of success on the ground.

Sounds risky? That depends.

Besides experience, improved modeling of fire behavior and improved communications, mechanically treating excess forest fuels either commercially, which provides raw materials for Montana’s timber industry or in many locations, pre-treating or slashing prior to ignition, decreases flame height, increases the burning window and reduces the risk of escapes.

In order to achieve healthy forests and increase their resiliency by restoring mosaics and patchiness, we need to actively manage them and restore their ability to survive future disturbance.

We must master re-establishing fire on our forested landscape or Mother Nature will under her prescription-hot, dry, windy summer day with an oversupply of tinder dry fuel.

We risk losing much of our forest diversity, large heritage trees standing in dense, overstocked stands, and the wildlife and soils that rely on a dynamic and diverse forest condition.

Sanders is with the Montana Wood Products Association.