Fire + Merkley Summer 2019

The forest has adapted to fire, shouldn't we?

Fire season is approaching, which means misinformation about forests and fire will be soon coming your way! In order to prepare, I invite you to read this excellent article about fire history, ecology, and policy.

One important topic the essay doesn't address is the intersection of forests, fire and climate change - a complex relationship currently being (mis)used to justify increased logging in National Forests.

First, a refresher on the role of forests in the carbon cycle: Forests remove CO2 from the atmosphere through photosynthesis and store the carbon in their wood, leaves, needles, root systems, fungal networks, etc. Globally, forests account for about one-half of terrestrial carbon stores!

When trees naturally die or burn, they decay and CO2 is released back to the atmosphere, some immediately, but mostly over hundreds of years. At large scales, the processes of storage and release of carbon were once in approximate balance. Individual forest stands might be affected by fire, wind, insects, or disease, but across entire landscapes, the cycle of growth, decay, and combustion produced a balanced level of carbon emission and storage. Historically, forests were a crucial part of maintaining fairly stable global levels of atmospheric CO2.

Profit-driven, industrial logging severely diminished native forests’ capacity to regulate carbon in the atmosphere and now over half of the world's forests are gone. Even so, the forests that remain are still pulling carbon out of the atmosphere and could store it for hundreds or thousands of years if left to grow.

What happens to all that carbon when a fire comes through? Perhaps surprisingly, almost all of the carbon stays in the burned forest! I could explain at length – but it’s more fun to have Dotty the Spotted Owl tell you how in this short video.

In a very recent study scientists agreed with Dotty, finding that less than 5% of mature forest biomass is consumed in fires. The lead author was inspired to do the study because he kept hearing people, even other scientists, overstating the amount of CO2 emitted from forest fires. In contrast, logging leads to the loss of 85% of the carbon stored in the forest, with only 15% remaining in long-lived wood products.

Now, while forest fires don’t affect climate change, climate change is affecting forest fire (though not as much as you might think!). Between the media and politicians' statements, I understand why folks think climate change is causing “record wildfire seasons.”  However, isn't true if we go back more than a half century. As illustrated in this graph, forests in the western U.S. burn far less today than they did before the mid-20th century.

We need to bring more balance to the carbon cycle and more truth to policies and management around forest fire!