From Our Boulder Backyard: New Info on How Changing Climate Affects Future Fire Danger

One of the many great things about living in Boulder for us science geeks is the lively scientific community, and the fascinating research that comes out of our own backyard. There is something fun about bumping into one of my husband’s colleagues at the hardware store with his toddler son, and then the next day discovering that he is the second author on a significant piece of remote-sensing-based research I’m reading.

The dad in question is Noah Molotch, and the article, by Ernesto Trujillo, Molotch and others at the University of Colorado, was recently published in Nature Geoscience. The research team used remotely-sensed data to uncover a surprisingly strong relationship between snowpack and mid-elevation forest greenness. To measure forest greenness, they used Normalized Difference Vegetation Indices (NDVI) from 26 years of continuous data from NOAA's Advanced Very High Resolution Radiometer (AVHRR). They then compared this forest greenness with long-term data from 117 snow stations maintained by the California Cooperative Snow Survey, a consortium of state and federal agencies.

As Molotch explains, “If snowpack declines, mid-level forests become more stressed, which can lead to ecological changes in the distribution and abundance of plant and animal species and to more vulnerability to fires and beetle kill.”

A Sierra Nevada forest in Sequoia National Park: snow depth and forest pattern are related. Credit: University of Colorado, Boulder.

Although this research was based on data from the Sierra Nevada, it hits close to home. Near Boulder and throughout the western United States many of us spend a lot of time in the mid-elevation forests.  It has been impossible to miss the increasing wildfires and beetle outbreaks in these areas.  This study helps explain how regional warming over the past 50 years, leading to decreased snowpack in mid-elevation forests, may have contributed.