Mapping Tree Mortality in the California Sierra Nevada

Current year tree mortality poster map
Client:   The Martis Fund

Drought has severely damaged California's forests in the Sierra Nevada. Unseasonably warm temperatures and lack of moisture have fostered the spread of bark beetles and brought other stresses, killing over 100 million trees in the mountain range and more throughout the state. The Martis Fund is a philanthropy that supports forest management and habitat restoration in the North Lake Tahoe region and asked GreenInfo to prepare maps showing the nature of tree mortality in their region. 

The USDA Forest Service has been actively engaged in tracking and addressing tree mortality in California due to the presence of huge national forests in the state. The risks of ecosystem collapse, massive wildfires, erosion, and many other threats are real and very challenging. To help them manage, USFS has established an aerial monitoring program that now annually surveys much of the forested areas of the Sierra, with data available for each of the past three or four years. The agency has also developed a very compelling map, shown at left, showing the rapid mortality of trees from 2014 to 2016, to go along with its news story about reaching the 100 million tree mark.

GreenInfo used the USFS data to prepare more focused maps for the region of concern to The Martis Fund.  These maps use branding developed earlier for the fund, and include both a year by year comparison map, as well as a single map for the immediate region where The Martis Fund operates.

The most recent year data, for 2016, shows several distinct patterns from the aerial survey that may be subject to further revision as the data is processed.  The data breaks used by GreenInfo are not yet calibrated to the degree of threat (for instance, it is undetermined whether 5-9 trees per acre is a significant loss rate or a closer-to-normal rate).  These will be further assessed in the future.  Regardless, the rapid advancement of tree mortality is unmistakable and of great concern to anyone who cares about the Sierra.

The maps were developed using Esri ArcGIS software, and printed as large posters for use by the fund.

Focus:   Conservation, Philanthropy  

Services:  GIS Services, Maps 

Tags:   Esri ArcGIS, forests, national forests  

Project Years: 2016

GreenInfo Network creates, analyzes, visualizes and communicates information in the public interest. We specialize in mapping and related technology for nonprofits and public agencies, focusing on using it for conservation, social equity, public health, environment and foundation grant making.
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