National Forest Foundation

Aspen Center for Environmental Studies Develops Forest Health Index

NFF Grant Partners and Projects


(Above) The Maroon Bells Wilderness provides drinking water for locales as far away as Los Angeles, emphasizing the need to monitor air and water quality in our high elevation forests.

The Forest Health Index is a groundbreaking new tool developed by Aspen Center for Environmental Studies to help Colorado’s Roaring Fork Valley community make sense of the complex environmental conditions affecting our local forest. Our forest is the dominant feature of our local landscape, providing critical ecosystem services such as clean air and water as well as aesthetic and recreational benefits. Forest health, in large part, equates to environmental health.

The Forest Health Index monitors insect and disease infestations, such as the mountain pine beetle damage pictured here.

ACES’ Forest Health Index provides an annual “report card” for our watershed’s forests, utilizing data from over 20 climatic, ecological, and socioeconomic indicators. Examples include:

  • Frost Free Days
  • Critical Fire Risk
  • High Elevation Snowpack
  • Soil Moisture (monitoring supported by a National Forest Foundation grant!)
  • Insect and Disease Infestation
  • Elk Population Health
  • Wilderness Use

But what defines a healthy forest? Our notion of forest health is based on the premise that a healthy forest is one that is resilient to change and able to provide for local ecology as well as human goals. To that end, the Index is analyzed through the lens of four widely agreed upon public goals for forest health, which are:

The Forest Health Index is utilized by local agencies to make land management decisions. This insect-damaged forest adjacent to the city of Aspen has since been restored.

How are the Forest Health Index scores calculated? Essential aspects of forest health such as resiliency are difficult to measure, especially within systems as large and complex as a forest. To create a scoring system that applies across such diverse datasets, the score for any given indicator is based on the magnitude of change between the current state of that indicator and its historic or “normal” state. An indicator with a score of 100 signifies virtually no departure from “normal” conditions. To that end, the Forest Health Index is truly a metric of forest change.

The overall Forest Health Index score for the Roaring Fork Watershed in 2014 was a 78 out of 100, indicating a moderate departure from natural variability, ecosystem function, and sustainable use.

The overarching goal of the Index is to communicate changes in the health of our forest, generate community dialogue, and inform management and policy efforts. Users of the Forest Health Index include:

  • Land Managers
  • Research Scientists
  • Educators
  • Local Residents and Visitors

Modeled after the international Ocean Health Index, we are currently exploring ways to export the Forest Health Index to other mountain communities. To explore ACES’ Forest Health Index, please visit .

Although this forest on the flanks of Capitol Peak is stunning to look at, a Forest Health Index score of 78 indicates that our high elevation ecosystems are not functioning the way they used to.

The Forest Health Index is a project of Aspen Center for Environmental Studies . ACES is partnering with Aspen Global Change Institute to design the index, gather and analyze data, engage with stakeholders, and evaluate its scientific accuracy. For inquiries about the Forest Health Index please contact ACES Forest Programs Director, Jamie Cundiff at or 970-925-5756.

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