At a Tipping Point: Strengthening Forest Resilience on the Navajo Nation

For thousands of years, forests on the Navajo Nation have held cultural, relational, and spiritual significance to the Diné people. Today, the Diné forest and woodland landscape, which covers roughly 4.9 million acres, supports community livelihoods through fuelwood, building materials, livestock forage, and drinking water. However, warmer temperatures and persistent drought may push the resilience of these crucial forests to a tipping point. In partnership with the Navajo Forestry Department (NFD), researchers funded in part by the Southwest CASC assessed the impact of climate variability on Navajo Nation forest health and, through collaborative research approaches, identified pathways to improve forest resilience. 

In a recent publication, the researchers highlight how they assessed Diné forest stands, which vary in their vulnerability to two major climate risks: high-severity stand-replacing fire and drought-induced mortality. The team analyzed the impacts of climate at three different scales: individual trees, forest stands, and the larger forested landscape. They found that tree growth in forests on the Navajo Nation has declined across all three scales due to warming temperatures and prolonged drought. Warmer-than-average spring and fall temperatures reduce tree growth as much as, or more than, reduced precipitation, making heat a key driver of forest stress, particularly for larger trees. At the forest stand level, productivity of dominant tree species has steadily declined since the early 1990s, which corresponds to a period of rising temperatures. Across landscapes, forest growth has become increasingly synchronized, meaning that drought now affects all areas similarly. Even high-elevation stands, once considered climate change refugia, are facing the impacts of warmer springtime temperatures.

The research also highlights potential management options that NFD managers can take to improve forest resilience, such as maintaining lower tree densities, reducing competition for soil moisture, maintaining diversity of tree age and size, and decreasing fire risk through fuel reduction. They suggest that a combination of conventional forest management tools and Traditional Ecological and Indigenous Knowledge could help sustain forest health while honoring the cultural, spiritual, and ecological values central to the Navajo Nation. This research illustrates how co-produced science and culturally rooted management can play a critical role in safeguarding the future of Diné forests.

Read the full publication, published in Trees, Forests, and People.