Woodlands across the western United States are at risk from extreme heat, drought, wildfire, and mismanagement. These forces threaten not only the future of woodlands themselves, but also the livelihoods of rural and tribal community members who rely on these ecosystems for important resources and services. These problems are particularly acute in the pinyon-juniper woodlands of southern Utah and the broader Four Corners region of the American Southwest, where climate change is pushing trees beyond their ecological limits, and where Indigenous households rely on these woodlands for sources of fuel for home heating and cooking.

To understand these dynamics and the ability of this coupled socio-environmental system to persist into the future under varying climate and harvesting regimes, this project convened an interdisciplinary team of atmospheric scientists, anthropologists, biologists, geographers, policy experts, and tribal members. Team members include not only experienced researchers, but also undergraduate and graduate trainees, post-doctoral fellows, and early career faculty, many of whom come from underrepresented backgrounds, including tribal communities. The team collected and synthesized data on climate dynamics, tree growth and mortality, and Indigenous firewood harvesting in order to model future scenarios and identify conditions capable of ensuring woodland health and Indigenous livelihoods into the future. 

Results indicate that climate change will significantly reduce pinyon-juniper woodland biomass over the next one hundred years, with precipitation having a strong influence. While some changes may be gradual, others may be episodic events such as drought-induced mass mortality and wildfires. This project documented one such event with nearly one quarter of pinyon-juniper patches experiencing at least 10% relative canopy mortality over the study period resulting from climatic and site-specific characteristics. While drought-induced tree mortality events are hard to predict, project members identified several factors including the interaction of physiological- and community-level attributes. When die-off events do occur, they may initially provide a temporary windfall for Indigenous wood-haulers who have strong preferences for harvesting standing dead wood following traditional ecological knowledge, though long term biomass reductions may limit the ability of households to meet their energy needs. This has the potential to disrupt a significant proportion of the population as approximately 90% of households surveyed rely on firewood for some part of their home energy budget. These households also come from low income brackets, which may limit their ability to buffer shortfall with other more expensive fuel sources. 

Modeled scenarios suggest the resilience of both woodlands and livelihoods is most likely to occur under three conditions: if target reductions in global greenhouse gas emissions are met, when local household demand for woodfuel is kept near current or reduced levels, and when land management decisions incorporate the needs of Indigenous wood-haulers to maintain access at reasonable time and travel costs. While reducing emissions is beyond the control of local agencies and communities, sustainable interactions between woodlands and local communities may still persist if the other conditions are met. Notably, co-management practices which embed tribal community members in policy decisions will help facilitate both woodland function and firewood access for community members, especially as Indigenous wood haulers retain traditional ecological knowledge and provide ecosystem services that can promote woodland health. These findings suggest clear pathways that if pursued at a landscape-scale will allow these systems to persist into the next century. Such a strategy may be able to mitigate the impacts of climate change on woodlands in this region and elsewhere.

Last Modified: 05/22/2024
Modified by: Brian F Codding