Managing for ecological resilience of pinyon-juniper ecosystems during an era of woodland contraction

Dryland woodland ecosystems worldwide have experienced widespread drought- and heat-related tree mortality events coupled with extreme wildfire behavior. In contrast to other forest types where the emphasis has been on the silvicultural enhancement of ecosystem resilience and restoration of structural heterogeneity, limited frameworks are available for management to improve drought resilience in semiarid woodlands. This challenge is especially acute in pinyon-juniper woodlands, a dominant vegetation type across western North America that has experienced extensive tree die-off over the past several decades while simultaneously undergoing expansion in portions of its range. In this paper, we describe the critical and urgent need to manage for future drought resilience in these highly vulnerable ecosystems and synthesize the current state of knowledge on how to enhance woodland resilience to drought coupled with high temperatures and associated disturbances. We present a landscape prioritization framework for guiding management goals and practices that requires prioritization of efforts based on the need for action and the probability of a positive outcome. Four guiding factors include historical woodland structure and drivers of long-term landscape change, current vegetation structure and composition, future climate suitability, and habitat and resource value. In summarizing the strength of evidence supporting our recommendations, we identify critical knowledge gaps and highlight the importance of adaptive management strategies that reflect current uncertainties. This will ultimately allow for improved management of diverse semiarid woodland ecosystems that are undergoing substantial changes due to past and present land use, biological invasions, and climate change.