Background Managing landscape fire is a complex challenge because it is simultaneously necessary for, and increasingly poses a risk to, societies and ecosystems worldwide. This challenge underscores the need for transformative change in the way societies live with and manage fire. While researchers have the potential to act as agents of transformative change, in practice, the ability to affect change is often constrained by siloed and biased expertise, rigid decision-making institutions, and increasingly vulnerable social-ecological systems where urgent rather than long-term solutions are prioritized. Addressing these challenges requires more holistic and equitable approaches to fire research that promote new models of transdisciplinary thinking, collaboration, and practice. Results To advance transformative solutions to this complex fire challenge, we propose four principles for conducting transdisciplinary fire research: (1) embrace complexity, (2) promote diverse ways of knowing fire, (3) foster transformative learning, and (4) practice problem-centered research. These principles emerged from our experience as a group of early-career researchers who are embedded within and motivated by today’s complex fire challenge within British Columbia (BC), Canada. In this forum piece, we first describe the four principles and then apply the principles to two case studies: (1) BC, a settler-colonial context experiencing increased size, severity, and impacts of wildfires, and (2) our ECR discussion group, a space of collective learning and transformation. In doing so, we present a unique contribution that builds on existing efforts to develop more holistic fire research frameworks and demonstrates how application of these principles can promote transdisciplinary research and transformation towards coexistence with fire, from local to global scales. Conclusions In this forum piece, we identify and apply four guiding principles for transdisciplinary fire research. Collectively, these principles can foster more inclusive applied fire research that matches the scope and scale of today’s fire challenge and promotes transformative change towards coexisting with fire.

Warming temperatures and changing weather patterns are causing more frequent and severe disturbances in western North American forests. The increasing length and severity of recent wildfire seasons have annually caused widespread injury to millions of trees, facilitating the subsequent outbreak of various subcortical insect species that infest damaged hosts. The subcortical woodboring beetle assemblage (Coleoptera: Cerambycidae and Buprestidae) comprises insects that feed primarily within the phloem and sapwood of defensively compromised trees, often causing severe degradation of high value stands slated for post-fire salvage logging. We studied three 2017 fire complexes within mature Douglas-fir (Pseudotsuga menziesii) forests in southern British Columbia to investigate the post-fire infestation patterns of woodborers. We observed the highest levels of woodborer infestation in forests with moderate to high levels of fire injury, rather than in extremely burnt stands with greater tree mortality. We also found that woodborer infestation likelihood could be predicted from a combination of tree height and fire injury for individual trees. In addition, infestation was more likely in large (>13.1 m tall) rather than small trees (<13 m tall) with the same levels of fire injury. We conclude that the woodboring beetle assemblage present in dry interior Douglas-fir forests is more aggressive and ubiquitous than previously observed, and these insects actively attack and kill living trees that may otherwise survive after fires with both economic and ecological ramifications. Economically, post-fire salvage may be more effective in preventing woodborer population build-up and timber degradation by targeting moderately scorched stands immediately after wildfire. Ecologically, woodborer impacts to trees that would otherwise survive may compromise their biological legacy and impair the diversity and composition of future Douglas-fir stands.

Regional reconstructions of air temperature over the past millennium provide critical context for ongoing climate change, but they are temporally limited in the recent period or absent for many parts of the world. We demonstrate the use of latewood blue intensity (LWB) to reconstruct current-year growing (warm) season maximum temperatures (T-max) in the low-to-mid latitudes (30 degrees-50 degrees N) of western North America. We present a new tree ring network comprised of 26 LWB chronologies developed from living, high-elevation Engelmann spruce (Picea engelmannii Parry ex Engelm.) sampled across the western United States. The LWB parameter shows strong, positive (r = 0.65-0.73), and temporally-stable correlations with growing season T-max. From this network we present 4 regional T-max reconstructions, which characterize regional temperature histories across western North America from northern Mexico to southern British Columbia over the past 4 centuries. Our comparison of these 4 temperature reconstructions highlights the spatial patterns of regional temperature trends throughout time. These reconstructions provide important updates and increased data point density to the tree ring temperature proxy network of the Northern Hemisphere. We highlight the use of blue intensity methods at both low- and mid-latitude upper tree line locations to increase the presence of strongly temperature-sensitive records at increasingly lower latitudes of the Northern Hemisphere. (C) 2021 Elsevier Ltd. All rights reserved.