Treesearch

Understanding how drivers of ecological disturbance operate across scales is important in an era of increasing disturbance activity. Severe and extensive Dendroctonus bark beetle outbreaks across western North America have left in their wake dominance by shade-tolerant and commonly late-seral trees such as subalpine fir (Abies lasiocarpa), which can foster resilience of forest cover. However, subalpine fir decline (SFD) is a poorly understood phenomenon that has killed trees across millions of hectares in western North America with unknown consequences for future forest resilience. How...

Supporting wildfire management activities is frequently identified as a benefit of forest roads. As such, there is a growing body of research into forest road planning, construction, and maintenance to improve fire surveillance, prevention, access, and control operations. Of interest here is how road networks directly support fire control operations, and how managers incorporate that information into pre-season assessment and planning. In this communication we briefly review and illustrate how forest roads relate to recent advances in operationally focused wildfire decision support. We...

Wildfires have important effects on wildlife habitat. Within fire perimeters, ‘fire refugia’ are unburned or less severely burned areas that contain residual pre-fire habitat structures and facilitate species persistence following fire. However, fire refugia may vary in their relative quality. The ability to evaluate the relative quality of fire refugia for wildlife habitat may help efficiently allocate resources for post-fire conservation planning, especially for at-risk species. Using spatial overlays of habitat models and burn severity data, we developed the refugia index, a flexible...

The distribution of fuels is recognised as a key driver of wildland fire behaviour. However, our understanding of how fuel density heterogeneity affects fire behaviour is limited because of the challenges associated with experiments that isolate fuel heterogeneity from other factors. Advances in fire behaviour modelling and computational resources provide a means to explore fire behaviour responses to fuel heterogeneity. Using an ensemble approach to simulate fire behaviour in a coupled fire-atmosphere model, we systematically tested how fuel density fidelity and heterogeneity shape...

A continual improvement of our understanding about factors that influence tree regeneration is needed to inform landscape-scale restoration efforts across the western USA. This is increasingly important because changing climate and disturbance regimes will influence where restoration efforts should be implemented across landscapes. In this study, we used Forest Inventory and Analysis (FIA) data to model ponderosa pine (Pinus ponderosa C. Lawson var. scopulorum Engelm.) seedling presence across FIA plots in Arizona and New Mexico, USA. Additionally, we analyzed archived soil samples from...

Forest classifications by disturbance permit designation of multiple types of both old growth forests and shorter-lived forests, which auto-replace under severe disturbance, and also identification of loss of the disturbance type and associated forest. Historically, fire and flooding disturbance regimes, or conversely, infrequent disturbance, produced unique forests such as disturbanceindependent forests of American beech (Fagus grandifolia), eastern hemlock (Tsuga canadensis), and sugar maple (Acer saccharum) in the Eastern United States. However, disturbance has changed to primarily...

In July-August 2019, seven Armillaria isolates (derived from rhizomorphs and mycelial fans of infected roots) were collected in association with woody hosts in the central Mexico: states of Guanajuato (MEX204), Jalisco (MEX206, MEX208, MEX209), and Michoac´an (MEX211, MEX214, MEX216). All seven isolates were identified as Armillaria gallica based on translation elongation factor 1a (tef1) gene sequences (GenBank accession nos. MN839636 to MN839642 for MEX204, MEX206, MEX208, MEX209, MEX211, MEX214, and MEX216) and somatic pairing tests against known tester isolates.

Predicting species response to climate change is a central challenge in ecology, particularly for species that inhabit large geographic areas. The mountain pine beetle (MPB) is a significant tree mortality agent in western North America with a distribution limited by climate. Recent warming has caused large-scale MPB population outbreaks within its historical distribution, in addition to migration northward in western Canada. The relative roles of genetic and environmental sources of variation governing MPB capacity to persist in place in a changing climate, and the migratory potential at...

Dryland ecosystems play an important role in the global carbon cycle, including regulating the inter-annual global carbon sink. Dynamic global vegetation models (DGVMs) are essential tools that can help us better understand carbon cycling in different ecosystems. Currently, there is limited knowledge of the performance of these models in drylands partly due to characterizing the heterogeneity of the vegetation and hydrometeorological conditions. The aim of this study is to evaluate the performance of a DGVM for drylands to facilitate improved understanding of gross primary production (GPP)...

Active wildfire seasons in the western U.S. warrant the evaluation of post-fire forest management strategies. Ground-based salvage logging is often used to recover economic loss of burned timber. In unburned forests, ground-based logging often follows best management practices by leaving undisturbed areas near streams called stream buffers. However, the effectiveness of these buffers has not been tested in a post-wildfire setting. This experiment tested buffer width effectiveness with a novel field-simulated rill experiment using sediment-laden runoff (25 g/L) released over 40 min at...