Treesearch

As wildfires in the western US grow in both size and intensity, forest policymakers and managers seek effective ways to mitigate and adapt to increasing wildfire risk. In some regions, such as the western Pacific Northwest, where wildfires historically burned infrequently, climate change and housing development appear to be altering wildfire regimes while bringing greater numbers of people living in greater proximity to potentially more fire-prone forests. Developing effective strategies for family forest owners to adapt to the wildfire regimes of the future will depend on designing...

Keystone trophic interactions have disproportionate impacts on the structure and function of ecosystems by regulating the flow of nutrients through food webs. However, human disturbances alter animal habitat use and foraging behavior, with uncertain consequences for trophic interactions and the ecosystem functions they support. We simulated human activities to manipulate a keystone process—animals transporting salmon-derived nutrients from aquatic to terrestrial ecosystems—and documented the effects on animal behaviors and associated ecosystem functions. We used acoustic playbacks to alter...

Background: Wildfire can dramatically influence terrestrial landscapes, but effects on biodiversity can be hidden beneath the water’s surface. Following the 2020 Labor Day wildfires in Oregon’s western Cascade Mountain Range, we sampled 25 Oregon streams and 6 Washington streams representing a gradient of fire severity and pre-fire forest stand age to determine the effects of megafires on watershed biodiversity. In each watershed we used environmental DNA (eDNA) metabarcoding and traditional field surveys (Surber or electrofishing) to assess biodiversity.Results: Our results suggest...

Widespread mortality poses a major conservation challenge for foundation species whitebark pine (Pinus albicaulis Engelm.). We assessed whitebark pine forest structure, composition, and persistence potential in Idaho and Nevada, USA following mountain pine beetle (MPB), wildfire, and no recent disturbance by comparing overstory and regeneration relative abundances, classifying postdisturbance communities, and gauging persistence via residual mature trees and seedlings. Wildfire mortality spanned all species and sizes and exceeded MPB mortality, which was limited to larger pines. Disturbance...

Old growth forests in coastal Alaska and British Columbia represent some of the most expansive temperate rainforests on Earth, supporting high biodiversity, substantial carbon stocks, and the cultural heritage of Indigenous communities. Despite their importance, spatially consistent information on the distribution of old growth and mature forests in this region remains limited. We addressed this gap by integrating data across two national forest inventory programs with remotely sensed predictors. Forest inventory plots were classified by forest type and successional status (old growth,...

Ecosystems carry memory through the material remains of organisms. Foundation species—trees, grasses, corals, and oysters—while alive are central to ecosystem structure, and the remains of these organisms continue to influence ecological processes after death. We conducted, to our knowldge, the first continental-scale exploration of how dead foundation species influence living conspecifics, leveraging long-term experiments and observations (2 to 32 years) from 10 ecosystems (five terrestrial and five marine) across the US Long Term Ecological Research Network. We found that material...

Potential natural vegetation (PNV) classification and mapping are foundational tools in planning in forestry and related fields to identify appropriate biophysical environments for vegetation communities across the landscape. The need for this information has grown over recent decades as attention has shifted to planning over large geographic areas. Our goal of this work is to develop a consistent, continuous potential vegetation map of both forest and nonforest for Washington, Oregon, and California.We built a PNV map using wall-to-wall, 30-m maps of current forest attributes from the...

Riparian zones are important ecotones, integrating terrestrial and aquatic functions that support ecosystem productivity. A key ecological role of riparian zones is the production of large conifers that eventually enter the stream and provide important habitat complexity within the freshwater ecosystem. Many riparian zones in south-east Alaska were heavily disturbed during logging operations from 1950 to 1980, which depleted the large wood supply to streams. Abundant conifer and red alder regeneration was common after harvest, replenishing a young population of trees, but the presence of...

Background: High-severity fires leave behind a pulse of dead trees that contribute to fuel accumulation over time. Prescribed fire and logging fire-killed trees can reduce surface woody fuels after fire, but their effects on subsequent wildfire effects are not well understood.Aims: This study examined the potential for post-fire logging and prescribed burning to manage post-fire fuels and mitigate future wildfire effects.Methods: We used surface woody fuel surveys from high severity patches within 68 wildfires (1970–2007) to model post-fire logging effects on fuel consumption and fire...

In wildland fires, wind affects fire propagation, emission intensity, and smoke transport; therefore, uncertainties in wind simulations can critically impact PM2.5 concentration produced by coupled fire-atmosphere models or chemical transport models. These uncertainties must be addressed prior to assessing other parameters that may affect model-predicted PM2.5 concentrations through comparisons with observations. This study simulated prescribed fire events with accurate ignition pattern design and high spatial-temporal resolutions using the coupled fire-atmosphere model WRF-SFIRE. We...