Treesearch

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...

Forest inventory and monitoring is critically important to the long-term success of forest ecosystems, particularly given increasing levels of disturbance from wildfire, insects, disease, and human activity. Since its inception under the McSweeney-McNary Forest Research Act of 1928, and following revisions in the 1998 Agricultural Research, Extension, and Education Reform Act and 2014 Agricultural Act (“Farm Bills”), the U.S. Department of Agriculture (USDA) Forest Service Forest Inventory and Analysis (FIA) program has conducted continuous monitoring of the Nation’s forest resources,...

Background: Prescribed burning is an important silvicultural tool used to reduce wildfire hazard by removing accumulated forest floor debris to improve wildlife habitat and to mimic the natural role of fire in the environment. Ladder fuels, which provide vertical fuel continuity between ground and crown fuels, pose a risk to the use of prescribed burning by increasing the likelihood that a surface fire may spread vertically resulting in undesirable fire behavior and unplanned fire effects. To minimize this risk, an improved understanding of the ignition criteria of ladder fuels is essential...

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...

Rapids are common in steep rivers, often forming where flow transitions from supercritical (Froude number, Fr>1) to subcritical (Fr<1) through a hydraulic jump. When upstream Fr is supercritical but close to 1, this transition may occur as an undular hydraulic jump, exhibiting a train of stationary waves downstream of the jump toe. Previous studies proposed a method to estimate discharge using only UHJ wave spacing and channel width combined with a wave dispersion equation for large water depths relative to the UHJ wavelength. This method is based on the hypotheses that, by their presence,...

The Northwest Climate Adaptation Science Center convened 92 researchers and practitioners from 37 different organizations across Washington, Oregon, and Idaho to create a community of practice around the ecological impacts of extreme heat in the region, using the record-breaking 2021 Pacific Northwest heat wave to explore potential impacts and adaptation responses. Through a kick-off meeting, workgroups, and final workshop, participants synthesized the state of knowledge around the biophysical, management and practice, and policy and human dimensions of this topic and identified research...

Concepts and models of fire refugia are increasingly important components of forest management and adaptation discussions in the context of wildland fire, forest and habitat conservation, and global change. Recent stand-replacing fires in mature and old-growth forests of the Pacific Northwest (PNW) region of the western United States have increased land manager and scientific interest in fire refugia that can provide important ecosystem services. Here we provide an overview of fire refugia concepts and products being actively developed and applied in forests of the PNW (Washington, Oregon,...