Treesearch

A deeper understanding of the influence of fine-scale fuel patterns on fire behavior is essential to the design of forest treatments that aim to reduce fire hazard, enhance structural complexity, and increase ecosystem function and resilience. Of particular relevance is the impact of horizontal and vertical forest structure on potential tree torching and large-tree mortality. It may be the case that fire behavior in spatially complex stands differs from predictions based on stand-level descriptors of the fuel distribution and structure. In this work, we used a spatially explicit fire...

The influence of forest treatments on wildfire effects is challenging to interpret. This is, in part, because the impact forest treatments have on wildfire can be slight and variable across many factors. Effectiveness of a treatment also depends on the metric considered. We present and define human-fire interaction, fire behavior, and ecological metrics of forest treatment effects on wildfire and discuss important considerations and recommendations for evaluating treatments. We demonstrate these concepts using a case study from the Cameron Peak Fire in Colorado, USA. Pre-fire forest...

Seed mass is an ecologically important trait that often differs considerably among ecotypes. Yet, because few studies examine the impacts of seed mass on adult life-history traits, its role in local adaptation is unclear. In this study, using accessions of Panicum hallii that spanned the two major ecotypes, we examined whether covariation between seed mass, seedling and reproductive traits impacts ecotypic divergence and local adaptation. The perennial grass P. hallii has two distinct ecotypes - a large-seeded upland ecotype adapted to xeric environments and a small-seeded lowland ecotype...

Switchgrass, a potential biofuel crop, is a genetically diverse species with phenotypic plasticity enabling it to grow in a range of environments. Two primary divergent ecotypes, uplands and lowlands, exhibit trait combinations representative of acquisitive and conservative growth allocation strategies, respectively. Whether these ecotypes respond differently to various types of environmental drivers remains unclear but is crucial to understanding how switchgrass varieties will respond to climate change. We grew two upland, two lowland, and two intermediate/ hybrid cultivars of switchgrass...

Genesee Fire Protection District (GFPD) and members of the Board contacted the Wildfire Research Center (WiRē) early in 2021. GFPD serves a community of approximately 1,500 homes and 3,600 residents. The community borders the south side of I-70 and runs south up varied topography with varied vegetation to approximately 8,000 feet of elevation and is considered to be at extremely high risk of wildfire. In 2020, GFPD worked with the Forest Stewards Guild to update their Community Wildfire Protection Plan (CWPP). GFPD and WiRē collaborated to collect household-level data in an effort that is...

The wolf (Canis lupus) is among the most controversial of wildlife species. Abundance estimates are required to inform public debate and policy decisions, but obtaining them at biologically relevant scales is challenging. We developed a system for comprehensive population estimation across the Italian alpine region (100,000 km2), involving 1513 trained operators representing 160 institutions. This extensive network allowed for coordinated genetic sample collection and landscape-level spatial capture-recapture analyses that transcended administrative boundaries to produce the first estimates...

Environmental factors control species distributions and abundances, but effectiveness of land use and disturbance variables for modeling species generally is unknown compared to climate, soil, and topography variables. Therefore, I used predictor variables from categories of 1) land use and disturbance, 2) climate, and 3) soil, topography, and wind speed to model the relative abundances (i.e., percentage of all trees) of 65 common tree species in the eastern United States, with a contrast to presence-absence models of species distributions. First, I modeled variables within each category...

Land area in urban use may be growing faster than population growth, increasing urban sprawl. With calibrated population density thresholds from the Worldpop population model, area and densities can be measured for suburban and urban density classes (≥ 250 humans per square kilometer) at global and national scales and both broad multi-city agglomerations and fine city cores during 2000 to 2020. Globally, net expansion of suburban and urban, urban, and high-density urban area was 930,000, 545,000, and 215,000 km2, respectively, with 25% to 35% of expansion located in India. Area containing...

Background: One issue in invasive plant ecology is identification of the factors related to the invasion process that increase number of non-native species. When invasion by non-native species increases, so does the probability that some non-native species will become harmful, or classified as invasive species, which disrupt natural ecosystems with attendant economic and social costs. I quantified patterns of how non-native species richness varied with vegetation types and human populations. To evaluate the relative importance of different predictor variables for invasion pathways in the...

Pollen reconstructions of tree genera in North America since glaciation are available, but species distributions predicted for paleoclimate based on tree inventories may inform knowledge gaps. Here I examined the distributions of 25 species or species groups from 20 000 years ago (ka) to 5 ka to give potential paleoecological ranges of boreal and temperate tree species. I also assessed the effects of correlated climate variables on species distribution models for current and past climate, which were modeled with the non‐linear random forests classifier. Climate change alone was enough to...