Treesearch

High rates of atmospheric N deposition can increase ecosystem N availability and stimulate N losses from soils via nitric oxide (NO; an air pollutant at high concentrations) and nitrous oxide (N2O; a strong greenhouse gas) emissions as predicted by N saturation theory. However, it remains unclear whether theories developed in mesic ecosystems apply to drylands, where plant N uptake and N availability are often decoupled. NO and N2O are produced during the oxidation of ammonia (i.e., nitrification) by ammonia-oxidizing archaea (AOA) or ammonia-oxidizing bacteria (AOB). Because AOB may be...

Context: Species-agnostic connectivity models are often used to inform management over broad spatial scales. The four main approaches to species-agnostic models parameterize resistance to movement based on naturalness, structural features, climate, or geodiversity variables. Though all four of these factors simultaneously affect species movement and flow of ecological processes, they are rarely combined.Objectives: We built upon an approach that uses all four of these factors to model current and future ecological connectivity for the Crown of the Continent Ecoregion, in Canada and the...

The International Association for Fire Safety Science (IAFSS) established the permanent working group known as LOF&BE (Large Outdoor Fires and the Built Environment), as an outgrowth of the 2017 Lund Workshops held in conjunction with the 12th IAFSS Symposium [1-3]. Subsequent workshops were held at the 11th Asia-Oceania Symposium on Fire Science and Technology (AOSFST) [4], Interflam 2019 [5], Virtual Workshops in 2020 [6], and 13th IAFSS Symposium (virtual) in 2021. LOF&BE aims to bring the community together to tackle large outdoor fire problems such as wildland fires, wildland-urban...

Background: Forest structural characteristics, the burning environment, and the choice of ignition pattern each influence prescribed fire behaviors and resulting fire effects; however, few studies examine the influences and interactions of these factors. Understanding how interactions among these drivers can influence prescribed fire behavior and effects is crucial for executing prescribed fires that can safely and effectively meet management objectives. To analyze the interactions between the fuels complex and ignition patterns, we used FIRETEC, a three-dimensional computational fluid...

To understand the impacts of changing climate and wildfire activity on conifer forests, we studied how wildfire and post-fire seasonal climate conditions influence western larch (Larix occidentalis) regeneration across its range in the northwestern US. We destructively sampled 1651 seedlings from 57 sites across 32 fires that burned at moderate or high severity between 2000 and 2015; sites were within 100 m of reproductively mature western larch. Using dendrochronological methods, we estimated germination years of seedlings to calculate annual recruitment rates. We used boosted regression...

Understanding the factors influencing species range limits is increasingly crucial in anticipating migrations due to human-caused climate change. In the boreal biome, ongoing climate change and the associated increases in the rate, size, and severity of disturbances may alter the distributions of boreal tree species. Notably, Interior Alaska lacks native pine, a biogeographical anomaly that carries implications for ecosystem structure and function. The current range of lodgepole pine (Pinus contorta var. latifolia) in the adjacent Yukon Territory may expand into Interior Alaska, particularl...

Turkish pine (Pinus brutia) is a widely distributed species in fire-prone regions of the eastern Mediterranean, where it is of economic and ecological importance. After wildfires, damaged trees are usually salvage logged out of concern that fire-injured individuals will eventually die. While fire is a major cause of Turkish pine mortality, the species has traits, such as thick bark, that should confer some resistance to low-intensity fire. The aim of this study is to develop post-fire tree mortality models for Turkish pine to support post-fire management decisions. We selected 510 Turkish...

Background: Recognizing the complexity and varied nature of forest fuelbeds is crucial in understanding fire behavior and effects on the landscape. While current modeling efforts often consider fine and coarse woody debris surface fuel loads, those options do not always provide the most complete description of the fuelbeds. Both masticated fuels and cones can be a significant part of the fuelbed, with the potential to influence fire behavior and effects, but they are not currently captured in planar intersect methods or Photoload fuel sampling methodology. Cones are prevalent in most...

Instream temperatures control numerous biophysical processes and are frequently the subject of modeling efforts to understand and predict responses to watershed conditions, habitat alterations, and climate change. Air temperature (AT) is regularly used in statistical temperature models as a covariate proxy for physical processes and because it correlates strongly with spatiotemporal variability in water temperatures (Tw). Air temperature data are broadly available and sourced from sensors paired with Tw sites, remote weather stations, and gridded climate data sets - often with limited...

Planning and prioritizing forest and fuel treatment programs on vast, mixed-owner landscapes can be a wicked challenge. A typical project involves multiple management objectives, constraints on treatment location, and the resulting plans that must meet regulatory standards for analysis and consideration of multiple alternatives. Researchers with the USDA Forest Service Rocky Mountain Research Station developed the ForSys Planning System to help managers prioritize forest and fuel management investments and understand tradeoffs among alternative scenarios. The development of ForSys was...