Treesearch

This assessment of South African wildland fire management is part of a broader effort from the International Programs Office of the U.S. Forest Service to assess the wildland fire situation across Africa. The assessment was guided by an Integrated Fire Management approach, which incorporates a holistic understanding of fire on the landscape and the many trade-offs of management actions. This assessment is based on a survey administered from June – July 2023 and captures the diverse perspectives of 108 survey respondents. Findings from this assessment reveal the following: (1) a perception...

Translocations are the intentional movement of animals across landscapes for conservation purposes and are used as a common method for restoring populations. Fisher (Pekania pennanti) populations have been extensively reintroduced and augmented in the Western United States, often using multiple source populations. To date, little is known about the success of past translocation efforts for Fisher recovery in the West, nor what the effects of using distinct populations for translocations were on contemporary population composition and genetic diversity. To understand the effects of historic...

Machine learning models are typically data-hungry algorithms that require large data inputs for training. When they produce wall-to-wall remote sensing products, model validation also requires large sets of temporally harmonized field observations. Crowdsourcing may offer a potential solution for the collection of photo interpretations for the training and validation of spatial models of tree canopy cover (TCC), as it harnesses the power of a large anonymous crowd in the completion of repetitive discrete analyses or human intelligence tasks (HITs). This study explores the factors that...

In 2023, a new generation of National Land Cover Database (NLCD) Tree Canopy Cover (TCC) data were produced that include annual 30m gridded time-series products for the Conterminous United States (CONUS). These NLCD TCC v2021.4 products have more frequent time steps, inter-annual coherency, lower product release latency, improved accuracy, uncertainty metrics, and documentation over previous versions. Our methodology leveraged Google Earth Engine (GEE) to generate annual time-series composites from Landsat and Sentinel-2 imagery that were used to predict annual pixel-wise TCC. Next, we...

Although half of Earth’s population resides in the wildland-urban interface, human exposure to wildland fires remains unquantified. We show that the population directly exposed to wildland fires increased 40% globally from 2002 to 2021 despite a 26% decline in burned area. Increased exposure was mainly driven by enhanced colocation of wildland fires and human settlements, doubling the exposure per unit burned area. We show that population dynamics accounted for 25% of the 440 million human exposures to wildland fires. Although wildfire disasters in North America, Europe, and Oceania have...

Critically burnt slopes are treated after a wildfire to reduce erosion and the impacts of eroded soil and ash on downstream water quality. Conventional post-wildfire erosion mitigation methods including mulch, barrier, and seeding treatments have some drawbacks that may result in low efficiency. Polymeric materials, xanthan gum (XG) and polyacrylamide (PAM), are shown to be effective alternatives to the conventional methods in controlling post-wildfire erosion of bare soil. This study evaluates the use of XG and PAM for controlling post-wildfire erosion when the soil surface is covered...

Wolverine (Gulo gulo) and Canada lynx (Lynx canadensis), listed as threatened under the United States Endangered Species Act, inhabit remote mountainous terrain across multiple western states. To address challenges associated with collecting long-term occupancy and demographic data for both species, we developed and tested a modified non-invasive camera and hair snag (C&H) monitoring system for simultaneous long-term monitoring of wolverine and Canada lynx (lynx hereafter). We aimed to adapt wolverine monitoring for concurrent use with lynx; redesign the data collection framework and...

Rewilding is increasingly recognized as an impactful conservation strategy, but a key question remains: how do ecological systems respond to the return of species long absent from the landscape? Predicting these responses is challenging due to complex direct and indirect interactions, especially amid anthropogenic changes. The ongoing range expansion of grizzly bears (Ursus arctos) in western North America offers a unique opportunity to develop and test predictions about the effects of a large, generalist omnivore returning to its historic range. We developed a priori predictions that...

Background: Wildfire simulation models are used to derive maps of burn probability (BP) based on fuels, weather, topography and ignition locations, and BP maps are key components of wildfire risk assessments. Aims: Few studies have compared BP maps with real-world fires to evaluate their suitability for near-future risk assessment. Here, we evaluated a BP map for the conterminous US based on the large fire simulation model FSim. Methods: We compared BP with observed wildfires from 2016 to 2022 across 128 regions representing similar fire regimes (‘pyromes’). We evaluated the distribution...

Wildfire ash and water-repellent soil are new materials that are formed after a wildfire that change the mechanical and hydraulic behavior of wildfire-burned slopes. Wildfire ash is known to be typically hydrophilic and to retain water, whereas the water-repellent soil layer acts as a hydraulic barrier. However, there is limited in situ soil water content data to understand the short- and long-term impacts of wildfire ash and a water-repellent soil layer on the hydromechanical behavior of burned slopes. This study investigates the trends in water content of wildfire ash, water-repellent...