Treesearch

Nepytia janetae is a previously innocuous non-eruptive species that has recently incurred multiple devastating outbreaks in the American Southwest. We report information on the life cycle, biology, and impact of this species learned during the first 3 known outbreaks in spruce-fir and mixed-conifer forests of the Pinaleño Mountains and White Mountains of Arizona and the Sacramento Mountains of New Mexico. N. janetae is a univoltine, autumn- and winter-feeding wasteful defoliator with 3-yr eruptive outbreaks. Outbreaks terminate with parasitism, viral infection, starvation, and in one...

Fire regimes are changing across the globe, with new wildfire behaviour phenomena and increasing impacts felt, especially in ecosystems without clear adaptations to wildfire. These trends pose significant challenges to the scientific community in understanding and communicating these changes and their implications, particularly where we lack underlying scientific evidence to inform decision-making. Here, we present a perspective on priority directions for wildfire science research—through the lens of academic and government wildfire scientists from a historically wildfire-prone (USA) and...

The term ‘megafire’ is increasingly used to describe large fires worldwide. We proposed a size-based definition of megafire - fires exceeding 10,000 ha arising from single or multiple related ignition events. A recent perspective in Global Ecology and Biogeography argues against a size-based definition of megafire and suggest that the term is too emotive for scientific use. We highlight that many scientific terms originate from common terms. These terms are often defined once they enter the scientific lexicon, enhancing both scientific understanding and public communication. We argue 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...

Forests are changing rapidly due to drought, disease, wildfire, and forest management, with unknown impacts on snowmelt resources. While hyper-resolution forest hydrology models capture the effects of canopy cover amount and arrangement on snowpack, they are too complex for landscape-scale assessments. Here, we evaluated two statistical approaches to emulate high-resolution (1 m) mechanistic model maps of snow variables for future application in forest management and drew inferences about topographic vs. forest canopy controls. We tested a simple landscape classification using one or more...

Wildfires accelerate soil erosion. Preventive fuel management and post-fire control measures are two distinct strategies that can be used to mitigate wildfire-induced soil loss with varying effectiveness and costs. Here, we quantified the impacts and effectiveness of pre- versus post-fire treatment strategies on soil loss mitigation. We coupled fire simulations with soil erosion modelling to estimate annual wildfire-induced soil loss for two watersheds in Portugal. We identified optimal treatment locations with the aim of maximizing the reduction in soil loss, and estimated treatment...

Designing large-scale fuel reduction programs has increasingly become a complex planning process owing to multifaceted fire management objectives that vary in space and time. In many fire-prone systems, fuel management strategies rely on fuel break networks (FBN) and fuel treatment mosaics (FTM) to mitigate wildfire impacts. While both archetypes are being widely implemented as part of newer fire management initiative, managers must decide how to allocate investments to best achieve desired long-term outcomes. This problem creates a new spatial prioritization paradigm that has long-term...

In the Great Basin of the western United States, annual grass invasion has initiated a novel grass-fire cycle that has transformed vast areas of semi-arid shrublands into non-native annual grasslands that now burn frequently. After the initial transformation, the system is so fire prone that it is difficult to find areas that have not burned repeatedly. We evaluated how the ecosystem responds in the absence of repeated fire to determine if management interventions preventing it could be used to restore the native shrubland.We created a regional-scale chronosequence of areas that burned...

Recruitment is the most sensitive plant life stage to environmental filters. Yet, most research linking functional traits to environmental filters has focused on adult plants with little known about early plant traits, their interactions with environmental filters, or their relation to species abundance. Likewise, how such relationships might vary between native and exotic species or influence plant invasion outcomes is unclear. We quantified regeneration traits for 12 native and 12 exotic (naturalized and invasive) forbs and evaluated trait relationships and their associations with...

Whitebark pine (Pinus albicaulis, PIAL) and foxtail pine (P. balfouriana, PIBA) are slow-growing, high-elevation, five-needled pines. Recently, PIAL has experienced significant mortality while PIBA has experienced minimal decline. PIBA exists in two disjunct southern (PIBAS) and northern (PIBAN) populations. Our study compared juvenile physiological and morphological traits between the two species (PIAL, PIBA) and foxtail populations (PIBAN, PIBAS) to investigate mechanisms underlying responses to environmental stressors in their high-elevation environments. We grew four-year-old PIAL and...