Treesearch

1. A combination of forest thinning followed by prescribed burning is widely applied in the western United States to increase ecosystem resistance and resilience to disturbances. Understory plant community responses may be driven by both management treatments and climatic factors. Thus, responses to treatments during a 20-year megadrought have implications for the role of management in fostering adaptive capacity to climate change. 2. We used a network of five sites (600 plots) spanning an environmental gradient in ponderosa pine (Pinus ponderosa) forests of the American Southwest, an...

The Late Holocene Dry Period (LHDP, 3100-1800 cal yr BP) is well established as a period of extreme aridity across lowlands of the Great Basin (GB) yet little has been elaborated about high mountain conditions. Further, temperatures have not been comprehensively addressed at any elevation, although the period is often implied to have been warm. Despite a literature on the early Neoglaciation in the GB, conditions at high elevations have not been incorporated in previous treatments of the LHDP. We compile existing and new data on locations and ages for early Neoglacial advances in mountains...

Background The capacity of forest fuel treatments to moderate the behavior and severity of subsequent wildfires depends on weather and fuel conditions at the time of burning. However, in-depth evaluations of how treatments perform are limited because encounters between wildfires and areas with extensive pre-fire data are rare. Here, we took advantage of a 1200-ha randomized and replicated experiment that burned almost entirely in a subsequent wildfire under a wide range of weather conditions. We compared the impacts of four fuel treatments on fire severity, including two thin-only, a...

Wildland fire is a major global driver in the exchange of aerosols between terrestrial environments and the atmosphere. This exchange is commonly quantified using emission factors or the mass of a pollutant emitted per mass of fuel burned. However, emission factors for microbes aerosolized by fire have yet to be determined. Using bacterial cell concentrations collected on unmanned aircraft systems over forest fires in Utah, USA, we determine bacterial emission factors (BEFs) for the first time. We estimate that 1.39 × 1010 and 7.68 × 1011 microbes are emitted for each Mg of biomass...

With increasing outdoor recreation participation in the U.S., managers face the challenge of balancing visitor experiences with the protection of natural resources. To address declining management capacity, agencies seek to involve both new and established recreationists in local stewardship behaviors. However, community involvement in stewardship efforts is hindered by a lack of understanding of the connection between recreationists’ antecedent conditions and their behavioral intentions. This study focuses on a wildland recreation setting near a western U.S. city to examine the relationshi...

Invasions by non-native plant species after fire can negatively affect important ecosystem services and lead to invasion-fire cycles that further degrade ecosystems. The relationship between fire and plant invasion is complex, and the risk of invasion varies greatly between functional types and across geographic scales. Here, we examined patterns and predictors of non-native plant invasion following fire across the western United States. We specifically analyzed how the abundance of nonnative plants after fire was related to fire characteristics and environmental conditions, such as...

Reestablishing appropriate tree species is an important step in converting off-site monocultures into woodlands. Species conversion is often necessary, as off-site exotic species rarely function like woodland species. However, when off-site tree species are native, and functionally redundant to woodland species, conversion may be unnecessary. To explore this possibility in the southeastern United States, we reviewed the literature on trait differences among the primary southern pines and qualitatively assessed the effect of their identity at the species and stand-levels. In this region,...

Forests are vital for sustaining biodiversity and regulating climate. However, the fragmentation of these criticalecosystems poses a serious threat to their ecological integrity and the myriad of organisms they support. In thispaper we compare the degree of forest connectivity derived via the traditional approach of using a binary forestcover map with a new approach using a grayscale tree cover density map. Because connectivity is scaledependent,the comparison is repeated for a series of analysis scales. We find that exploiting the additionalinformation on tree cover density improves the...

Although necromass decay rates are limited by the slowest portions to decompose, most decomposition studies examine only the earliest stage of decay. As such, these studies run the risk of yielding misleading results regarding the relative contributions of different decomposers. For example, the contributions of macroinvertebrates to wood decomposition remain mostly unknown beyond the first 50% of mass lost, despite drastic changes in substrate conditions over time. We sought to clarify how the macroinvertebrate contribution to decay changes over the course of wood decomposition in the...

Anticipating and preparing for the future are among the challenges land managers face when making decisions about how to balance the public's desire for outdoor recreation with ecological concerns. A recent General Technical Report by Lynne Westphal, emerit research social scientist with the U.S. Department of Agriculture Forest Service Northern Research Station, aims to assist managers by analyzing potential changes in recreation on public lands 30 years into the future.