Treesearch

Agaric fungi of the southern Appalachian Mountains including Great Smoky Mountains National Park are often heterozygous for the rDNA internal transcribed spacer region (ITS) with .42% of collections showing some heterozygosity for indels and/or base-pair substitutions. For these collections, intra-individual haplotype divergence is typically less than 2%, but for 3% of these collections intra-individual haplotype divergence exceeds that figure. We hypothesize that high intra-individual haplotype divergence is due to hybridization between agaric fungi with divergent haplotypes, possibly...

Research has found that community wildfire protection planning can make significant contributions to wildfire mitigation and preparedness, but can the planning process and resulting Community Wildfire Protection Plans make a difference to wildfire response and recovery? In case studies conducted in four USA communities with Community Wildfire Protection Plans in place when wildfires occurred, we saw a range of Community Wildfire Protection Plan projects designed to change the path and intensity of the wildfires. In most of our communities, the Community Wildfire Protection Plan and...

Climate change in the 21st century will affect tree growth in the Pacific Northwest region of North America, although complex climate–growth relationships make it difficult to identify how radial growth will respond across different species distributions. We used a novel method to examine potential growth responses to climate change at a broad geographical scale with a focus on visual inspection of patterns and applications beyond sampled areas. We examined projected changes in climate within species distributions of mountain hemlock (Tsuga mertensiana), subalpine fir (Abies lasiocarpa),...

This publication provides an overview of invasive plants found in forests of the State of Virginia based on an annual inventory conducted by the Forest Inventory and Analysis (FIA) Program at the Southern Research Station (SRS) of the Forest Service, U.S. Department of Agriculture in cooperation with the Virginia Department of Forestry. These estimates and coverage maps will be updated on a periodic basis. For more information regarding past inventory reports for this State, inventory program information, field sampling methodology, and estimation procedures, please refer to the citations...

Yellow toadflax and Dalmatian toadflax are problematic invasive plant species in North America. Yellow toadflax was introduced multiple times to the United States from Europe, beginning in the late 1600s. Dalmatian toadflax has similarly been repeatedly introduced to the United States, starting in 1874. Both species are known to inhabit disturbed areas, competing for limiting resources with native plant species. Both are obligate outcrossed species, which allows them to maintain a high level of genetic diversity. Both species are known to inhabit a wide range of ecosystems.

Following what was then one of the most destructive fire years on record, President Bush signed into law the Healthy Forests Restoration Act of 2003. The law requires no less than fifty percent of all funds allocated for hazardous fuels reductions to occur in the wildland-urban interface (WUI), with the aim of enhancing the protection of homes and reducing the costs of fighting wildfire. Available resources, however, have not been able to keep up with the accumulation of fuels and a rapidly expanding WUI. In 2012, wildfires burned 9 million acres in 67,000 separate fires throughout the...

Microbial respiration depends on microclimatic variables and carbon (C) substrate availability, all of which are altered when ecosystems experience major disturbance. Widespread tree mortality, currently affecting pinon-juniper ecosystems in southwestern North America, may affect C substrate availability in several ways, for example, via litterfall pulses and loss of root exudation. To determine pinon mortality effects on C and water limitation of microbial respiration, we applied field amendments (sucrose and water) to two pinon-juniper sites in central New Mexico, USA: one with a recent (

We created six new tree-ring chronologies in northern Utah, which were used with preexisting chronologies from Utah and western Wyoming to reconstruct mean annual flow for the Logan River, the largest tributary of the regionally important Bear River. Two reconstruction models were developed, a ''Local'' model that incorporated two Rocky Mountain juniper chronologies located within the basin, and a ''Regional'' model that also included limber pine and pinyon pine chronologies from a larger area. The Local model explained 48.2% of the variability in the instrumental record and the juniper...

Trends in streamflow timing and volume in the Pacific Northwest United States have been attributed to increased temperatures because trends in precipitation at lower elevation stations were negligible. We demonstrate that observed streamflow declines likely are associated with declines in mountain precipitation, revealing previously unexplored differential trends. Lower-troposphere winter (November-March) westerlies are strongly correlated to high elevation precipitation but weakly correlated with low elevation precipitation. Decreases in lower-tropospheric winter westerlies across the...

Armillaria species display diverse ecological roles ranging from beneficial saprobe to virulent pathogen. Armillaria solidipes (formerly A. ostoyae), a causal agent of Armillaria root disease, is a virulent primary pathogen with a broad host range of woody plants across the Northern Hemisphere. This white-rot pathogen grows between trees as rhizomorphs and attacks sapwood as mycelial fans under the bark. Armillaria root disease is responsible for reduced forest productivity due to direct tree mortality and non-lethal infections that impact growth. Here, we characterize a transcriptome of a...