Treesearch

Stand-density reduction treatments are widely applied to restore historic stand structure and increase resistance to high-severity fire in dry ponderosa pine forests. Little is known about whether the removal of competition also alters tree responses to drought, and if so, how long those effects persist, or the underlying mechanisms. This study evaluates tree growth, seasonal tree-ring stable-carbon isotope patterns, and tree mortality over 23 years following thinning treatments with and without prescribed fire in a ponderosa pine forest of western Montana, USA. The treatments increased...

Background: Development and application of DNA-based methods to distinguish highly virulent isolates of Fusarium oxysporum f. sp. koae [Fo koae; cause of koa wilt disease on Acacia koa (koa)] will help disease management through early detection, enhanced monitoring, and improved disease resistance-breeding programs. Results: This study presents whole genome analyses of one highly virulent Fo koae isolate and one nonpathogenic F. oxysporum (Fo) isolate. These analyses allowed for the identification of putative lineage-specific DNA and predicted genes necessary for disease development on...

Over the last century, anthropogenic activities have caused substantial declines in the abundance of chum salmon (Oncorhynchus keta) throughout their range in western North America. As a result, chum salmon were listed as threatened under the U.S. Endangered Species Act in 1999. Recovery strategies have been developed, but limited baseline data on distribution impedes implementation of these strategies. Traditional methods for identifying spawning distribution (e.g., spawning ground surveys) may be inadequate for rare species like chum salmon because of a low detection probability. In...

Cheatgrass (Bromus tectorum) has increased the extent and frequency of fire and negatively affected native plant and animal species across the Intermountain West (USA). However, the strengths of association between cheatgrass occurrence or abundance and fire, livestock grazing, and precipitation are not well understood. We used 14 years of data from 417 sites across 10,000 km2 in the central Great Basin to assess the effects of the foregoing predictors on cheatgrass occurrence and prevalence (i.e., given occurrence, the proportion of measurements in which the species was detected). We...

The actions of residents in the wildland-urban interface can influence the private and social costs of wildfire. Wildfire programs that encourage residents to take action are often delivered without evidence of effects on behavior. Research from the field of behavioral science shows that simple, often low-cost changes to program design and delivery can influence socially desirable behaviors. In this research report, we highlight how behavioral science and experimental design may advance efforts to increase wildfire risk mitigation on private property. We offer an example in which we tested...

Research Highlights: This experiment compares a range of combinations of harvest, prescribed fire, and wildfire. Leveraging a 30-year-old forest management-driven experiment, we explored the recovery of woody species composition, regeneration of the charismatic forest tree species Larix occidentalis Nutt., and vegetation and soil carbon (C) and nitrogen (N) pools. Background and Objectives: Initiated in 1967, this experiment intended to explore combinations of habitat type phases and prescribed fire severity toward supporting regeneration of L. occidentalis. At onset of the experiment, a...

Identifying genetically appropriate plant materials for seed based restoration relies on the principle of local adaptation where the objective is to match adaptive genetic characteristics to variation in ecological clines pertinent to plant establishment and persistence. In this study, basin wildrye (Leymus cinereus (Scribn. & Merr.) Á. Löve) sources from 25 wild populations and 4 commercial varieties were planted at 4 test sites. We assessed initial establishment and short term persistance. Plantings failed at 2 sites in both 2013 and 2014, with too few plants to quantify differences. At...

Soil properties, including microbial composition and nutrient availability, can influence the emissions of plant volatile organic compounds (VOCs) that serve as host-location cues for insect pests and their natural enemies. Agricultural practices have profound effects on soil properties, but how these influence crop VOCs remains largely unknown. The aim of this study was to investigate the effect of agricultural practices on constitutive and herbivore-induced VOC emissions by a major staple crop through soil legacy effects.

Predictive models of post-fire tree and stem mortality are vital for management planning and understanding fire effects. Post-fire tree and stem mortality have been traditionally modeled as a simple empirical function of tree defenses (e.g., bark thickness) and fire injury (e.g., crown scorch). We used the Fire and Tree Mortality database (FTM) - which includes observations of tree mortality in obligate seeders and stem mortality in basal resprouting species from across the USA - to evaluate the accuracy of post-fire mortality models used in the First Order Fire Effects Model (FOFEM)...

Emerging applications of ecological resilience and resistance concepts in sagebrush ecosystems allow managers to better predict and mitigate impacts of wildfire, invasive annual grasses, and other disturbances. Soil temperature and moisture strongly influence the kind and amount of vegetation and are closely related to sagebrush ecological resilience to disturbance and resistance to invasive annual grasses (Chambers et al. 2007, 2014a, 2014b). Consequently, soil taxonomic temperature and moisture regimes can be used as indicators of resilience and resistance at landscape scales to depict...