Treesearch

This study evaluates the consumption of coarse woody debris in various states of decay. Samples from a northern Idaho mixed-conifer forest were classified using three different classification methods, ignited with two different ignition methods and consumption was recorded. Intrinsic properties that change with decay were measured including carbon to nitrogen ratio, density, heat content, lignin content, moisture content and surface area-to-volume ratio. Consumption for logs in different stages of decay is reported with characterization of wood properties. Results indicate very decayed...

Fire severity influences post-burn structure and composition of a forest and the potential for a future fire to burn through the area. The effects of fire on forests with mixed severity fire regimes are difficult to predict and interpret because the quantity, structure, and composition of forest fuels vary considerably. This study examines the relationship between fire severity and post-burn fuel characteristics in forests with mixed severity fire regimes. We sampled live and dead canopy and surface fuels across four fire severity classes on three wildfires that occurred on the east side...

Two prairie-clovers, Dalea ornata (Douglas ex Hook.) Eaton & J. Wright and Dalea searlsiae (A. Gray) Barneby, are perennial forbs found sporadically in the U.S. Intermountain West. Their seed is desirable for use in rangeland restoration. We experimentally characterized the breeding biologies of D. ornata and D. searlsiae in a common garden, surveyed their pollinator guilds, and sampled their seed predators. The 2 Dalea species, being primarily xenogamous, have comparable pollination requirements. For flowers manually pollinated with outcross pollen, an average of 42% of D. ornata flowers...

The influence of land use on potential fates of nitrate in stream ecosystems, ranging from denitrification to storage in organic matter, has not been documented extensively. Here, we describe the Pacific Northwest component of Lotic Intersite Nitrogen eXperiment, phase II (LINX II) to examine how land-use setting influences fates of nitrate in streams.

Participatory processes for obtaining residents' input about community impacts of proposed environmental management actions have long raised concerns about who participates in public involvement efforts and whose interests they represent. This study explored methods of broad-based involvement and the role of deliberation in social impact assessment. Interactive community forums were conducted in 27 communities to solicit public input on proposed alternatives for recovering wild salmon in the Pacific Northwest US. Individuals identified by fellow residents as most active and involved in...

Permafrost soils are a significant global store of carbon (C) with the potential to become a large C source to the atmosphere. Climate change is causing permafrost to thaw, which can affect primary production and decomposition, therefore affecting ecosystem C balance. We modeled decadal and millennial soil C inputs, decomposition constants, and C accumulation rates by plotting cumulative C inventories against C ages based on radiocarbon dating of surface and deep soils, respectively, in subarctic tundra soils undergoing minimal, moderate, and extensive permafrost thaw near Eight Mile Lake...

To compensate for losses in overwintering habitat, elk are fed hay in winter at approximately 37 locations throughout the western United States. These winter feeding programs concentrate elk activity, and there is concern that such concentrations could degrade plant communities. Except for one study focused exclusively on aspen (Populus tremuloides), ours is the first to quantify vegetation responses to supplemental winter feeding of elk. The western Wyoming feedground we studied was established in winter 1981-1982, and supplemental feeding occurred every winter through 2006. Transects...

Research on the degree to which carbon (C) availability limits growth in trees, as well as recent trends in climate change and concurrent increases in drought related tree mortality, have led to a renewed focus on the physiological mechanisms associated with tree growth responses to current and future climate. This has led to some dispute over the role of stored nonstructural C compounds as indicators of a tree's current demands for photosynthate. Much of the uncertainty surrounding this issue could be resolved by developing a better understanding of the potential functions of non-structura...

Northern sweetvetch (Hedysarum boreale Nutt.) is an herbaceous perennial legume of the Rocky Mountains, USA, whose seed is desired for rehabilitating degraded plant communities. Through experimental pollinations, the necessity of pollinators was shown by the failure of autogamy, despite stigmas first becoming receptive in the bud in close proximity to the dehiscing anthers. Nonetheless, the species proved to be self-fertile, initiating as many fruits through selfing as outcrossing. Incremental benefits of outcrossing only later manifested in superior fruit development, seed maturation and...

The Great Basin as defined on a floristic basis includes the hydrographic Great Basin plus the Owyhee Uplands and Snake River Plain of southern Idaho (Fig. 1). The region encompasses about 60 million ha, of which more than two-thirds are publicly owned. Vegetation ranges from salt desert and sagebrush shrublands in the basins to conifer forests in the more than 200 mountain ranges. Historic land management opened the environment to invasion by exotic annual grasses, primarily cheatgrass (Bromus tectorum). Resulting changes in fire regimes and more recent human disturbances such as energy...