Treesearch

Infiltration rates in undisturbed forest environments are generally high. These high infiltration rates may be reduced when forest management activities such as timber harvesting and/or prescribed fires are used. Post-harvest residue burning is a common site preparation treatment used in the Northern Rocky Mountains, USA, to reduce forest fuels and to prepare sites for natural and artificial tree regeneration. Prescribed burn operations attempt to leave sites with the surface condition of a lowseverity burn. However, some of the areas often experience surface conditions associated with a...

Recognition that increasing levels of CO2 in the atmosphere will affect the global climate has spurred research into reduction global carbon emissions and increasing carbon sequestration. The main nonhuman sources of atmospheric CO2 are animal respiration and decay of biomass. However, increases in atmospheric levels are attributed mainly to fossil fuel burning and land use change. While efforts to hold down emissions of CO2 continue, increases in CO2 emissions can also be offset, to a degree, by accumulation in carbon sinks such as plant biomass and oceans. It is therefore prudent to...

Many researchers and land management personnel want photographic records of the phases of their studies or projects. Depending on the personnel and the type of project, a study can result in a few or hundreds of photographic images. A data base system allows users to query using various parameters, such as key words, dates, and project locations, and to view images matching the query. This application helps select and locate images for presentations, reports, and publications. The image data base is also available on the World Wide Web.

To manage various recreation opportunities, managers and planners must consider the spatial and temporal scale of social process when identifying opportunities on base maps. However, analyses of social process and spatial form are often treated as two distinct approaches--sociological and geographical approaches. A sociologist might control for spatial form by adopting landscape zones before examining social process (such as the attainment of solitude). On the other hand, a geographer might control for social process (by selecting and studying visitors who attain solitude for example)...

Visitor use data was collected for the years 1987 to 1998 from sea kayak guide/outfitters, charter boats, lodges and rental businesses operating in western Prince William Sound, Alaska. The majority of the Sound is part of the Chugach National Forest and includes the 2.1 million-acre Nellie Juan Wilderness Study Area, where most recreational use examined in this study is concentrated. Results show that use increased from 6,646 visitor-days in 1987, at an annual rate of 7.5%, to approximately 12,786 visitor-days per season in 1998. Concurrently, gross revenues per beach for guide/operators...

Human impacts on the Earth’s ecosystems are globally pervasive. Wilderness areas, although largely protected from direct human impact at local scales, nevertheless are subject to global changes in atmospheric composition, climate and biodiversity. Research in wilderness areas plays a critical role in disentangling natural and anthropogenic changes in ecosystems by providing a network of sites where local impacts are minimized relative to adjacent, more intensely managed areas. Three case studies are discussed to illustrate the role of wilderness areas in global change research and,...

This review evaluates the effects and importance of disturbance and climate change on plant community dynamics in the United States/Mexico borderlands region. Our primary focus is on knowledge of physiognomic-level change in grasslands and woodlands of southeastern Arizona and southwestern New Mexico. Changes in vegetation physiognomy have broad implications for management and land use in the borderlands.Historically, livestock grazing and fire were the dominant disturbances in borderland ecosystems. Livestock grazing accelerates the rate of establishment and growth of woody plants...

In the north central United States, leaf rust caused by Melampsora medusae is a major disease problem on Populus deltoides. In this study we identified molecular markers linked to a M. medusae resistance locus (Lrd1) that was segregating 1:1 within an intraspecific P. deltoides family (C9425DD). Previous field results were contiied in the controlled environment of a growth chamber through an excised whole-leaf inoculation method. Using bulked segregant analysis we identified two random amplified polymorphic DNA (RAPD) markers (OPG10340 and OPZ191800 that are linked to Lrd1. Based on...

Global Positioning System (GPS) telemetry enables biologists to obtain accurate and systematic locations of animals. Vegetation can block signals from satellites to GPS radio collars. Therefore, a vegetation dependent bias to telemetry data may occur which if quantified, could be accounted for. We evaluated the performance of GPS collars in 6 structural stage categories of 3 forest vegetation types to attempt to quantify the relation between GPS locations and forest vegetation.

We investigated the effects of stand size resulting from current logging practices on occurrence and species richness of song birds in the Black Hills. Richness of forest interior and forest interior/edge songbirds was not related to stand area (P > 0.40) in stands of ponderosa pine (Pinus ponderosa) in the Black Hills. Brown creepers (Certhia americana) occurred only in stands of unmanaged forest >18ha, but large diameter trees appeared to be more strongly associated with brown creepers than stand area. Ovenbirds (Seiurus aurocapillus) occurred in all size categories of stands but more...