Treesearch

A decadent, mixed stand of Wyoming big sagebrush, Artemisia tridentata wyomingensis, and mountain big sagebrush, Artemisia tridentata vaseyana, located north of Cisco, Utah, was subjected to one-way and two-way chaining treatments in November 1987. The effect of the treatments on plant community characteristics and shrub vigor was documented over a 3-year period. Stand density was reduced 60 percent on sites chained two ways and 43 percent on sites chained over once. Shrubs on one-way chained sites produced more leader growth in 1989 and 1990 than those on untreated sites or sites chained...

This paper examined the application of state-of-the-art remote sensing image enhancement and classification techniques for mapping land cover change in the Peloncillo Mountains of Arizona and New Mexico. Spectrally enhanced images acquired August 1985, 1991, 1996, and 2000 were combined with environmental variables such as slope and aspect to map land cover modifications using a machine learning classifier. Change-map accuracies ranged between 68% and 80%. Maximum land cover change occurred in grassland ecosystems (>25% change in cover), caused primarily by prescribed burning practices in...

Pioneers traveling along the Oregon Trail from western Nebraska, through Wyoming and southern Idaho and into eastern Oregon, referred to their travel as an 800 mile journey through a sea of sagebrush, mainly big sagebrush (Artemisia tridentata). Today approximately 50 percent of the sagebrush sea has given way to agriculture, cities and towns, and other human developments. What remains is further fragmented by range management practices, creeping expansion of woodlands, alien weed species, and the historic view that big sagebrush is a worthless plant. Two ideas are promoted in this report:...

Fish movement during sampling may negatively bias sample data and population estimates. We evaluated the short-term movements of stream-dwelling salmonids by recapture of marked individuals during day and night snorkeling and backpack electrofishing. Bull trout Salvelinus confluentus and rainbow trout Oncorhynchus mykiss were captured in sufficient numbers to evaluate instream movements and the influence of stream habitat on movement. Salmonids moved upstream more often than downstream, which suggests that fish fled in response to sampling procedures. Fish movement rates were related to...

Commercial production of tree seedlings often includes various biocidal soil treatments for disease control. Such treatments can be effective in eliminating or reducing disease organisms in the soil, but may also eliminate non-targeted beneficial soil organisms, such as mycorrhizal fungi, that improve seedling performance, both in the nursery as well as the outplanted environment. The arbuscular mycorrhizal fungal (AMF) relationship has been verified for some important western coniferous species such as incense cedar (Calocedrus decurrens [Torr.] Florin), coastal redwood (Sequoia sempervire...

Presently, the flora of the Sierra de Mazatán contains 357 species of vascular plants distributed in 248 genera and 80 families. The families with the most species are Asteraceae (48), Fabaceae (45), Poaceae (28), Euphorbiaceae (18), and Acanthaceae, Cactaceae, Scrophulariaceae, and Solanaceae (11 each). The results show that the flora of the Sierra de Mazatán is diverse. However, with additional collections, the number of species could double. For the future, it would be necessary to collect sites that were not sampled; in different habitats, especially on the north side, and in Cerro...

WinXSPRO is an interactive Windows software package designed to analyze stream channel cross section data for geometric, hydraulic, and sediment transport parameters. WinXSPRO was specifically developed for use in high-gradient streams (gradient > 0.01) and supports four alternative resistance equations for computing boundary roughness and resistance to flow. Cross section input data may be from standard cross section surveys using a rod and level or sag-tape procedures. WinXSPRO allows the user to subdivide the channel cross section into multiple sub-sections and has the ability to vary...

The well-documented relationship between topography and biodiversity is particularly profound in the Madrean Archipelago. However, despite this recognition, most studies of the Sky Island biogeography have used only a first-order qualitative description of the topography (e.g., average vertical relief and mean elevation). Exploiting the availability of high-resolution DEMs (digital elevation models), we have undertaken a rigorous quantitative analysis of the topographic fabric of the region and explored its utility for evaluating the relationship between topography and biodiversity. Using...

The Madrean Archipelago harbors one of the most diverse mammalian communities in North America. We used the Web of Science literature search tool to assess the diversity of peer-reviewed publications on mammals in Arizona and New Mexico as an indicator of publications in the region. The number of publications of all mammals was lower than expected with a mode of 0 and a median of 1. Species were not studied equally in Arizona with most measures suggesting a disproportionately large number of publications on the Order Artiodactyla and small numbers of publications on the Orders Rodentia and...

The USDA Forest Service Missoula Technology and Development Center (MTDC) provides technical expertise, new equipment prototypes, and technology transfer services to Federal, State, and cooperator forest tree seedling nursery managers. Current projects at MTDC include a nursery soil moisture meter, remote data collection systems, low cost weather stations, soil compaction tester, shielded herbicide sprayer, seedling wrap, copper treatment for Styroblocks™, and whitebark pine seed scarifier. Recently completed projects include nursery soil sterilization, hardwood cuttings preparation...