Treesearch

Limits on the overall number of recreationists permitted to enter or visit wilderness, national park backcountry or whitewater rivers have been formally established for about 30 years. Such limits have usually been established to protect biophysical or social conditions from unacceptable impacts in the face of rapidly rising amounts of visitation. Use limits are one of a number of tools available to managers, but represent a particularly intrusive and controversial one. Use limit policies may have significant negative displacement effects, are implemented within a regional context - even...

The current scholarly and management approach to wilderness solitude has relied on substitute measures such as crowding and privacy to measure solitude. Lackluster findings have been only partially explained by additional social-spatial factors such as encounter norms, displacement, product shift, and rationalization. Missing from the discussion has been an exploration of the meaning of solitude and a questioning of the basic assumption of its social-spatial structure. In this paper, the concept of solitude is approached from an attitudinal perspective that emphasizes psychological...

Patterns of shoot elongation of 2-yr seedlings from native North American populations of ponderosa pine and Douglas-fir were compared to those of Argentine land races originating from unknown provenances. The comparisons were conducted in Moscow, Idaho (USA), and suggested that the ponderosa pine land race was descended from a California provenance at low or middle elevations but that the growth potential of the land race was only mediocre in comparison to eight native populations. The Douglas-fir land race exhibited a relatively high growth potential in comparison to 19 native provenances...

Effects of fire at two levels of intensity on beetle diversity in shortgrass steppe were examined. The experimental design was completely randomized, with 3 treatments and 4 replicates per treatment. Treatments were two levels of fire 1) dormant-season fire (relatively hot), and 2) growing-season fire (relatively cool), and unburned plots. The response variables were arthropod species richness and abundance. The intermediate disturbance hypothesis predicts that maximum species richness occurs at intermediate levels of disturbance. Data obtained in this study support that prediction....

The exotic tree, Russian olive (Elaeagnus angustifolia), has invaded riparian zones throughout much of the western Unites States. Although promoted as a useful species for wildlife because of its abundant edible fruit, evidence for its value to breeding birds remains sparse. We compared relative rates of usage, nest success, and cowbird parasitism of birds breeding in Russian olive versus native tree species at a site where Russian olive is a minor component. Some species, such as the Mourning Dove (Zenaida macroura) and Yellow-breasted Chat (Icteria virens), preferentially placed their...

The potential for aspen regeneration in conifer stands has been underestimated on the Salida Ranger District. Harvest of mature aspen stands on the Salida and San Carlos Districts encouraged regeneration. Following harvest, the Douglas-fir and some Engelmann spruce stands in the Arkansas Hills area regenerated primarily to aspen. Disturbance through aspen harvest, prescribed fire, wildfire, and other approaches is critical to aspen sustainability and health for the San Isabel National Forest. Disturbance must take place to regenerate the aspen component and reduce the conifer invasion.

Land management agencies in northwest Wyoming have implemented an active prescribed fire program to address historically altered fire regimes, regenerate aspen, and improve overall watershed functions. Treated clones are susceptible to extensive browsing from elk concentrated on supplemental feedgrounds and from wintering moose. Previous attempts at fire-induced aspen regeneration in the area indicate various levels of success due to existing herbivory levels. Belt transects were established in fire-treated aspen clones along the Gros Ventre drainage, northeast of Jackson, Wyoming. Sucker...

In 1996, I inventoried over 90 aspen stands in 12 timber sales that had been clearcut >3 years previously. Units that regenerated adequately were larger, had higher slope angles, and had soils with a thick Mollic surface layer. Units that regenerated inadequately often had plant species that indicated high water tables. The factors associated with inadequate regeneration were high water tables, heavy browsing, soils with a thin Mollic surface layer, and logging practices that compact large portions of the unit. One of these factors alone often does not lead to inadequate aspen sprouting....

We measured the effects of the 1996 Pole Creek fire, Fishlake National Forest, Utah, on available soil N and net N mineralization for three summers after the fire using an ion exchange membrane (IEM) soil core incubation method. Fire in mixed aspen/conifer increased the amount of available NH4, and a subsequent net increase in soil nitrification was observed. Release of NH4 from the ash and a net increase in soil nitrification were still observed 3 years after the fire. The fire-caused increase in available soil N provides a source of N for aspen regrowth.

This paper reviews characteristics and properties of aspen wood, including anatomical structure and characteristics, moisture and shrinkage properties, weight and specific gravity, mechanical properties, and processing characteristics. Uses of aspen are evaluated: sawn and veneer products, composite panels, pulp, excelsior, post and poles, animal bedding, animal food supplements, fuel applications, and novelties. Aspen is a preferred species for paneling, veneer products including matchsticks and chopsticks, waferboard and oriented strandboard (OSB), fiberboard, pulp, excelsior, research...