Treesearch

There are few documented cases of gallinaceous birds caring for offspring other than their own. Willow Ptarmigan (Lagopus lagopus) usually mate monogamously, with pairs remaining together throughout the breeding season, but they occasionally are polygynous (Hannon 1984, Martin and Cooke 1987, Martin 1989). If males are removed from monogamous pairs after breeding, replacement males may fill the openings and adopt the brood (Martin 1989). We observed four cases of apparent adoption by Merriam’s Wild Turkeys (Meleagris gallopavo merriami) during 1987, 1988, and 1989 while collecting data to...

In 1983 zinc phosphide, strychnine with prebait, and strychnine without prebait were applied to black-tailed prairie dog (Cynomys Zudovicianus) colonies in west central South Dakota. Short-term (four days later) and long-term (one year later) impacts of the rodenticides on Horned Larks (Eremophila alpestris) and other granivorous birds inhabiting prairie dog colonies were evaluated. Horned Larks and 49 other bird species were observed. Immediate impacts reduced Horned Lark relative densities 66% with strychnine only and 55% with prebaited strychnine. Zing phosphide caused no measurable...

A standard campsite model is proposed and then manipulated to examine the influence of individual variables on amount of vegetation loss. Amount of impact is influenced by amount of use, vegetation fragility, vegetation density, and the degree to which activities are concentrated spatially on the site. Degree of concentration also influences the importance of the other explanatory variables. Amount of use and vegetation fragility are equally important determinants of impact and are most Influential where activity concentration is low. The curvilinear relationship between amount of use and...

This publication, a compilation of 28 technical articles on various aspects of forest nursery management in western North America, consists of two sections. The first 10 papers comprise the Target Seedling Symposium, and discuss the latest methods of describing and measuring the ideal seedling for reforestation purposes. Morphological characteristics such as height, diameter, stocktype, root system size, and mycorrnizae are covered. Considerable attention is paid to physiological tests such as root growth potential, hydraulic conductivity, cold-hardiness, mineral nutrition, seedling...

Fire in southwestern ponderosa pine induces changes in soil properties including decreasing the amount of nutrients stored in fuels (forest floor, woody litter, and understory vegetation) increasing the amount of nutrients on the soil surface (the "ashbed effect"), and increasing the inorganic nitrogen and moisture content in the mineral soil. Soil temperatures are increased above lethal levels under heavy fuels, probably killing both microbes and roots. Soil pH appears not to be substantially affected by burning in this forest type. The greatest changes in soil properties occur where...

The mountain pine beetle, Dendroctonus ponderosae Hopkins, is a member of a group of beetles known as bark beetles: Except when adults emerge and attack new trees, the mountain pine beetle completes its life cycle under the bark. The beetle attacks and kills lodgepole, ponderosa, sugar, and western white pines. Outbreaks frequently develop in lodgepole pine stands that contain well-distributed, large-diameter trees or in dense stands of pole-sized ponderosa pine. When out-breaks are extensive, millions of trees may be killed each year. Periodic losses of high-value, mature sugar and...

The Forest and Rangeland Renewable Resources Planning Act of 1974 (RPA), P.L. 93-378, 88 Star. 475, as amended, directed the Secretary of Agriculture to prepare a Renewable Resources Assessment by December 31, 1975, with an update in 1979 and each 10th year thereafter. This Asessment is to include "an analysis of present and anticipated uses, demand for, and supply of the renewable resources of forest, range, and other associated lands with consideration of the international resource situation, and an emphasis of pertinent supply, demand and price relationship trends" (Sec. 3.(a)).The 1989...

Presents highlights of Arizona's forest resources as of 1985. Describes the extent, condition, and location of the State's timberlands and woodlands and briefly discusses levels of some nontimber use of forest land. Includes statistical tables: area by land classes, ownership, wood volumes, growth, mortality, and product removals.

Moisture retention curves were prepared for representative basaltic (silty clay loam) and sedimentary (sandy loam) soils in Arizona by two methods. With the vapor pressure method, small soil samples come into equilibrium moisture content with saturated salt solutions of known water potential. The other method measured the water potential of soil samples directly using thermocouple psychrometers. Both methods produced similar curves for the tine-textured basalt soil. However, the r1 curves for the coarse-textured sedimentary soil were unequal. The vapor pressure method, the simplest, least...

We substantiate our contention that our multivariate analyses (Rexstad et al. 1988) mimic analyses found in the wildlife literature. We caution users of multivariate techniques that data collected in our discipline are unlikely to meet the restrictive assumptions of these techniques. Even if assumptions are met, we contend interpretation of the results is likely to lead to invalid inferences.