Management strategies were compared, including thinning and the production of fuelwood versus larger size-class volume, to develop a management plan for the mesquite woodland of the southern Arizona study site. Pre-commercial thinning of mesquite stands is not economic and the production and separate marketing of the larger size class at current stumpage rates gives only marginally higher returns than fuelwood alone, $9.57/ha/yr compared to $9.13/ha/yr. Equations were developed for prediction of fuelwood volume and for estimating volume in stem pieces 20 cm or greater in diameter. Estimated growth rates were 0.43 m3/ha/yr for the upland areas and 0.84 m3/ha/yr for the riparian areas. The culmination of mean annual increment suggests a rotation age of 40 years.

No description available.

No description available.

This study was conducted to measure the effects of thinning coppice on Emory oak (Quercus emoryi). Thinning treatments were applied to sprouts of different ages. Height and diameter measurements were taken immediately after thinning and again one year later. Sprouts were classified into 5 age groups, 4 stump diameter groups, and 4 residual sprout groups. The interactions of these treatments and their effect on volume growth were analyzed. The results showed volume growth per stump was directly related to the number of sprouts per stump; volume growth per sprout was inversely related to the number of sprouts per stump; volume growth per stump and per sprout were both significantly affected by the age of the sprout at the time of thinning; and that stump diameter size had no significant effect on volume growth.

No description available.

No description available.

Pima Association of Governments 208 Project / Nonpoint Source Pollution, A Report on Tasks 5321, 5327, and 5332 / Prepared by: Water Resources Research Center and College of Agriculture / The University of Arizona, November 1977

No description available.

The purpose of this study has been to test public perceptions of both scenic quality and recreational acceptability of southwestern ponderosa pine forests exibiting one-to-five years of recovery from both light and severe fire. Public fire-effects information documents were also constructed and tested. Appropriate ponderosa forest areas in Arizona were selected and randomly photographed. Population samples, drawn from Tucson, Arizona, first read fire-ecology or "control" information brochures and then rated forest scenes on 1-to-10 scales for scenic quality and for acceptability for selected forms of outdoor recreation. Respondents finally answered a short fire-knowledge, fire-attitude questionnaire. Ratings were subjected to SBE analysis (Daniel and Boster, 1976), and analysis of variance was applied to both ratings and questionnaire results. The clearest distinction drawn, for both scenic quality and recreational acceptability, is between light-fire and severe-fire effects. Light fire improves scenic quality for a 3-to-4 year period, while severe fire seriously detracts from scenic quality for an unknown length of time exceeding the 5-year period tested. Recreational acceptability is differentiated according to the recreational activity selected: camping is nearly twice as sensitive to severe fire effects as scenic quality, and is somewhat disrupted by light fire effects; picnicking is second-most impacted by severe fire effects; hiking or backpacking is affected by severe fire to about the same degree as scenic quality; nature study is least affected. Picnicking, hiking and nature study are not significantly affected by light fire. Provision of fire-effects information does not significantly affect scenic or recreational evaluation of forest burn areas. The fire-effects information brochures produced general "halo" effects on both fire knowledge and fire attitude in the groups sampled. Fire knowledge shifted toward the expert position that fire effects are less severe than generally believed. Fire attitude shifted toward the expert position of greater tolerance for fire in ponderosa ecosystems. Results show prescribed burning as generally acceptable. The results of this study demonstrate distinctions between affect (perceptual evaluations) and cognition (questionnaire response). Scenic and recreational evaluations emerge as clearly distinct entities.

A moderately intense, broadcast, understory, prescribed burn in 3 previously unburned ponderosa pine stands in southeastern Arizona felled or consumed 50% of all ponderosa pine snags ≥ 15 cm dbh. Large moderately decayed snags were most susceptible to burning. Large snags in the early stages of decay were preferred as nest sites by cavity-nesting birds. Numbers of live woody plants were reduced by 40%, mortality was greatest among shrubs and small trees. Canopy volume was reduced by 19%, the greatest impact was below 5 m. No species of cavity-nesting birds, or birds that associated with understory vegetation disappeared in the first season after burning, but 3 species decreased, and 1 species increased in abundance. The minor impacts of a single treatment with broadcast understory burning on bird populations will be ephemeral, but a repeated burns could have greater, and more lasting effects on the avian community.