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Study objectives included determining whether prescribed burning affected ponderosa pine growth; mathematically modeling the growth response to burning; and determining whether forest management history affected growth response. I sampled 188 trees from two areas near Flagstaff, Arizona; one area (Brannigan Flat) had been logged and thinned, and the other (Chimney Spring) had not; both were burned in 1976. Within each study area, control and burned plots were of similar age, vigor, height, and competition index. Trees at Chimney Spring were older, less vigorous, and taller, and had a higher competition index than at Brannigan. For each tree, periodic basal area increment (PBAI) was calculated for the years 1974-1984. To determine which variable would best model growth, postfire PBAI (individual years, 1977-1984) was correlated with previous growth (average PBAI 1974-1976); crown ratio; competition index; thinning index; and diameter. Two models of growth response were developed; one oriented toward satisfying theoretical and research goals, and the other, toward management applications. Growth was modeled using stepwise multiple linear regression, and the dependent variable was postfire PBAI. Research Model independent variables were previous growth, years (climate), and treatment-year interaction, and 72% of total variance was explained. Fire affected growth significantly and negatively for two years, and then burned trees grew similarly to control trees. Management Model independent variables were crown ratio, competition index, crown ratio, subject tree diameter, year, and treatment, and 52% of total variance was explained. This model, too, indicated a slight negative effect of burning on growth. Management history was not a significant determinant of growth response. Both models validated well; the ratio of observed-to-predicted residual mean square was 1.04 and 0.91 (Research and Management Models, respectively). Thinning index was not significantly related to postfire growth, but a change in carbohydrate allocation from stem wood to crown and root expansion could have resulted in observed burning effects. Management implications include (1) short-term growth decline may result from burning, (2) management history did not affect growth response, and (3) burning impact is greatest in dense stands of small trees.

Measurement of relative near-view scenic beauty and prediction of changes in scenic beauty with timber stand management, grazing, and downed wood management are necessary to integrate scenic beauty into the multiple use decision-making framework. Although traditional landscape quality assessment procedures are of limited use in measuring or predicting the relative scenic beauty of near-view forest scenes, extension of psychophysical methods to measurement of forest scenic beauty offers an approach to effectively incorporate scenic beauty into forest management. Biological and physical variables were inventoried at sites within ponderosa pine timber stands in northern Arizona. Four color slides, also taken at those sites, were later rated for scenic beauty by groups of people, and the ratings were scaled to provide scenic beauty estimates per site. Highly significant multiple regression models, expressing scenic beauty as a function of the biophysical variables, accounted for up to 60, 50, and 80 percent of the variance in scenic beauty for pre-harvest sites, post-harvest sites, and pre-harvest timber stands, respectively. It seems possible at this point to specify a general ponderosa pine model, to be calibrated for specific damage-free areas within the Southwest. Herbage and large ponderosa pine contribute to scenic beauty, while numbers of small pine trees, mechanical ground disturbance, and downed wood, especially as slash, detract from scenic beauty. Areas of northerly aspect, lower overstory density, and less tree clumping were preferred. Moderate harvest tends to improve scenic beauty once the stand has recovered from obvious harvest effects. The recovery period can be greatly reduced by slash cleanup. Grazing can seriously detract from scenic beauty. Up to a point, over the range of practical timber stocking levels, increasing stocking results in greater net present worth from timber, forage, and water yields minus management costs, and lower scenic beauty. Beyond that point both net present worth and scenic beauty decline.

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Site index curves were constructed for the Emory oak (Ouercus emoryi) woodlands of the San Rafael Valley in southeastern Arizona. The woodlands primarily consisted of trees that were of sprout origin. Growth was rapid for 10 years, moderate from 10 to 20 years, and slow after 20 years. No trees in the study area were more than 40 feet tall. Stepwise regression analysis was used to analyze the relationship between site index and site factors. Important variables included available soil water holding capacity, percent volume of coarse fragments, radiation index, percent sand, litter depth, and soil pH. Two models were developed; the r² values were 0.56 and 0.49, respectively. Analysis of variance was used to test for differences between site index on different soil types and slope positions. All statistical tests were conducted using a 0.10 level of significance. The sample consisted of 100 trees. Most of the factors were involved with availability of water to the tree roots. Emory oak grows in a dryland area where water is a limiting factor. Therefore, the effect that soil and terrain has on the availability of water to tree roots is an important impact on the site index for Emory oak woodlands.