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Air and bark temperatures, horizontal wind speed, and solar radiation are characterized for ponderosa pine stands considered susceptible and nonsusceptible to attack by the mountain pine beetle in the Black Hills. South-side bark temperatures during midday hours, maximum differences between north-side bark temperatures and air temperatures, maximum differences be tween south-side bark temperatures and air temperatures, and solar radiation were greater in the nonsusceptible stand than in the susceptible stand. Air temperatures, north-side bark tempera tures, and horizontal wind speeds were not significantly different between the two stands. The potential influence of these factors on stand susceptibilty to beetle attack is evaluated.

Site index curves for white fir (Abies concolor) in Arizona, New Mexico, and southwestern Colorado were developed using height-age measurements and an estimated guide curve and 95% confidence intervals for individual predictions. The curves were developed using height-age data for 1,048 white firs from 263 study sites distributed across eight national forests. These site index curves can be used with standard inventory data for estimating potential site productivity for white fir in the southwestern United States.

Ten-year diameter and basal area growth were determined for partially cut stands at 4 locations. Average diameters in the partially cut plots generally increased by 1 inch or more, while average diameter in the uncut controls increased by 0.9 inches or less. Individual tree growth is discussed in relation to potential susceptibility to mountain pine beetle infestation. Basal area increases ranged from 0.9 to 1.9 ft2/acre/ yr in partially cut plots, while basal area increases in the control plots ranged from 0.4 to 1.4 ft2/acre/yr. Endemic mountain pine beetle infestations and snow breakage accounted for most of the mortality on the plots, which decreased the residual basal area and basal area growth. Increases in basal area are used to estimate the length of time required for various stand densities to reach the susceptibility thresholds for mountain pine beetle infestation. Stand marking may influence future susceptibility to beetle infestations.

No abstract

Stand characteristics associated with mountain pine beetle (Dendroctonus ponderosae Hopkins), infestations within a 2.15 ac (0.87 ha) plot were analyzed to determine characteristics most strongly correlated with the infestations. Trees per acre, basal area, quadratic mean diameter, minimum diameter, and the range of diameters in MPB infested groups were significantly different from those in noninfested groups. Maximum diameter was not different between infested and noninfested groups. The results are discussed in regard to the mountain pine beetle-host relationship and stand management. For. Sci. 42(3):310-327.