Growth of ponderosa pine stands in relation to mountain pine beetle susceptibility

Abstract

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.

Growth of lodgepole pine stands and its relation to mountain pine beetle susceptibility

“…Because the various susceptibility factors in the Shore and Safranyik method will not significantly change with future growth of the existing trees in the GSLs, the future susceptibility of the partially cut GSLs appears to remain essentially constant until substantial ingrowth occurs or the larger diameter trees die. This differs sharply with the situation in ponderosa pine wherein the susceptibility of partially cut stands with BAs >80 are thought to increase with BA growth on the residual stand (see Obedzinski et al 1999). However, because BA growth on residual trees is not part of the Shore and Safranyik system for LP, such growth does not influence future susceptibility.…”

“…In comparison to the lone PP GSL 120 (see Obedzinski et al 1999), most of the LP GSL 120s achieved the 150 threshold before the ponderosa pine GSL 120. As with the GSL 80s, the lesser time intervals for the LP GSL 120s are probably attributable to greater site productivity and the greater number of trees per acre even though the trees are generally smaller than those on the comparable ponderosa pine site.…”

“…The current and future susceptibility of each partially cut GSL was also estimated by determining when its BA might reach the BA thresholds of 150 and 120 ft 2 /acre (see Obedzinski et al 1999). In previous work in ponderosa pine, Sartwell and Stevens (1975) believed that BA >150 ft 2 /acre was a critical level for MPB infestation.…”

“…Comparing time intervals for LP GSL 80s with those for ponderosa pine GSL 80s (see Obedzinski et al 1999), the LP GSL 80s will reach the basal area threshold of 150 ft 2 before the ponderosa pine GSL 80s do. Similarly, the LP GSL 80s will reach the threshold of 120 ft 2 about the same time or sooner than ponderosa pine GSL 80s.…”

Probability of ponderosa pine infestation by mountain pine beetle in the Colorado Front Range

“…Hawksworth and Wiens, infection. Examination of susceptibility to attack in ponderosa pine has been conducted mostly in the Black Hills of South Dakota (Sartwell and Stevens, 1975;McCambridge and Stevens, 1982;Schmid and Mata, 1992;Schmid et al, 1994;Olsen et al, 1996;Obedzinski et al, 1999) and in Oregon (Sartwell, 1971;Sartwell and Dolph, 1976). In sum, these studies indicate that mountain pine beetle-caused ponderosa pine mortality is related to stand density.…”