Water potential was measured in five ponderosa pine (Pinusponderosa Laws.) in each of four stands of different growing-stock levels at two locations in the Black Hills of South Dakota. Mean water potentials at dawn and midday varied significantly among growing-stock levels at one location, but differences were not consistent. Mean dawn and midday water potentials within growing-stock levels significantly decreased during the summer but showed minor increases during the overall decline. Stress levels were considered high enough to influence physiological functioning and, therefore, influence susceptibility to mountain pine beetle (Dendroctonusponderosae Hopk.) attack. Mountain pine beetle infestations did not develop within the stressed stands, which suggests that resistance may be only one factor in the outbreak scenario.
Evaluating Forest Vegetation Simulator Performance for Trees in Multiaged Ponderosa Pine Stands, Black Hills, USA
