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Published: 2005

Total Pages: 36

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Ponderosa pine mortality due to mountain pine beetle (MPB) activity has been detected in air and ground surveys of the Black Trout Analysis Area on the South Park District of the Pike-San Isabel National Forests and Comanche and Cimarron National Grasslands. The South Park Ranger District has proposed mechanical and prescribed burn silvicultural treatments on approximately 12,500 acres of National Forest Lands to salvage trees killed, to reduce MPB infestations, to reduce disease impacts and to reduce the potential for crown or high intensity wildfires within designated areas of the Black Trout Analysis Area.‍?Lakewood Service Center-Forest Health Management (LSC-FHM) personnel used aerial survey information and ground surveys to determine stand conditions and the level of beetle infestation in the Black Trout Analysis Area. Ground surveys included strip samples and systematic variable radius (VR) plot samples. Strip samples indicate MPB population trends by comparing the number of trees infested in 2004 and the number of MPB-killed trees in 2003. VR plots record stand density and tree diameter which is used along with available stand exam data to determine stand susceptibility.‍?Results indicate an increasing population trend in 4 of 9 units surveyed and a decreasing trend in 5 of the units where MPB had already killed many trees. Although many stands have already suffered high levels of mortality, there remains a high risk of infestation to all susceptible stands in the proposed treatment areas. Average stand diameters, age, tree density and elevation indicate that stands in the proposed treatment areas are either moderately or highly susceptible to MPB outbreaks.‍?Management actions to address the MPB infestation in the Black Trout Analysis Area are discussed. Sanitation and salvage of beetle infested trees and reducing stand density in the uninfested portions of the proposed treatment areas may help reduce MPB impacts and reduce stand susceptibility to MPB attack.