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Pacific Southwest Research Station
Tahoe Science Projects supported by SNPLMA
Restoration strategies for whitebark, western white, and sugar pine in the Lake Tahoe Basin: ecological and epidemiological considerations
Detlev Vogler, USDA Forest Service-Pacific Southwest Research Station, Institute of Forest Genetics
Links with ecosystem health, resource conservation (vegetation, soil, water), and biological diversity are central to the health of Lake Tahoe. The white pine species – whitebark (Pinus albicaulis), western white (P. monticola), and sugar pine (P. lambertiana) are important components in low to upland forest communities. Interactions among anthropogenic disturbances such as historical logging and fire suppression, an exotic pathogen (Cronartium ribicola, cause of white pine blister rust [WPBR]), and climate‐driven outbreaks by Dendroctonus ponderosae (mountain pine beetle) have significantly affected populations of white pines in lower montane, upper montane and subalpine forests. White pine blister rust is one of the greatest threats to white pine sustainability and survival. In the Lake Tahoe Basin this invasive pathogen is significantly affecting recruitment potential and survival of small and intermediate-sized trees. Such adverse demographic effects can have long-lasting consequences on population structure and dynamics. Comstock era logging, in some locations, has reduced effective population numbers and genetic variation of sugar pine. Both influences (i.e., WPBR and historical logging) can significantly affect how these species respond to other stressors, such as global climatic change. Strong evidence of negative population and genetic effects warrants white pine restoration in the Lake Tahoe Basin. Mitigating anthropogenic influences will require restoring effective population numbers, deploying WPBR‐resistant material, 'facilitating' recruitment, enhancing genetic variation, and planting drought‐tolerant genotypes.
Relation to Other Research Including SNPLMA Science Projects
The SNPLMA Round 7 project ("Natural and anthropogenic threats to white pines from lower montane forests to subalpine woodlands of the Lake Tahoe Basin: an ecological and genetic assessment for conservation, monitoring, and management") has completed a comprehensive cone collection of white pines for seed-banking and determined the current population status (e.g., stable, declining, or growing) of these species on Federal and non‐Federal lands. This work served to identify populations that warrant restoration. This is the first study of its kind to determine resistance frequency of C. ribicola at a landscape‐level for three species of white pines. Projects by the investigators funded through SNPLMA Round 9 ("Conservation, management, and adaptive responses of Western white pine to environmental change"), Round 10 ("Conservation, management, and restoration of whitebark pine in the Lake Tahoe Basin") and the Nevada Division of State Lands Lake Tahoe License Plate Program ("Conservation, management, and adaptive responses of Sugar pine to environmental change") are evaluating the adaptive genetic variation of ecologically important plant traits such as water‐use efficiency, disease resistance, phenology, growth, and survival in the three white pine species of the Lake Tahoe Basin. These studies will provide valuable information about suitable plant material for deployment in restoration projects for current and future environmental conditions in the Lake Tahoe region as well as make available hundreds of seedlings for restoration.
Expected date of final products:
|Last Modified: Mar 7, 2013 06:28:04 PM|