Skip to main content
Shawn T. McKinney, Diana F. Tomback
Year Published:

Cataloging Information

Fire Ecology
Insects & Disease
Management Approaches
Recovery after fire
Subalpine wet spruce-fir forest, Subalpine dry spruce-fir forest

NRFSN number: 8391
FRAMES RCS number: 7354
Record updated:

We tested the hypotheses that white pine blister rust (Cronartium ribicola J.C. Fisch.) damage in whitebark pine (Pinus albicaulis Engelm.) stands leads to reduced (1) seed cone density, (2) predispersal seed survival, and (3) likelihood of Clark's Nutcracker (Nucifraga columbiana (Wilson, 1811)) seed dispersal. We gathered data from two sets of paired forest sites in the Bitterroot Mountains of eastern Idaho and western Montana that were similar in topography, canopy structure, tree species composition, and successional stage, but differed in rust infection level, crown kill, and tree mortality. We counted initial (mid-July) and final (late August) seed cones, observed vertebrate seed predator activity, and documented nutcracker seed dispersal in study sites in 2001 and 2002. High-rust sites had higher rates of seed predation relative to cone abundance, lower predispersal seed survival, and fewer observations of nutcracker seed dispersal than paired low-rust sites. These findings suggest that as blister-rust-induced damage increases within stands in the Bitterroot Mountains, the likelihood of nutcracker seed dispersal decreases. We propose that whitebark pine in heavily rust-damaged forests may not self-regenerate and would therefore require planting of seeds or seedlings from genetically rust-resistant trees.


McKinney, Shawn T.; Tomback, Diana F. 2007. The influence of white pine blister rust on seed dispersal in whitebark pine. Canadian Journal of Forestry Research. 37(6): 1044-1057.