Heartrot fungi's role in creating picid nesting sites in living aspen

Abstract

To determine the number of cavity-containing aspens in old-growth (>80 years), we counted the number of stems containing cavities in 132 0.02-ha plots in Wyoming. There were 8.7 cavities/ha of aspen type. At least 84% of the cavity stems were alive when the initial cavity was constructed; 60% were alive when examined. Fruiting bodies and Phellinus tremulae (a heartrot fungus) were present on 71% of all cavity-bearing stems but on only 9.6% of all stems >15 cm d.b.h. Cavities were present in 7.7% and 0.2% of living stems with and without fruiting bodies, respectively. Average d.b.h. of cavity stems was 27.4 cm. During a 4-year interval, 74 of 226 snags >15 cm d.b.h. fell, giving an average instantaneous rate of snag loss of r = -0.099. Ninety-six new snags >15 cm d.b.h. were created during the 4-year study period. Our results indicate that some primary cavity-nesting birds in northwest Wyoming preferentially selected living aspens with heartrot as nest sites and that the average longevity of aspen snags >15 cm d.b.h. is about 10.7 years.

Parent Publication

• Sustaining aspen in western landscapes: Symposium proceedings; 13-15 June 2000; Grand Junction, CO

Citation

Hart, John H.; Hart, D. L. 2001. Heartrot fungi's role in creating picid nesting sites in living aspen. In: Shepperd, Wayne D.; Binkley, Dan; Bartos, Dale L.; Stohlgren, Thomas J.; Eskew, Lane G., comps. Sustaining aspen in western landscapes: Symposium proceedings; 13-15 June 2000; Grand Junction, CO. Proceedings RMRS-P-18. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 207-214.