Nearly a Decade of Community Change Documented for a Montane Forest in Utah

William S. Bradshaw Michael T. Stevens Department of Biology Utah Valley University, 800 W. University Pkwy., Orem, UT 84058

The montane forests of the Wasatch Mountains in Utah are found between 2300 m and 3000 m with the chaparral shrublands below and the alpine forests above. Annual precipitation in this community is 74 cm and the average annual temperature is 3 ℃. In September over eight consecutive years (2013-2020), Plant Ecology students at Utah Valley University sampled trees and shrubs in a montane forest near the Mount Timpanogos trailhead in Utah County, Utah. In this area, woody plants that were at least 1.7 m tall (breast height) were sampled in 13-34 quadrats along 50-m transects. We determined relative frequency, relative density, relative dominance, and the importance value for 14 species. Importance value is a composite metric that takes into account frequency, density, and dominance. This report focuses on trees and shrubs that were encountered in at least seven out of eight years. Most of the species showed consistent trends over time. However, the importance value for quaking aspen (Populus tremuloides) and Douglas-fir (Pseudotsuga menziesii) decreased over the eight-year period while white fir’s (Abies concolor) importance value increased. The patterns that we observed can be explained by rates of recruitment. Neither quaking aspen nor Douglas-fir regenerate well in the shade and both species are favored by fire. In this maturing forest that hasn’t recently burned, levels of shade are increasing. In contrast, white fir’s recruitment has been higher over the eight-year period due to its shade tolerance and its status as a climax species in western North America. 

Additional Abstract Information

Presenter: William Bradshaw

Institution: Utah Valley University

Type: Poster

Subject: Plant Sciences

Status: Approved

Time and Location

Session: Poster 10
Date/Time: Wed 1:30pm-2:30pm
Session Number: 6503