Canopy Structure and Phenology of Alpine Tundra Vegetation

• Main Author: Fareed, Marcee
• Format: Text
• Language: unknown
• Published: Utah State University 1972
• Subjects: Arctic; Tundra
• Online Access: https://dx.doi.org/10.26076/a81a-b5ef; https://digitalcommons.usu.edu/etd/6314

An inclined point frame was used to measure leaf area indicies in an alpine tundra Kobresia stand and Deschampsia meadow on Niwot Ridge, Colorado. Measurements were made throughout the summer of 1971 at vi various heights in the canopy and for each species in the two communities. Maximum leaf area indices of 2.2 and 2.0 occurred in the Kobresia and Deschampsia sites, respectively. The Kobresia site was characterized by a single dominant species, Kobresia myosuroides, and a predominance of vegetation within 2.5 cm of mean ground level. The Deschampsia site had no single dominant species. The region of maximum foliage shifted from the 2.5 to 5 cm height zone in June to the 5 to 10 cm zone in early August. Phenological observations revealed a greater number of vegetative contacts in the Deschampsia site on all sampling dates. Certain shared species varied in their phenological patterns. It is suggested that differences in the duration of snow cover and surface melt-water may be related to the variation in phenological patterns in the two sites. In both communities, maximum LAI occurred when flower and fruit production overlapped. Arctic tundra LAI values, measured using similar methods, were less than half the maximum LAI values reached in the alpine communities examined here.