Mean wind patterns and snow depths in an alpine-subalpine ecosystem as measured by damage to coniferous trees.
Deformations of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) trees were surveyed for the purpose of determining climatic wind speeds and directions and snow depths in the Glacier Lakes Ecosystem Experiments Site (GLEES) in the Snowy Range of SE Wyoming, USA. The area is at 3400 m altitude, and trees have a range of structures varying from undeformed and erect to krummholz mat. Tree deformations were recorded at 50- and 100-m grid intervals over areas of c. 30 and 300 ha, respectively, over the GLEES. The climatic mean wind speed was estimated to be 7.4 m s-1; the mean air flow was predominantly westerly. The snow depths ranged from <0.2 to 5.5 m, depending on topographic features and vegetative architecture. Compared with snow depth surveys, precipitation measurements, and a degree-day snow depth model, the average snow depth estimated by the tree deformation method was 70% of the long-term mean. The tree deformation method was useful for detailed estimates of wind speed, wind direction, and snow depth at a fine scale in complex terrain, where meteorological instrumentation and snow survey data are minimal.