C-1 (3018 m) climate station: Precipitation data.

Precipitation data were collected from a ridgetop climate station southeast of Niwot Ridge (C-1 @ 3018 m) throughout the year using chart recorders. The station was initially instrumented with a standard 8-inch precipitation gauge installed with the rim 1 m above ground. Measurements were made on an approximately weekly basis. A recording precipitation gauge was installed at the beginning of January 1965, with the installation in the clearing positioned so that the gauge rim subtended an angle of 45 degrees to the tree crowns although the most effective angle is 30 degrees according to Leaf (1962). Precipitation was caught in a bucket containing ethylene glycol (to melt snow) and light oil (to prevent evaporation). As the weight of the bucket increased, a pen moved up via a spring mechanism and recorded on a rotating chart. Precipitation was recorded on a continuous basis