Abstract

Temperature, one of the most influential factors controlling the growth and distribution of plants, was measured during a three month summer period within several stands of vegetation. The stands represented four distinct plant communities: sagebrush-grass, mountain brush, aspen, and conifer. Measurements were obtained by a sucrose inversion method which gave exponential average or effective mean temperature (eT) values. Registerants, small glass vials filled with a sucrose-buffer solution, were placed in the air 10 decimeters above the ground level and in the soil 1, 5, and 10 decimeters below the ground level. The sites were carefully described with respect to plant cover and composition, soil profile, soil moisture, precipitation, elevation, aspect, and slope. Each site and plant community varied with respect to some of these factors. Several prominent relationships between the air and soil temperatures and various site factors were encountered. The sagebrush-grass and mountain brush sites had significantly higher temperatures than the aspen and conifer sites. Air and soil temperatures varied inversely with elevation. Soil temperatures varied inversely with soil depth and the variation was statistically significant. Soil temperatures at the one decimeter depth in adjacent sites were nearly 2° C higher in the site with a sparse shrub cover than in the site with a very dense shrub cover. On adjacent sites with opposite exposures the south exposure had soil temperatures which were nearly 6° C higher than the north exposure. Moist sites had lower temperatures than dry sites. Sites with 2 inches of litter and duff had cooler soil temperatures than sites with only 1 inch. Temperature differences between plant communities were measured with the sucrose inversion method even though the various site factors also had their effect upon the temperatures. It was not the intent of this paper to interpret interactions of the various site factors with temperature. It is concluded that the sucrose inversion method of temperature measurement is an easy to use, inexpensive, reliable method for use in ecological studies.

Degree

College and Department

Life Sciences; Plant and Wildlife Sciences

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