Date of Award:


Document Type:


Degree Name:

Master of Science (MS)




John D. Schultz


Shortwave solar radiation was measured in the late winter of 1967 by means of actinographs below the canopy of two lodgepole pine stands, one thinned and the other unthinned, in northern Utah. Observations were made at four randomly selected stations in each stand and at one station in a large clearing. Radiation available below the thinned and unthinned stands was compared, and radiation in the open was compared with radiation beneath each stand.

Nearly a ll differences between stands were significant as were the differences between each stand and the open area.

A close correlation was shown between total radiation in the open and total radiation beneath forest stands.

It was concluded that the radiation beneath either the thinned or the unthinned stand was above the minimum (ca. 10 percent of full sunlight) required for adequate reproduction of Engelmann spruce and subalpine fir.