Effects of Burning on a Galleta‐Black Grama Range Invaded by Juniper

A relationshil) between soil wetness and rate of evaporation similar to one developed under controlled conditions can be extracted from field data which include environmental fluctuations. This extraction, based on a comparison with a standard environment, is termed a "standardization" and consists of employing a computed ratio in place of water loss rate values. A second ratio obtainable from the field data provides a basis for assessing the effect on the evaporation microclimate of variations in the physical environment other than those of moisture. Observations made in three contiguous sites in the Oregon Coast Range yielded a standardized relationship between evaporation rate and soil wetness which was common to all three sites. Thinning of a stand of 50-year-old Douglas fir from 400 to 100 stems per acre resulted in a change in evaporation microclimate only 14% as great as the difference between the unthinnedl stand and the open site nearby. REFERENC ES