The purpose of this experiment was to measure the difference in temperatures influenced by skirted and unskirted cirrus trees under cold temperatures. Sixty citrus trees (oranges and lemons) planted on a hillside were skirted at 18 inches above ground level for this experiment. The experiment was conducted over 96 days, in which daily minimum temperature readings were taken. In addition to the thermometers, four thermographs were used to record constant temperate and duration of frosty nights.
In 79 of the 96 days of the experiment, the skirted treatment showed an increase in the temperature compared with the unskirted treatment at an average increase of 0.25°F. Statistical differences between treatments ranging from 0.5°F to 0.7°F were found for three different days at temperatures in the 40's. No statistical differences between treatments were found at temperatures in the 30's. The thermograph readings showed no differences in the duration of cold temperatures between skirted and unskirted treatments.