Effects of Pruning on Rainfall Interception in a Minnesota Red Pine Stand

The effect of pruning on rainfall interception was determined by removing 50 percent of the live crown length from all Pinus resinosa Aik. trees in one of the paired plots in each of two replications. After treatment, 49 storms were measured for throughfall, only 28 of which producedmeasurable stemflow. Although treatment did not significantly affect seasonal throughfall or stemflow, an increase in the former was noticeable for small storms while a decrease in the latter was characteristic for larger storms. The throughfall increase ranged from 46 percent of the grossprecipitation for storms between about .01 and .04 inch, to about 7 percent (possibly not significant) for storms between .16 and .77 inch. The stemflow decrease for storms between .77 and 3.81 inches averaged about 1.5 percent of the gross precipitation. Small increases in the net precipitationof small storms probably did not significantly affect soil moisture supplies.