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Abstract
In 1956 Hallinl reported some observed effects of pruning ponderosa and Jeffrey pine based on the response after 5 years. This report is an extension of those observations, after a 10-year reexamination of the experiment. Hallin suggested that half the live crown, or six-tenths of total height of the tree could be pruned without adverse effects on growth. Pruning out three-fourths of the live crown resulted in death of 52 percent of such treated trees at the end of 5 years. Also of considerable interest was the rapid growth rate found for open-grown trees on the poor site where the study was installed. Practical guides to pruning heights were also given. In general, the 10-year data substantiate Hallin's conclusions.
Citation
Gordon, Donald T. 1959. Ten-year observations on pruned ponderosa and jeffrey pine. Res. Note PSW-RN-153. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 4 p