Effects of Crown Pruning on Height and Cone Production by Loblolly Pine after 6 Years
The effects of several different types of crown pruning, begun at different tree heights, on flowering by grafted loblolly pine seed orchard trees were evaluated periodically for 6 years. Some of the pruning methods were based on those commonly used on fruit trees, where bowl-shaped crowns result from removal of vertically growing shoots. Unfortunately, even pruning twice a year for several years did not often result in a fruit tree type crown because loblolly pine has extremely strong apical control. Even when horizontal growth by several vigorous lateral branches was encouraged, one of them usually became vertical and suppressed the growth of the more horizontal branches. The overall result of our treatments was a significant decrease in height growth and a correspondingly greater decrease in cone production. Even on those few trees that developed bowl-shaped crowns, the width of the crown made harvest of interior cones difficult. We conclude that the benefits of height control, even if begun early, are more than offset by decreases in cone production.
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Author(s): Michael S. Greenwood, David L. Bramlett
Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1989
Section: General Session: Seed Orchard Management