Submitted to: Southeastern Pecan Growers Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 19, 2009
Publication Date: March 15, 2010
Citation: Wood, B.W. 2010. Hedge pruning of 'Desirable' pecans. In: Proceedings of Southeastern Pecan Growers Association, January 10-12, 2010, Savannah, Georgia, 103:15-20. Interpretive Summary: Increasingly severe alternate bearing and loss of nut yield and quality is a side-effect of excessive orchard crowding. A type of mechanical hedge-type pruning was shown to be effective for reducing orchard crowding of ‘Desirable’ cv. pecan; however, due to relatively low sunlight levels pruned trees in the southeastern U.S. do not respond to hedging as well as those in the southwestern U.S. This new pruning strategy offers growers a means of increasing nut yield and quality, while extending orchard productivity.
Technical Abstract: Long-term productivity of commercial pecan [Carya illinoinensis (Wangenh.) K. Koch] enterprises in relatively low-light environments, such as the southeastern U.S., are limited by excessive tree crowding as orchards age. An effective horticultural strategy for countering this problem in relatively high-light environments is mechanical hedge-type pruning; however, uncertainty persists regarding the best strategies in low-light environments. This report describes the results of a four-year study regarding the response of ˜ 25-year-old ‘Desirable’ pecan trees to different mechanical hedgerow-type, moderate canopy width (i.e., 2.43 m cuts from tree axis), pruning strategies. Canopy treatments were non-pruned control (NPC), annual dormant season side-hedge pruning on two faces (HD), annual summer season side-hedge pruning on two faces (HS), and alternating annual dormant season side-hedge pruning on a single alternating face (HD2). Relative to the NPC treatment, all three pruning strategies a) reduced in-shell nut yields by roughly 19-38%, b) reduced marketable nut-meat yield by about 19-36%, c) failed to stimulate shoot development or fruiting within the central interior zone of tree canopies, d) increased kernel percentage of nuts, e) increased nut-meat grade, f) substantially reduced alternate bearing intensity (0.51 to ˜ 0.20), and g) reduced orchard crowding. Pruning associated reductions in nut yield appears sufficient to limit the commercial usefulness of annual or biennial mechanical hedgerow-type pruning of ‘Desirable’ pecan orchards at moderate canopy widths in relatively low-light environments such as the southeastern U.S.