One-time pruning of pecan trees induced limited and short-term benefits in canopy light penetration, yield, and nut quality

Twenty-five-year-old 'Cape Fear', 'Desirable', and 'Kiowa' pecan [Carya illinoinensis (Wangenh.) C. Koch] trees were either not pruned, or subjected to single selective or mechanical pruning using a mechanical hedger [or hedge pruning (HP)] in the dormant season 2003. Canopy light interception, yield, and nut quality were monitored during a period of three years. Leaf area index and light interception were significantly affected during the first growing season after treatment application, but after three years canopies grew back to control levels. In general, there were small positive effects observed on yield and nut quality after pruning. Minor improvements were recorded for 'Desirable', in which yield was affected positively by both pruning strategies in 2004. However, most effects disappeared by the third year. 'Desirable' responded better than 'Cape Fear', whereas no beneficial effects were recorded on 'Kiowa'. In 2005, yield was significantly reduced in HP trees of 'Cape Fear' and 'Kiowa'. Alternate bearing index was unaffected by pruning treatment or cultivar. Kernel percentage increased only in HP 'Desirable' trees in 2003 and 2004. Kernel quality was improved in HP 'Cape Fear' and 'Desirable' in the first growing season after treatment application, but not in 2004. In 2005, quality was again improved in HP 'Desirable'. The results of the current study indicate that one-time pruning of pecan trees induce positive short-term effect on light, but not necessarily an increase in productivity and nut quality.