Influence of Tree Thinning on Vegetative Growth, Yield and Fruit Quality of ‘Fuji’/M.9 Apple Trees in the High Density Orchard

As apple trees mature, it is important to maintain good light distribution within the canopy to produce market-able fruits. Tree thinning is the selective removal of a proportion of trees growing in the orchard to provide more growing space and a good light environment for the remaining trees. This study was conducted over 3 years (14–16 years after planting) to investigate the influence of tree thinning on vegetative growth, yield, fruit quality, and blooming in the 14 years old slender spindle ‘Fuji’/M.9 apple trees planted with the tree space of 3.2 x 1.2 m. The trees were placed in a control group (no thinning; 260 trees per 10 a) or a tree thinning group (thinned 50% of the control; 130 trees per 10 a). The tree thinning successfully improved light penetration, yield per tree, fruit red color, and yield efficiency for 3 years