High Density “Tree Walls”1

Abstract

Abstract The general trend to higher tree density in apple orchards has been almost totally dependent on the use of the size-controlling rootstocks with more dwarfing rootstocks required as the tree density increased. With the use of such rootstocks becoming common in commercial orchards and the continued evaluation by researchers, a number of problems have become apparent including poor anchorage; greater susceptibility to winter injury, drought or “wet feet”, root rot, crown rot and fireblight; and graft incompatibility. In the case of peaches, nectarines, and other stone fruits, the lack of satisfactory size controlling rootstocks has dampened the trend to high density as observed in apple plantings. Several peach rootstocks have been evaluated and may show promise for increased hardiness or other beneficial effects but none have more than a minimal effect on size control.