Howard walnut trees can be brought into bearing without annual pruning
General Material Designation
[Article]
First Statement of Responsibility
Lampinen, Bruce D; Edstrom, John; Metcalf, Samuel; Stewart, William L; Negron, Claudia M; Contador, M. Loreto
SUMMARY OR ABSTRACT
Text of Note
In traditionally managed Howard walnut orchards, trees are pruned annually during the orchard development phase, an expensive operation in terms of labor and prunings disposal costs. Our observations and some prior research by others had suggested that pruning may not be necessary in walnut. In a trial of pruned and unpruned hedgerow trees over 8 years, beginning a year after planting, we documented canopy growth, tree height, yield and nut quality characteristics and also the effects of fruit removal. Pruning altered canopy shape but did not lead to increases in canopy development, yield or nut quality. Although fruit removal stimulated more vegetative growth in both the pruned and unpruned treatments, fruit removal did not result in an increase in midday canopy photosynthetically active radiation interception or cumulative yield when fruit removal was stopped after year 4. After 8 years, there were no significant differences in tree height, nut quality or cumulative yield among any of the treatments, which suggests that not pruning young Howard orchards could provide a net benefit to growers.
SET
Date of Publication
2015
Title
California Agriculture
Volume Number
69/2
PERSONAL NAME - PRIMARY RESPONSIBILITY
Entry Element
Lampinen, Bruce D; Edstrom, John; Metcalf, Samuel; Stewart, William L; Negron, Claudia M; Contador, M. Loreto