The use of treeshelters and application of stumping in the establishment of walnut (Juglans regia)

Abstract

The effects of three treeshelter treatments (none, 75 cm and 120 cm tall) and a stumping treatment on establishment of walnut (Juglans regia L.) were tested over four growing seasons. Treeshelters were beneficiai for both tree height increment and stem diameter growth. However, the 120 cm tall shelters promoted earlier fiushing than the other shelter treatments, resulting in a risk of increased frost damage. Additionally, a substantial degree of stem dieback occurred during one dormant season in the 120 cm shelters when 46 per cent of tree height was lost, whereas there were no significant differences for dieback between those trees without shelters and those in 75 cm shelters (20 per cent and 15 per cent, respectively). Medium-sized (60 or 75 cm) shelters are therefore recommended where possible for the successful establishment of walnut. Stumping promoted rapid early height increment but gave no longer-term benefit, as stumped trees never attained a height equal to intact trees. There were no significant interactions between treeshelter and stumping treatments.