WIND STRESS ON YOUNG ORCHARD TREES

Abstract

Tree growth and leaf water stress measurements were taken on 3 year old Red Fuji apple and 5 year old Fayette peach trees under drip irrigation. Measurements on apples were taken from trees growing at specific distances away from a 6m high Eucalyptus windbreak perpendicular to prevailing winds and apple rows. Total wind run was measured in 3 locations within apple rows. Total branch growth and trunk circumference data can be related to windspeeds, apple tree row self sheltering, and shade from the windbreak. The most total growth occurred within a distance 42m from the wind break. Measurement on peaches were taken from trees growing down a slope. Constant windspeed and direction was collected from anemometers located at the top and bottom of the hill. Trunk circumference and total tree growth increased as wind exposure decreased. Trees exposed to 11.9 kph winds had a smaller leaf temperature-air temperature differential compared to trees exposed to 9.4 kph. Leaf stomatal resistance and water potential data suggest that trees exposed to wind were under water stress. Even a slight difference in wind exposure caused water stress responses.