Early growth of six native Australian tree species in windbreaks and their effect on potato growth in tropical northern Australia

Abstract

A study to examine the early growth of a number of tree species planted in windbreaks and to quantify the benefit of two 30-month-old windbreaks (one with two rows of trees and one with three rows of trees) to the production of potato (Solanum tuberosum L.) was conducted on a farm land in tropical north-eastern Australia. Three Eucalyptus (E. microcorys F. Muell, E. tessellaris F. Muell and E. torelliana F. Muell), two Callistemon (C. salignus Smith and C. viminallis Smith) and two Melaleuca species (M. armillaris Smith and M. linariifolia Smith) were used to form the windbreaks. Tree performance in the windbreaks was evaluated based on the measurements of height, height to the lowest branch, crown length along the row, and number of branches per plant. Potato vegetative growth including plant height, crown size, and leaf length, width (measured at the widest part of the leaf), and number per plant, was measured at ages 2, 4, 6 and 8 weeks. E. microcorys and E. torelliana, showed rapid height and branch growth while retaining low branches and are considered highly suitable for windbreaks. The porosity of the three row and two row windbreaks were 37.2% and 60% respectively at age 30 months. The windbreaks increased potato plant growth in height and leaf number with vegetative plants being tallest at 3 h from the windbreaks. However, the windbreaks had limited effects on leaf length and width. It was found that potato plants grown close to windbreaks yielded more potatoes than those grown at the furthest positions, with the highest production at 3 h. Overall, the windbreaks studied increased potato yield by up to 7.7%.