Growth of Small-Leaf Mahogany Crop Trees in St. Croix, U.S. Virgin Islands

Abstract

Small-leaf mahogany, introduced to St. Croix in the U.S. Virgin Islands more than 200 years ago, has naturalized widely and now dominates Estate Thomas, a small USDA Forest Service property characterized by shallow, very stony soil. In 1962, 109 mahogany trees were liberated from competition and measured periodically until 1996. The study trees averaged 20 cm in diameter at the start of the study and 29 cm at the final measurement, when the total height averaged 11m and the merchantable height averaged 4 m. Although the study trees increased in diameter very slowly (0.25 cm yr⁻¹) during the 34-year period, they grew about 50% faster than the unthinned control trees. Mortality during the period was 17%, most of it the result of a hurricane that struck in 1989. The trees are minimally merchantable now at about 82 years old and would be about 170 years old at a more favorable diameter of 0.5 m.