Hurricane Damage to Mahogany Crowns Associated with Seed Source

Abstract

The International Institute of Tropical Forestry’s mahogany provenance test was established with collections from México, Central America, and the Caribbean. In 1989, when the trees were 26 years old, Hurricane Hugo damaged three of the stands in Puerto Rico and St. Croix, U.S. Virgin Islands. Four months after the storm, tree diameters were measured, and the percentage of the crowns of trees removed by the storm was estimated. Nearly 4 years later, the percentage of the normal crown complement then present was estimated. Using analysis of covariance, with site and poststorm diameter as covariants, the effect of provenance (16 seed sources) was evaluated. The percentage of crown lost in the storm was significantly influenced by provenance. Percentage of full crown volume 4 years after the storm was significant, but it was probably more an effect of the original loss than of regrowth. Small-leaf mahogany and the northern sources of big-leaf mahogany were the most resistant to storm damage; Pacific coast mahogany and the southern sources of big-leaf mahogany were most affected. Crown recovery, measured by change in percentage of the estimated full crown complement over the 4-year period between measurements, was significantly affected by provenance. Those provenances suffering the greatest crown loss tended to make a greater percentage recovery, although they did not catch up with those provenances that had suffered less initially.