Morphological variation of Cedrela odorata (Meliaceae): contrast between natural and managed populations

Abstract

Background and Aims: Cedrela odorata (Spanish cedar) is a tropical tree native to America with an important international trade market. In this study, the morphological variation of C. odorata was compared among three conditions: logging, plantations, and natural populations, with the objective to evaluate the current condition of managed populations after harvesting and in plantations, in contrast to relatively well-preserved populations.Methods: Two sites were chosen for each condition. The population density and four morphological attributes were measured: diameter at breast height, height, angle of branch insertion and crown form. A multivariate approach was used to compare the morphological variation among conditions (generalized discriminant factors analysis) and determine total variation distributed among size classes (cluster analysis), as well as assignment of these classes to each condition (canonical correspondence analysis).Key results: Four significantly different size classes were identified among all populations with specific association to condition. Strongest correlations were between highest trees with natural populations and small trees with plantations. Forest management, including harvesting and plantation conditions, reduced the phenotypical variation and modified the dasometrical attributes of C. odorata. The logging of the better shaped phenotypes increased the smaller size trees frequency compared to commercial size individuals, and changed the forest composition favoring small categories.Conclusions: The forest exploitation generates homogenization in median height-class and the plantation in lower height-class. In both cases, the harvestable trees are scarce, even after 20 years of management; and they are non-existent in plantations of 15 years. These results suggest that the removal of the highest trees, as well as forest plantations, are not being effective to wood production since they do not reach commercial sizes in the time of recovery or projected growth.