XVI International Botanical Congess

During their ontogeny, the tropical lianas Bauhinia guianensis and Condylocarpon guianense produce wood types with different mechanical properties. Characterization of mechanical properties at water contents below and above fibre saturation point gave wood-type specific data for different ontogenetic stages concerning (1) longitudinal Young's modulus and longitudinal torsion modulus and (2) the damping behavior (dissipation of mechanical energy). Chemical characterization has resulted in the first quantitative data concerning the amounts of cellulose, hemicelluloses and lignin of the analyzed liana tissues and demonstrates the distinct lignification patterns of these tissues. The mechanical properties are discussed on the basis of property-density-equations, presented by Gibson & Ashby in Cellular Solids (Pergamon Press, Oxford 1988). The chemical composition and lignification patterns are interpreted in terms of their possible mechanical significance.University of Freiburg, Botanical GardenSchaenzlestrasse 1, 79104 Freiburg, Germany