Relations between wood variables and how they relate to tree size variables of tropical African tree species

Abstract

To contribute to a deeper understanding of interspecific relations between wood and tree size variables, 23 angiosperm tree species in two East African rain forests were investigated. The tree size variables were maximum tree height, maximum diameter, and maximum crown area. Wood was analyzed in regard of the physical variables specific gravity, water and gas fraction as well as the chemical variables carbon content and nitrogen content. All three tree size variables showed a significantly positive relation to each other. The wood physical variables showed negative correlations between the gas fraction and both specific gravity and the water fraction. Also positive relations were found between the water fraction and nitrogen content and between wood specific gravity and carbon content. Between tree size and wood physical variables, the gas fraction showed positive relations to both maximum tree height and diameter, while wood specific gravity was negatively related to maximum tree height and diameter. No significant correlations were found between the wood physical variables and the maximum crown area. Relationships among tree size variables can be explained by static constraints, while relations between the wood physical variables can be explained by a trade-off underlying structure and survival to support the species specific life strategy and tree architecture.