抄録
Leaf longevity of tropical shrub species was examined with reference to the intensity of disturbance. Species with lower stem hardness likely prioritize a higher volume of growth at early growth stages over the physical strength of the stem. This trait is thought to be advantageous for species suffering frequent disturbance, thus it is believed that stem hardness could be used as a measure of adaptability to disturbance. The weight ratio of leaves to stalks on a twig is an important parameter to assess the leaf longevity satisfying the minimum maintenance costs of a twig. In this study, the leaf longevity of shrubs was shown to be reciprocally related to the weight ratio. Based on this relationship, it was revealed that these species gain suitable leaf longevity by regulating this weight ratio under conditions of the minimum maintenance. A positive correlation between leaf longevity and stem hardness was also observed among shrub species. Assessment of the niche of these species in a secondary sere according to stem hardness verified that leaf longevity increases with progressing succession as a result of regulation of the weight ratio.
