Leaf optical properties in Venezuelan cloud forest trees

Leaf optical properties and related leaf characteristics were compared for thirteen cloud forest tree species differing in successional status. Sun le aves were sampled for the eight pioneer species and sun and shade leaves we re sampled for the five climax species. Sun leaves had a slightly higher ab sorptance than shade leaves, although differences were small. Sun leaves ha d a higher leaf mass per unit area (LMA) and a lower chlorophyll concentrat ion per unit leaf mass, resulting in similar chlorophyll concentrations per unit leaf area and hence similar light harvesting capacities as shade leav es. However, shade leaves realized a higher efficiency of absorptance per u nit leaf biomass than sun leaves. There were few differences in leaf charac teristics of sun leaves between the climax and pioneer species. Absorptance values of cloud forest species were comparable with values reported for ra in forest and more seasonal forest species. Intraspecific variation in leaf absorptance was largely the result of variation in LMA, whereas interspeci fic variation in leaf absorptance was largely a result of variation in chlo rophyll concentration per unit leaf area.