A weak relationship between crown architectural and leaf traits in saplings of eight tropical rain-forest species in Indonesia

Abstract

AbstractThere are two trade-offs at the levels of leaves and crowns, i.e. assimilation capacity per leaf mass is greater for shorter-lived leaves, and unbranched species grow faster in height by allocating carbon more to trunk than to leaves and branches compared with highly branched species. The hypotheses were tested that the degree of branching (LTB) correlates with leaf traits and that height growth rate is negatively correlated with the degree of branching and leaf life span (LLS) by examining saplings of five canopy and subcanopy species, two shrub species and one invasive subshrub species (Clidemia hirta) in a tropical rain forest, West Java, Indonesia. Of the eight species, the most and least branched species wereCastanopsis acuminatissimaandMacaranga semiglobosa, respectively. Leaf traits examined were leaf size, LLS, leaf mass per area (LMA), leaf nitrogen concentration per mass (Nmass) and per area. LLS tended to be positively correlated with LMA, and negatively correlated withNmass. Leaf size was negatively correlated withLTB, but the other leaf traits were not correlated withLTB. The height growth of the eight species was low, irrespective ofLTBand LLS, for understorey individuals. The height growth of gap individuals was negatively correlated with LLS for the eight species, and also negatively withLTBfor the seven species other than one subshrub species. Thus, the degree of branching was correlated with leaf size only among the five leaf traits, and both leaf life span and the degree of branching affected the height growth of gap individuals, except for the subshrub species.