Nutrient accumulation in aboveground biomass of planted tropical trees: a meta-analysis

Abstract

<div><p></p><p>Efficient nutrient use is essential for biomass production by tropical trees growing in infertile soils. Accumulation of nitrogen (N) and phosphorus (P) in the aboveground biomass of four groups of tree stands [<i>Acacia</i>, <i>Eucalyptus</i>, N₂-fixing trees excluding <i>Acacia</i>, and other non-N₂-fixing broadleaved (ONNFB) trees] were investigated using meta-analyses of a range of biomass data to test the hypothesis that fast-growing <i>Acacia</i> and <i>Eucalyptus</i> trees accumulate fewer nutrients. Data for 83 tropical tree stands were selected from the literature. Standardized major axis regressions were applied between the log₁₀-transformed biomass and N or P accumulation. Nutrient use efficiency was compared with aboveground biomass and topsoil conditions. The slope of the regression between aboveground biomass and N accumulation for <i>Eucalyptus</i> was significantly smaller than the slopes for the N₂-fixing trees (excluding <i>Acacia</i>) and the ONNFB trees. N use efficiency of <i>Eucalyptus</i> increased with biomass more than that of N₂-fixing trees (excluding <i>Acacia</i>) and the ONNFB trees, because their stems and twigs tended to accumulate less N than in the other groups as biomass increased. The regressions between aboveground biomass and P accumulation had a common slope, and the intercepts of <i>Acacia</i> and <i>Eucalyptus</i> were significantly lower than that of ONNFB trees. P use efficiency of <i>Acacia</i> was consistently higher than that of the ONNFB trees. P use efficiency is more affected by other factors like soil conditions than is N use efficiency, and the differences in the tree groups significantly affect the use efficiency of both nutrients. These results explained some aspects of the general suitability of <i>Acacia</i> and <i>Eucalyptus</i> species for tropical plantations on infertile soils.</p></div