Root distribution in an Amazonian seasonal forest as derived from delta C-13 profiles

Carbon isotope ratios of the main stem in trees, saplings, and seedlings we re correlated with their main stem diameter in an Amazonian seasonal forest . This correlation became the basis of using carbon isotope ratios of roots from various levels of the soil profile in order to determine root distrib ution from emergent, canopy and subcanopy trees, saplings and herbaceous un derstorey plants. It was observed that the distribution of roots in the soi l profile is horizontally and vertically heterogeneous. Pockets of roots fr om saplings or herbaceous understorey plants were found as deep as 4 m and pockets of roots from emergent trees were found as shallow as 1 m depth.