Ontogenetic Growth of Cecropia pachystachya Can Explain Recent History of Swidden Agriculture in a Riparian Forest

Abstract We evaluated the pontential architectural analysis of Cecropia pachystachya to estimate tree age and reconstruct growth history in the Brazilian Cerrado. By examining internode length, branch, and inflorescence scars, we employed a retrospective method developed for Amazonian species to date growth cycles in this seasonal environment. Variations in internode length facilitated annual delimitation, with individuals producing an average of 31.4 ± 4.8 nodes per year. Most trees were approximately six years old, aligning with farmer-reported land-use history. Growth analyses indicated a biannual pattern in internode production and flowering, likely influenced by solar insolation rather than rainfall. Branching exhibited weaker, supra-annual periodicity. Despite considerable inter-individual variability in C. pachystachya, internode length remained a reliable indicator of annual growth. These findings endorse architectural analysis as a cost-effective tool for ecological monitoring and estimating pioneer species age in landscapes impacted by swidden cultivation.