Height growth strategies of Mimosa scabrella along a chronosequence

Abstract

Assessing variations in tree allometry is useful for understanding height growth strategies in relation to life-history trajectories, light competition and environmental restrictions. Scaling exponent and asymptotic heights obtained from height–diameter (HD) models may elucidate how trees optimise growth strategies and the potential drivers that influence tree height. Our main objective was to explore how the HD relationship in Bracatinga (Mimosa scabrella) varies along stands chronosequence and life history. The study was carried out in discontinuous stands located across the metropolitan region of Curitiba, southern Brazil. We used HD data from 300 temporary plots in chronosequences dating from a disturbance, which represented stand development after intervention, covering the life history of the species. Power and exponential models were fitted to data to describe the HD relationship over time. Mixed-effects models were applied to explain the height variations by stand characteristics. We found that tree height and allometry were influenced by stand development phase and tree life stage along the chronosequence. Changes in tree height were also driven by light competition related to certain stand characteristics, such as basal area, stem density and species diversity. We concluded that growth strategies are conditioned by interactions between light requirements along a tree’s life history and successional stand evolution. The results revealed that gradual changes in tree development might be recognised by stationary data along chronosequences. Quantifying changes in HD allometry has ecological and practical applications for explaining the strategies and drivers underpinning tree growth and providing useful knowledge for improving growing stock predictions and stand management.