Strong impacts of lianas on tree allometry lead to overestimation of tropical forest carbon stocks and sink

Abstract Lianas are quintessential components of tropical forests competing strongly with trees for resources. Yet, their role in the structure and functioning of forests is rarely studied. Here, we investigate the impact of lianas on the carbon stocks and sink potential of an intact moist tropical forest in Panama using 3D terrestrial laser scanning. We find that liana-infested trees are significantly shorter with smaller crown areas, thereby resulting in a significant liana-induced reduction in stand-level carbon stocks (5.3%) and coarse woody productivity (24.5%). The widely used pantropical allometric model overestimates the carbon stocks by 10% and underestimates the liana impact on woody productivity by 1.5% at the study site with current infestation level. Increasing liana abundance across Neotropics will further worsen this impact. We show that by ignoring liana impact in carbon estimation, we are currently overestimating the potential of nature-based climate solutions to lock up atmospheric carbon.