Tree Damage as an Ecological Process: Evidence from a Pantropical Monitoring Program
Daniel Zuleta1* (ZuletaD@si.edu), Gabriel Arellano2, Sean M. McMahon1,3, Salomón Aguilar4, Sarayudh Bunyavejchewin5, Dairon Cárdenas6, Chia-Hao Chang-Yang7, Alvaro Duque8, Musalmah Nasardin9, Rolando Pérez4, I-Fang Sun10, Yao Tze Leong9, Renato Valencia11, Stuart J. Davies1, Jeffrey Chambers12
1Forest Global Earth Observatory, Smithsonian Tropical Research Institute, Washington, DC; 2Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI; 3Smithsonian Environmental Research Center, Edgewater, MD; 4Smithsonian Tropical Research Institute, Balboa, República de Panamá; 5Forest Research Office, Department of National Parks, Wildlife, and Plant Conservation, Bangkok, Thailand; 6Herbario Amazónico Colombiano, Instituto Amazónico de Investigaciones Científicas (SINCHI), Bogotá, Colombia; 7Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan; 8Departamento de Ciencias Forestales, Universidad Nacional de Colombia–Sede Medellín, Colombia; 9Forestry and Environment Division, Forest Research Institute Malaysia, Selangor, Malaysia; 10Center for Interdisciplinary Research on Ecology and Sustainability, National Dong Hwa University, Hualien, Taiwan; 11Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador; 12Lawrence Berkeley National Laboratory, Berkeley, CA
Forests are key to mitigating climate change. However, large uncertainties remain on how these ecosystems will respond to future environmental changes, especially in the tropics, where high species diversity implies different responses to a particular stressor. Here, evidence is presented of a key, but underappreciated, ecological process in the dynamics of tropical forests: tree damage. Observations were used from 29 annual mortality and damage censuses across seven tropical forest plots of the Forest Global Earth Observatory network in the neotropics and Asia to study the role that damage to living trees has on forest dynamics. Tree damage was one of the most important mortality risk factors and contributed to a substantial, yet rarely quantified, proportion of total forest biomass losses in these forests. Researchers also showed that conventional forest inventories that ignore tree damage result in: (1) overestimates of aboveground biomass (AGB) stocks by 4% (1 to 17% range across forests) because they assume that trees are structurally completes, (2) underestimates of total AGB loss by 29% (6 to 57% range across forests) due to overlooked damage-related AGB losses, and (3) overestimates of AGB loss via mortality by 22% (7 to 80% range across forests) because of the assumption that trees are undamaged before dying. Damage on living trees is likely to become more important as the frequency and severity of forest disturbances increase.