dead tree

Tree Mortality & Damage


Tree mortality is a key component of forest functioning and dynamics, affecting forest structure, community composition, and biogeochemical cycles. Yet, much uncertainty remains on the causes and consequences of tree mortality, especially in diverse tropical forests where species may vary widely in their responses to particular conditions. To tackle this knowledge gap, ForestGEO established a program of frequent tree damage and death assessments across multiple plots. The sampling design, the description and rationale of the variables collected for each tree were published in Arellano et al. 2021.

To date, this program has:

  1. identified critical challenges when estimating changes in tree mortality (McMahon et al. 2019),
  2. contributed to the development of volume models to quantify tree damage (Zuleta et al., 2022a),
  3. provided a ranking of importance of tree mortality risk factors across tropical forests (Zuleta et al., 2022b),
  4. quantified carbon losses associated with tree damage and mortality (Zuleta et al., 2023), and
  5. contributed to the parametrization of a crown damage module in the FATES vegetation model (Needham et al., 2022).

While this program focuses on large forest plots, the protocol herein aims to assess factors at the stem level and, thus, can be used as a guide to assess tree vigor and death in smaller forest plots or projects with different tree sampling designs. For specific questions regarding the protocol, please contact Gabriel Arellano ( or Daniel Zuleta (

This work is part of the Next Generation Ecosystem Experiments-Tropics, funded by the US Department of Energy, Office of Science, Office of Biological and Environmental Research.

Example datasheets for fieldwork: in English | in Spanish
Protocol for fieldwork: in English | in Spanish


Arellano, G., Medina, N.G., Tan, S., Mohamad, M. and Davies, S.J. (2019), Crown damage and the mortality of tropical trees. New Phytol, 221: 169-179.

McMahon, S. M., G. Arellano, and Davies S. J. (2019), The importance and challenges of detecting changes in forest mortality rates. Ecosphere 10(2):e02615. 10.1002/ecs2.2615

Arellano, G., Zuleta, D., & Davies, S. J. (2021). Tree death and damage: a standardized protocol for frequent surveys in tropical forests. Journal of Vegetation Science, e12981.

Needham, J. F., Arellano, G., Davies, S. J., Fisher, R. A., Hammer, V., Knox, R. G., Mitre, D., Muller-Landau, H. C., Zuleta, D., & Koven, C. D. (2022). Tree crown damage and its effects on forest carbon cycling in a tropical forest. Global Change Biology, 28, 5560–5574.

Zuleta, D., Krishna Moorthy, S.M., Arellano, G., Verbeeck, H., and Davies, S.J. (2022a). Vertical distribution of trunk and crown volume in tropical trees. Forest Ecology and Management, 508: 120056.

Zuleta, D., Arellano, G., Muller-Landau, H.C., McMahon, S.M., Aguilar, S., Bunyavejchewin, S., Cárdenas, D., Chang-Yang, C.-H., Duque, A., Mitre, D., Nasardin, M., Pérez, R., Sun, I.-F., Yao, T.L. and Davies, S.J. (2022b), Individual tree damage dominates mortality risk factors across six tropical forests. New Phytologist, 233: 705-721.

Zuleta, D., Arellano, G., McMahon, S. M., Aguilar, S., Bunyavejchewin, S., Castaño, N., Chang-Yang, C.-H., Duque, A., Mitre, D., Nasardin, M., Pérez, R., Sun, I.-F., Yao, T. L., Valencia, R., Krishna Moorthy, S. M., Verbeeck, H., & Davies, S. J. (2023). Damage to living trees contributes to almost half of the biomass losses in tropical forests. Global Change Biology, 29, 3409–3420.