STRI Internship Program


Project: Evaluating microbial-driven internal decay of living trees over time and space, and implications for tree mortality and forest dynamics

Project title

Evaluating microbial-driven internal decay of living trees over time and space, and implications for tree mortality and forest dynamics

Photo credit: STRI Panama

Mentor name

Dr. Erin Spear, STRI Staff Scientist.
Javier Ballesteros, Lab Manager


Barro Colorado Island (BCI)

Project summary and objectives

Tree death is a key process shaping forest structure and composition. When a rainforest tree dies, precious resources become available for nearby plants, the act of falling can crush adjacent trees, and biomass turns to necromass. Identification of the drivers of tree mortality is essential for predicting forest dynamics under climate and land use changes, as well as future carbon storage. Together, stem breakage and uprooting account for more than half of tree deaths, and these sources of mortality often occur when a tree has extensive internal decay (heart rot) caused by fungi. Centered on Barro Colorado Island (BCI)’s 50-ha ForestGEO plot, the research team will use sonic and electrical resistance tomography (detailed methods in Gilbert et al. 2016) to quantify internal decay (fungal heart rot) in living trees; investigate the interplay between internal decay and disturbance in shaping tree health; and complete the first long-term (10 years), large-scale measurements of heart rot dynamics in any tropical forest, allowing us to explore the causes and consequences of these infections in unprecedented depth. We will connect the internal and external health of the tree with historic damage, tree growth and mortality, and ultimately forest dynamics and carbon sequestration.

Mentorship goals

As a member of a collaborative team of ecologists, the intern will use sonic and electric resistance tomography to measure internal decay in living trees across BCI’s 50-ha ForestGEO plot. They will gain practical research experience with: sampling design and techniques; tomography equipment; tree identification; plot navigation; ImageJ; and the statistical program R. The intern will join a vibrant lab ( and broader international research community comprised of scientists at all career stages. Interns will be encouraged to co-author publications.

Desired Background

Basic understanding of plant sciences/botany/biology. Experience working in the field, particularly in hot and humid conditions, is desirable. Some experience working with spreadsheets, entering and cleaning data is also desirable.

List of suggested readings

Gilbert, G. S., Ballesteros, J. O., Barrios‐Rodriguez, C. A., et al. (2016). Use of sonic tomography to detect and quantify wood decay in living trees. Applications in Plant Sciences, 4(12), 1600060.

Putz, F. E., Coley, P. D., Lu, K., Montalvo, A., & Aiello, A. (1983). Uprooting and snapping of trees: structural determinants and ecological consequences. Canadian Journal of Forest Research, 13(5), 1011-1020.

Boddy, L. (2001). Fungal community ecology and wood decomposition processes in angiosperms: from standing tree to complete decay of coarse woody debris. Ecological Bulletins, 43-56.

Marra, R. E., Brazee, N. J., & Fraver, S. (2018). Estimating carbon loss due to internal decay in living trees using tomography: implications for forest carbon budgets. Environmental Research Letters, 13(10), 105004.

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