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Climate change, photosynthesis and tree growth in tropical montane forest

Supervisor: Edmund Tanner

Reference code: C142

Importance of the area of research:  Climate change is easily seen in tropical montane rain forests (e.g. Pounds et al 1999), but the relative importance of changes in light (due to less fog) or changes in temperature is not clear. It is possible to distinguish the two effects by comparing the growth of potted plants in judiciously chosen of sites in tropical montane forest where climate is measured.

What the project will involve:  

Potted tree seedlings and saplings will be grown in natural soil and moved to specifically chosen sites in the mountains of Panama, which vary in their temperature, their light environment. From measurements of growth, photosynthesis and other physiological variables (e.g. stomatal conductance and leaf temperature) it will be possible to infer the major factors limiting photosynthesis and growth, and how these might change as a result of global climate change. Other experiment could include eliminating the low light on foggy days by providing extra illumination (a scaled down version of the “stadium lights experiment” of Graham et al 2003).

What the student will be doing:  Based at the Smithsonian Tropical Research Institute in Panama, and in conjunction with Dr K Winter, the student will set up potted plants of relevant lowland and montane species and transport them to suitable field sites where the light and temperature are measured. They will measure growth, photosynthesis and other parameters in the potted plants in the various locations. Data will be analyzed to assess the importance of species, light and temperature on growth and physiological parameters.

Training that will be provided:  The student will be given training and supervision in making physiological measurements, first in Cambridge and then in the Winter Lab. At STRI in Panama. Training in experimental design, and the analysis of experimental data, analyzing data and writing papers will also be given.

Field work funding. We will apply to the Cambridge Fieldwork Fund.


Graham, E.A., Mulkey, S.S., Kitajima. K., Phillips, N.G., and Wright, S.J. (2003) Cloud cover limits net CO2 uptake and growth of a rainforest tree during tropical rainy seasons. Proceedings of the National Academy of Sciences, 100, 572 - 576.

Pounds, JA; Fogden, MPL; Campbell, JH (1999) Biological response to climate change on a tropical mountain. Nature 398, 611-615.