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School of Geography

Alex Chambers-Ostler Alex Chambers-Ostler

Contact details

School of Geography
University of Leeds
University Road
Leeds LS2 9JT   UK



Project title

The role of hydraulic limitation in determining maximum tree height attainment across a tropical moisture gradient?

Project overview

Taller trees hold greater biomass, dictate ecosystem structure and increase biodiversity. The global trend is for taller trees to persist in wetter environments, however, few studies have attempted to determine the mechanistic drivers of such trends. The hydraulic limitation hypothesis proposes that as height increases, the amount of work needed to pull water up also increases, due to increasing resistance. There are ecophysiological trade-offs that can be made that allow the transport of water at greater heights. However, these imply differences in competitive ability or safety against embolism.

This project will determine whether tree height is limited by water availability across a range of sites by analysing hydraulic traits that convey the trade-offs that trees might make in order to achieve the maximum height possible. Different trees may utilise different hydraulic strategies, and therefore different species will be used that are present across a large moisture gradient.

Initial analysis shows tree height across South America to increase with water availability up to a point, after which tree height does not increase any further. If, as hypothesised, water availability determines tree height up this point, a different factor is likely to be limiting height attainment in the wetter portion of the range, such as nutrient availability.


This project will aim to understand the role of hydraulics in determining maximum height attainment across a pronounced moisture gradient. This will allow an understanding of the mechanisms underlying the changes in forest height seen across South America, and provide an insight into how future climate shifts may influence the ability of forests to store carbon.


Research Affiliations

Ecology and Global Change


NERC studentship

Short Curriculum Vitae

Link to CV