Sunday, 26 October 2014

Up the Amazon

Amazing sunset from the boat as we make our way to the field station at Caxiuana.
We have been very fortunate to be invited to participate in a long-running drought experiment at Caxiuana, Para State, Brazil. The experiment is to establish what happens to the trees in the Amazon when they experience a severe drought. This has happened twice recently,with so-called 1 in a 100 year drought events occurring in 2005 and 2010. These resulted in large-scale mortality or trees and loss of carbon. But many questions remain about resilience, rates of loss and recovery and these are hugely important to understand what will happen to the Amazon under predicted increases in drought frequency and severity.

A view of some large Amazonian trees in the drought plot.
A major difficulty is quantifying the relatively subtle changes in structure that are hypothesised to occur in the upper canopy, not just the loss of large trees (or even small ones). So we are collaborating with Patrick Meir, Ed Mitchard and Lucy Rowland from the University of Edinburgh, along with their Brazilian colleagues at the Museo Goeldi in Brevez, to scan the drought plot at Caxiuana. The 1 hectare plot has had 50% rainfall exclusion for over a decade, making it one of the most droughted pieces of forest in the world. The neighbouring 1 ha plot has been set up as a control, to allow a direct comparison and assessment of the impact of drought.

We arrived this week to scan the two plots, aiming to explore the impact of drought on the canopy in terms of its strcutre, biomass and then differences in the upper canopy. The journey in and the field station and site are spectactular - 500 km by boar up-river to a beatiful, incredibly remote location. We have spent 3 days so far and have scanned nearly all of the drought plot. A few hiccups along the way, including two laptops that have expired due to the humid air, we think. We've managed to revive them with judicious drying and cooling, but we've been warned - the tropics kill electronic stuff. No kidding!