Adventures with a laser scanner: FACE time

Our latest trip was to the Amazon again, this time to the ZF2 forest site, north of Manaus, central Amazonia.

Hellooooo Amazonia!

Field station at the ZF2 research site.

The Brazilian government are funding an extremely ambitious new Free Air CO2 Enrichment (FACE) experiment at the site, to try and answer the question "What will the Amazon rainforest response be to elevated CO2 levels over the next century or so?" See the Science feature on the experiment from May 2016.

Model projections of change in the Amazon over the next century. From Lapola et al. (2009).

These FACE experiments are a well-established, if logistically challenging way to take a peek into the future and look at large-scale ecosystem response to climate. FACE experiments are an attempt to duplicate the kind of treatment/control replicate lab experiments we are all familiar with. But full scale! There have been a wide range of these projects over the last 20 years or so, in a range of ecosystems, but never in the Amazon. Until now.

Upward-looking panorama of the FACE ring tower and canopy.

AmazonFACE is establishing 8 30m diameter rings, each with a tower in the centres, which will have CO2 piped into the canopy, raising the ambient CO2 to around 600 ppm (50% or so above current normal levels) for the next 10-15 years. The rings span a range of forest conditions, and have paired plots fairly nearby which will be the controls. Within the rings, and at the wider site, the climate and wide range of soil, plant, biotic responses will be measured, as the rings are established and the CO2 is switched on (planned for start 2018).

We were very privileged to be invited by Prof. David Lapola and his AmazonFACE team to come and use our lidar to scan the FACE rings at the outset of the experiment, to try and characterise the plot biomass and structure. We also aim to establish a baseline of the canopy structure against which future changes can be compared, as well as to try and unpick the structural differences between the rings at the outset.

A single scan from our Riegl, centred on the middle of one of the AmazonFACE rings (colour is vertical height, from blue to green).

A close up of a single scan within the ring above, showing the tower at the centre. Some of our reflector targets can be seen in bright red to the right of the large tree in the centre (colour represents return intensity of the laser pulse, from blue to red).

Top view of scan taken using our ZEB-REVO mobile laser scanner, with the tower visible in the centre (colour represents vertical height, from blue to green).

After some amazing logistical and paperwork help from David and his team, particularly Bruno Takeshi who is the guy who does everything (including driving through and over and fallen trees!), Matheus and I spent a very busy few days scanning the FACE rings with our lidar. We had a great deal of help from Dr. Florian Hofhansl, the resident ecophysiology expert, and other station researchers. We collected 8 rings with our Riegl and I also managed to scan them with our GeoSLAM ZEB-REVO. Florian's overview of the experiment is really informative, with detailed maps and plans etc. Check it out.

Despite some minor travel hiccups (losing not one, but both our laptops, on different flights; we got them back, albeit one only on the way back out), the occasional unseasonal tropical downpour, fallen trees and getting savaged by some tiny horrors (me), the expedition has been a great success and I'm really excited about the results. It's also been great to establish some new research collaborations with the Brazilian AmazonFACE team and their colleagues from elsewhere. Huge thanks to the team and cNPQ, INPA and the colleagues, for bringing us out and organising the trip.