PhD researcher developing technique to estimate biomass and carbon more efficiently

With climate change a pressing issue, measuring carbon in forests and understanding how efficiently carbon is stored is increasingly vital.

Tom Potter, a doctoral researcher from the Centre for Landscape and Climate Research in our Department of Geography, set out to further develop a technique to estimate biomass and carbon more efficiently, using state-of-the-art mobile LiDAR sensors across multiple and complex forest environments.

To do this, Tom took his research and GeoSLAM’s ZEB-REVO, a lightweight mobile 3D laser scanner, to the Eden Project in Cornwall, United Kingdom.

Why the Eden Project?

“I’ve assessed a broad range of forest types throughout the UK using the ZEB-REVO”, said Tom. “However, I wanted my research to include data not only relevant to the UK but also abroad, so that any new technique could be used when conducting surveys in the UK, Brazil, Congo basin and beyond. Luckily, the Eden Project in Cornwall allowed my research to look beyond the UK’s ecological landscape, at a fraction of the cost of going abroad.

“Being fairly representative of the different kinds of forests found around the world (its specimens are themed into all the different geographic regions of the world), and with a rainforest ‘biome’ of over 1,000 tropical tree and plant species, the Eden Project was the perfect location to further the scope of my research. I approached them in February 2016 with a view to using them as a ‘surrogate rainforest’ and started work shortly after.”

Why the ZEB-REVO?

Conducting his research was not without its limitations. The Eden Project reflects a true tropical forest, so its specimens are arranged in high-density plots. For fixed point scanners this creates a problem of shadows – known as ‘occlusion’ – whereby the nearest features will block out features behind. This also limits the ability to acquire accurate measurements to create a comprehensive 3D model – this is where mobile mapping has an advantage.

A 3D model of an area of the Eden Project

Furthermore, the biome that was explored - containing the Eden Project’s tropical plant and tree species - is open to the public and is a popular tourist destination, as well as requiring thorough daily maintenance and ongoing construction work. As a result, Tom was left with just over three hours most mornings – insufficient time for a traditional static survey. Surveying equipment that is mobile and able to take readings from even the densest areas, and fast, was needed to ensure precise scans were taken to calculate biomass and carbon accurately.

Given the limitations he faced, Tom found the mobility and speed of the ZEB-REVO to be the perfect solution. Weighing just 1kg, the scanner head can be pole mounted, handheld or even attached to a vehicle or drone, and collects over 43,000 measurement points per second. Instead of hundreds of time-consuming static scans, Tom was able to capture all angles by simply walking in a loop around the rainforest environment.

“Working with Dana Pertea, GeoSLAM pre-sales engineer, I was able to look at our first scan within an hour of data collection,” said Tom. "Using GeoSLAM Desktop local processing software, the raw scan data is processed on-site, with no internet connection required – useful when in an actual rainforest! This benefitted the research greatly, as it let me quickly target gaps in the data and inform where next to survey.”

Looking to the future

The next step is to convert the point cloud data into 3D volume-based plots and derive above ground biomass and carbon densities for multiple types of tropical forest. These will then be referenced against the Eden Project’s own data, which will allow the total amount of biomass and carbon above ground to be calculated in terms of a forest plot rather than specific trees above an arbitrary size.

When the current phase of his research project is complete, Tom hopes to compare his findings with datasets from overseas. After this, a comprehensive dataset can be built, containing information for any type of forest that scientists can use to make calculations with minimal survey effort or expertise.

Projects like Tom’s have only become possible with the advancement of 3D mobile survey technology, and can serve as a growing resource for the forestry industry. The technology is already changing how surveyors work in sectors such as commercial building surveying, construction and stockpile and mine mapping, taking a fraction of the time of traditional methods.

Having already been applied successfully in forestry resource management, tree counting, forest mapping and biomass removal monitoring, it’s an exciting time for the forestry industry. Mobile mapping technology allows for improved methods to monitor the health of forests around the world, and can be used to overcome global challenges along the way, such as accurately measuring the volume of carbon and how efficiently emissions are being absorbed.

• For further information on GeoSLAM and to find out more about the ZEB-REVO, visit the GeoSLAM website

Using GeoSLAM’s ZEB-REVO device to map an area in the Eden Project