Forests act as both a carbon sink by absorbing carbon dioxide (CO2) from the atmosphere, and a carbon source emitted by forestry. This makes them a key link in understanding how climate change will unfurl, and in managing its effects. Yet little is understood about forests’ double-edged role. An EU-funded project tracked tree growth and carbon emissions in forests across Europe and South Africa, drawing lessons for the sustainable management of Europe's more temperate, but warming, forests.
Clear is that more needs to be done to boost forest’s carbon sink function, and minimise their carbon emissions. Scientists working on the 3-year EU-funded project CLIMATE-FIT FORESTS which was concluded April 2015, improved knowledge of the carbon functions of forests and forestry. Their research will feed into efforts to predict how climate change could affect tree growth in European forests, and reduce its impact.
Meanwhile, the tools they developed deepen knowledge of the amounts of carbon emitted by different forest harvesting systems, reducing the impact of forests as a carbon source.
Pre-empting a warmer and drier climate
The EUR 205 800 project was coordinated by the German partners, Technische Universität München (TUM), Chair of Forest Yield Science and the team of scientists studied forests on a north to south ‘climate gradient’, comparing central European forests in Germany, Switzerland and Italy to those in South Africa, where warmer and drier conditions are already present.
By studying South African forests we intended to pre-empt what could happen in European forests, which will be exposed to conditions similar to those in South Africa today if climate change predictions hold true, explained Enno Uhl, the project coordinator at TUM.
Variable shoot and root growth rates
The team used an approach that draws together existing strands of forest science. They used dendroecology, for example, which involves studying the spacing between the annual growth of tree rings, tree physiology and forest modelling. Their work covered a wide range of scales from plant organ – such as roots and shoots – and tree scale, to an entire forest, aiming to understand forests as a carbon sink as holistically as possible.
We found that forests in the temperate climates of Central Europe are currently experiencing accelerated growth rates, which leads to higher rates of carbon absorption. We also uncovered that trees react to changes in climatic conditions by varying the growth rates of their roots and their shoots. Drier conditions lead to greater growth in root compared to shoots, said Uhl.
Uhl believes that this knowledge can help improve estimations of the amount of carbon in a forest – and therefore its role as a carbon sink – by understanding root growth.
Forst machine operations software
Meanwhile, they looked into forestry operations to uncover the different sources of carbon release and developed a tool for measuring carbon release – or fuel consumption – by machines used. The Integrated Forest Operations Software (iFOS) can be used by the forestry industry to monitor, assess and reduce the CO2 footprint of forest machines.
CLIMATE-FIT FORESTS created a database – called CO2 FORMEC – of carbon emissions from forest operations in the countries studied. It tracks emissions from more than 500 forestry operations, allowing for an overview emission quantities in different harvesting systems.
Our project has helped support forestry by providing information on how to reduce emissions and improve forest productivity. This, in turn, has a positive impact on the environment by reducing forest’s carbon source function, said Uhl.
During the project, 30 fellows were funded as part of the international research staff exchange scheme under the EU’s Marie Curie funding programme. Project results have been published in several scientific papers, and have triggered further studies by project partners. Meanwhile, the forestry industry in South Africa is using CLIMATE-FIT FOREST findings to help plan and improve its operations.