What makes for good wood?

A truckload of wood leaves a CIB sawmill. Photo by Laurenanne Mefan

The Congo Basin, which spans several Central African countries, hosts the world’s second-largest tropical rainforest. Covering over 2 million square kilometres, this vast forest is a critical asset for the planet and its inhabitants – and particularly for the countries that rely on it directly. 

The Democratic Republic of Congo (DRC), the Republic of Congo (RoC), Gabon, Cameroon, and the Central African Republic (CAR) have significant economic ties to these forests – most notably through the timber sector. In 2022, timber production in the region reached 20 million cubic metres: it’s a cornerstone of each of their economies and provides substantial income and employment opportunities for millions of people. 

RoC, for instance, derives 5.6 percent of its GDP from timber, making it the second-largest employer after the state. However, sustainable development in this sector requires a thorough understanding of the distribution and quality of the resource: timber characteristics play a crucial role in determining its uses and commercial value.

Through the EU-funded ‘Applied research in ecology and social sciences in support of sustainable management of forest ecosystems in Central Africa’ (RESSAC) programme, the Centre for International Forestry Research and World Agroforestry (CIFOR-ICRAF) is supporting a consortium to explore and better understand the ecological and genetic determinants of wood quality in various forest species that are currently harvested for timber in the RoC.

The consortium comprises researchers from RoC’s Marien Ngoubi University, the French Centre for Agricultural Research and Development (CIRAD), the Free University of Brussels, and local industrial timber company Congolaise Industrielle des Bois (CIB), which is a subsidiary of agribusiness leader Olam Agri. 

They’re investigating how environmental conditions, genetic diversity, and other factors impact the wood quality of various tree species within RoC’s native forests. “With this project, we aim to determine wood quality, which is vital to CIB and, by extension, the country’s economy,” said Richard Sufo, a scientist at CIFOR-ICRAF.   

“We believe that research has a crucial role to play in the sustainable management of Central Africa’s forests,” said Vincent Istace, Olam Agri’s sustainability director. “It allows us to better understand forest ecosystems and assess the impacts of climate change, to name just a few of its benefits. For Olam Agri, it helps us to develop more sustainable harvesting techniques in collaboration with the best specialists, and that’s the main reason why we’re engaging in it.”

The project activities officially kicked off in August of 2023, with an initial focus on CIB’s annual harvest in Kabo, a district in the far north of the country. “The primary objective was to identify the tree species present in the area,” said Tientcheu Yogom Boniface, the postdoctoral fellow involved in the project, who is based at Marien Ngoubi University. “A total of 138 tree species were identified, and 47 wood samples were collected for further research.” 

Currently, the research is centred on three main sites in Northern Congo – Kabo, Loundoungou, and Mimbeli – and focuses on four important timber species: Fraké [Terminalia superba], Ayous [Triplochiton scleroxylon], Sapelli [Entandrophragma cylindricum], and Padouk [Pterocarpus soyauxii]. The researchers have found considerable variation in wood quality within these species, which may be attributable to factors such as soil characteristics or intrinsic qualities.

Research team members carry out analysis prior to tree harvesting. Photos by Laurenne Mefan/CIFOR-ICRAF

The second stage of the research is carried out in collaboration with the harvesting team: as each tree is harvested, scientists closely follow the process, and a portion of the felled tree is then recovered and transported to CIRAD in Montpellier, France. 

“At CIRAD, anatomical and quality analysis as well as infrared spectroscopy analysis are conducted on the wood samples,” said Boniface. “These analyses allow us to identify various wood qualities, including density, strength, and other relevant characteristics that we aim to preserve.”

Team members examine a tree stump in the forestry area. Photo by Laureanne Mefan/CIFOR-ICRAF

Leaves and cambium samples are also gathered and transported to the Free University of Brussels for genetic analysis. The morphometric, ecological, and genetic data collected is then combined and analyzed to uncover the origins of the wood’s quality. 

The process sometimes includes teasing out cases where several species are grouped under a single forest species name, which can mask variations in physicochemical properties and wood quality. Such misrepresentation can be misleading for end users, and underscores the importance of this research. 

The project also contributes to training master’s students and junior researchers within the research community. Most importantly, it benefits CIB by enhancing its understanding of wood properties and positioning in the market. Ultimately, the knowledge gained will inform better use of wood sourced from the Congo forests, for the long-term benefit of its people and ecosystems.

Acknowledgements

This research is sponsored by the RESSAC (Applied research in ecology and social sciences in support of sustainable management of forest ecosystems in Central Africa) programme. Funded by European Union, this programme aims to focus research work on the ‘oprational solutions’ that need to be invented and implemented by local stakeholders, who are faced with the concrete challenges of sustainable natural resource management as part of their mandates or their day-to-day sociao-economic activities.