05.07.2024
During the course of this project, the University of Liège Gembloux Agro-Bio-Tech mobilised a wide range of skills to respond as effectively as possible to the needs expressed by the partner companies with a view to developing new species.
The PPECF and the industrial, academic and associative partners are thanked for their investment by the project managers.
The rate of reconstitution is one of the fundamental parameters of management plans. Although this rate is supposed to guarantee the sustainability of resources, it is only calculated for a single rotation, and a value of less than 100% is tolerated under current forestry legislation. However, the low regeneration rate of certain species means that the stock cannot be replenished in the long term, and we are witnessing a significant loss of production potential for certain forest species. This loss is very worrying for two main reasons. Firstly, it threatens forest biodiversity because the flora and fauna associated with the species harvested are disturbed. Secondly, it jeopardises the economic viability of companies. To remedy this situation, more and better species need to be exploited.
There are two possible ways of doing this:
As a result, the EHPVAL (species with high value-adding potential) project aimed to identify and develop high-potential tree species, both in terms of wood content and in terms of extracting high added-value biomolecules. The specific objective was therefore to increase the list of current commercial species and diversify products by focusing on species that are economically profitable to exploit and whose regeneration guarantees the sustainability of the resource. In so doing, the project aimed to reduce the harvesting of "classic" species whose regeneration is not guaranteed.
The main results achieved include:
- Characterisation of the properties of eyek wood (Pachyelasma tessmanii). It is recommended that this wood be used for cabinet-making, indoor/outdoor furniture or fittings. Harvesting of this species must be accompanied by enrichment planting, as there are few young trees in the forest.
- Characterisation of mubala wood (Pentaclethra macrophylla). This species is very present in semi-deciduous forest and large volumes are potentially available. Its wood has been characterised and is comparable to that of Bubinga, Béli or Pao Rosa, and can be used for hydraulic works, bridges, heavy carpentry, decking and terrace boards. However, processing yields are low due to the poor conformation of most of the trees (21% of trees over 40 cm belong to the first two quality classes) and to the mice that create galleries.
- The omvong (called eyoum in Cameroon) is a complex of 4 species, one of which is new to science. Only one of these species has good processing yields: Dialium polyanthum. Its wood is comparable to that of Azobé and can be used to make railway sleepers or for hydraulic engineering. Sawing it is made difficult by the silica and requires the use of carbide blades.
- Ossoko (called sorro in Gabon) (Scyphocephalium mannnii) is locally very abundant. Its wood could be used for moulding, panelling, furniture making and cabinet making. However, its bole is very grooved. In order to optimise its exploitation, the project has drawn up a cubage tariff and suggests limiting exploitation to individuals with a diameter of more than 1m20 below the flutes.
- Eveuss (Klainedoxa gabonensis) is interesting because its perfect wood can effectively replace hardwood species such as Azobé or Okan. It can therefore be used for railway sleepers, hydraulic engineering and heavy timberwork. However, perfect wood sometimes accounts for only a small proportion of logs because of the high level of transition wood. If this species is to be exploited to its full potential, it must also be possible to exploit the transition wood, which is less durable, in order to obtain sufficient yields.
- In terms of the molecules present in wood and bark, omvongs (eyoums) offer very good prospects. Significant anti-plasmodial activity has been demonstrated, as well as antioxidant and antimicrobial activity. In addition, Dialium polyanthum bark offers a promising approach to combating malaria.
