Mopane "bricks" for green energy?
A sustainable source of wood may be on the cards, thanks to the bush clearing project in Kruger National Park, known as Working for Woodlands.
By Bonny Bridgeford, Health and Safety Co-ordination & Support Technician, Invasive Species Clearing Unit, South African National Parks (SANParks).
Kruger National Park has a total road network of 1750 km gravel and 910 km of tar road. Due to the impact of the road networks, some areas are experiencing bush encroachment by indigenous plant species. Bush encroachment is a term used for “stands of listed plants where individual plants are closer to each other than three times the mean crown diameter”.
Plants in this group are not alien plants, but indigenous plants that tend to become abnormally abundant when areas are disturbed/ degraded due to unnatural conditions within the ecosystem, such as excessive water run off caused by the roads. The tree densities here are denser and the canopies are much closer to each other. This effect can be noticed up to 15 m from the road.
Within the KNP, Colophospermum mopane (Mopane), found mostly in the northern region of the park, is a declared indicator of bush encroachment. The KNP Bush clearing initiative funded through the Department of Water Affairs (DWA) was introduced to tackle this problem. The Park is experimenting with different removal methods and the team is currently clearing approximately 70% of the Mopane trees within 15m of the road edges. All established trees with a circumference of more than 25cm will not be removed.
The project currently employs 35 people from the local communities and is skilling workers to become machine operators. A total of between 2350 and 2950 hectares will be cleared within the project period.
The intention is to create a sustainable project were Mopane that is removed is not treated with herbicide. This will allow the Mopane to regenerate and then provide a sustainable source of wood for the longer term.
Some research has been conducted into the possibility of using the entire Mopane tree for the creation of a “Mopane brick” which can be used as an energy source in the same way as charcoal. Chipping of the tree is followed by drying and compacting to processing all parts of the tree in an environmentally friendly process – resulting in the perfect “green” energy source.