|Title: ||The potential and risks of using exotics for the rehabilitation of Ethiopian dryland forest|
|Authors: ||Van Wyk, Gerrit ×|
Muys, Bart #
|Issue Date: ||2007 |
|Series Title: ||Journal of the Drylands vol:1 pages:148-157|
|Abstract: ||Climax tree species normally would fulfill the ultimate function at the end of the succession chain when land is rehabilitated. In the natural forest such trees would eventually be the veterans of the primary forest that usually replace pioneer trees of the secondary forests. Exotic trees, when used for plantations, usually fill the role of pioneers because they capture a degraded site easily.
Such capturing of the site would depend on the site conditions as well as the adaptation of the species being used. Once the species grow well, it may be a deliberate decision not to replace such pioneers with climax forest species, the reason being the useful role that exotic species could play in the economy of the region concerned. However, there also may be risks involved in using exotic species in such an interrupted succession chain. Case studies from South Africa are discussed to, firstly, illustrate the potential of exotics, especially eucalypts, in providing much needed timber while also protecting the natural forest. These species, when genetically improved, can reach yields of more than 20 m3·ha-1·year-1, even under relatively dry conditions. Secondly, the risk of using exotics, such as eucalypts and Australian Acacias, e.g. in terms of water use, uncontrolled spread and destruction of local biodiversity, is discussed and examples are given of management procedures to manage the risks. Finally, some suggestions are proposed on strategies to be followed for the use of exotics in the Ethiopian highlands, especially on the questions how much, where and how to use them. It is pointed out that, with sufficient control, including spatial planning, policy and legislation, exotic species could play an important role in filling economic and social demands that need not be in conflict with environmental objectives.
|Publication status: ||published|
|KU Leuven publication type: ||IT|
|Appears in Collections:||Division Forest, Nature and Landscape Research|