3.1. In situ conservation activities
3.2. Ex situ conservation activities
3.3 Selection and genetic improvement
3.4. National priority species
Protected areas
Approximately 32,729 hectares, representing about 7 %, constitute the 66 gazetted forest parks located in different parts of the country. These are mainly on poor soils.
In the early 1950s, the colonial administration placed particular emphasis on Borassus aethiopum (Rhun palm) and Bambusa spp. (Bamboo) areas in recognition of anticipated future dependency on these species for improved housing. Other major timber tree species such as Khaya senegalensis (mahogany) and Milicia regia (Iroko) and others were equally protected in natural stands. Until 1983 no forest management plans were established for the individual forest parks or plant species, with the exception of the Gmelina plantations.
Following the 1983 inventory results, 7 of the gazetted national forest parks were brought under management. There have been 10 others since 1996. Most of these parks are within the Western, Lower River and Central River Divisions. The management plan for each of these parks makes provision for the conservation of indigenous (especially when threatened) plant species common in the area. More emphasis is placed on in-situ natural regeneration, than artificial and ex-situ regeneration.
Traditional agroforestry parklands systems
Little or no woodland cover characterizes areas of intensive cultivation. These areas are noted for large and widely spaced tree species such as Parkia biglobosa, Bombax buonopozense, Khaya senegalensis, Acacia albida, and Adansonia digitata. Cordyla africana (Bush mango) and Elaeis guineensis (oil palm) provide lots of by-products (fruits, palm oil, palm wine) than the primary use of the wood. Such species are most often found on farmlands and are protected by local farming communities. Combretum sp., Pterocarpus erinaceus and Terminalia macroptera are less suitable or are other wise more adaptive and tolerant to annual bush fires. They are therefore found in all areas including farmlands.
Forest enrichment
The conservation of some economically valuable timber tree species is promoted through enrichment planting. The seedlings are often raised in the nursery and include Antiaris africana, Afzelia africana, Albizzia ferruginea, Anacardium occidentale, Ceiba pentandra, Cordylla africana, Daniellia oliveri, Eucalyptus camaldulensis, Khaya senegalensis, Leucaena leucocephala, Lophira lanceolata, Parkia biglobosa, Prosopis africana (provenances of The Gambia and Senegal), Pterocarpus erinaceus and Tectona grandis.
Currently there is no ex-situ conservation collection programme for forest tree species. Seeds of both exotic and indigenous species, when acquired are often stored in an open wood shelf under normal temperature conditions before sowing. There are no nationally recognized seed sources; the managed forest parks could serve as seed sources. Some of the unmanaged parks with relatively good stands in respect of species diversity and population could equally be potential sources for seed production and supply without treatment. Seed collection in most cases is contracted to unprofessional individuals in the villages with little or no control of the provenances, collection process, seed handling and storage for quality production. Nursery attendants are also engaged in seed collection. There is need for improvement in the mechanism for seed collection, and in the training of seed collectors in situ and ex-situ conservation.
Species trials
Currently little is known about our indigenous tree species in respect of their characteristics particularly in their different locations. Trials had been established in 1959 and in the early sixties with exotics and indigenous tree species. However, there is little evidence that these trials were analysed. Consequently, a tree species trial with both indigenous and exotic species was conducted to identify the most suitable tree species for plantation. The species included Tectona grandis, Khaya senegalensis, Albizzia ferruginea, Milicia regia, Pterocarpus erinaceus, Prosopis africana, Parkia biglobosa and Eucalyptus camaldulensis. The objective of the trial was to (1) test different indigenous and exotic species in different site conditions, (2) identify their nursery requirements, site and soil preparation and maintenance for their propagation and (3) to select the most suitable tree species for production of required products such as firewood, timber, fruits, fodder, medicine, ornaments and soil improvement. Criteria for selection included (a) demand and acceptability of the people, (b) legal restrictions, (c) experience and available information, (d) compatibility with other land use systems, (e) expected yields, (f) cost of establishment, (g) adaptability to site conditions, and (h) government policy.
Table 3: List of species identified as high national priority
|
Indigenous species |
Exotic species |
|
Acacia albida |
Anacardium occidentale |
