In most Anglophone African countries the area of secondary forest is unknown, as is the area per vegetation type. Some inventories have been carried out in the past, but data pertain most often to timber extraction and thus concerns only the commercially valuable species. The highly fragmented landscapes found in many African countries makes it difficult to define boundaries between vegetation types (some just several hectares in size), which complicates making precise assessments.
The products and services of secondary forests are deemed particularly beneficial to rural communities (see Table 1). Their livelihoods depend on this resource for a variety of reasons. In drier areas, fuelwood is an important product acquired from secondary forests, either for subsistence or commercial purposes. In this respect, the resprouting and coppicing abilities of secondary forest species are highly valued. In many rural areas, modern medical facilities are absent and people depend largely on traditional medicines derived from secondary forests for their health. The agricultural potential after fallow, due to improved soil characteristics and fertility, is another important feature of secondary forests. Although rural communities that inhabit these forests possess
Medicinal bark products from forest and woodland, Durban Herbal Market, South Africa
a wealth of traditional knowledge and practical experience, the increasing demand for land and conflicting land tenure issues have often led to the further degradation of secondary forests.
With the disappearance of primary forests, logging companies have come to rely more on secondary forests for timber extraction. For example, in Ghana 70% of the exported wood is derived from secondary forests, enhancing the economic importance of this resource in generating foreign exchange earnings. Unfortunately timber harvesting is still often conducted in a destructive manner and the area destroyed still far exceeds the area restored.
The ecological importance of secondary forests is still underestimated, but some references are made to the potential for combating erosion and soil-runoff, watershed management and carbon sequestration.
Table 1: The importance of secondary forests in Africa
Ecological Importance
Socio-economic Importance
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The management of secondary forests should be an integral part of the conservation and sustainable use of all types of forests. However, they require a different set of guidelines and principles than those of relatively undisturbed forest, especially if recovery of the vegetation is slow or inhibited. Unfortunately, the management of secondary forests in most African countries has been given insufficient attention and they are rarely part of forest management systems or plans. Nevertheless, in various countries interest in secondary forests is emerging and valuable research and development have been initiated.
The following working definition of tropical secondary forests was proposed at the Nairobi workshop:
Forests regenerating largely through natural processes after significant disturbance (human and natural) of the original forest vegetation at a single point in time or over an extended period, and displaying a major difference in forest structure and/or canopy species composition with respect to nearby primary forests on similar sites.
The following key elements were identified:
Woodlands are a major vegetation type in Africa. Whether these are secondary or not, is often unclear. Determining the extent of disturbance in this vegetation type is more complex than in closed canopy forests where disturbance is more readily perceived. Comparatively, woodlands contain fewer species and thus changes in species composition are more difficult to measure. Structural aspects are also influenced to a lesser degree than in closed, multi-layered forests. However, if the frequency and intensity of disturbance in woodlands is too high, the seed production and fertility of tree species may be affected, resulting in decreased regeneration and further degradation of this important resource.
Secondary vegetation that has the potential to evolve into woodland or forest is considered in the definition above. There are several documented cases of grass- and shrub lands evolving into woodlands and open canopy forests after fire protection measures were implemented. The definition of secondary forest should perhaps be further expanded to include these vegetation types more appropriately, whereby grass- and shrub lands are considered a seral stage in the development of vegetation.
Typologies that are based on the underlying process of the formation and subsequent development pathways of secondary forests, as developed at the Samarinda workshop for Tropical Asia, are not wholly applicable in the African context. An appropriate framework for typologies should perhaps be based primarily on vegetation types and subsequent land-use rather than disturbance regimes. The applicability of any framework will depend on the local forest types (closed versus open forests, dry versus wet forest), and should be further elaborated at country level or regional level.
The term "secondary forest" is an ecological one, indicating that these vegetation types differ ecologically from less disturbed forest types. The term may be to some extent confusing, implying that these vegetation types are perhaps of lesser value. However, despite the phrase "secondary", these forests are of primary importance. In order to develop and implement adequate policies and management tools the causes that lead to their formation are of paramount importance and have to be taken into account.
