(This article is based partly on an International Union for the Conservation of Nature (IUCN )/Conservation for Development Centre report to the Government of Tanzania, “Agricultural Development and Environment Conservation in the East Usambara Mountains”, IUCN Regional Office, Nairobi, November 1985.)

As Norman Myers so succinctly puts it, “Tropical forests offer a wealth of environmental services”. (The Primary Source: Tropical Forests and our Future). Not least in those services is the regulation of floods and the mitigation of droughts; two climatic phenomena that afflict all Africa at one time or another. In close association come the additional services provided through the prevention of soil erosion, the control of sedimentation and the provision of a rich store of biomass suitable for multipurpose sustained economic development – that is, if only it were managed correctly.

Rarely are tropical forests accorded a realistic evaluation of their costs and benefits in development planning. Their conservation appears to be an expensive luxury to loggers and national exchequers alike. In reality, however, such short term exploitation hides the longer term cost of damage to the forest, its locale and the many services it provides. There is no reason why conservation and development should not be compatible. The East Usambara Mountains of Tanzania is a good case in point.

The East Usambaras are at the seaward end of a chain of forested, acid, igneous mountains stretching from near the Kenya-Tanzania border right down to southern Malawi. Although adjacent to the sea at Tanga, they are a highland massif of 400km above 600m altitude with the highest point at 1250 m. About 300 km are forested, of which 80 percent has forest reserve status. The mountains receive 1500 to 1200mm of rainfall annually, ensuring an ideal growing environment of this ecological ‘island’ for a dense hardwood tropical rainforest. The tall canopy trees include endemic varieties such as Cephalosphaera and other timbers of exceptional economic value.

The forest cover is of crucial importance to the Usambaras themselves, the surrounding region and potentially to the economy of Tanzania. These forest roles may be summarised as:

* water catchment protection: the forest is vital to the storage and slow release of water to the lowland surrounds. The town of Tanga is reliant on Usambaran water and its slow release through the dry season to the coastal plains. Similarly, the forest cover protects the lowlands from floods. On both counts – drought and floods – recent years have seen a worsening position.

* topsoil fertility: the soils are primarily Acrisols, the leached, highly weathered soils of Africa, with no reserves, only transient fertility and virtually all nutrients bound up in the biomass and not in the soil.

* Use for shade-demanding crops, primarily spices. Cardamom is a big cash earner for local farmers and it is grown in the understorey to the forest where it demands shade and the nutrients of the forest litter. Continuous cardamom, however, cuts out forest regeneration.

* Timber is an important product and is exploited by the state-owned sawmills and by private pit sawyers. Up to 20 varieties of the largest trees are in great demand for such high-value products as veneers and furniture. Low density and selective exploitation is probably sustainable but the devastation caused by the sawmills operations is irreversible on these soils.

* The gene pool of the Usambara is the richest and most diverse in Africa for such a small area. Many plants are of economic interest not only for timber but for fruit, medicines and other products. Many are absent or rare anywhere else .

The notion of ‘hands-off’ conservation is unrealistic in the Africa of today; all the above forest roles can be achieved by selective and careful exploitation, and the use of the forest not only as a stock of resources but also as an environmental protector. In short, conservation and development.

Threats to the forest come from three sources: the loggers are the most obvious but are relatively easily controlled if existing regulations were enforced; the spice cultivators are a medium-term but not intractable problem. It is the pressure for cultivable land, coffee and tea plantations (which already exist but in a degraded state) and annual cropping that is the major uncertainty for the future. What can be done to head off the threat?

Arguably the Usambaras present an opportunity to combine forest preservation with catchment protection and resource utilization. It is clear that no single strategy can provide the whole answer; it will have to be a mixture of several activities, among which the most obvious are :

total protection and enforcement of forest reserve status on the more rugged parts to prevent gross erosion, and certain core areas to act as gene pools;

village-centred and village-planned development activities; to promote rational utilisation of the forest and/or to provide alternative income sources from occupations such as dairying, fruit, village industry etc; rehabilitation of existing tea estates and their improved management; to provide remunerative job opportunities on land that is already alienated from the forest, and to encourage some of the spice cultivators back into forest clearings;

communication, training and education, especially in the vital role of forests; the interactions between vegetation, drought and floods; and the idea that conservation need not mean throwing a fence around the forest and shooting trespassers.

These are heady challenges. Nevertheless, in response to the catalogue of repeated failures in agricultural development, the EEC has agreed to fund a first phase of conservation and development activities in the East Usambaras. It remains to be seen whether they will succeed because the inter linkages in the natural environment are complicated enough, but when combined with land utilisation they become like the proverbial plate of spaghetti – tangled and apparently endless. However, a start will be made on a pilot project basis to test the various options, to learn-by doing on a small scale and to lay the basis for deciding how to exploit and preserve the forest while protecting the catchment and the surrounding plains from the vagaries of an unkind climate, droughts and floods.
Michael Stocking

Dr. MICHAEL STOCKLING is a soil scientist in the Overseas Development Group, University of East Anglia, working mainly on soil conservation, agricultural development for small farmers, and soil fertility and productivity

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