Context

The Usambaras are one of four major highlands in North East Tanzania. Each of these highlands has higher rainfall, so greater agricultural productivity and higher population densities than the surrounding lowlands. However, these highlands present problems for farming. The steep gradients encourage rapid surface runoff of rainwater and soil erosion, especially after forest has been cleared. The muddy rivers and layers of soil deposited at the foot of bare slopes around Soni village after heavy rain showers are obvious evidence of these problems. Increased tree cover is essential if greater environmental degradation is to be avoided. The Usambaras are also part of a series of highland blocks known as the Eastern Arc. They include the Taita Hills in Kenya, the Pare Mts, the Usambaras, the Uluguru Mts near Morogoro, and the Udzungwa Highlands near Iringa. These mountains are characterized by exceptional biodiversity of global significance, so tree conservation and planting of indigenous species is in the long term interests of Tanzania.

The road through Mazumbai Forest in the Western Usambaras. Unfortunately such forest now covers less than 10% of its original extent. Mazumbai is one of several patches of forest which have potential as a tourist attraction.

Aims

The initial intention was to plant the upper slopes of Soni Seminary with tree species that are quick-growing, so that the soil erosion and environmental damage occurring in 2007 can be halted . The species planted are also expected to provide a sustainable future income for the Seminary and thereby enable the cost & quality of the boys’ education there to be improved.   When the initial planting of those slopes is complete it is planned to promote reafforestation elsewhere within the Usambaras.   Most of the land where tree planting is currently happening have been planted with exotic species e.g. eucalyptus, pines or grevillea. Thus, original indigenous forest now covers less than 5% of the Usambaras around Soni. SGG is now encouraging partners in this locality to plant at least 10% of new ground with indigenous species before they entirely disappear from the local scenery. In some locations SGG will support tree-planting only if all the seedlings are indigenous.

The upper slopes Soni Seminary. In 2006 much of this land was used for subsistence farming: by 2009 it was the beginnings of young forest.

Progress

In 2007 the weeds on the upper slopes of Soni Seminary were cut and 1850 new seedlings planted. This work was repeated in 2008, so that in February 2009 SGG estimated that there were approximately 3,273 young trees established since 2006 on those slopes. By 2009 there was limited land there which remained to be planted, so the emphasis changed to finding new partners and locations where tree-planting could take place. The other shift in planting policy concerned much greater planting of indigenous species. SGG still supports the planting of quick-growing exotics, such as grevillea, which are known by local people to produce a reliable sustainable income in the near future, and which can help reduce soil erosion. However, we now wish to encourage at least 10% of future seedlings to be indigenous, even when the landowners need to derive an income from the forest. In areas of high biodiversity (e.g. the buffer zones around Amani Reserve) all seedlings should be indigenous, and SGG is now looking for partners who will implement the planting of indigenous forest anywhere within the Usambaras.

A small tree nursery at Amani.