Occurrence data of tree species for crystalline Mountain Forest of Tanzania.

The Eastern Arc comprises the ancient crystalline mountains that run from the Taita Hills in Kenya to the Makambako Gap just to the south-west of the Udzungwa Mountains, Tanzania and that are under the direct climatic influence of the Indian Ocean (Lovett, 1990). These mountains support forest and some grassland and heathland vegetation, although large areas have been converted from natural vegetation to agriculture and plantations. There is a chain of somewhat similar montane forest areas extending from southern Tanzania to Malawi, Mozambique and Zimbabwe. However, these more southern forests are not so directly under the Indian Ocean climatic regime, are subject to more variable convectional rainfall patterns, and the forests do not possess the species richness and endemism of the Eastern Arc. Together, the Eastern Arc and these other montane forest areas comprise the Tanganyika-Nyasa Mountain Forest Group.