sentences:  A series of Heinrich events followed, with an associated drying of the East African climate at 50, 35, 30, 24, 16 and culminating with the Younger Dryas period 12kya.31-21 kya was a cool dry phase, with vegetation belts lowering.Upper montane forest species occurred where presently lower montane forest species are and there is evidence that montane forest was widespread at lower altitudes.