32 SYLVICULTURE IN THE TROPICS n . i 



species which shed their leaves periodically, the majority 

 are evergreen. Some of the trees from the moist zone 

 are also found to extend into this, such as Khaya 

 senegalensis and Detarium senegalense, the timber of 

 both of which is exported under the name of "African 

 mahogany," Funturnia elastica, Diospyros mespili- 

 formis, etc. ; while among the other important trees 

 may be mentioned some other species of Khaya, 

 Pseudocedrela ("scented mahogany"), Afzelia, Tetra- 

 pleura, Chlorophora excelsa, Lovoa excelsa, possessing 

 a timber not unlike that of teak, Terminalia, Mirnu- 

 sops, etc. ; while among the lianas there are Landolphia 

 oivariensis and L. Droogmansiana ? yielding good 

 rubber, and others of the same genus, Clitandras and 

 Carpodinus, giving inferior rubber. The oil palm, 

 Elaeis guineensis, is also characteristic of this zone. 



On the eastern side of the continent the forests do 

 not, as a rule, take quite such fine proportions, except 

 perhaps under special conditions, such as proximity to 

 water. The country is more broken up by stretches of 

 savannah and savannah forest, due partly to drier 

 climate and soil, and partly to fires. This theory is 

 supported by various writers, such as Signor Philippi, 1 

 and by Sir Harry Johnston. 2 The latter says : 



" I am sometimes led to believe that the whole of 

 Africa was once covered with more or less dense forest, 

 but that the climate of the eastern half of the continent 

 being drier than in the west, the ravages of bush fires 

 started by man have made greater headway than the 

 reparatory influence of nature. Only in specially 

 favoured tracts enjoying exceptional rainfall, or else 

 provided with underground springs, could the forest 

 always remain green and full of sap all the year round, 

 and thus be able to choke out the fire, or, in the wet 

 season, to make sufficient growth to repair the ravages 

 sustained by bush fires." 



But this is a subject which we shall refer to, later on, 

 in its proper place. The species of the trees composing 



1 Ruwenzori : Duke of the Abrvazi' 8 Expedition, - British Central Africa. 



