104 COLONIAL REPORTS MISCELLANEOUS. 



to the mixed deciduous and evergreen forests on the hills. 

 Wherever the original moist evergreen forests once covering the 

 latter have been destroyed the secondary growth replacing it is 

 assuming the mixed deciduous character. Lower down the hill- 

 sides and along the valleys at the foot, adjacent to the plains, 

 clearings of the mixed deciduous forests have resulted in the 

 encroachment of the open savannahs and their occupation of the 

 cleared areas. 



The great drawback to these conversions is, of course, from 

 another point of view, the fact that the species occupying the 

 different areas are replaced by others more suited to the altered 

 conditions, and this in time leads to the scarcity of those plants 

 associated with the original environment. For instance, the 

 majority of species of timber trees, and others of economic im- 

 portance, that are confined in their distribution to the moist ever- 

 green forests disappear from the scene under the altered condi- 

 tions, and the same holds good with regard to agricultural and 

 other crops such as cocoa, rubber plants, &c., that are dependent 

 for successful cultivation on moist conditions. 



It is on these grounds that I strongly recommend that a pro- 

 tective belt of forest be left intact along the borders of the main 

 cocoa-growing centres, especially those in Aquapim and Kwahou 

 where extensive dry areas are situated at no great distance from 

 them. Examples of similar transformations are to be seen 

 wherever extensive destruction of the forests has taken place 

 along the borders of the various zones of forest vegetation in 

 Ashanti and Northern Kwahou, and are most apparent in the 

 regions where the mixed deciduous forests approach the open 

 savannah zone. The importance of leaving untouched suffi- 

 ciently extensive belts of forest to regulate the water supply, 

 more especially in the catchment basins of streams that may in 

 the future be required for irrigation works, the water supply of 

 distant towns, and for navigation, will be evident from the above 

 remarks. 



For all such protective purposes there is no doubt that the 

 evergreen forests are the more desirable type. The mixed 

 deciduous ones are to a large extent defoliated during the dry 

 season, just when the supply of moisture in the soil requires the 

 most protection against exposure to the fierce heat of the sun and 

 desiccating winds. They are, however, better than having no 

 protection at all. 



In my opinion the influence forests have in mitigating 

 extremes of climate in the tropics is their most important func- 

 tion. On the presence or absence of these extremes depend the 

 existence of the various types of vegetation. However abundant 

 the rainfall of a locality may be during the monsoon period, if it 

 is habitually followed by a prolonged dry season it can never in 

 the tropics, except where telluric influences such as moisture in 

 the soil near streams affect plant growth, be covered with the 

 typical evergreen vegetation. Once a prolonged dry season 

 becomes an established condition of affairs edaphic influences 

 depending oil the physical and chemical properties of the soil 

 assume an importance in relation to plant growth that is quite 



