GOLD COAST REPORT OX FORESTS. 71 



suppressing, either by direct crowding or otherwise, the growth 

 of more valuable species, especially timber trees. Throughout 

 those portions of tropical Asia and Africa with which I am per- 

 sonally acquainted, the presence of grass in any large quantity is 

 synonymous with the occurrence in the dry season of forest fires. 

 Excepting in areas where fire protection has been a success, these 

 fires, whatever their origin is, may be looked upon for all prac- 

 tical purposes as one of the estahlished natural conditions against 

 which the vegetation has to contend. Fortunately for the plants 

 it so happens that the very same contrivances and adaptations that 

 enable them to successfully occupy such localities (that is, those 

 in which the supply of moisture in the soil is deficient) also enable 

 them to some extent to resist the injurious effects of the fires. 

 Almost all the species inhabiting the zone of vegetation exposed 

 to this danger have developed an extraordinarily thick bark quite 

 out of all proportion to the rest of the stem tissues. To prove 

 this it is sufficient to select at random any two species, say one 

 from the moist evergreen forests and the other from the dry open 

 ones, when it will be found, quite nine times out of ten, that the 

 latter has an absolutely (not merely proportionally) thicker bark. 

 Again, some of the species of trees occupying fiery areas have 

 enormously thickened roots (similar thickening, together with 

 the formation of bulbs, &c., is a common adaptation amongst 

 shrubs and herbs growing in dry soils) that, though woody, are of 

 monstrous growth compared with the stems. Such plants are cut 

 down every year by the fires, but send up shoots and stems again 

 during the rainy season, and so a struggle is kept up till the stems 

 eventually reach a sufficient height to enable the crown to escape 

 from the direct action of the flames, when a more rapid growth 

 becomes possible. The loss in wood increment from such causes 

 is very great. Plants accustomed to these conditions show extra- 

 ordinary vitality, and it is often impossible to kill them except by 

 grubbing up the roots completely. 



Perhaps the best example of an adaptation, amongst West 

 African tree*, to resist the arid conditions prevailing in the 

 -I'vannahs, is shown by the baobab (Adansonia <li/n1ntn. and some 

 other species of the same genus), the stem of which is thickened to 

 such an extent as to give it the appearance of a gigantic carrot. 

 This development is accompanied by changes in the wood tissues 

 that enable the xtein to function as a reservoir for storing water in, 

 and thus to replace its loss from transpiration during the dry 

 season of the year. It is probable that a large proportion of the 

 plants belonging to the savannah forests that mature their fruit 

 during the dry season do so after the annual fires have passed over 

 the land ; enough statistics, however, have not been collected to 

 establish this point. 



The grasses, on the other hand, appear to suffer very little in- 

 jury from the fires, and, if anything, seem to shoot up with renewed 

 vigour very shortly after they have been exposed to their action. 

 Their main vegetable period is. as a rule, earlier than that of the 

 trees inhabiting the same localities, and is practically at an end 

 by the middle of July. It begins at the end of March, imme- 

 diately after the annual fires, and is completed in July. Thanks 

 to the dispersal of their seeds by wind agency, as well as to the 



