112 SYLVICULTURE IN THE TROPICS n .n 



For example, Acacia arabica will grow on low shelving 

 banks of rivers on heavy soil which is periodically 

 flooded, but A. planifrons in Southern India and A. 

 Verek in the Sudan on poor sandy soil, and A. tortilis 

 on sandy soil in arid localities. A. Seyal will thrive 

 on black cotton soil with a moderate rainfall, and 

 A. mellifera on similar soil with perhaps a certain 

 admixture of salt, while A. Swna, or in places A. Seyal 

 var. Fistula, will be found forming pure crops in clayey 

 depressions. But, more commonly in the Tropics, and 

 especially in regions of abundant rainfall, most of the 

 forests are composed of mixed crops. 



Although, in the descriptions of forests given in the 

 first part of this volume, the names of mostly valuable 

 species were given, it is unfortunately the case that in 

 many places these valuable species are in a distinctly 

 small proportion among the number of species which 

 compose the crop, some of which are of no immediate 

 value to the owner of the forest, nor likely to be of 

 much value for some time to come. In some cases this 

 small proportion is due to the shade-avoiding nature of 

 the more valuable 'trees, owing to which their number 

 has been gradually reduced by suppression ; or it may 

 be due to a lesser resistance to forest fires, or still 

 more commonly to indiscriminate fellings, by which 

 most of the valuable species have been eliminated and 

 further reproduction made impossible. 



The problem which the forester has to solve, both in 

 the creation of new crops and in the maintenance and 

 regeneration of existing forests, is how to obtain a proper 

 composition of species so as to reach the maximum of 

 utility for the owner. It is necessary that the species 

 grown in the forest should all be suited to the locality, 

 and that they should interfere with each other as little 

 as possible. There should be, if possible, a suitable 

 mixture of shade-bearing and shade-avoiding species, 

 the former being in preponderance, especially in the 

 early stages, as they are more soil-improving. In the 

 creation of pure crops the chief consideration will be 



