233 



above for, on the one hand, much money has been uselessly 

 spent in parts of India on sowings and other operations with 

 the object of forestalling the slow operations of nature by 

 quickly afforesting areas occupied by pioneer plants with more 

 valuable forest trees and, on the other hand, cases have occur- 

 red where the premature wholesale removal of sueh pioneers 

 has retarded the natural evolution of valuable forest by many 

 decades. 



From what has been said above we see that a virgin forest, 

 in a sense, represents the final product of centuries of work on pj ant 

 the part of nature, the final result of countless struggles in Generatkms- 

 which only those plants survived and for a time occupied the or Cr P s - 

 ground which were able to exist under the conditions of the 

 environment prevailing at the time. At first, the absence 

 of a suitable nutritive substratum rendered impossible the 

 existence of the majority of plants, and minute alga3 and 

 lichens were left in undisturbed possession. Later, the 

 accumulation of humus soil which could retain a sufficient 

 quantity of moisture allowed grasses and herbaceous plants 

 to obtain a footing, and they ousted the algae and lichens. 

 Finally, a still deeper soil with moist subsoil enabled 

 woodland to vanquish the grassland. The first plant settlers 

 have to struggle against the very unfavourable conditions 

 of the non-living environment, while later arrivals have to 

 face a keen fight for existence against other competing 

 plants. The scientific Forester, it is true, has to interfere with 

 the operations of nature to a certain extent, since it is his busi- 

 ness to see that the most valuable plants, from his point of 

 view, are favoured as much as possible in the struggle for exist- 

 ence. At the same time this power can only be usefully ex- 

 ercised within very definite limits and the interference to be 

 useful must be intelligent and exercised so far as possible in the 

 light of a good knowledge of the principal factors at work in 

 each case. Man cannot, for instance, establish flourishing 

 woodland in a locality which can only support grassland and 

 by an unintelligent interference with the vegetation on an area 

 he may reduce woodland to a desert. 



213. A phenomenon analogous in Succession 



many respects to the succession of different types of vegeta- communities 

 tion noted above may often be seen in the Sub-Himalayan on alluvial 

 tract of India. Here on the banks of boulders, shingle and deposits 

 sand brought down by the rivers the first arrival is frequent- Simaia aa 

 ly Dalbergia Sissoo which in such places forms gregarious forests. Tract. 

 This species with its deep and far-reaching ro Dt .system helps to 



