272 CLARENCE F. KORSTIAN 



Institute, Dehra Dun, India, consider three principal soil types, 

 each of which is characterized by distinct types of vegetation. 

 The poorer soils, containing a large percentage of sand and a 

 relatively small amount of silt, are frequently shallow, with 

 gravel and boulders below. These soils are essentially dry and 

 bear a dry forest with Acacia catechol and Dalbergia sissoo promi- 

 nent, or grassland with Saccharum munja dominant. The well- 

 aerated deep loams are covered with a sal forest or grassland 

 with Saccharum narenga (often mixed with Anthistiria gigantea 

 subsp. arundinacea) dominant. The poorly-aerated deep loams, 

 differing from the w^ll-aerated soils in containing more clay 

 and silt, in actually being heavier, or in having the water-table 

 nearer the surface, are characterized by a moist forest with 

 Betula frondosa, Stereospermum suaveolens, Terminalia, Cedrela 

 toona and others, or grassland with Erianthus ravennae (often 

 mixed Avith Anthistiria gigantea subsp. villosa) dominant. 



More recent work by the same investigators^ indicates that 

 the dominant grasses on an area are excellent indicators of the 

 soil conditions. In northern India, where Saccharuin narenga 

 and A7ithistiria gigantea subsp. arundinacea tend to be dominant, 

 the soil moisture and aeration are suitable for the best develop- 

 ment of sal and the moist type of sal forest prevails, in the 

 shaded parts of which the reproduction suffers from poor soil 

 aeration. Such grasses as Saccharum munja, Saccharum spon- 

 taneum, Eragrostis cynosuroides, Imperata arundinacea, Vetiveria 

 zizanioides,. Andropogon contortus and Ischaemum angustifolium 

 usually indicate a soil too dry, or too heavy, for the best develop- 

 ment of sal and such forests as occur are of the dry sal type. 



Pearson^", in discussing the effect of a cover of aspen {Populus 

 tremuloides) upon the estabUshment of Douglas fir {Pseudotsuga 

 taxifolia), has made a very interesting comparison of two dif- 

 ferent sites which occur at the transition between the Douglas 



® Hole, R. S. and Singh, Puran. Oecology of Sal {Shorea rohusta) ; Part II, 

 Seedling Reproduction in Natural Forests and its Improvement. Indian Forest 

 Records, Vol. V, Part IV, pp. 83-84. 1916. 



1" Pearson, G. A. The Role of Aspen in the Reforestation of Mountain Burns 

 in Arizona and New Mexico. The Plant World 17: 249-260. 1914. 



