320 THE JOUKNAL OF INDIAN BOTANY. 



the Allahabad thorn scrub is not truly xerophilous. According to 

 Brandis the area ought to be able to support a "really successful 

 forest". In adjacent hilly regions, especially to the south, where 

 there is a much smaller amount of land suitable for cultivation, and 

 the population consequently is much less, a successful forest occurs 

 (Fig. 16). It appears as if forests and density of population may be 

 definitely correlated with each other in India. 



We must assume then that if the human factors were lessened or 

 eliminated, the area would more or less rapidly pass into the complete 

 thorn scrub stage, or even into a true thorn forest. In the protection 

 of the grasses, shrubs, and trees of this forest,' a more mesophyfcic type 

 of forest would develop. Some of the thorn scrub trees, as Zizpyhus 

 jujuba, Acacia arabica, and Alangium lamarckii, would develop to 

 much larger dimensions (Fig. 15). Butea frondosa would become 

 abundant. Such a forest is pioneer to the climatic climax in the 

 mountainous region to the south. Other trees, as Dalbergia sissoo 

 Eoxb, and Holoptelea integrifolia Planch, at present exclusively culti- 

 vated would quite readily become self-perpetuating components of 

 such a forest. Finally, there would be the slower influx of truly climax 

 trees from neighboring forested areas. 



The development of such a forest might result in some increase 

 of rainfall, making conditions still more favorable for the development 

 of a high forest. Brandis records (2) an instance of slight increase 

 of rainfall following thorough-going protection of a large forest tract 

 in Central India. Certainly a dense intermediate forest, with its 

 accompanying herbaceous and shrubby floor vegetation, would greatly 

 conserve rainfall by preventing rapid run-off of the monsoon rains, 

 and by increasing the relative humidity during the hot season. 



Climatic climax monsoon deciduous forest stage. Probably the 

 dominant constituents of the ultimate climatic climax forest would 

 be immigrants from neighboring forested areas to the north and 

 south. We should expect to find Terminalia tomentosa Bedd, and 

 Tectona grandis L., dominant. Almost certainly species of Sterculia, 

 Bombax malabaricum DC, Anogeissus latifolia Wall, Stephegyne 

 parvifolia Korth., Buchanania latifolia Eoxb., Eugenia jambolana 

 Lamk., and other fine trees, and Dendrocalamus strictus Nees would 

 invade the area from the forests both to the north and to the south. 

 Acacia catchu Willd., and even Shorea robusta Gaertn, might finally 

 be represented. With such immigrants, and in the protection of their 

 shade, a new herbaceous and shrubby vegetation, at present unknown 

 in the area, would spring up. Perhaps several species now found only 

 in favored places in protected planted groves would become compon- 

 ents of this undergrowth. 



