52 THE STKUGSLK FOB EXISTENCE. 



standing in the midst of evergreen neighbours can survive on 

 the sole condition that from the earhest years they grow more 

 rapidly, not only upwards but also laterally, than their compa- 

 nions. 



Bsgarding the rafe of growth in height of our various species in different parts of 

 •their respective habitats no trustworthy information is as yet available. In a continent 

 like Initia, we are bound to obtain widely difiering figures for one and the same spe- 

 cies according to the locality and the legion in which it may grow in each case. Un- 

 til such information is forthcoming, it will be extremely useful to construct compa- 

 rative diagrams of the relative rapidity of growth of different species standing toge- 

 ther in one and the same forest. 



The varying rapidity of growth of each apeoies should be delineated by a curve 

 with its. generating rectangular co-ordinates, the abscissa representing the age, and 

 the ordinate the height of the average tree at that age. Figure 1 is such a compara- 

 tive diagram for two trees, A and B ; the curves are traced by means of the respective 

 heights attained at 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 years of age. The 

 dUgram shows at a glance that up to the age of i9 years B grows iastif than A ; at 

 6',) it is overtaken by the latter, which then gets away from it. The rapidity of growth 

 of A is slow for the first ten years, then becomes rapid up to seventy years, after 

 which it deQrsasea gradually, and becomes almost stationary. B, on the other hand, 

 grows up rapidly at once, until it reaches the age of 50 years, and then makes little 

 head afterwards. In the diagram ^ in. on the a«is of X, or the horizontal line, re- 

 presents one yg^r, and similary ^ in. on the axis of Y, or, which comes to the sanje 

 thing, on the perp^ijdisular line, represents one foot. 



Similar diagrams may be cq^strllct§d to represent relative rapidity of lateral exten- 

 - sion, 



IX. Maximum height attatnabm.— This condition finally de- 

 cides what trees, out of those that survive up to a certain stage of 

 growth, shall form the crop, or, if there are species present that are 

 shade-enduring enough, to constitute a permanent undergrowth, its 

 upper story. Of the companions of sal there are only the Termi^ 

 nalias, some Alhwias, Adina, cordifolict, some Eugenias, and half 

 a dozen other species which attain the same height as that noble 

 tree, and which, therefore, compete with it for a place in the lofty 

 leaf-canopy of the full-grown forest. In Central India (including 

 Northern Bombay), teak is generally a small tree, and is hence, 

 wherever more powerful countervailing conditions do not prevail, 

 easily beaten by its taller companions. Deodar is, outside the region 

 of the firs, the tallest tree in the forests where it grows; whence 

 its gregariousness wherever other circumstances, such as soil, mois- 

 -ture, &c., are favourable. Again, Mesuaferrea is, with the excep- 

 tion of Altlngia excelsa, the tallest tree in the large areas which it 

 covers almost by itself in Assam. The teak in Burma, and the 

 Artooarpas Chaplasha in Assam, although unfavourably circum- 

 stanced in many other respects to struggle for existence with their 

 companions, are able to hold a permanent place in their midst ow- 



