PURE CROP OF UNIFORM AGE. 13 



independent formation from the shoots themselves, plants, whoso 

 crowns do not yet meet, nevertheless engage in a struggle for room 

 and for sustenance in the soil. 



The conditions which, in the case under consideration, influence 

 and finally decide the struggle for existence are 



I. RELATIVE INNATE VIGOUR. As far as seedlings alone are 

 concerned, why some should possess more innate vigour than others, 

 cannot always be explained. The larger heavier seed does not in- 

 variably produce the stronger plant. In the same seed-bed, some 

 plants will be found to be larger, more vigorous and more hardy 

 than others. Again, the larger plant is not necessarily the stronger 

 one or the one more tenacious of life. 



As regards coppice-shoots, their size and vigour do not always 

 correspond with the apparent vigour and fitness of the parent stool 

 or plant ; nor, just as in the case of seedlings, are their size and 

 apparent strength always a proof of their innate vigour. As com- 

 pared with seedlings of their own age, stool-shoots and suckers are, 

 up to a certain age, much larger and stronger ; but such of the 

 latter as survive now catch up the former and in the end attain a 

 higher stature and greater spread of crown. Coppice-shoots deve- 

 lop, soon after they come up, a large ramified root-system of their 

 own. This enables them not only to draw sustenance from soil 

 situated at some distance from their stems, but also to invade the 

 thin, weak, scarcely-branched roots of young seedlings, which they 

 starve by appropriating, thanks to their greater vigour of assimila- 

 tion and transpiration, most of the nourishment present in the soil. 

 In this last respect root-suckers are the most to be feared by the 

 seedlings. 



II. GREATER SUITABILITY OF SOIL AND SUBSOIL. In the case 

 under consideration, as long as two neighbouring plants are quite 

 young and small, the influence of soil and subsoil on their relative 

 development is of only slight importance ; since it is seldom, except 

 in extremely rocky, stony, or uneven ground, that these factors of 

 growth vary from point to point to a sufficient extent to influence 

 them differently. Nevertheless, if there is, owing to any other 

 cause, a very marked disparity between the plants, and the soil is 

 shallow and the subsoil unfavourable, the more vigourous one by 

 pushing- down its roots too rapidly and too deep into the ground, 

 may receive a sudden check in its growth as soon as the subsoil has 

 been reached. Again, if young seedlings and coppice-shoots are 

 growing up side by side, an unfavourable soil and subsoil will give 



