22 THE gTBUGGLE FOE EXISTENCE. 



to the rapidity of growth of the shoots. Under any circumstances, 

 unless the crop is very open, the mutual contact between the root- 

 systems of the'yarious indi\'iduals is always maintained. In the 

 case of root-suckers identical results follow if the parent tree has 

 been removed or broken off near the ground; otherwise there is 

 never a contraction but, on the contrary, a continual expansion of 

 the root-system. 



VI. Age of crop. As already mentioned in the opening of 

 this Section, although every plant individually has-from the very 

 beginning to contend against causes of injury extraneous to the forest 

 or arising out of location in an unfavourable soil, the mutual strug- 

 gle for existence in a crap composed entirely of seedKngs does not 

 commence for some years, until the plants are old enough to have 

 spread out their roots and crowns and attained mutual contact. On 

 the other hand, when coppice-shoots form a portion of the crop, the 

 commencement of the mutual struggle is contemporaneous with 

 the appearance of the crop itself. But whensoever this struggle be- 

 gins, it is always at first of a comparatively mild character, but 

 becomes rapidly keener and keener while the trees are going 

 through the most active period of the phase of longitudinal growth, 

 during which certain individuals so outstrip their neighbours as to 

 completely suppress them. As the activity of longitudinal develop- 

 ment slackens, so does the mutual struggle for existence become, 

 for a limited time at least, less severe, the combined result mainlv of 

 the diminishing number of stems and the more equal race between 

 the su^^^vors. But as soon as the phase of active lateral develop- 

 ment sets in, the struggle, in spite of the absolutely small number 

 of trees left, again increases in intensity, although its nature is now 

 considerably changed. In the former case there was a very marked 

 disparity in the heights of the competing trees, which, being more- 

 over very restricted in their lateral development, had a comparatively 

 weak hold of the ground, the consequence being that those over- 

 topped were so hopelessly beaten, that they easily succumbed under 

 the victors. But in this second phase the struggle is between mostly 

 large masterful trees, possessing great powers of resistance, and none 

 of them able to gain the easy victory attainable, as in the first phase, 

 by loftier stature ; hence the smaller percentage of casualties during 

 this time, notwithstanding the extreme severity of the struo-o-le. To- 

 wards the close of the period of active lateral development, the num- 

 ber of stems having so diminished that each tree has nearly all the 

 room it require^, the mutual struggle rapidly becomes less keen until- 

 it ceases altogctlier, mIicu wth advancing years the A-itaUty of the 



