rtlEE CHOP OF TriflFOEM ACtE. 23 



ultimate survivors gradually failing, the crowns no longer develop 

 their original wealth of foliage, but on the other hand contract 

 (consequent on the drying up and disappearance of, at first, the 

 smaller branches and then the larger limbs), and the trees die one 

 by one from sheer old age. The natural process here described, of 

 the gradual disappearance of the majority of the individuals origi- 

 nally composing a crop, is well illustrated by Th. Hartig's example 

 cited on page 11. 



VII. Relative longevity according to origin of individuals. 

 Here we have obviously no concern with the relative longevity of 

 individuals as influenced by the separate or joint action of all the 

 various causes discussed under the other heads of the present Case. 

 What we have to do is only to distinguish between the relative lon- 

 gevities of seedling trees, trees on stools, and suckers. Culms may 

 be left out of account altogether, for they are no better than mere 

 branches. Stool-shoots and suckers indeed are also braUches by 

 origin, but they ultimately enjoy a separate individual existence. 

 Although accurate observations are wanting, it is certain that seed- 

 ling trees are the longest lived, and that the younger the parent stool 

 or tree is, the more nearly do stool-shoots and suckers approach 

 seedling trees in longevity. Owing to their origin stool-shoots are 

 generally not so long-lived as suckers, and the disparity is always 

 greater the older the parent stool is, for in proportion to the size 

 of the stool will always be the risk of unsoundness in the butt, and, 

 after a certain age, also the want of vigour of the shoot. 



VIII. Relative rapidity of growth. — ^As already explained 

 in several places above, seedlings always go through a longer or 

 shorter period of waiting, during which they are establishing them- 

 selves ; while, on the other hand, stool-shoots and suckers push up 

 rapidly as soon as they are produced, attaining in their very first 

 year the same size as seedlings from 5 to 20 years and upwards old. 

 This, so to say, exaggerated development they owe to the large 

 amount of reserve matter stored up in the parent stool or tree. 

 Suckers, if the tree which produced them is still standing, main- 

 tain this rapid growth at the expense of the parent until they have 

 developed a complete root-system of their own ; but stool-shoots 

 soon exhaust the reserve matter of the parent stool, and then, being 

 left entirely dependent on themselves, their growth generally falls 

 off and in a few years they are overtaken by the seedlings and even 

 passed by them. It is obvious that the younger the stool is, the 

 more nearly will the mode of growth of the daughter-shoots resem- 

 ble that of a seedling. Culms differ from all the rest in that they 



