PLANTATION, PLANTING. 



portion of foliage above that part. 

 Again, it may be stated that if one 

 tree has a clear stem of 20 feet in 

 length, and another has one of 40 feet, 

 the roots and tohage of both being 

 equal, the layer of new wood will be 

 much thinner in the latter case than 

 in the former ; for the deposition of 

 woody matter will have to extend 

 over double the surface in the tall 

 tree. It may be also remarked that, 

 in general, if a tree be left entirely to 

 nature, it will ultimately produce a 

 greater bulk of wood, taking stems 

 and branches together, than would be 

 the case if subjected to pruning. Ex- 

 cept, however, in the case of growing 

 for fuel, pruning is more or less neces- 

 sary. The value of a timber-tree de- 

 pends chiefly on the stem, the branch 

 timber being of less value. The ob- 

 ject to be kept in view in pruning for 

 timber is the production of a clean 

 stem with as small a proportion of 

 branches as possible. But it has been 

 explained that the growth of the stem 

 depends on the quantity of foliage, 

 and without branches a sufficient 

 quantity of foliage cannot be main- 

 tained. While, on the one hand, an 

 undue preponderance of branches is 

 prevented by pruning, yet, on the 

 other, as much foliage should be pre- 

 served as circumstances will permit. 

 " An excessive privation of foliage 

 should never be occasioned at any 

 one time. It is therefore advisable 

 to commence pruning early, in order, 

 as it were, to repress irregularities in 

 the bud. At all events, whenever an 

 irregularity can be clearly distinguish- 

 ed as such, it should be checked. 

 Thus, when a shoot, occupying the 

 position of a branch, ascends in com- 

 petition with the top, or leading shoot, 

 and is allowed to go on for years, the 

 stem will have a forked character ; 

 or if the competing portion be ampu- 

 tated after it has acquired a large 

 size, the timber will be rendered un- 

 sound. But if the shoot from which 

 this aspiring limb took its rise had 

 been stopped in the first or second 

 season of its growth in summer, the 

 tree might have been grown with a 

 clean, regularly tapering stem. It is 



only great irregularities, however, 

 that should be meddled with during 

 tiie Ciirly growth of the plant ; other- 

 wise the increase of roots is prevent- 

 ed, such increase being reciprocal 

 with that of the branches. 



" Young shoots of the above de- 

 scription may be checked by being 

 shortened in summer ; but no large 

 branches should be cut off at that 

 season, nor after the sap begins to 

 flow briskly in spring. Towards au- 

 tumn, however, when the leaves have 

 nearly ceased to carry on their func- 

 tions, pruning may be very properly 

 performed ; and some species, for 

 example, the birch and maple, require 

 to be pruned at that time, otherwise 

 they are apt to bleed. The period at 

 which bleeding, that is, an extravasa- 

 tion of sap, takes place with greatest 

 force, is immediately before the burst- 

 ing of the buds in spring. If a branch 

 be cut off when it is in foliage, the 

 remaining portion draws the sap 

 and prevents effusion at the wound. 

 Some derangement will of course be 

 produced in the flow of sap ; and a 

 diminution of the process of lignifica- 

 tion and of the formation of roots will 

 be occasioned, owing to the abstrac- 

 tion of a certain extent of foliage. 

 But when the sap is in motion, and 

 the leaves at the same time not ex- 

 panded, the amputation of a branch 

 is followed by a flow of sap, which 

 appears to drain from every part of 

 the tree. The sap becomes stale on 

 exposure to the air ; it then aflects 

 the cambium and inner bark, often 

 to a considerable extent below the 

 wound, and if these are not in all 

 cases so far completely killed, yet 

 they are generally more or less in- 

 jured, and canker is apt to ensue. 



" Suppose it were required to rear 

 a tree so as to have a stem of clean- 

 grown timber as tall and as tliick 

 as could possibly be obtained in any 

 given time. The first consideration 

 is the root, the plant being supposed 

 to be young, with a top or upright 

 leading shoot, and several side branch- 

 es. All these should be left undis- 

 turbed in the first instance, unless 

 such of the latter as may recjuire a 



587 



