vi] METHODS OF TREATMENT 37 



time it must be remembered that a tree cannot support the 

 effects of sudden isolation several times without some degree of 

 injury and loss of quality. Also we have to arrange for a pro- 

 gressive process of selection, because a large proportion, probably 

 two-thirds, of the standards of two rotations old, will have to 

 be eliminated as unfit for further reservation, and there will 

 probably be only two or three trees per acre left of sufficient 

 value to be worth reserving for four or five rotations. The pre- 

 scription in our working-plan will therefore run somewhat as 

 follows, taking these figures simply as an example: There will 

 be reserved about forty standards of all ages per acre, and no 

 tree, unless in exceptional circumstances, will be retained for 

 more than four rotations (when they would probably be about 

 TOO years old), and that at each felling about two- thirds of the 

 number of standards of each age will be felled, and only the 

 best retained. Then a rule embodying the well-known silvi- 

 cultural conditions that control the selection of stems for 

 reservation from out of the underwood, relating to species, 

 origin, shape, etc., will be given, and lastly the distribution of 

 the reserves must be remembered, and, if for example there are 

 to be forty standards per acre, there should be four standards 

 reserved on each square chain. 



In the above example, there might be on every acre, twenty- 

 seven standards of one rotation's age reserved from out of the 

 underwood, nine standards of two rotations of age, and three 

 standards of three rotations of age, which would ordinarily be 

 felled at the close of their fourth rotation. 



Prescriptions will then be drawn up for whatever subsidiary 

 operations may be considered necessary. These will be cleanings 

 and thinnings, which will be carried out by area on purely 

 cultural lines. There may be one or two cleanings carried out 

 while the underwood is still young, then one cleaning perhaps 

 at mid- rotation, and a thinning about half-a-dozen years before 

 the coppice is cut. The frequency and nature of these tending 

 operations will depend entirely on cultural considerations, and 

 on the light-requirements and relative rate of height-growth of 

 the principal species. The rules should state the nature and 

 object of each operation, but it is to be presumed that the 



