20 BRITISH FOREST TKI.1> 



GROWTH OF TIMBER CROPS IN GENERAL. 



Under timber is comprised all wood used for technical 

 purposes. 



Timber trees differ essentially from shrubs in the pro- 

 duction of a bole, trunk or stem to a greater or less height 

 above the ground before ramifying to form their crown, and 

 as a rule the length of the bole is dependent to a consider- 

 able degree on the density of the crop. Under timber crop 

 is understood the quantity of material growing on any 

 particular area, whilst under growing stock is comprised all 

 the crops growing on the total area for which a working plan 

 has been constructed ; under normal circumstances, when 

 a fall of timber takes place annually, it includes all the 

 timber crops ranging from the very youngest up to that now 

 mature, the area covered by each of the annual crops being 

 equal to the total area divided by the number of years 

 included within the full period of rotation, and the total 

 number of annual crops included within the growing stock 

 being of course equal to the number of years included in 

 the period of rotation or turnus ; it includes, in short, the 

 various timber crops growing on each of the annual falls or 

 clearances. 



The timber crop may be a pure forest consisting of a 

 homogeneous wood, grove, or holt formed of one species of 

 tree only, or it may be a mixed forest made up of some 

 principal or ruling species with one or more subordinate or 

 minor species scattered throughout it in hursts or clumps, in 

 groups or clusters, in patches or knots, in rows or lines, and 

 individually or singly. 



When the timber crop is allowed to attain its full maturity 

 and attainable dimensions in height and girth, it is said to 

 be treated as high forest or high timber forest, but when cut 



