STIMULATION OF INCREMENT 165 



conduct partial clearances in coniferous crops to such an 

 extent that the annual rings will be increased beyond a 

 normal width ; though the case is different with hard- 

 woods. 



It should be remembered that timber of the highest 

 technical value should have annual rings of the same width 

 throughout. Generally speaking, trees will form wide rings 

 until the canopy is close ; then the rings will be narrower, and 

 will again become wider on a thinning taking place. 



In the early part of a rotation, trees growing vigorously 

 will form wider rings than in the latter part of a rotation 

 under relatively similar conditions ; for as maturity is reached 

 their vigour declines. 



Now, whereas the vigour of a whole crop may be declin- 

 ing, and the annual increment on the saleable timber may 

 represent a lower rate of interest than that which seems 

 reasonable, and whereas in many cases it would be considered 

 prudent to clear cut the whole crop and invest the money, 

 realised by the sale thereof, so as to yield a higher rate of 

 interest, it will often be possible, by making a partial clear- 

 ance, to so stimulate the crop that is left, that a better invest- 

 ment, or one equally as good, will be effected. 



By this means it is quite possible that the crop left may 

 increase in value at the rate of 4 or 5 per cent., or even more, 

 whereas formerly it was earning perhaps only 2\ or 3 per 

 cent. 



Thus it is evident that the rotation for a portion of the 

 crop can often be beneficially prolonged from a financial point 

 of view. 



It must be remembered that besides the increase in 

 actual volume there will usually be an increase in the quality 

 or price per foot at which the timber would sell, as the 

 individual trees will have a larger girth than is usually the 

 case. 



By means of partial clearances, timber of large girth can 

 be produced in a much shorter period than would usually be 

 the case. The girth increment will be somewhat similar to 

 that which obtains in the case of standards over coppice, 



