NATURAL REGENERATION. 155 



i. ADVANCE GROWTH. 



In almost every mature wood groups of young 

 growth are found, which have sprung up here and 

 there before the regeneration cuttings have been com- 

 menced; such young growth is called " advance growth ." 

 Under the compartment system it is not 'much valued, 

 partly because it gives the young^rop an uneven character, 

 and partly because, having stood for some time under 

 the shade of the whole wood, it is not always capable 

 of developing into healthy full-sized trees ; hence it is 

 frequently removed altogether to make room for a 

 uniform new crop. Under the group system all patches 

 of advance growth, which are still healthy and capable 

 of developing into full-sized trees, are carefully 

 husbanded. They form the nuclei of the first regenera- 

 tion groups; the old trees standing over them are 

 removed when no longer required, then the groups are 

 enlarged, as indicated above, by gradually cutting away 

 the immediately adjoining trees in narrow bands. 



ii. DIFFERENCES OF AGE, GROWTH, COVER, AND SPECIES. 



Many old woods are naturally of uneven age. In such 

 cases the oldest parts are first taken in- hand, followed 

 by the next age gradatijon, and so on. 



Again, certain parts have from one reason or another 

 not kept pace in development with the rest, nor are 

 they likely to make up for it. They should be taken in 

 hand first, so as to avoid loss of increment. 



Frequently certain parts have thinned out naturally, 

 followed by an interruption of the leaf canopy; they 

 must be attacked first of all. ' 



