74 CHARACTER AND COMI'OSITION OF WOODS. 



species with almost miithemalicKl accuracy. On the whole, 

 mixed woods otier substantial advantages over pure woods. 

 At the same time it must not be forgotten, that the treatment 

 of pure woods is much simpler, than that of mixed woods. 

 Hence, the former may be preferable, whenever really competent 

 managers are not available. 



8. Hull's for the. Foniuttii))! of Mixed Woods. 



The advantages of mixed woods, which have been detailed 

 above, will only be realised under certain conditions, the more 

 important of which are tbe following : — 



{a.) The locality must be, a priori, suitable for the favour- 

 able development of each of the species in the mixture. 



{h.) The mixture must be of such a nature, that the factors 

 of the locality do not suffer ; they must, whenever possible 

 be improved. This will only be the case if the principal, 

 or more numerous, species is soil improving. As indicated 

 above, exceptions occur when woods are treated under a short 

 rotation, or when the quality of the locality is such, that it 

 does not require to be assisted by the improving action of the 

 trees growing on it. 



(c.) The mixture must be so arranged that one species does 

 not oust the others, and establishes a pure wood. The exces- 

 sive development of one species may be <letrimental to the 

 others, or even kill them outright. In this respect the 

 toughest and least sociable species carries the day, these quali- 

 fications being dependent on shape, light requirement and 

 height growth of the species. 



Sliape. — Each species must be given that growing space 

 which is re(iuired for its proper development. In this respect 

 the several species differ considerably. Conifers, for instance, 

 have a different shape from broad-leaved species. Again, 

 some species are better able than others to stand an infringe- 

 ment of their proper growing space. Thus, the broad-crowned 

 oak is liable to suffer considerably in crowded woods, while 

 spruce stands an infringement in space comparatively easily. 



