7fi CHARACTER AND COMPOSITION OF WOODS. 



Fiiiiitli liiilr. — Two or more lij^lil (lein;iii(lin<f species should 

 not be peniianeiitly mixed, because the soil deteriorates, and 

 the faster growing suppresses the slower growing species. 



Exceptions to this rule are admissible : — 



(a.) On very fertile localities. 



(h.) On very inferior localities, where nothing else will 

 grow. 



(o.) If the wood is treated under a short rotation, or as 

 coppice, or if it is intended to underplant the wood 

 at an early age with a shade bearing and soil 

 improving species. 



Temporary mixtures of two or more light demanding 

 species occur frequently, especially where a slower growing 

 species has to be protected against frost or drought ; for 

 instance, oak with nurses of larch, Scotch pine, or birch. 



FiftJi Ridr. — The circumstances of each case must decide 

 whether the species should be mixed by single trees, groups, 

 lines, or strips. 



Two shade bearing si)ecies of equal height growth, for 

 instance, may be mixed by single trees, but if the quality of 

 the soil changes from place to place, it may be desirable to 

 arrange the mixture by groups, placing each species on the 

 more suitable spots. Again, if a light demanding species is 

 to be raised with a faster growing species, the mixture should 

 be by groups, and not by single trees. In such cases the 

 groups are frequently given the shape of strips. Oak and 

 beech are now so mixed in the Spessart mountains, that the 

 groups of oak extend over areas ranging from one to ten and 

 even more acres, the rest of the area being taken up by 

 beech. In this way the suppression of the oak by the 

 beech is i)re vented. 



All mixtures may be brouglit under one of the following 

 three classes : — 



Mixture of shade bearing species. 



Mixture of shade bearing and light demanding species. 



Mixture of light demanding species. 



