CHAP, vi.] Advantages of Mixed Woods 1 25 



for themselves such degree of density of canopy as is requisite 

 for the due conservation of the productive capacity of the 

 soil, and for the prevention of its gradual, but inevitable, 

 deterioration. 



Even on the better classes of soil, pure crops or mixed woods 

 of valuable light-demanding species only Oak, Ash, Maple, 

 Larch, Pine, &c. grown without admixture of any shade- 

 bearing species, are apt to thin themselves out naturally at so 

 rapid a rate as to favour branch and coronal development to 

 an extent inconsistent with a studiously economical utilization 

 of the woodland soil. This, too, is a drawback not in any way 

 obviated by underplanting. But an admixture of one or other 

 of the shade-bearing species (Beech, Hornbeam, Spruces, Silver 

 Firs), according to the nature of the soil and situation, not only 

 protects and stimulates the productive capacity of the soil, but 

 at the same time acts mechanically in stimulating to growth in 

 height, and in preventing the formation of short boles and of 

 stout branches that would prejudice the technical utility and 

 the market value of the timber produced. 



It is a matter of practical experience, needing no discussion, 

 that Larch and Scots Pine form more valuable boles, and 

 contain a larger percentage of heart-wood, when grown in 

 admixture with Spruce or Silver Fir than as pure crops. 

 And all the more valuable species of deciduous trees gain 

 in shape, increment, and age up to which they may be advan- 

 tageously grown from technical and financial points of view, 

 when the Beech, or on moister descriptions of soil, the 

 Horn-beam, forms a part of the crop. But these beneficial 

 effects are even more distinctly noticeable when mixed crops 

 are formed, on suitable soils, of conifers and broad-leaved 

 trees even when all are shade-bearing, as in the case of 

 Spruce and Silver Fir forming crops along with Beech. 



In consequence of the greater increase in the total quantity of 

 timber produced in mixed crops as compared with pure woods, 

 and of the more favourable circumstances affecting the forma- 



