CHAP. VIL] Formation of Mixed Woods 139 



and Black Pines alone, if timber crops are to be grown at all ; 

 or undrained tracts may be better suited for Alders, Willows, 

 or Poplars than for any other genera ; or again, the circum- 

 stances of local marts may be such as to ensure a constant 

 demand for one particular class of timber, which thus becomes 

 the most remunerative crop under these special conditions. 



In most mixed woods of about equal age certain species, 

 either through greater energy of growth in height, or in conse- 

 quence of soil and situation specially favouring their develop- 

 ment, or from some combination of both these factors, attain 

 such advantages in rate and extent of development as to induce 

 or necessitate a corresponding decrease below the normal de- 

 velopment in the other species. Hence sooner or later these 

 latter trees, unless specially tended, have to be removed from 

 the crop even although they may not have attained their 

 physical and technical maturity. It thus happens that, in many 

 cases, towards the end of the period fixed by the Working Plan 

 for mixed woods, the mature crop consists mainly of one 

 species ; and this is usually that which has shown itself most 

 capable of bearing shade. And when this species is being 

 reproduced and harvested, advantageous opportunities are once 

 more given for the formation of mixed crops by the planting 

 out of stout transplants of the more valuable kinds of trees 

 on whatever patches of soil seem most suitable to their healthy 

 growth and vigorous development. 



With their denser crops, their better conservation of the 

 productive capacity of the soil, their higher percentage of stems 

 of large dimensions, clean growth, and good technical pro- 

 perties, their power of satisfying demands for various kinds 

 and qualities of timber, and their comparative security from 

 calamities and devastations arising from either organic or in- 

 organic causes, it can hardly be denied that mixed woods are 

 more profitable, and rest on a much more secure financial basis 

 than pure forests, provided always that they are formed of the 

 species for which the soil and situation are best suited, and 



