NUMBER OF TREES TO THE ACRE. 



37 



It has been stated, as a general rule, that full half of the trees first 

 planted at 4 feet apart should be removed before the growth is 20 feet 

 high ; the number should not exceed 800 to the acre, when 30 feet high ; 

 and when 40 feet, not over 300 to 350 to the acre, the soil and exposure 

 being the most favorable that are found. Others reckon the space be- 

 tween at one-fifth of the height. 



Some idea of the capacity of soil for tree-growth, under the best man- 

 agement in Europe, may be formed from the statement that an acre of 

 ash, elm, or sycamore 40 years old will contain 2,000 to 3,000 cubic feet 

 of timber, and when 60 years old double this amount. This is, besides 

 the successive thinnings, which become, when near a market, an impor- 

 tant source of income, and when the growth becomes large, may be 

 more in value than the cost of management and interest of investment. 

 These thinnings should be continued as long as necessary, and in full- 

 grown forests may sometimes be required in forests 80 years old. As a 

 general rule, larch, spruce, and other conifers require less space than 

 broad-leaved deciduous trees. Larch is supposed to do well in good soil, 

 with 9 feet space around it. 



It is also observed that certain trees bear the shade of other species 

 better than that of their own, and that therefore a mixture, as for in- 

 stance, of oak and beech, will grow nearer together than either species 

 would if alone. 



The following table shows the number of trees upon an acre, at the 

 distance specified, and the number that might be left at different ages, 

 with the proportional value of the thinning, taken at these several 

 periods : 



The amount of timber grown on a given area, in some of the govern- 

 mental forests of Europe that have been planted and managed accord- 

 ing to the rules of forestal science, is very much greater than the same 

 soil would grow in wood if left to itself. So striking is the difference, 

 that Dr. Berenger, who is at the head of the Italian school at Vallom- 

 brosa, remarks, in the Journal of Forestal Economy (Giornalle di Ucon- 

 omia Forestale, 1871-'72 : 



That while an uncultivated woodland taken for a long period, and countinor inter- 

 est and taxes, would yield almost nothing to the capital invested, it is well estab- 

 lished that the same land, managed according to modern science, would, in the long 

 run, yield a revenue both conspicuous and constant. 



PLANTATION OF DIFFERENT SPECIES. 



Without attempting to discuss the artistic effects which become a 

 study in landscape-gardening and the laying out of parks, we will con- 

 cisely state some suggestions that have been made as worthy of atten- 

 tion by those who wish to apply them. 



By placing a plat of white pine in the center, and surrounding it by 

 successive belts of Norway spruce, Scotch pine, Austrian pine, white 



