144 THE FOREST LANDS OF FINLAND. 



61 30' N, ; Midland Finland, from lat. 61 30' to lat. 64 ; 

 and North Finland, from lat. 64 to 68. 



There are given tables of growth in each zone of the 

 country of pine and spruce at all ages, from 30 to 200 

 years, in periods of ten years, giving the gross increase in 

 fathoms of 100 cubic feet, and the number of trees per 

 tunnland, and the cubic contents per tree. A table of the 

 growth in each zone of birch, giving the ages from 10 

 years to 100, the number of trees, and the cubic measure- 

 ment of the timber per tunnland. 



There are given in the same tables, in alternate ten 

 years, what is designated Uttgalbras, which I suppose to 

 be the decrease occasioned by the felling and thinning, or 

 decay of trees; and by curves are given in one chart a 

 representation of the increase in the cubic measurement 

 per tunnland and of the height of the trees, with advan- 

 cing age ; and in a second the diminution in the number 

 of trees per tunnland with advancing age. 



In the body of the work it is stated : ' The diminished 

 growth in height of trees toward the north is seen in the 

 height of first-class trees of 100 years' growth, selected for 

 examinations. The height of those in South Finland was 

 above 83 feet ; of those in Midland Finland, about 70 feet ; 

 of those in Northern Finland, scarcely 58 feet. 



' The average or medium increase of wood in growth of 

 trees of 100 years of age, on the most fertile soil was 



In South Finland, - - 99 cubic feet per tunnland. 

 In Middle Finland, - - 81 ,, ,, 



In North Finland, 50 ,, 



On spots of medium fertility 



In South Finland, 77 cubic feet per tunnland. 



In Middle Finland, 62 



In North Finland, 38 ,, 



On places the least fertile, as on pine moors, which, con- 

 stituting the greater part of the woodlands of Finland, 

 may be considered as representing the prevailing increase, 



In South Finland, - - 55 cubic feet per tunnland. 

 In Middle Finland, 46 



In North Finland, 26 



