144 THE FOREST LANDS OF FINLAND. 
61° 830° 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 10 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 Utigalbras, which I suppese to 
be the decrease occasioned by the felling and thinning, or 
decay of trees; and by curves are given in one chart a 
répresentation 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 3 35 
On spots of medium fertility— 
In South Finland, - - 177 cubic feet per tunnland. 
In Middle Finland, - 62 ” ” 
In North Finland, - : 38 33 is 
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, - 56 cubic feet per tunnland. 
In Middle Finland, - - 46 5 PA 
Jn North Finland, - - 26 35 “3 
