GEOGRAPHICAL DISTRIBUTION OF TREES, 49 
through which it passes, in proportion as it rises in alti- 
tude, the degree of weakness of vegetative life. To the 
weeping birch succeeds the betula acer, which replaces the 
white birch; after which comes the birch of the prairies, 
which passes in its turn through different gradations of 
size, and which at the Polar Circle is nothing more than a 
_stunted shrub, of pyramidal form, and covered with moss. 
In a paper on European forests, which appeared in the 
Building News for. 1878, it is stated:—‘ The total area of 
forest- producing land in Norway is computed at about 
37,000,000 acres, but in this survey considerable so-called 
forest land consists of comparatively unproductive rocks, 
swamps, and moors. The pine and fir, even more than in 
Sweden, constitute the riches of the Norwegian forests. 
The Scotch fir is found up to the most northern latitudes, 
and grows there up to a height of 3,400 feet above the 
sea level. The spruce fir ceases near the Arctic Circle. 
The forests are principally situated in the east of Norway, 
near Christiania, Hamar, Trondhjem, and Christiansand. 
Those of Bergen have long since been exhausted. In the 
_ western districts of the country forests can hardly be said 
to exist. As in Sweden, strict forest laws are now in 
force, but the mischief done in former times by indiscri- 
minate felling will take a long time to repair. 
