GEOGRAPHICAL DISTRIBUTION OF TREES. 43 



been given on no mean authority a statement to the effect 

 that, in Norway, journeying from north to south, and 

 in some parts of the country in descending from a great 

 elevation to the valley or plain, we pass through successive 

 zones, which have been characterised as the zone of per- 

 petual snow, where only a few ice plants, lichens, and 

 mosses grow; the zone of the willow and birch; the zone 

 of the pine and fir ; the zone of the oak ; the zone of 

 the beech ; and the zone of the cultivated fields. The 

 statement may be useful as a memorandum ; but, if 

 great stress be upon it, it may break down. I have only 

 found it true to the extent that there are here birch woods, 

 or forests, reaching further north than any forest of pine 

 or fir, though trees of these may be found in the same 

 latitude; that willows are found in higher latitudes than 

 these ; and that there are forests of fir and pine further 

 north than oaks ; and oaks further north than beeches ; 

 and beeches growing further north, and at a high ereleva- 

 tion, than general cultivation has extended. But beyond 

 an indication of these facts, I think the statement cited 

 may mislead. 



To the northernmost zone is assigned, as a character, its 

 production of the birch, Betula odorata, Bechet. It flour- 

 ishes throughout the whole country; but it is in west 

 Finmark that it appears forming veritable forests ; else- 

 where it is found, as a tree which delights in the light, 

 very frequently dispersed over clearings in pine and fir 

 forests, and besides, on lands completely cleared of woods. 

 The altitudinal limits of this tree are in Southern Norway 

 about 1,100 metres; in the diocese of Drontheim from 

 600 to 700 metres ; and in Finmark from 300 to 400 metres 

 above the level of the sea. The birch is in Norway a tree 

 of fine growth, and often takes an elegant form, with the 

 exterior branches pendant in long clusters, measuring as 

 much as 5 metres, or 17 feet. The birch may attain to 

 a great age. It is not rare to meet with birches 

 from 20 to 25 metres, 67 to 84 feet, in height, and To 

 metres, 5 feet, diameter at the ground. The crown may 



