Picea obovata generally forms the greater part of the taiga, associated with the 

 preceding one and the cedar. There are to be found trees over 30 m. high, and about 

 75 cm. in diameter at a man's height. In moist places, it frequently occurs together 

 with the silver-fir, growing like the latter in alpine situations nearly up to the limit of 

 tree vegetation. 



Pinus Cembra var. sibirica especially occurs in more or less moist and 

 swampy places. It does not generally form woods alone, but accompanies the two pre- 

 ceding ones. It is to be found in the lowland as well as right up to the limit of trees, 

 being of all trees the one climbing highest up the mountains in these regions, and in 

 possession of a great power of enduring cold. Not only in the lowland but also in the 

 mountain valleys, at rather great elevations, it is seen to attain gigantic dimensions, being 

 influenced, however, near the very Hmit of tree vegetation by the climatic conditions. 

 In the mountains, the alpine variety coronans especially predominates, represented by 

 low, distorted specimens, growing right up to the bare mountain. In the Sayansk district 

 there generally does not exist any transition zone with birch-thickets between the 

 wooded and the alpine regions. The prettiest cedar we had occasion to see during 

 our journey, was growing in the Sayansk eruptive territory, where the soil in many 

 places was not very fertile. The temperature here oscillates between 40° C. of heat and 

 50° C. of cold, the daily changes of the temperature being very considerable as well. 

 The rainfall makes the same quantity as over great parts of Scandinavia, and it is 

 therefore probable that this tree also is able to thrive here. 



Pinus silvestris attains a height of about 35 m., measuring to about 1,5 m. in dia- 

 meter. It especially occurs in sandy soil, where it frequently grows unmixed, or in 

 many places on loamy, hmy or dry and stony ground, mostly accompanied by other 

 conifers, above all the larch. 



Fig. 23. Larch forest near Ust Sisti-kem ; scattered white- 

 stemmed birches in left foreground. 



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