Larix sibirica also assumes mighty dimensions here, measuring to 45 m. in height, 

 and about 2 m. in diameter at a man's height. Generally the larch does not form at 

 any rate continuous forests of considerable extent, as it occurs sparsely together with other 

 conifers, especially with pine and foliferous trees. It seemed to be able to endure the 

 dry steppe climate better than any other conifer, being of especially common occurrence 

 in the dry, Devonian sandstone territories, where it also forms woods over tracts of 

 some extent, in part even without any admixture of other trees. In such places the veiy 

 largest specimens also are to be found. In the Urjankai country, the larch therefore 

 especially occurs in the lower, hotter, and drisr tracts, that is, in the wooded steppe region. 

 However, this is not due to sensitiveness to the cold, for in northern Siberia the larch 

 grows as far to the north as the other conifers, or farther still (up to 72 '-2° north 

 latitude), and even as for north as in the J a k u t s k district, it becomes large and 

 well grown. In the Urjankai country, it also reaches up to 1700 — 1800 m. above 

 sea-level, i. e." right up to the tree limit. It is, accordingly, one of the most hardy 

 conifers here, and is far from being dependent on the summer heats. The reason why 

 it is especially restricted to lower altitudes after all, is that these regions are 

 drier, and accordingly less suited for other conifers to do quite well. For the larch is 

 of all the coniferous trees the one being best able to endure the dry climate, while 

 it is evidently expelled from the moister tracts by more shade-giving conifers. Thus 

 it is the conditions of moisture, and not the summer heats, which, in my opinion, are 

 the cause of the existing distribution of the larch in these regions. The ground in 



Fig, 24. Trunks of cedar in the primeval forest near Kusliabar. 



In the foreground mainly Sambuaus racemosa, Asperula odorata, 



and various species of ferns. 



