of years, seemed to be able to occupy the ground here, frequently nearly sole pre- 

 vailing. Later on, various foliage trees also seize, especially birch and aspen, and some 

 few others. At the same time, the character of the floor vegetation will also be changed 

 in the process of time. Thus, the dense growth of Epilobium is gradually mixed up 

 with various other herbs, such as divers grasses, Ac.onitum, Solidago, Tlialiclrum, 

 Hypochaeris, Pediciilaris, and the like, or it is little by little replaced by various species 

 of ling, as Empetnim, Arclostaphijlos, Vaccinium, etc. But even a long time after the 

 fire has raged and all the dry trunks have been blown down and have disappeared, 

 young coniferous forest many a time is looked for in vain, wanting as it were, strength 

 to conquer again the ground once lost. The tall and old foliferous trees, however, testify 

 how long time may have elapsed since the fire ravaged here. Coal and black charred 

 trunks in the ground are an unmistakable evidence of the conflagration once devasta- 

 ting the forest in this place. 



Krassnow, who visited the western portions of the Altai, the territory about 

 B i e 1 u c h a, in the summer of 1882, calls attention to the fact that burnt stretches of 

 the forest were common in those regions as well, and he, too, has noted that though it 

 was a long time since the fire had been raging, no new forest had yet arisen, but the 

 ground was covered with a waving sea of various herbs, several feet high. In upland 

 regions, however, he has observed that the forest seemed to have a greater facility for 

 reappearing. He is of opinion that the reason of this must be that eventual larch seeds 

 entering, become suppressed by the dense herbaceous vegetation, which, in this man- 

 ner, direct prevents the ecesis of the forest. Since the birch and other foliferous trees, 

 however, seemed to be more apt to grow out again, he is of opinion that this is due 

 to the fact that the birch with its lighter fruits, also furnished with wings, giving 

 greater buoyancy for the promotion of the spreading, has a better chance of finding a 

 spot open enough for its seeds to germinate and the young seedlings to develop, while 

 the more heavy seeds of the larch will have more difficulty about this. At higher eleva- 

 tions, the conifers are said to enter more readily burnt areas of this sort, because the 

 vegetation of the forest floor is supposed to be less dense here, and thus the seeds of the 

 conifers were assumed to be more apt to find an open spot where to estabhsh thems- 

 elves. I will point out this, indicating that the suppression of the forest thus not only may 

 be attributed to modification of the soil, as for inst. by destruction of the mould and 

 the like. 



Though, it is true, instances are known of a dense plant cover, at any rate for 

 some time, being able to prevent the development of tree vegetation, this explanation, 

 however, as set forth by Krassnow, appears rather improbable to me in this particular 

 case, anyway when given in such a general form and concerning long periods. Even 

 apart from the fact that also the seeds of the conifers, as is known, are furnished with 

 wings making them adapted for wind-carriage, it is strange that none of all the millions 

 of seeds ripening in the surrounding forest should be able to find a place — as well as 

 those of the birch — so as to enable some plants to grow out and thereby pioneer the 



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