Periodical Literature. 201 



and small rains from reaching the soil ; it also may cripple and 

 lead to the death of old trees, where the moss cover is very dense, 

 so that in raked areas a much better condition was observed. 



Since 1906 moss covered and moss free areas have been 

 specially inspected as regards the establishment of natural vol- 

 unteer growth, the investigation being favored by an unusually 

 full seed year in 1906. The counting of plants was made by the 

 method of quadrat sample areas of 1 m side, 20 such on each four 

 sample plots, thinned in different degrees, namely, I light, II 

 moderate, III severe thinnings, and IV severe opening. 



The results rounded off are laid down in the following table : 



/. //. //. IV. 



Year. 



o 3 £ o £ £, o 



£h ^ S Jh S § H 



Thousands of Plants. 



1906, 80 7 87 112 60 172 122 62 184 166 38 204 



1907, 20 5 25 48 13 61 57 38 95 89 16 105 



1908, 10 6 16 30 14 44 30 29 59 28 31 59 



The observations of 1906 show, if no differentiation of moss 

 cover is made, an increase of plants with increased light supply. 

 But, if the differentiation is made, in each case very considerable 

 reductions occur in the moss covered parts which is, of course, 

 explained by the difficulty of germinating in the moss cover es- 

 pecially of the more open stands. 



In the counting of 1907 a decrease in the number of plants is 

 found everywhere, but the differences between moss covered and 

 moss free plats is not as pronounced. 



In 1908, which proved a very dry year the difference between 

 the two conditions is still further lessened and in the open posi- 

 tions has practically vanished. 



Percentically expressed in relation to the plant number of 

 1906 there were still left in 1908: 



I II III IV 



On moss free soil, 12 17 17 14 per cent. 



On moss covered, 7 8 16 15 per cent. 



