Current Literature. 223 



reference to natural reproduction and soil flora, and to site classi- 

 fication ; the difficulty of regeneration in the Norrland open pine 

 forests forms a special series ; the problem of the change of forest 

 to moor and of making moor soils available, as well as other soil 

 problems ; races of tree species ; diseases and damages ; distri- 

 bution of tree species. 



The volume, beautifully printed on fine paper, profusely and 

 beautifully illustrated brings separate articles on snow breakage 

 in North Sweden; on results of sowing of pine and spruce from 

 foreign seed; on diseases of the pine in Norrland, with special 

 reference to its regeneration ; on the seed yield in 1912 ; a descrip- 

 tion of an unusual stand ; thinning experiments. 



Just as in Canada snow breakage is rare in Sweden, especially 

 North Sweden, because snow falls usually at low temperature, 

 hence is light, while the trees, pine with a thin foliage and branch 

 system, spruce with a drooping habit, do not carry much. Yet, 

 in 1910-11, considerable damage was experienced, mostly in alpine 

 situations. The interesting fact comes out that the areas lately 

 exploited, i. e. thinned out, sufiFered most. 



To the Swedish foresters belongs the honor of having first 

 pointed out or practically realized the significance of the de- 

 rivation of seed supply, the use of foreign seed in the State forests 

 having been forbidden as early as 1882; in 1888 an import duty 

 being enacted, and in 1899 and 191 1 by its increase the impor- 

 tation rendered unprofitable. Yet, upon failure of the home crop, 

 from time to time foreign seed had to be admitted even in the 

 State forests. The somewhat inconclusive trial plantings have 

 shown that the spruce from German seed (probably from Harz 

 mountains) is neither from the point of view of climatic adap- 

 tation, nor from that of increment objectionable. Even stands of 

 50 to 60 years show in no direction any detrimental development. 

 With the exception of pronounced frost situations it is frost hardy 

 even as far north (in one case) as 63° N. 



For the pine, however, very different experiences are extant. 

 Even if developing well at first, in the second or third decade the 

 form becomes undesirable, crooked and otherwise defective. It 

 is, however, questionable whether this refers to German seed, 

 or seed secured through German sources, the derivation of which 

 is unknown. Owing to a longer leaf period, earlier sprouting and 

 longer growing, the shoots are liable to frost; poor wood and 



