Periodical Literature. 125 



SILVICULTURE, PROTECTION AND EXTENSION. 



Forstinspektor Hauch of Denmark, whose 

 Density important discussion on the influence of the 



and spreading habit of different species on 



Variation spacing in plantations we briefed in Vol. 



in III, p. 181, discusses further the spreading 



Spreading capacity of species under repeated refer- 



Capacity. ence to Johannsen's work on "Heredity." 



He believes to have discovered a correla- 

 tion between this capacity and the tendency of tree species to 

 form straight slender stems and regular growth. The relation 

 between spreading habit and root system has been suggested in 

 the former article. 



With maple, ash, alder which are characterized by small spread- 

 ing capacity, an upright growth is much more the rule, than with 

 oak and beech which have great spreading capacity, similarly 

 spruce and pine are distinguished. 



Even in stands of the same species, but of different derivation, 

 the same phenomenon is exhibited : as the oak stands grown from 

 Danish and German acorns at the Danish Experiment Station 

 show, the Danish oaks showing a crooked and irregular form, 

 which the foreigners never develop. Several illustrations exhibit 

 the difference. The stands of foreign derivation also show a 

 larger number of dominant stems, a result of smaller spreading 

 habit and this habit, the author thinks, is a heritage. 



Nevertheless, he contends that not too much value must be 

 placed upon the selection of seed material with reference to the 

 variation of spreading habit of the same species in different 

 localities. For, after all, this difference is only relative, the 

 specific habit great. Hence, dense sowings or plantings for spe- 

 cies with spreading habit cannot be avoided ; and thereby the 

 advantage of securing a wide variation of forms is also secured. 

 Most of the quantities quoted by authors for seed and plant 

 quantities touch the extreme limits of the needful ; what is 

 really necessary we do not know, and hence, to be sure, larger 

 quantities than are usually employed with these species are re- 

 quired. 



In the cited oakstands, in which very large quantities were 

 used, (12 to 15,000 per acre) the advantage of this becomes 



