56 EOEEST PLANTING. 



equal to the primitive, nor the third to the second, and 

 so forth. 



And then there arose a diversity of opinions relative to 

 the ends and objects to be reached by rotations in forest 

 culture, and this was the more important, as upon the 

 decision of this controversy would depend the determin- 

 ation of the proper (that is, the most economical) time 

 of the growing-period of forest trees. In this regard 

 there prevail four- different opinions, which are based 

 upon the following principles : 



1. — The principle of the uninterruptly continued pro- 

 duction of the same kind of trees in a certain wooded 

 area. — By putting into practice this principal, there will 

 at the same place always be the same pure stock of trees, 

 and as for their cutting time, those periods will be ob- 

 served which will secure the continuance of the original 

 stock. 



This system, called the block system, and worked in 

 rotation, was not long since the most popular in Ger- 

 many, because it satisfied the national predilection for 

 extended forests of large Beeches, Oaks and Evergreens. 

 The growing periods for the single lots of the rotation 

 were of long duration, viz. : from 120 years to 140, and 

 even 200 years. 



But the increased demands made by the industries for 

 other kinds of wood, and the decreasing demand for the 

 high-priced Beeches as fuel, on account of the inex- 

 haustible supply of cheap mineral coal, shook the foun- 

 dations of a system which had no regard for the wants 

 either of the present or of the future. And then it was 

 shown that the " sustained " production of the wooded 

 area and its fertility could even be better retained by 

 growing such kinds of wood as are now more in use — 

 Ash, Maple, Elm, Alder, etc. — and that a growing period 

 of from 60 to 80 years allotted to said modern trees, was 



