104 Germany. 



although at first agreeing with Hartig, later in his sec- 

 ond edition (1817) changes his mind and improves both 

 upon the biological explanation of Spath and the prac- 

 tice of Hartig, pointing out that the latter came too late 

 with his assistance, that the struggle between the individ- 

 uals should be anticipated, and the thinning repeated as 

 soon as the branches begin to die, but he also recognizes 

 the practical difiBculty of the application of this cultural 

 measure on account of the expense. Curiously enough 

 he recommends severer thinnings for fuel-wood produc- 

 tion than for timber forests. 



Pfeil accentuates the necessily of treating different 

 sites and species differently in the practice of thinnings. 

 Hundeshagen accentuates the financial result and the 

 fact that the culmination of the average yield is se- 

 cured earlier by frequent thinnings. Heyer formulates 

 the " golden rule :" "Early, often, moderate," but insists 

 that first thinning should not be made until the cost of 

 the operation can be covered by the sale of the material. 

 Propositions to base the philosophy and the results of 

 thinning on experimental grounds rather than on mere 

 opinion were made as early as 1835 to 1828, and again 

 from 1839 to 1846, at various meetings of forestry as- 

 sociations, until in 1860 Brunswick and Saxony in- 

 augurated the first more extensive experiments in thin- 

 nings. The two representatives of forest finance, 

 Koenig and Pressler, pointed out in 1842 to 1859, the 

 great significance of thinnings in a finance management 

 as one of the most important silvicultural operations for 

 securing the highest yield. 



In spite of the advanced development of the theory of 

 thinning, the practice has largely lagged behind, be- 



