Thinning Practice. Ill 



' s 



of the expense. Curiously enough, he recommends 

 severer thinnings for fuel-wood production than for 

 timber forests. 



Pfeil accentuates the necessity of treating different 

 sites and species differently in the practice of thin- 

 nings. Hundeshagen accentuates the financial result 

 and the fact that the culmination of the average yield 

 is secured earlier by frequent thinnings. Heyer formu- 

 lates 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 phil- 

 osophy and the results of thinning on experimental 

 grounds rather than on mere opinion were made as 

 early as 1825 to 1828, and again from 1839 to 1846, 

 at various meetings of forestry associations, until, 

 in 1860, Brunswick and Saxony inaugurated the 

 first more extensive experiments in thinnings. The 

 two representatives of forest finance, Koenig and 

 Pressler, pointed out, in 1842 to 1859, the great sig- 

 nificance 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, 

 because of the impracticability of introducing inten- 

 sive management. Only lately, owing to improve- 

 ment in prices and the possibility of marketing the 

 inferior material profitably enough to justify the 

 expenditure, has it become possible to secure more 

 generally the advantages of the cultural effect. Within 

 the last thirty or forty years, great activity has been 



