Methods of Thinning. 105 
cause of the impracticability of introducing intensive 
management. Only lately, owing to improvement 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 ad- 
vantages of the cultural effect. Within the last twenty- 
five years, great activity has been developed among the 
experiment stations in securing a true basis for the 
practice of thinning. 
New ideas were introduced through French influence 
and by others independently in the latter part of the 
eighties, when the distinction between the final harvest 
crop (Fr. élite, le haut) and the nurse crop (le bas) was 
introduced.*) 
The physiological basis for the practice of thinning 
upon experimental grounds, was advanced by the botan- 
ists Goeppert and R. Hartig, and among foresters, the 
names of Kraft, Lorey, Haug, Borggreve, Wagener and 
others are intimately connected with the very active dis- 
cussion of the subject now going on in the magazines. 
Thinnings have become such an important part of the 
income of forest administrations (25 to 40% of the total 
yield) that the prominence given to the subject is well 
justified, and a more modern conception of the advan- 
tages of thinnings and especially of severer thinnings is 
gaining ground. 
The proposition, now much ventilated, of severe thin- 
nings near the end of the rotation, in order to secure 
an accelerated increment (Lichtungshiebe) is, however, 
*The conception of such subdivision and the English nomenclature was 
independently first employed by the writer in his Report for 1887, as Chief of 
Forestry Division, when discussing planting plans for the prairies. 
