In spite of the advanced development of the theory of thinning, the practice has largely lagged behind, because 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 advantages of the cultural effect. Within the last thirty or forty 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.[4] [4] 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. The physiological reasons for the practice of thinning upon experimental basis, were advanced by the botanists Goeppert and R. Hartig, and among foresters, the names of Kraft, Lorey, Haug, Borggreve, Wagener, and others are intimately connected with the very active discussion of the subject lately 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 advantages of thinnings and especially of severer thinnings is gaining ground. The proposition, now much ventilated, of severe opening up near the end of the rotation, in order to secure an accelerated increment (_Lichtungshiebe_) is, however, much older; Hossfeld, in 1824, and Jäger in 1850, advocated this measure for financial reasons, while Koenig and Pressler anticipated the development of an individual tree management by pruning, and differentiation of final harvest and nurse crop, a method which is working itself out at the present time. 5. _Methods of Forest Organization._