The Rise of Silviculture. 551 



experiences, the significance of which Diiesberg points out, the 

 complete explanation of which he persistently seeks, setting each 

 in proper relation to all the rest and to whatever facts scientific 

 investigators have contributed either to support or contradict. 

 In the light of this critical examination of the interdependence of 

 forest and soil he shows how the even-aged high forest outrages 

 nature. And "Every offence comes home in time." Unguided 

 Nature produces a prosperous harmony from the reaction of soil 

 and plant and animal life in the forest. Man is not to interfere 

 with a high hand in Nature's work, but must exert himself to 

 understand the growth of an unmanaged forest and observe the 

 natural laws of its development, and then, with conscious design 

 and a clear understanding of the proper methods, try to further 

 this natural growth, to lend a hand and direct it towards the pro- 

 duction of economic values. Following such a course Diiesberg 

 — to our astonishment — developes the selection forest. "Beauty 

 vigor, soil, protection and freedom from disease, and, as a result 

 of all these things, high yields are the characteristics of the selec- 

 tion forest and the reasons for advocating it." Merely because 

 it does not lend itself so readily to forest management and ad- 

 ministration, as do less cumbersome though less productive forms 

 of forest, most foresters have hesitated to advocate this, the most 

 natural kind of a forest. To remove this hesitancy Diiesberg 

 proposes a simple type of selection forest which recognizes every 

 essential feature of the uneven-aged forest, produces the highest 

 yields and is most simply managed. His selection forest has for 

 its units small areas of a size determined by the diameter of the 

 crown of a full grown tree in the virgin forest. These areas thus 

 differ with different species. Their typical shape is that of the 

 regular hexagon. Seven of these hexagons, one central and six 

 peripheral are termed a Group (Gruppe) and form the cutting 

 area for one complete rotation. Cuttings are not made in each 

 group every year, but only at regular intervals. If cuttings are 

 made at intervals of five years five groups epitomize the whole 

 forest. Each one of the seven hexagons in a group is termed a 

 Clump (Trupp). The clump is 2-, 3-, 4-, 5- or 6- partite ac- 

 cording to the number of age-classes it contains. If in a mixture 

 all species are eventually to be introduced into each group, the 

 sizes of the group and of the clump are determined by the crown 

 breadth of the broadest-crowned species. The Pedunculate oak 



