ANNUAL EXCURSION. 93 



WINTERTHUR. 



ESCHENBERG FOREST. 



The town forest of Winterthur lies some miles to the north- 

 east of the town of Zurich. The forest covers an area of some 

 30,000 acres. The geological formation is similar to that of the 

 Sihlwald district and gives rise to the same deep, sandy, loamy 

 soil. The annual precipitation of this locality is about 40 inches. 

 Grotving stock. — Unlike the Sihlwald this forest consists 

 almost entirely of the coniferous species spruce and silver fir. 

 There is no definite succession of cutting series, but fellings are 

 made in groups, as a result of which there is considerable 

 variety in the forest. Here conifers have replaced the original 

 hardwoods, since they were found to pay better. 



Management. — The old system was one of "clear cutting" 

 in high-forest, and there is still an area of 1500 acres of high- 

 forest which is worked on a rotation of 100 years. The ordinary 

 rotation of the greater part of the forest is 120 to 140 years. 

 The management is being directed at present to produce (i) 

 the highest possible volume per acre, (2) the highest possible 

 money return. The regeneration period varies from 20 to 30 

 years. As the result of the " group " system of regeneration 

 the soil has been greatly improved in its productive capacity. 

 In addition valuable "light increment " is put on by the stems 

 of the oldest "age -class," since they occupy more or less 

 isolated positions. The total increment in some of these classes 

 may amount to as much as 238 cubic feet per acre. Thinnings 

 require to be very carefully carried out as a dense weed-growth 

 occurs on the ground. Operations are not conducted over large 

 areas, and all thinnings are made very light. 



The regeneration of the forest is proceeded with in the following 

 manner: — In crops which are about 75 years of age "light 

 fellings" are commenced, as a result of which a crop of 

 brambles immediately appears on the ground. These are cut over 

 and rooted out at once, the latter operation helping to prepare 

 the soil for seed. Full seed years of spruce occur here only at 

 intervals of from 8 to 10 years, but a certain quantity is obtained 

 every year and this is relied upon for regeneration purposes. 

 The "light fellings" are made partly in groups, or in "Horsts," 

 or in strips. In each case silver fir forms the nucleus of the 

 group, and, under the influence of side light, spruce comes in and 



