ANNUAL EXCURSION. 9I 



place in the i8-year-old wood. These are carried out with the 

 following objects in view: — (i) to favour the conifers; (2) to 

 remove the cankered and unhealthy stems ; (3) to realise revenue. 

 The thinnings recur at intervals of 5 years up to the age of 30, 

 at intervals of 7 years between the ages of 30 and 50, and every 

 decade up to 70 years, after which the produce is included in 

 the final yield. Thinnings are thus made early and frequent 

 so as to obtain large girth classes as soon as possible, and 

 in order to lessen the damage done by snow. 



The forest is divided into two working - sections — the 

 Oberesihlwald, which has a rotation of 90 years, and the 

 Unteresihlwald, which is managed on a rotation of no years. 



The annual possibility or yield of the forest is calculated 

 according to Heyer's method, viz. — 



yield = real increment + real growing stock - normal G. S. 

 a = rotation. a 



The real increment =6219 f.m. pro ha. and year. 



The yield thus calculated = 6630 f.m. per year. 

 Thinnings = 2250 f.m. per year. 



Total = 8880 f.m. per year on 1000 ha. 

 i.e. per ha. 8-9 f.m. = 124-6 cub. ft. per acre per annum. 



Transport. — The transport of the forest produce is carried out 

 entirely by the forest staff, and a large variety of methods is 

 adopted. The locality is so irregular in contour, so cut up by 

 streams, and so liable to erosion that the cost of road construction 

 and maintenance would be prohibitive. The following are the 

 chief methods of transport employed : — 



1. The Permanent Tramway. — This traverses the forest for 

 a distance of some 5 miles, and leads directly to the saw- 

 mill. It is employed in the transport both of timber and 

 firewood. The gauge is 24 inches with rail weight of 28 lbs. 

 per running metre (3J feet). The road on which it is laid is 

 5i feet broad and has a gradient which ranges from 3 to 7 

 degrees. The curves on the track vary from 49 feet radii to 

 106 feet radii. The momentum of the loaded trucks carries 

 them down, the speed being controlled by powerful back brakes 

 (Plate VI. fig. 6). The empty trucks are pulled up by oxen. 



2. Sledge Road. — This provides a very effective method of 

 bringing firewood down short slopes to depots on the line of 

 the tramway. The sledge track is built with slender beech 

 branches about 5 feet long, which are laid across any path 



