44 



PROTECTION AGAINST MAN. 



On poor soil, in exposed places, longer close-periods are 

 required than for good soils, sheltered positions, and mild 

 climates, since trees then grow faster. Sheep can be driven 

 earlier than cattle or horses into a forest. 



The calculation of the open area in a forest is given in the 

 following formula : 



Let F = area of forest, 

 f = closed area, 

 /i = F / = open area, 

 s = close- time, 

 r = rotation of forest. 



Then,/=F* 



. I. 



For example, a forest of 1,000 acres area, with a rotation 

 of 100 years, and a close-time of 25 years : 



f)K 



The closed area = 1,000 -=f- = 250 acres. 



100 



The open area = 1,000 ~ = 750 acres. 



LOO 



Speaking generally, according to G. L. Hartig, the following 

 areas should be closed : 



Broadleaved forest . . . J to J of the whole area. 

 Coniferous do. . . . J to J ,, 



Coppice do. . . | to f 



According to Hundeshagen, the close-time should be as 



follows : 



SYSTEM OF MANAGEMENT. 



