61 



No tree should be marked for felling within 40 yards of the edge of the forest, as it 

 is required to leave a protective fringe against the destructive action of winds and fires. 

 Left alone, the boundary becomes clean and hardened as it were against external 

 influences. On the contrary, gaps are created if trees are felled, and there being no pro- 

 tection from the one side, the young growth may not thrive. It has been shown that 

 the observance of this rule is also required for protection against fires. 



It is of extreme importance that the annual yield arrived at for each section should 

 not be exceeded on any account. Jardinage in which fellings become excessive, does 

 not differ materially from the ordinary irregular working which so speedily brings about 

 the ruin or degradation of a forest. When the fellings exceed the increment, the forest 

 wastes away ; the marketable timber disappears, and the young growth thins and does 

 not recover. Glades make their appearance and the forest may fall into ruins. This has 

 been the fate of some of the " cut out " South African forests. 



Adopting the method proposed, very few sound trees would be taken in forests that 

 have been overworked, and the bulk of the produce would be limited to damaged 

 trees and wastewood ; but most often the receipts would not cover the additional 

 expenditure that the opening of this forest would involve, and the forest had better remain 

 closed. 



ANNUAL YIELD. The annual yield would vary considerably ascording to the 

 character of the forest. Judging from sample areas, and adopting a rotation of 100 

 years, the annual yield by volume would reach 100 cubic feet per acre in the Gwangwane 

 forest, 70 cubic feet in the Impetyne forest, 14 cubic feet in the Mahutywa forest. 

 At Knysna it would only average 6 cubic feet, and in some of our overworked forests 

 probably still less. By proper management, the steady annual yield of yellowwood forests 

 should reach 70 to 30 cubic feet per acre, according to the fertility of the ground. 

 Comparing with European figures, in Baden the annual yield of mixed forests averages 

 51*8 cubic feet per acre.* According to Burckhardt, the mean annual increment of 

 normally stocked forests 100 years old is in Germany, in cubic feet per acre, neglecting 

 thinnings, 70'9 to 40'0 for oak, and 105*6 to 42*9 for spruce ; and figures for other 

 European forests do not diverge much from these. 



FELLING SEASON. Which is the best season for felling timber has long been a 

 vexed question, some pretending that summer felled timber is the most durable, but the 

 majority preferring to fell trees in winter, when the deciduous kinds are leafless. Winter 

 felled timber some- times contains less sap than that felled in summer, but the difference 

 is seldom considerable. Bauschinger f has shown that in timber tested within three months 

 of felling, the winter felled timber is 25 per cent, stronger than the summer felled, but the 

 difference disappears after a long time of seasoning. There is in Natal a prevalent belief 



* Sir D. Brandis, Notes on Forest Management in Germany, London, 1888, p. 3. 

 t W. C. Unwin. The Testing of Materials of Construction, London, 1888, p. 400. 



