STORMS. 543 



bark, or which are forked, diseased or affected with fungi. If 

 the proper density of the crop would be impaired by wholesale 

 removal of bad trees, begin with the worst and remove the 

 others in future thinnings. It is better in thinning spruce- 

 woods not to dig up stumps, as in so doing the roots of 

 neighbouring trees may be cut through. Heavy thinnings in 

 lanky and hitherto densely growing woods are dangerous. 



ii. Trees along the borders of a forest should be allowed to 

 branch low down the stem. 



iii. Endangered border trees standing over young growth 

 may be temporarily preserved by thinning out their crowns, 

 and cutting those branches which extend at right angles 

 to the direction of the prevailing wind. This has been 

 successfully carried out with spruce at Stammheim, in 

 Wiirttemberg. 



iv. Carefully avoid all causes leading to defects in trees; 

 thus, resin-tapping should be stopped in spruce forests, 

 deer which peel trees should be shot, and careful forest 

 protection secured. 



c. During Fellings. 



i. Avoid very long rotations, as the area of a forest exposed 

 to danger from storms increases in proportion to the length 

 of the rotation. Thus, considering that danger from storm 

 commences when the trees are fifty years old, we have : 



With 120 years' rotation -^-ths of the area endangered. 

 ,, 90 ,, ,, <ytns ,, ,, 



60 Jth 



ii. All greatly exposed places in mountainous regions should 

 be regenerated by the Selection system, and the slopes should 

 not be touched till the summit has been regenerated. 



iii. Eegeneration in narrow strips commencing in the direc- 

 tion opposed to the prevailing wind, should be substituted for 

 regeneration extending at once over a whole compartment, 

 especially in spruce forest. 



In the Black Forest, where silver-fir predominates, the 

 group system of felling in patches, gives excellent results, as 

 plentiful natural regeneration results. 



