544 



PROTECTION AGAINST WINDS, 



iv. Woods should always be regenerated in the direction 

 opposed to the prevailing ivinds, that is, generally, from east or 

 north-east to west or south-west, so as to secure a constantly 



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r-4 r-3 r-4 r-1 r 



Fig. 247. Normal arrangement of age-classes in a wood ; r, length of rotation. 



graduated succession of young woods on the windy side of the 

 older woods. Nothing can ward off storms better than such a 

 slope of trees as is shown in Fig. 247. 



As such a succession of felling-areas may encourage insect 

 attacks and would not be practicable over the whole area of a 

 forest, it is usual to arrange the age-classes in a number of 

 cutting-series, running more or less parallel to one another 

 through the forest from east or north-east to west and south- 

 west. Age-classes are, however, seldom so arranged that an 

 old wood will not occasionally be found directly opposed to the 

 force of the wind, after it has been exposed by felling another 

 mature wood to the west of it, and in such cases, a severance- 

 felling is required. 



This is a narrow clearing made through a wood, to 

 strengthen the border trees on its weather side, so that by 

 the extension of their crowns and root-systems, they may 

 protect the dense wood beyond them from storms. Severance- 

 fellings should be forty to fifty feet broad, and as nearly as 

 possible at right-angles to the direction of the prevailing 

 wind ; they must be made before the trees are too old to 

 respond to the increased exposure to light. Spruce woods, in 

 which a severance-felling is to be made, should not be more 

 than 20 80 years old. The cleared space should be at once 



