54 PROTECTION OF WOODLANDS. 



comes, so that, with the tops pointing to the ground, it covers the 

 soil somewhat in the same way as slates lie on a roof. 



The woven fences or hurdles, which have also the object of 

 breaking the violence of the wind and preventing the raising of 

 the sand, are of special use in operations conducted over extensive 

 areas very much exposed to the wind. They are erected facing 

 the direction of the prevailing wind, that is to say, they run from 

 north to south and face westwards, where westerly winds prevail, 

 and are bent into a half-moon shape at the ends in order still to 

 form a protection even when the winds are deflected to north or 

 south ; they subdivide the whole area into a series of strips, whose 

 breadth, or the space between the parallel lines of fencing, is 

 dependent mainly on the local circumstances of each case, but 

 varies from 100 feet on sloping, broken ground, or more exposed 

 localities, to 200 feet apart on level tracts. 



The erection of the fences takes place by driving piles or poles 

 of Scots Pine, about 4 to 6 inches in diameter, and about 5 feet 

 in length, into the ground at distances of about 2|- to 3 J feet apart, 

 according to the nature of the material available for filling in the 

 woven work, the posts being driven in to such a depth as only to 

 leave about 40 inches out of the ground. Between these upright 

 posts green Pine branches, or occasionally broom, or reeds, or 

 sedges, are woven in horizontally, but not too closely, only to such 

 an extent that drifting sand may sift through to the other side 

 when blown about by the wind, and thus prevent the hurdles 

 being thrown by the pressure of sand heaping itself up against 

 them ; the object of the hurdles is not so much to intercept 

 the sand, as to prevent its becoming drift through the action of 

 the wind. In some cases, Poplar and Willow poles are used as 

 the uprights, in order that, if there be any subsoil-moisture, they 

 may take root, and thus be saved from rotting ; whilst in other 

 places, in order to reduce the requisite number of dear poles, the 

 hurdles are formed with uprights up to 10 feet apart, lashed 

 together by means of horizontal battens between which the Pine' 

 twigs, brushwood, &c., are woven vertically; this kind of fencing 

 has found the most extensive application in many localities. 



By breaking the violence of the wind, these lines of fencing give 

 the sand a chance of remaining at rest ; whilst by a simultaneous 

 covering of that part of the intermediate strips, furthest removed 

 from the lee and shelter of the hurdles in front, with sods of turf, 



