628 



PROTECTION AGAINST SHIFTING SAND. 



In France the cluster pine is sown with other seeds in the 

 following proportion for an acre : 



Cluster pine seed . . . .26 Ibs. 



Furze or gorse . . . . 2J 



Genista . ... . 2J ,, 



Marram grass . . . . 2J 



Seeds to attract insectivorous birds 2J ,, 



As the seed is sown, it is covered with 1,000 faggots, 3 feet 



in girth and 5 feet long per acre of furze, broom, heather or 



pine branches, furze being 

 preferred wherever it is 

 available. The faggots are 

 evenly distributed over the 

 area and opened out, and 

 the sowing is then com- 

 menced on the land side 

 towards the littoral dune 

 under protection of a 

 wattle - fence intended to 

 keep off the sand blown 

 back by the land breeze. 

 Each row of seed is covered 

 by the branches, which are 

 placed in rows with their 

 lower ends towards the sea, 

 so that each succeeding row 

 of branches partly covers 



Fig. 285. Psamma arenaria, Beauv. 

 b Surface level of ground, c Rhizomes. 



the preceding one, being 

 arranged like slates on a 

 roof and kept steady by 



spadefuls of sand thrown on them at intervals of 2 feet. 

 Areas of about 300 feet long by 60 feet broad are thus sown 



at one time. Between 1862 and 1874, 5,200 acres were thus 



sown in the Gironde at a cost of 30,646. 



c. Tending the Woods. 



The sand grasses used in fixing the dunes must not be cut 

 or pastured. The water rat and the larvae of Polypliyllafullo, 

 L., are the most dangerous enemies to the grass rhizomes. 



