626 PROTECTION AGAINST SHIFTING SAND. 



5. Protective Coast Forest Zone, wider the Shelter of 

 the Littoral Dune. 



a. Desrriplion. 



Under the shelter of the Httoral dune, a protective zone 

 of various woody si)ecies mixed with gorse, species of genista, 

 heather, Tamarix, etc., is then allowed to spring up, but is 

 generally planted or sown artificially. 



The species chiefly grown near the Baltic coast is the .Scots 

 pine, over 8,000 acres of this species having l)een phinted near 

 Dantzig between 1795 and 1850. 



In Zealand, the imcinata variety of the mountain-pine 

 {Pinus montana, Mill.) has been used, and its great success is 

 due to its indifference to soil and climate, and its habit of 

 retaining its lower branches green for long periods. In France 

 the cluster pine is chiefly used, but it is liable to be frozen when 

 grown too far to the north. 



Spruce, birch, or white alder may be mixed with the pines, 

 and in South-west France pedunculate oaks and Q. Tozza, 

 D.C. In depressions, the common alder, poplars, and willows 

 may be grown. 



The different varieties of Pinus Laricio, Poir., and especially 

 the Corsican variety, maples and the silver poplar, are well able 

 to withstand the force of the strong sea-winds. 



As a rule, the growth of protective forests near the sea coast is 

 poor, on account of the strength of the sea breeze and the poor 

 nature of the sand in which the trees grow, and which is being 

 constantly heaped over their roots, but protection and not timber 

 is required in a zone extending from 600 to 2,000 feet beyond 

 the littoral dune, and which if left un planted would be a bare 

 sandy tract tending to spread inland and ruin existing forests. 



In a coast-protection forest, short terminal shoots, procum- 

 bent stems, one-sided crowns and a leaf-canopy sloping down 

 seawards, are evidences of the struggle these woods carry on 

 with the wind, but it is a forest all the same. 



The conditions of growth greatly improve as the distance 

 from the sea becomes greater, so that further inland, especially 

 if the sand contains little flakes of mica, even superior species 

 such as beech or silver-tir may be grown, as in Alsensund 



