COVER AND PROTECTION 129 



Of course this is an exceedingly cheap method. It has, however, the 

 disadvantage of favoring a high percentage of loss. It is only desirable 

 on exceedingly rich or fertile soil where the spade, dibble, or grub hoe 

 can be used to advantage. With very compact clay the method is 

 rarely successful, since the roots will not secure sufficient aeration. 



In the forest of La Gardiole, on exceptionally difficult ground, the seed- 

 lings are raised in pots and set out directly without disturbing the root 

 system. This system is very expensive. When 2-year-old aleppo pines 

 are planted in pots the stock cost, prior to 1912, approximately $4.82 

 per thousand trees plus transport; to-day it would be at least $10 to 

 $12. In the drier localities where sowing by the seed-spot method had 

 been employed, the few surviving seedlings were under the shade of 

 the stone which anchored the branches or under the shade of the stumps 

 or the larger branches. Apparently even better results would have been 

 secured if heavier protective cover had been used. The object of the 

 reforestation project of La Gardiole was to serve as an example to the 

 surrounding population and if possible to temper the hot climate of 

 Marseilles. 



Cover and Protection. — On slopes or soils that are so unstable that 

 forest trees cannot be planted at once it is first necessary to anchor the 

 soil with grass or shrubs. The best shrubs to use are those of rapid 

 growth, since they must be able to take possession of the soil and fight 

 successfully against the effects of erosion. Usually the seed of French 

 grass and rye-grass pure or in mixture is used. The sowing is done in 

 the spring from the top down in order that the lower lines of sowing 

 will not be covered with debris from the higher elevations. Since the 

 seed is so small it is covered with an extremely thin layer of soil. Strips 

 of sod are planted in order to stop the erosion of the surface soil and 

 in order to make possible the growth of trees. These strips or benches 

 of sod are planted horizontally on the slope. In very easily eroded soil, 

 such as the glacial muds, it is often necessary to protect the brush or sod 

 by fascines in horizontal strips. No general rule can be laid down as 

 to when to apply sod and when, to use brush, but it is true that shrubs 

 resist erosion better and are often preferable to sod in maintaining 

 certain kinds of unstable ground. The shrubs are sown or planted, 

 layered, or suckered. The hazel may be sown or planted, while the 

 cherry and the alder are planted. The willows and the poplars are 

 usually layered but the aspen and the willow may be reproduced from 

 slips. 



It is of interest to note that the seeding of some of these shrubs often 

 takes place naturally after the bed of a stream has been fixed by means 

 of correction works. It often happens, however, that the slopes are 

 too steep to be stabilized by any vegetation. In such cases it is neces- 



