PROTECTION AGAINST FROST, ETC. 139 



FROST-LIFTING 



In February and March when there are frosts at night with 

 a thaw in the day we find that young seedlings are often 

 lifted out of the ground. This is due to the fact that the soil 

 rises with the frost, and the plants are raised also ; then when 

 the thaw comes the soil sinks again, but the plants do not. 

 When this has been repeated three or four times the plants 

 fall over and lie on the surface, and soon die if long exposed. 

 Nearly all species may be lifted, though this happens but 

 rarely with seedlings, such as oak and sweet chestnut, which 

 have long tap roots. Sitka spruce is specially liable. Frost- 

 lifting is not so bad on sandy soils as on stiffer ones. 



To prevent damage in nurseries the spaces between the 

 rows of seedlings should be covered with dead leaves. The 

 nursery and recently-formed plantations should be visited 

 daily in frosty weather, and all plants lifted should be at 

 once replaced in the ground. 



DROUGHT 



Drought is seldom to be feared in Great Britain, at any 

 rate not to such an extent as to damage established woods. 

 A long spell of dry weather in summer will, however, cause 

 a large proportion of failures in recently formed plantations 

 and, unless care 'is taken, to nursery plants. It is seldom 

 worth while to take measures against drought in the forest ; 

 failures in plantations must be rilled up the following planting 

 season. 



In the nursery drought may be guarded against by covering 

 spaces between the plants with a good layer of humus or dead 

 leaves, as this will keep the soil moist ; by sticking branches 

 of evergreen trees into the soil on the south side of beds 

 of seedlings in such a way that these will shade the bed in 

 the hottest part of the day; by covering beds with mats, 

 lifted up on short supports, during the hottest hours ; by 



