258 THE PROTECTION OF WOODLANDS. 



are dry months. The best protection against drought is to 

 retain the protection of existing trees, heather, &c. (so long 

 as required), or to plant nurses (as for protection against frost) 

 and remove them as soon as no longer needed. Sunburn or 

 bark-scorching by direct action of the sun makes patches of 

 bark on S. or S.W. sides of stems dry, crack, and fall off, and 

 the wood below that rot ; and this occurs oftenest when trees 

 are suddenly exposed to full sunshine. Smooth-barked trees 

 are most easily scorched, and rough-barked trees (Oak, Elm, 

 &c.) have the best natural protection. So far as practicable, the 

 S. and S.W. edges of maturing crops should not be suddenly 

 exposed; but sun-burnt stems along the edge should not be 

 cut, as the trees behind them will be just as likely to get 

 scorched. 



Heavy rainfall erodes the soil and carries away the finer 

 particles of earth and much of the beneficial humus, though 

 the action of woods in close canopy is to reduce such damage 

 to its minimum. Snow only damages trees if falling in large 

 quantities, by causing the branches to be bent down or broken 

 off. Of our common Conifer trees the brittle Scots Pine is most 

 liable to damage from snowbreak ; while among broad-leaved 

 trees Beech, Alder, Crack Willow, and Eobinia have the brit- 

 tlest branches. In Central Europe, where snow falls heavily 

 and lies long, young Spruce, Oak, and Beech woods are some- 

 times laid by snow-pressure, but this is seldom likely to occur 

 in Britain. Damage from snowbreak may occur anywhere or 

 all over in Scots Pine woods ; but in other kinds of tree-crops 

 it is chiefly confined to the edges of compartments, or to small 

 patches here and there. Heavy snow can be taken off young 

 ornamental trees in parks, avenues, or small plantations, by 

 shaking the poles or tapping them with a padded mallet ; but 

 in woodlands this is impracticable, and the only way of pre- 

 venting damage is to tend the woods carefully, especially with 

 regard to moderate thinning. 



