536 PROTECTION AGAINST WINDS. 



deviate from the vertical position, less by uprooting, and less 

 still in breakage. 



In the storm on the Baltic coast in 1872, in the Greifswald, 

 25-years-old Scots pines were affected. In 1876, 15 to 20- 

 years-old spruce and Scots pines were seriously damaged. In 

 some pole-woods 25 to 30 per cent, of the stems were bent an 

 angle of 30 degrees towards the east and north-east. 



(c) System of Management. High forests are most exposed 

 to danger from storms. The shelterwood compartment system 

 leaving mother trees evenly distributed over the felling-area, 

 is most endangered. In localities exposed to storms (mountain 

 sides, etc.) this system is inapplicable, as the mother trees are 

 inevitably blown down. 



Whether uneven-aged and irregular Selection forests suffer 

 more from storms than the even-aged woods of the Clear- 

 cutting system, is still an open question, which can only 

 be answered after thoroughly considering the modifying 

 influence of localities, and the degree of skill with which the 

 woods have been treated. Hesse believes that the Selection 

 and Group systems give more security against storms than 

 the Clear-cutting system, as the trees in the latter are more 

 crowded and have weaker roots, but under the former systems 

 the trees to be felled must be very carefully selected. 



Among the coppice systems, that of lopping side branches is 

 the worst, as trees so treated have long narrow crowns, on which 

 the wind can exert leverage. Pollards suffer less, and ordinary 

 coppice least of all. Coppice-with-standards is also storm- 

 firm, as only the standards can suffer, and damage to these 

 is inconsiderable, owing to their strong root development and 

 the uniformity of their crowns, due to their growth in the open. 



(d) Nature of Stem. Long, cylindrical stems with elevated 

 and expanded crowns, having high centres of gravity, and 

 affording strong leverage to the winds, are greatly exposed to 

 damage by storms. Thus standards in high forest above 

 young growth are peculiarly liable to be thrown or broken. 

 Damaged or sickly trees, such as forked trees, those with 

 deca3'.ed roots; trees injured by game, insects, cankers, fungi, 

 cup-shake, bark-scorching, etc., are very liable to windbreak ; 

 this, as a rule, occurs at the damaged place. 



