side, occasionally on that side only, branches ana leaves springing 

 from the root, have a chance to develop. Wind often causes 

 mechanical injury to parts. 



In Jutland lookliig towards the windward side the east appears 

 like a forest, tlie windward side like a heath. In "beech forests, 

 where light wind can enter the surface, vegetation is different 

 from that of the denser portions. 



In northern regions snow protects against transpiration. 

 Snow lies thickest in follows and quiet places, hence vegetation 

 is different there. 



Usfts siZ wind . 



1. Renewal of oxygen. 



2. Pert ilizat ion of plants and forest trees, some depending 

 entirely on wind. 



3. The small amount of moisture is prohahly the reason why the 



mosses and lichens can endure such low temperatures. 



4.1ryoody structures are well adapted to low temperatures. Most 



small plants of Arctic regions contain many wood fibres. Semi- 

 tropical plants when "brought to our region, do not receive heat 

 enough to develop their woody structure. Hence their tips die 

 and trees of this class hecorae only shruha with us. Woods in 



Siberia endure a minimum temperature -60°. (larch forests.) 



Hair covering . Hairs are cells filled mostly with air, and 

 containing little moisture. 



Minor prntflction . 1. Young plants and leaves have many minor 

 protections. In cold regions many plants are covered with a felt- 

 like or wooly substance. 



