[PHOTU BY A. IvNliCUTEL 



Planting on Dominion Forest Reserve. 



its way through the soil partly by 

 chemical action at the root tips and 

 partly by the force of the growth and 

 development behind, the root system 

 must develop in proportion to the tree 

 crown. If the root is too small it will 

 fail to support the tree and to supply 

 adequate moisture to make up for the 

 transp'ration from the crown. So the 

 cutting back of the roots when trans- 

 planting trees necessitates the cutting 

 back of the crown. And it may be 

 mentioned that the small root hairs are 

 the organs of absorption, and, as these 

 are quickly dried out and killed in the 

 sun and air, the roots of trees which are 

 being transplanted should be carefully 

 protected from exposure and be kept 

 moist. 



While the chief function of the root is 

 to supply moisture, they require air. 

 Even the bald cypress of the southern 

 swamps must push up its great root 

 knees above water to get an opportunity 

 to breathe. The effect of lack of 

 aeration of the roots is noticeable in the 

 fringe of dead trees which surrounds 

 many of the lakes in the lumbering 

 region where the waters have been 

 raised for any length of time above their 



normal height by lumbermen's dams. 

 Trees accustomed to grow in wet and 

 swampy places develop a spreading and 

 shallow root so as to keep in reach of an 

 air supply. The knowledge of the root 

 structure is important to the forester. 

 Some of the most beautiful theoretical 

 plans for the management of sprvice 

 forests in the Eastern United States by 

 cutting by the selection method were 

 spoiled by failing to remember that the 

 spruce is a shallow rooted tree, and the 

 pleasing stand of seed trees left to pro- 

 vide for reproduction were levelled to the 

 earth by the first windstorm. 



By what force the water is drawn up 

 through the root and elevated one 

 hundred, two hundred, three hundred 

 feet or more in the air is one of the 

 mysteries of vegetable physics. Atmos- 

 pheric pressure is not capable of raising 

 water above forty feet. Root pressure, 

 whatever that may be, or, if it is only 

 osmosis, that force by which one liquid 

 is absorbed through a meinbrane by a 

 stronger chemical solution, is inadequ- 

 ate. The pressure of the air bubbles in 

 the cells of the tree trunk, the chemical 

 or physical activity of the living cells, 

 the pull exerted by the osmotic action of 



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