INDIVIDUAL ELEMENTS 



155 



Table 48.— Grams of Lime in 100 Leaves^" 



In most cases there is a reduction in the absohite calcium content before leaf fall, 

 probably because of the dissolving action of rain. The lime content of full 

 grown leaves is often very great, sometimes constituting 52.82 per cent, of the 

 ash of the olive, 54.33 per cent, of the ash of the apple, 56.83 per cent, of the ash 

 of the orange and 34 to 60.9 per cent, of the ash of the grape. ^^ 



The data in Table 49 showing the simultaneous changes in the calcium 

 content of leaves and branches indicate that there is no removal of calcium from 

 the leaves to the branches. 



Table 49. — Grams of Lime in 100 Branches of Horse-chestnut and Their 



Leaves^ 



Branches 



Leaves 



July 29. 

 Sept. 11 

 Oct. 14. 

 Nov. 16 



4.274 

 6.549 

 5.938 

 5.804 



27.292 

 39.785 

 51.201 



In Bark and Wood. — Young bark contains considerable lime, about 40 per 

 cent, of the ash, chiefly in the form of calcium carbonate. It increases with age to 

 70 or 80 per cent, of the ash, sometimes reaching 95 per cent, in oak bark.^^ 

 Pear bark ash has been found to contain 33.88 per cent. Ume, apple bark ash 

 51.84 per cent, and grape bark ash 42.05 per cent." The seasonal variation is 

 counter to that of potassium, there being proportionately less calcium in the 

 bark in the spring than at other times. For example, in the walnut, bark ash was 

 found to contain 8.37 per cent, calcium on May 31 and 70.08 per cent, on Aug. 

 27.^^ Calcium increases with age in the wood also and the heart-wood contains 

 progressively more than the sap-wood, as Table 50 shows. 



In general 60 to 78 per cent, of wood ash is lime. In the orange it has been 

 known to rise to 68.88 per cent.^^ In the sap-wood there is less; in the pear 

 there has been found 27.39 per cent., in the apple 18.65 per cent, and in the grape 

 25.67 per cent.^'* In the heart-wood, the vessels and sometimes the tracheids, 

 wood fibers and parenchyma cells are filled with spherites of calcium carbonate. 

 The older the wood, the more calcium there is in its ash. 



