CHAP. IV.] 



The Food of Trees 



8.3 



supplies, their wood shows the following percentages of mineral matter 

 per TOO parts of dry tissue, according to Ebermayer 1 : 



And, according to the same high authority, the annual demands made by 

 pure crops of forest trees, for the formation of wood only, are per hectare 

 in kilogrammes, or approximately per acre in Ibs. avoirdupois, as under : 



Forstlich-natunvissenschaftliche Zeitschrift, 1893, pp. 225, 226. 



G 2 



