38 The Farm Woodlot 



this way, the tree is robbed of its normal amount of mois- 

 ture, and the leaves and twigs become shriveled, some- 

 times so severely that they cannot recover. The warmth 

 of spring starts growth in the plant once more. The sap 

 rises in the trees, the buds open, the leaves and flowers 

 come out, and the live tissue, that completely covers the 

 tree, stem and branches in an unbroken layer, begins 

 growth. During this period, the tree feeds on the surplus 

 food stored away the year before. The growth from the 

 growing points in the buds produces length of branch or 

 height of stem. The cambium produces diameter growth. 

 Neither stem nor branch ever grows in length except at 

 the end. There is a common belief that the fence wire 

 nailed on the trunk of a tree will rise as the tree grows. 

 This is not true. The trunk grows only in diameter. 

 This spring growth is producing the thin-walled layer 

 of cells found in the inner part of the ring in the cross- 

 section. When the leaves come out and the work of 

 manufacturing food begins, the thick-walled cells of the 

 outer part are formed. Through the summer, more food 

 is produced than can be used for growth, and this surplus 

 is stored away in the pith rays for the growth of the follow- 

 ing spring. This completes the yearly round of life in 

 the tree. The following years of growth are the same as 

 this second one. 



At ages varying with the species, flower buds are formed 

 and fruit produced. This occurs in some species, like 

 the jack pine, at the age of seven or eight years. Such 

 early fruiting, however, is premature and the seed, if 

 any is produced, rarely possesses any vitality. This is 

 more or less true of the first seed produced by any plant. 



