408 ANNUAL REPORT. 



season of the year. Starch is stored away for winter food in the 

 bud and the millions of sap cells in the bark that are connected 

 with the air cells, or stomata, of the outside bark. Through 

 those air cells from the outside surface of the bark and buds the 

 carbon in the air comes in contact with the sap cells containing 

 starch, gradually changes it to gas, or vapor, and it passes off 

 through the air cells of the bark during winter. This is what 

 prevents a tree from dying, or drying up, during the winter. 

 But in case the starch in the buds and sap cells of the bark be- 

 comes exhausted before vegetation starts in the spring, the tree, 

 or the part or parts exhausted, dies. This is erroneously called 

 sun scald, and usually occurs in March, or during a severe 

 drought, when there is little or no moisture at the roots. "When 

 the frost is out of the ground in the spring, and the temperature 

 gets up to sixty degrees or more, the starch remaining in the 

 buds, sap cells, and other parts of the tree is, by the action of 

 heat, carbon, and other elements, changed to sugar or sap, such 

 as we find at the proper season of the year in the hard maple 

 and other trees. In a few days after this chemical change takes 

 place, if the weather continues warm, the buds begin to swell and 

 little leaves appear. These receive carbon from the air, and the 

 sap at once flows to the roots and excites them to action, and 

 then the flow of food in solution from the roots ascends through 

 the sap walls of the tree to the leaves. Here it is spread out 

 through the leaves and assimilated, and becomns plant food, by 

 diffusion to the growing parts of the tree, and new cell structures 

 commence to form. This process of wood formation continues 

 till the annual growth is complete, which is indicated by the 

 forming of the terminal buds. Thousands of people here make 

 a fatal mistake, who have the erroneous idea that when the ter- 

 minal bud is formed the tree is ready to dig. Trees at this time 

 contain but little else than gas and water in their cells, and if 

 they are dug and exposed a few hours to the air will dry up. If, 

 a fruit tree is not checked by drought, low temperature, or unu- 

 sually cloudy weather, its annual growth should be complete by 

 the twenty-seventh of August. Then it commences to lay up its 

 winter food by filling its cells and new wood with starch, and is 

 assisted in the fall by cool evenings and nights, which harden 

 and ripen the wood, and during the heat of the day all surplus 

 moisture in a well-rii)ened tree tends to congeal and rupture the 

 wood, or bark. 



Wo have now followed the fruit tree through a vear and noted 



