420 ELEMENTARY STUDIES IN BOTANY 



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and this includes " harvesting the crop/' putting it into 

 the necessary forms, and disposing of the products. The 

 general motive of forestry, which runs through all of its 

 details, is to use the forest in -such a way that it may not 

 only continue to be productive, but increasingly so. To 

 insure this will require adequate protection of forest property, 

 a more complete use of forest products, and harvesting with 

 the future in mind. 



126. Character of the forest. An assemblage of trees is 

 called a " stand," and stands may be pure or mixed. A 

 pure stand is one in which all the trees, or nearly all, are of 

 the same kind ; while a mixed stand is one in which there 

 are various kinds of trees. There are three parts of a forest 

 to consider in forestry : (1) the canopy, (2) the forest floor, 

 and (3) the character of the tree trunks, which represent the 

 mass of wood. 



The canopy is made up of the interlacing crowns of the 

 trees, and it must be kept as uniform as possible. The 

 value of the wood depends upon this, for a good canopy 

 causes the lower branches to be shed while they are small, 

 and as a result the trunk is clean and free from knots. In 

 the formation of a forest, the forester sees to it that the 

 canopy rises as the trees grow. In a pure forest a uniform 

 canopy can be managed easily, but in a mixed forest the 

 canopy is a more complex problem, for the different trees 

 hold different relations to the light, some needing less light 

 than others. In such a case the canopy is developed in 

 stories in accordance with the light-needs of the different 

 trees. The canopy serves several purposes in the economy 

 of the forest. It manufactures the carbohydrate food for 

 the trees ; it shades the forest floor and thus prevents the 

 development of undergrowth, checks the drying out of the 

 soil, and shields the soil from dashing rains ; it also enriches 

 the soil with its leaf litter, making the forest soil the best of 

 soils. 



