282 AGRICULTURE. 



blown over; (2) the trunk is thus protected 

 from the direct rays of the sun, thereby prevent- 

 ing- sun-scald ; (3) that the tree's energy is con- 

 served by lessening the distance through which 

 the food is carried ; (4) that the fruit is easier 

 gathered. 



The greatest objection in heading a tree low 

 is that it renders cultivation more difficult. 



2. If a tree is grown for timber, a tall, straight 

 trunk should be encouraged by pruning off most 

 of the lateral branches and planting the trees 

 close together (Fig. 96), so that they will be 

 forced to grow upright to obtain the light. As 

 the trees develop, and room and food supply 

 become insufficient, some of them should be re- 

 moved. 



3. Slow-growing shade-trees require very little 

 or no pruning, save the removal of diseased or 

 broken branches. But rapid-growing shade- 

 trees — as, some of the maples — should have a 

 portion of the last season's growth pruned back 

 each year, thus forming a compact head, making 

 the tree stronger, and obviating the necessity of 

 severe top-pruning, which renders the tree use- 

 less (for shade, at least) for one year, as well as 

 presenting a very unsightly appearance. 



II. Pruning to Induce Fruitfulness. 



As has been said, the paramount natural pur- 

 pose of a plant is that of reproduction. Every 

 plant has a certain amount of available food. In 



