118 FIELD, FOREST AND FARM 



while the lower parts will languish and die out for 

 want of sufficient nourishment. If the branches are 

 not properly thinned the central ones, deprived of 

 the sun's vivifying rays, will remain poor, puny, 

 more or less blanched. On the other hand, the tree 

 ought to fill, as far as possible, the place assigned 

 it, in order that there may be no unproductive space. 

 "These conditions prescribe the tree's shape. 

 First of all, it should be symmetrical, in order that 

 the distribution of nourishment may be even and no 

 part of the tree be gorged with sap while another 

 part is deprived of it. Secondly, the sun's rays 

 should be allowed to penetrate everywhere so as to 

 ripen the fruit and facilitate in the foliage the im- 

 portant work of sap-elaboration. To attain these 

 different objects custom has fixed upon three princi- 

 pal shapes : the trellis, the pyramid, and the goblet. 

 In trellis pruning the tree spreads its branches sym- 

 metrically, right and left, against a wall. The wall 

 serves it as support and as shelter from the wind; 

 it also gives the foliage and fruit additional heat and 

 light by reflecting the sun's rays upon them. When 

 pruned to take the pyramid form, the tree has its 

 branches so trimmed as to decrease in length regu- 

 larly from the base to the summit and to remain far 

 enough apart to admit the light to the center. The 

 whole forms a sugar-loaf, a cone, into the midst 

 of which sun and air enter freely. It is the shape 

 most in accord with nature. Finally, the goblet- 

 shaped tree has a certain number of branches of 



