14 I'EINCirLES AND PRACTICE OF PRUNING 



occurs. It may be said, parenthetically, that this bleeding 

 may produce ill effects instanced as follows: 



15. Vine bleeding. — C. C. Newman has demonstrated 

 the evil effect of late spring pruning of muscadine grape- 

 \'ines.* 



T-xn \iiics f^rowiiiK side liy side were pruned, one November 15 

 and the oilier J'"ebruary 15. The vine pruned in November did not 

 lileeil ,it all as the spring advanced and produced a \V(-.nderful crop 

 lit line fruit. The \inc pruned in b'ebruary liegan to bleed as soon 

 as the weather turned warm, slowly at first, but bleeding more 

 freely as the siiring advanced. Urops nf saj) could lie seen steadily 

 dripping frnni the end of each vine that had been cut. The vine 

 pruned in b'eliruary was 10 days later in putting out leaves than the 

 one pruned in November. The growth was very feeble and it set 

 very little fruit, most of the canes dying during the summer. 



To form some idea as to the amount of sap that would flow from 

 a \iiie that had been pruned too late in the season, a third vine was 

 pruned in November, and on March 20 one cane, 'A inch in di- 

 ameter, was cut on the same vine and a rubber tube fastened over 

 it so as to conduct tlie sap to a large glass jug. the mouth of which 

 was closed with a cork, through which the rubber tube passed. The 

 vine began to bleed freely from the cane cut March 20, but the canes 

 cut in November did not bleed at all. A careful record was kept 

 of the sap collected, and in four weeks from the time the cane began 

 to bleed, 23 pounds of sap had been collected from this one cane. 

 The loss of sap through this cane affected the entire vine, and its 

 growtli was checked considerably. 



16. Transpiration is the passage into the air of water 

 in vapor form from lea\-es and other green and growing 

 parts of plants. Thus a ^'er_v■ great part of the water ab- 

 sorl)cd by the root hairs finds its way into the air. Cer- 

 tain plants (eucalyptus trees), because of their ability to 

 transpire immense quantities of water, are used to re- 

 mo\-e excess water from soils that cannot readily be 

 drained in any other way. As instances among agricul- 

 tural plants it may be mentioned that experiments with a 

 little tree have shown that (proportionately) an api)le tree 

 .'jO )ears old would probably transpire 2^>0 pounds of 

 water a day, or about 20 tons during the growing season. 

 At this rate an apple orchard with trees set 40 x 40 feet — > 



» S. C. Bulletin 132, Page 7. 



