52 INTERNATIONAL CONGRESS OF VITICULTURE 



springing from the ground level or just above it. The axiom "Never prune 

 when the wood is actually frozen" has some foundation in fact, for frozen 

 canes are brittle and are easily broken during handling. 



In the fall of 1911 an experiment was started in a Concord vineyard 

 eight years set to determine the affects of pruning at two widely separated 

 periods of the dormant stage. Five rows consisting of about 68 vines each, 

 trained on five different systems were pruned in the fall, approximately 

 three weeks after the leaves had fallen. Five other rows immediately 

 adjacent to, and representing the same five systems were pruned in the 

 spring a short time previous to the starting of sap flow. In the fall of 1912 

 records of fruit yields from the five pairs of rows were taken. As these 

 vines were planted in rows eight feet apart with the vines six feet apart in 

 the rows, there are 907 vines to the acre as against 680 when ordinarily 

 planted eight feet. by eight feet. The following table shows the yields for 

 the two periods: 



Fall pruned Spring pruned 



Tons per acre Tons per acre 



6.98 6.98 



6.9 6.75 



6.2 5.98 

 2.76 4.3 



6.3 5.94 



The variations appearing between the fall and spring pruned vines in this 

 table are by no means consistent and are those that are common to any 

 acreage of grapes or other fruits, grown under commercial conditions. 



The following table is a compilation of the yields for 1913 in the same 

 vineyard: 



Fall pruned Spring pruned 



Tons per acre Tons per acre 



2.48 2.94 



2.75 2.5 



2.82 2.96 



3.33 2.03 



2.24 1.64 



Here again it is seen that while three of the plats of the fall pruned, re- 

 turned somewhat larger yields than the companion spring pruned rows, 

 nevertheless two of the spring pruned in turn yielded the higher.. In practi- 

 cally all of our experiments this natural variation has shown prominently. 

 Certainly the data as here given does not warrant the drawing of conclu- 

 sions pro or con. 



The yields for the season of 1914 are as follows: 



Fall pruned Spring pruned 



Tons per acre Tons per acre 



6.2 7.4 



6.4 7.0 

 5.6 5.9 

 5.8 6.5 

 7.1 7.3 



For the first time since the beginning of the experiment we see that all 

 the spring pruned plats yielded slightly higher than the fall pruned. The 

 increase ranges from 1.2 tons per acre down to the minimum 0.2 tons. If 



