150 MASS. EXPERIMENT STATION BULLETIN 238 



shoots that had made over 6 inches growth were cut back from one-half to 

 two-thirds, the pruning being less severe in later years. 



2. Globular tree, not headed back. These were cut back at planting as in 

 (1) and in succeeding years thinned to approximately the same degree, but 

 no further cutting back was practiced. 



'3. Unpruned. These trees were not cut back at planting and were not 

 pruned at all except to cut out suckers starting from the base and to keep 

 the trunk clear of water sprouts. 



4. Modified leader. Tree not headed back. These trees were not cut back 

 at planting and in later years were thinned out as in (2). If a distinct leader 

 persisted it was cut at a height of 8 to 10 feet, the cut being made at a side 

 branch in two- or three-year-old wood. 



5. Leader tree headed back. These trees were not cut back at planting, 

 but in later years, while the leader was allowed to grow, all other shoots were 

 cut back as in (1) though the cutting back was a little less severe; they were 

 thinned out each year the same as the other pruned trees. 



6. Leader tree not headed back. These were treated like (.5) except that 

 no heading back was practiced. 



An eifort was made to thin all the pruned trees of each variety to the same 

 degree. This necessitated more cutting of the cut-back trees tlian of those 

 not cut back. This program was carried out annually, except in 1920, from 

 the start of the orchard until the spring of 1925 when the experiment was 

 brought to a close. The pruning was always done by the writer, or under 

 his inamediate supervision. In the spring of 1920 no pruning was done owing 

 to the absence of the writer, and the pruning in 1921 was somewhat more 

 severe than in other years. 



All prunings were weighed, the one-year wood and older wood being weighed 

 separately except in the earlier years. The weight of the cut-back tips was 

 also taken separately. Trunk diameters at a fixed point on the trunk were 

 taken; the amount of bloom of each tree was estimated, and the fruit weighed 

 each year. Other observations and measurements were taken from time to 

 time as will be brought out later. 



While the orchard has had a fair share of mishaps and it was necessary to 

 replant a few trees, the stand of trees is as even as is often seen in com- 

 mercial orchards. The most serious trouble met with was killing from the 

 severe cold of the winter of 1917-18. The Spy and Mcintosh did not suffer, 

 but the Baldwin, Rhode Island Greening and King trees suffered rather 

 severely. Some were killed back to the snow line; in others, while the bark 

 and a thin outer layer of wood were uninjured, the rest of the wood was 

 killed, resulting in a severe check in growth from which the tree recovered in 

 a year or two. Further comment on the relation of this winter injury to the 

 pruning experiments will be made. 



Towards the end of this ten-year period the trees showed signs of nitrogen 

 hunger and have since responded to nitrogen applications with better foliage 

 color and increased growth. 



Some of the trees proved untrue to name. The variety mixtures were as 

 follows: 



Baldwin, 10 trees. Stark and some unknown variety. 



Northern Spy, 2 trees. Palmer Greening. 



Rhode Island Greening, 30 Smokehouse and 1 Tolnian Sweet 



Mcintosh, 1 Baldwin. 



King, 2 trees an unknown variety. 



