upright branches which compete with the leader are 

 removed. The desirable branches to leave are weak and 

 horizontal. 



Year 2 — Dormant Pruning 

 (First Dormant Season) 



If summer training and pruning operations were 

 conducted during the first growing season, very little 

 dormant pruning is required. However, if vigorous 

 branches or upright grov^h were not removed, now is 

 the time to do this operation. 



Vigorous growth should not be allowed to remain 

 for two seasons; the growth and vigor of the leader and 

 other lateral branches vdll be unbalanced. 



The central leader is removed by heading into two- 

 year-old wood to a competing lateral. An alternative 

 method of central leader vigor control is to bend over 

 the central leader the previous summer, then return 

 the leader to the other side of the supporting post the 

 following spring (May or June). 



In this method, no heading cuts are made during 

 the second winter. The leader of a non-spur cultivar 

 should not be headed into one-year-old wood. 



The scaffold branches for the lower permanent tier 

 are selected; there are generally three to five perma- 

 nent lower branches. Scaffold branches are NEVER 

 headed into one-year-old wood, as this type of pruning 

 cut is too invigorating. Also, heading cuts into one- 

 year-old wood delay fruiting. 



Year 2 — Summer Training and Pruning 



As in year 1, limb positioning of lateral branches 

 should be continued and undesirable growth removed. 

 Proper limb positioning is critical for flower bud initia- 

 tion and development. Growth which competes with 

 the leader or is excessively vigorous should not be 

 allowed to develop during the growing season. 



Timing and techniques for training and pruning 

 are the same as those for year 1 summer. 



Years 



The tree should be in commercial production by 

 year 3 (third leaf), if a branched nursery tree was 

 planted. Dormant and summer pruning utilize the 

 same techniques as employed in the first growing 

 seasons. 



However, lower scaffolds will need to be shortened 

 with the use of stubbing cuts into two-year-old wood. 

 The leader v^all continue to be pruned to a replacement 

 lateral or tied over as in previous years. 



Continued pruning of the central leader to a com- 

 petinglateral, which is then trained upwards results in 



a central leader with a zigzag shape. This zigzag 

 configuration helps to reduce excessive growth in the 

 top of the tree as the tree matures. 



Year 4 



By the fourth leaf, maintenance pruning is con- 

 ducted. There are three major steps to remember: 



1. Renew upper scaffolds: after a branch has fruited, 

 it is generally removed completely, leaving a short 

 stub. 



2. Shorten lower scaffolds: head to aweak lateral on 

 older wood. This is used to restrict the tree to its 

 allotted space. 



3. Control central leader growth: use either replace- 

 ment pruning or tying down. After year 5, the 

 central leader is generally controlled by cutting to 

 a competing lateral on two-, three-, or four-year- 

 old wood. Bending over the leader is not recom- 

 mended. 



The same principles as outlined above are em- 

 ployed throughout the life of the mature slender 

 spindle orchard. Special caution is advised concerning 

 the vigor of the tree, particularly at the top of the 

 canopy. The growth MUST remain weak and must be 

 continually renewed after fruiting. 



If the top is allowed to become vigorous and domi- 

 nant, the fruiting portion of the lower third of the tree 

 is eliminated. All parts of the tree must receive light. 

 Shading also reduces fruit quality. 



The slender spindle system as described above is 

 the "pure" system. Modifications wall be devised to fit 

 Pacific Northwest growing conditions. The higher 

 light incidence and longer growing season in a desert 

 climate, as compared to the Netherlands where the 

 system was developed, will certainly mean that we 

 must adapt the slender spindle tree for our needs and 

 purposes. A taller slender spindle tree (eight feet) 

 would utilize light efficiency under Pacific Northwest 

 growing conditions. 



It may be necessary to use more heading into one- 

 year-old wood than the original slender spindle system 

 allows. Treatment of the leader may be modified to 

 light tipping on varieties such as Granny Smith, which 

 may require more feathery growth at the top of the 

 canopy, and tying, rather than heading, for devigora- 

 tion. 



Vertical Axis 



The "axe centrale" or vertical axis tree training 

 system was developed by Lespinasse in the 1970's. It is 

 a central leader tree trained to a three- or four-wire 



FmU Notes, Fall, 1989 



