98 



TRINCIPLES AND PRACTICE OF PRUNING 



induce long slender growth (Fig. 70). The same is true 

 in very humid climates (80). Shortening to keep the tree 

 heads within bounds may be done when the growths attain 

 lengths of 3 or more feet in a season, but since mature and 

 beariiig trees rarely make such excessive growths, the prac- 

 tice is usually needed only with unfruitful or young trees. 

 Excessive growth in mature trees generally indicates too 

 rich, moist soil, or excessive pruning; hence the remedy is 

 to check growth by making the proper 

 correction, or to have recourse to sum- 

 mer pruning, as practiced in Washington 

 (80). The proper correction for excess 

 moisture may be drainage or the use of 

 a thirsty cover crop, such as clover or 

 hairy vetch ; that for too great fertility, 

 a "nitrogen-ciinsuming" cover crop, such 

 as oats or rye ; that for excessive pruning 

 is to avoid winter pruning as much as 

 possible. Heading-in during winter will 

 only make matters worse. 



c. Shortening-in the annual growths of 

 dwarf trees is done to prevent the de- 

 vel(ipmcnt of tops out of proportion to 

 the roots. This feature deserves special 

 treatment. (Chapter XVI.) 



In all sh(.M-tening-in it must be re- 

 membered that increased pruning in the 

 interior of the top is necessary, especially 

 when the work is done early in the growing season. For 

 often lateral growths, especially on summer-pruned grapes, 

 lirove a great annoyance. The method is useful in helping 

 to secure sturdier branches and to develop frame limbs. It 

 need be employed less annually as the trees approach ma- 

 turity, when it may cease altogether. 



So far the discussion has considered the style of heading- 

 in usually practiced by gardeners and amateurs who seek 

 special!}' fine specimens of fruit. A simpler method prac- 



FIG. 71— TYPICAL 

 PASTURE - GROWN 

 WHITE PINE 

 Note that, ttioueh 

 SO feet higli, the 

 trunk is branctiy 

 nearly to the ground. 

 It \sill make inferior, 

 knotty and tapering 

 lumber. 



