1114 



THE FRUIT INDUSTRY IN NEW YORK STATE 



(a). Frost injury around the crown may take place among 

 trees of all ages and in all locations, whether they are on a steejv 

 slope or on level land. The injury usually occurs in the dead of 

 winter when the snow is on the ground. The snow, a foot or 

 more deep on the level, blows away from the crown of the trees, 

 after which the sun thaws the snow 011 the north side of the basin 

 and the water forms a pool that later in the day freezes. The day 

 following more snow thaws, and another layer of ice is formed. 

 This process is repeated until the basin of ice will not crack as 

 it would under more normal conditions. The distinguishing fea- 

 ture of the injury resulting to the tree is a restricted area of 

 bark about the crown. It may extend all around the tree or only 

 on one side. The bark dries and later offers a convenient breeding 

 place for one of the dead-bark fungi or the borers. 



Control. A tree girdled 

 in this manner cannot be 

 saved, although it may 

 live for several years if 

 only partly girdled. The 

 injuries themselves sel- 

 dom, if ever, heal over, 

 however. In western 

 New York an important 

 measure is taken so as to 

 prevent such injury to 

 peach trees as well as to 

 other trees (Fig. 851). It 

 has become general prac- 

 tice there to make a 

 mound just before the 

 ground freezes in fall, if 

 it has not been made pre- 

 viously, to guard against 

 the borer. In some soils, 

 mounds made earlier 

 wash down, thus making it necessary to remound in the fall. 



(b). The second type of injury occurs in the crotches of the 

 trees, where large irregular cankerlike areas appear at the junc- 

 tion of the limbs and trunk. This injury is common in various 



FIG. 356. FROZEN CROTCH 



