-2- 



applied. Secondly, the treatment must be applied before growth 

 starts. Thirdly, the present procedures of leader selection are 

 less time consuming than the NAA treatment. And lastly, a better 

 choice of a leader often can be made in mid-June and this job can 

 be combined with limb spreading with clothespins. Thus, we will 

 continue to suggest the present procedures of leader selection. 

 This involves selection of the uppermost shoot on the windward side 

 of a newly-planted tree when shoot growth is 6 to 8 inches in length, 

 Shoots competing with the selected leader should be rubbed or pruned 

 off for distance of approximately 6 inches down the stem. 



AAA******* 



WINTER INJURY TO FRUIT TREES Ifl 1978-79 



William J. Lord and Peter Veneman* 

 Department of Plant and Soil Sciences 



Pomologists in the early 1900's considered winter injury to 

 roots of fruit plants to be a major problem of fruit production 

 in northern growing areas. Thus, considerable time was devoted to 

 the study of low temperature effects on tree roots. However, a 

 search of literature shows that root-kill on fruit trees has occur- 

 red only once during this century in Massachusetts prior to this 

 past winter. 



G.E. Stone, Botanist for the Massachusetts Agricultural Experi- 

 ment Station, stated that root injury to apple trees occurred dur- 

 ing the severe winter of 1903-04. No mention was made of temper- 

 atures and snow cover in orchards that sustained injury. Minimum 

 temperatures at Amherst in December, 1903 and January, 1904 were 

 -3.5° F. and -26° F., respectively. The mean temperature for Janu- 

 ary was only 14.3° F. A total of 36 inches of snow fell at Amherst 

 in December, 1903 and January, 1904. 



Whether or not the snow cover was lost in the orchards where 

 winter injury occurred is not known. During the winter of 1898-99 

 winter injury was widespread in Wisconsin, Iowa, Minnesota, and 

 Canada. It was observed that where there was good snow cover there 

 was no root injury when air temperature went as low as -50° F. 



The winter of 1933-34 was also unusually severe but the injury 

 was confined to the above-ground tree portions. February was espec- 

 ially cold with a minimum temperature of -22° F. and a mean tempera- 

 ture of only 11.6° F. for the month at Amherst, MA. The 3 major types 



A 



Assistant Professor of Soil Sciences 



