14 MAINE) AGRICUI.TURAI, i;XP1;RIME;NT STATION. I909. 



"******* there were 950 orchards inspected with a total of 

 443,184 trees. The number killed outright was 24,613 or about 

 5.5 per cent. A safe estimate of the number injured would be 

 at least 25,000 more. So that 11 per cent of the whole number 

 of trees were killed or injured in 950 orchards." t Farther than 

 this many of the trees which were injured did not recover 

 sufficiently, partly on account of a heavy bearing year, follow- 

 ing, so that they were able to withstand the following winter of 

 1907-08, therefore, it is probable that if the census had been 

 taken again in the summer of 1908 the percentage of trees killed 

 directly or indirectly by the winter of 1906-07 would have been 

 found to be much greater than above quoted. 



The writer has elsewhere discussed in some detail the causes 

 which led to the large amount of winter killing in a single sea- 

 son*.. It is sufficient for our present purpose to state that after 

 a careful inspection of the weather records at Orono throughout 

 the fall, winter and spring of 1906-7 it seemed that conditions 

 which preaviled for a single week near the middle of January 

 were responsible for the injury, although it was doubtless 

 increased by the low temperature of — 28° F and — 25° F 

 recorded on Feby. 24, and March i, respectively. Figure 3 

 shows graphically the daily maximum and minimum fluctuations 

 in temperature in degrees Fahrenheit during the last 23 days of 

 this month. The observations were made at 2 P. M., using 

 official instruments. As a rule the minimum record is the tem- 

 perature of the early morning and the maximum that at about 

 or a little earlier than the hour of observation. 



Particular attention should be called to the fact that the two 

 lowest records of the season — 40° F. and — 35° F., are only 

 7 days apart and midway between them come two consecutive 

 days with records of +45° F. and -|-47° F. Moreover these 

 changes were quite abrupt, particularly on the 21st when from 

 2 P. M. to sometime before sunrise the next morning there was 

 a fall in temperature of 60° F., or in other words a change from 

 15° F. above the freezing point to 45° F. helozv the freezing 

 point in 12 or 15 hours. Following this in 48 hours is the sec- 



t Sixth Annual Report of the Commissioner of Agriculture, p. 282, 

 (Augusta, 1907). 

 * Proceedings of the Maine Pomological Society, pp. 36-46. 1907-8. 



