MAINE AGRICULTURAL LXPIiRIMEXT STATION. I91O. 385 



two warm days having a maximum temperature of -j- 45° F. 

 and +47° F. situated midway between. Moreover it will be 

 seen that the changes from extreme cold to thawing and back 

 to cold again were quite abrupt, particularly in the case of the 

 latter. Winter-killing of trees may occur, however, as the 

 result of a deficiency of moisture in the soil associated with 

 continued cold, dry winds in winter. 



Much of the danger from winter-killing can be avoided by 

 planting only those varieties which have been found to be per- 

 fectly hardy in a given locality. Only the most hardy varieties 

 should be planted in those parts of the State where the mini- 

 mum winteij temperature frequently reaches or approximately 

 reaches — 30° F. The planting of Baldwins and possibly Ben 

 Davis as large commercial ventures should be restricted to those 

 parts of the State where the minimum winter temperature, re- 

 peated at frequent intervals, seldom reaches below — 20° F. or 

 at the utmost — 25° F. The location of the orchard may have 

 much to do with hardiness. Low, heavy or wet soils should 

 be avoided,— ^it was orchards in such locations which suflfered 

 most in the severe winter-killing of 1906-7. Those which were 

 located on more or less sloping land with good air drainage, 

 with plenty of natural or artificial soil drainage as a rule suf- 

 fered much less from winter injury. 



There is considerable difference .of opinion among Maine 

 orchardists with regard to the value of wind-breaks. A very 

 good illustration of the good they may do was furnished by an 

 Orono orchard following the severe winter just referred to. 

 This orchard was badly injured, particularly on the north and 

 northw-est sides of the more exposed trees and in the direction 

 from which come the prevailing cold winds of winter. A nat- 

 ural wind break of evergreens and coppice growth was situated 

 so as to protect a portion of the trees and here the injury was 

 much reduced or absent altogether. 



Aside from the possible value of planting wind-breaks very 

 little can be done to prevent winter injury in orchards already 

 planted except to provide artificial drainage where necessary 

 and to avoid forcing the trees to too luxuriant and late growth 

 during the latter part of the season, as has already been men- 

 tioned. However, much of the ill effects following an adverse 

 winter may be eliminated by proper attention to the injured 

 trees. Observations made in Maine orchards for 4 seasons 



