FACTORS AFFECTING TART CHERRY ORCHARD BLOOM DATE, HARVEST DATE, AND YIELD IN DOOR COUNTY, WISCONSIN

Abstract

Door County, Wisconsin, is a small landmass forming a peninsula that extends into Lake Michigan. The moderating effect of the lake on regional weather makes it possible to grow tart cherries and other crops at latitudes that would otherwise be too cold for such agricultural practices. Growing up on an orchard in this community, I knew that orchards in the northern part of the county tended to ripen later, and this inspired me to investigate the evidence for a ripening gradient based on latitude. I also set out to identify the factors that most strongly influence bloom date, harvest date, and yield per acre of tart cherry trees in Door County. An additional goal was to identify which orchards were the most successful in terms of yield and determine why. I concluded that the factor with the highest impact on bloom and ripening time was average temperature in the months preceding bloom and harvest. Warmer temperatures in April translated to earlier bloom and warmer temperatures in April through July resulted in earlier harvest dates. Temperature also had an impact on yield, but the implications were less clear since there was not a known optimum temperature for producing the highest yield. I concluded that orchards in the south and on the bay side of the county do indeed tend to bloom and ripen earlier in the spring, but there was no clear gradient and many orchards that deviated from this trend. I did not find evidence for a yield pattern in terms of latitude or distance from Lake Michigan. Door County’s yield was comparable to the national average for tart cherry growing states.