Extreme cold weather can kill trees, and cold weather at the wrong time can damage trees. For example, a warm February and March in Michigan in 2012 brought early blooms to apple trees that then were killed by an April frost.
Some trees require cool temperatures, such as some fruit trees (peaches, cherries and blueberries) and nuts (almonds). Cold air along with less sunlight that comes with winter halts tree growth, preparing the tree to withstand freezing temperatures and then resume their growing the following spring.
The amount of time the temperature is between 32 and 45 degrees F is called “chill hours.” If these fruit and nut trees do not get their required number of chill hours, buds are delayed and the fruit can be small and underdeveloped.
You may have noticed the small crop of Georgia peaches this year. That is because the 2016 and 2017 Georgia winters were warm. As a result, the region lost as much as 85 percent of its peach crop. If winters continue to warm, these fruit trees will be less productive.
Georgia was not the only state with a chill hour deficit last year. Most of the U.S. had fewer chill hours than average.
Farmers have always been dependent on good weather and have learned to adapt to bad crop weather. Warming winters as a result of climate change bring new challenges.