Some tree species require a relatively short chilling period to overcome dormancy. It’s the same reason bulbs don’t start to grow as soon as you plant them in the fall.
The chilling requirement is an evolutionary adaptation that protects trees from starting to grow anytime they experience a brief warmup during the winter. This dormancy or chilling period is needed before normal growth will resume in the spring.Īs a general rule, most conifers need to accumulate at six to 10 weeks of exposure to temperatures below 40 degrees Fahrenheit in order to meet their chilling requirement to overcome dormancy. The dormancy process first begins because of decreasing photoperiod, but continues as trees respond to low temperatures around or just below the freezing point. Conifers will stop growing and set terminal buds as days become shorter even though the day temperatures are still relatively warm, but the nights are cool in August and September. The two most critical environmental factors that trigger the dormancy process are the reduction of light, or photoperiod, and low temperatures. This process helps them survive through winter until spring when they will come out of dormancy, de-harden and resume growth. Each year, trees follow a cycle of dormancy in the fall. To understand what is going on, we need to talk about how conifers develop and survive the winter. Often, Michigan State University Extension educators receive calls from homeowners in December because their Christmas tree has broken bud and started to grow while in the house.
0 kommentar(er)
