Did you know that fruit trees monitor time and temperature? From 250 to 1,000 hours of temperature below 10 degrees C are needed before a fruit tree can bud. Buds require extensive winter chilling while roots do not. The reason for this is obvious. If a chill time were not built into the buds, every time a winter thaw came along they would open. Then when the weather turned cold again the buds would be killed, and we would have no fruit.  This is another Dandy Design found in trees