Trees Prepare for Winter

Trees Prepare for Winter

Imagine standing naked outside on a cold winter day. When winter’s chill comes, people take shelter. If we have to be out, we put on more clothing. Most animals have fur or feathers to help keep them warm, and they also seek shelter from the cold. Trees in winter can only stand there and take it for months at a time. So how do trees prepare for winter?

Living cells in plants or animals consist primarily of water inside a membrane. If you leave a bottle of water in your car on a night when the temperature drops below freezing, you know it will freeze and break the bottle. That is because water has the unique property of expanding as it freezes. The same thing can happen in living cells. If the water in the cell freezes, it will expand and rupture the membrane. Animals that are endothermic (warm-blooded) generate heat within their cells by burning sugar to produce energy. Plants make sugar using light energy. With a few exceptions, they don’t produce heat.

How do trees prepare for winter? They use a process botanists refer to as “hardening.” The cell walls become more permeable to allow water to escape. At the same time, sugars, proteins, and acids in the cell are concentrated into a syrupy liquid, which acts as an antifreeze. The spaces between the cell walls become filled with ultra-pure water filtered through the cell walls. Pure water without stray atoms to form a nucleus around which ice crystals can grow, will freeze only at a much lower temperature. With the cells filled with antifreeze and spaces between having only ultra-pure water that can be super-cooled without freezing, the tree is ready for what the winter brings.

How does the tree know that it’s time to harden for winter? Fall weather can fluctuate quickly and dramatically. A tree can’t depend on the fickle weather because it could easily be fooled by warm days that suddenly turn cold, causing it to freeze to death. Trees know when to prepare for winter because of the length of the days – the “photoperiod.” Weather is unpredictable. The Sun is absolutely dependable. When the tree senses a decrease in light in each 24-hour cycle, it knows winter is coming, even if the weather is unusually warm. The pattern of changing daylight and darkness is exactly the same every year, even though the weather is capricious.

God engineered this incredibly well-designed system. “Then God said, ‘Let there be lights in the expanse of the sky to separate the day from the night. They will serve as signs for seasons and for days and for years’” (Genesis 1:14). Thus God designed the system which says, “Trees prepare for winter.” It’s another engineering marvel from the Creator.

— Roland Earnst © 2019