It’s wintertime and you’re probably tucked up in your home with a cozy fire, hot chocolate, and a good book. But what about the trees outside? The cold winter temperatures can seem unbearable, but even in this frigid weather, trees are still alive and well! How do they survive in such harsh conditions? Let’s take a closer look!
The secret to how trees can thrive in cold climates lies in their ability to become "cold hardy." A tree becomes cold hardy when its cells produce antifreeze-like compounds known as cryoprotectants. These compounds help trees withstand freezing temperatures by reducing the number of ice crystals that form inside cells, which would otherwise cause them to rupture and die. Additionally, some trees also have thick bark that acts as insulation against extreme temperatures. For trees that retain their foliage, the overlapping leaves trap air and also act as insulation, just like how we'd wear a sweater to keep warm!
Dormancy and Hibernation
Another key factor in a tree's survival during the winter months is dormancy. When temperatures drop below certain levels, many types of deciduous trees enter a state of dormancy where they stop producing leaves and flowers until more favorable conditions return. Similarly, evergreen conifers may go into a form of hibernation known as "winter sleep" where they slow down their metabolic rate and put all their energy into surviving the cold season.
Changing Cell Composition
Last but not least, trees change their cells to minimize cold damage. We can't see these cellular actions, but here's what trees are secretly doing:
Lower Water Content
Water expands as it freezes, and ice crystals are like daggers with their jagged, sharp edges. Both of these are bad news for cells and cell structures because ice may puncture and burst through. A simple strategy to avoid this is to simply have less water. As trees enter winter dormancy, they need less water anyway, so trees learned to get rid of that excess water!
Have More Proteins and Pectins
Ok, so the cells now have less water and less ice, which is great! But the bad news is, now there's all this empty space that can cause cell collapse. What can be done? Well, trees fill up some of the space with proteins and pectins. Think of pectins as plant "glue", it's what makes jam set. These proteins and pectins reinforce cell structure and also have the added benefit of restricting the size of any ice crystals that form, reducing ice damage.
Have More Unsaturated Fats
Cell membranes are mostly made of saturated fats - think butter. And how does butter feel when it's cold? Well, it's really hard and stiff. If cell membranes get hard and stiff, particles can't move through as well and metabolism is hindered. The solution? Change those saturated fats into unsaturated fats, something like oil. Think about how when oil goes in the fridge, it still stays fluid. This same fluidity helps trees function in cold temperatures.
Trees truly are amazing; they have evolved over thousands of years with strategies to survive even the harshest weather conditions nature throws at them! From antifreeze compounds to special cell modifications - there’s no doubt that we can learn a thing or two from Mother Nature about resilience and perseverance!