Why Evergreens are Ever Green

Why Evergreens are Ever Green

In winter we can’t help but notice evergreens.  With Christmas trees indoors and evergreens retaining their green color outdoors, they can be hard to miss.  Have you ever wondered though, why evergreens stay green through the winter months?

One reason evergreens stay green all year, and particularly during colder months, are their leaves.  Generally, the leaves of evergreens are different from the leaves of deciduous trees.  Evergreen leaves can be strong, needle-shaped, and have a wax-like coating.  Because of this, their leaves lose relatively less water in winter and summer than leaves on deciduous trees.  This water is necessary for photosynthesis to continue in the leaves, which it does during the winter.  Also, these leaf characteristics help them resist cold which helps them endure and not dry out during colder months.

Another reason evergreens can stay green in winter is that they have sort of an “antifreeze” in them.  This “antifreeze” is a mixture of substances that flows within the trees and goes to their needles.  It lowers the freezing point of water in the needles and this allows them to survive colder temperatures than they would be able to without it.  Although this is effective, evergreens can still freeze if temperatures get cold enough.

Another reason evergreens can stay green during the winter is that their systems slow down.  Although they don’t become as inactive as deciduous trees, this slowing down helps them survive the colder months, and helps them retain their leaves.

Lastly, evergreens stay green during the winter because they can store nutrients effectively.  They can use these stored nutrients during the winter which helps them survive and stay green during colder months.

Although evergreens can stay green overall throughout the year, not all their leaves are always green.  Evergreen trees do drop needles, they just don’t drop them in a large group like deciduous trees do.  Evergreen trees are growing and dropping needles throughout the year and the dropping isn’t as noticeable as with deciduous trees and so the trees appear to always stay green.  You might notice most needles falling during spring, but as new needles are growing out, the trees can retain their overall green color.  Although it depends on the species and conditions, evergreen needles can stay green and alive on a tree for two, four, or a number of years.

Both evergreens and deciduous trees have adaptations for cold weather.  Deciduous trees react to cold weather by dropping their leaves.  Evergreen trees retain their leaves and green color throughout the year because of the adaptations we’ve mentioned above.  The basic idea though is that both evergreens and deciduous trees can survive the winter, they just do so in different ways.