Why Evergreen Trees Stay Green

February 21, 2022

Deciduous and evergreen are two types of trees.  Each type has a different life cycle.  Deciduous trees lose their leaves in the fall and evergreen trees keep their leaves during the fall and winter.  Both types use photosynthesis to convert sunlight, water, and carbon dioxide into oxygen and sugars which gives the leaves their green color.  Chlorophyll is the most common chemical that uses photosynthesis.

During the fall, daylight hours grow shorter, and temperatures get cooler.  The leaves of deciduous trees have only one growing season, so to conserve energy for the shorter days, their production of chlorophyll is turned off.  The leaves change into the brilliant reds, oranges and yellows colors that signal the beginning of the winter season as they die. 

Evergreens have strong leaves that are rolled up as long, thin needles with a waxy coating.  The needle shape enables the evergreens to conserve water during the summer and winter to allow the photosynthesis process to continue.  This is why the needle leaves can remain attached longer and stay green all year.

Evergreens are hardy trees that have systems that allow them to lower the freezing point of water in their cells.  It allows them to survive cold temperatures, but they are still vulnerable to extreme cold.  Subzero temperatures can cause cells to freeze and kill the tree.  Evergreens grow in a way that allows snow to fall off easily, but heavy snow loads can cause branches to break causing potential damage to property or people.

It is normal for evergreen needles to fall off on the inner parts of the tree.  The leaves make a good mulch layer.  But if the evergreen is losing needles at the branch tips, there may be a problem.  The tree may have an insect infestation or a disease.  Call Integrity Tree Care to check the tree’s condition and make sure it is still healthy and growing strong.