As you look into the landscape and see the bare branches of deciduous forests, evergreen trees are hard to miss. When it comes to dormancy, evergreen trees must equip their needles and branches strategically to survive the winter. Although these species do not physically emulate their leaf-bearing neighbors, they are still in a period of reduced activity. Their hibernation is slightly different.
Evergreens fall under the in the plant class Gymnosperm. This means that their seeds are exposed or not protected by any fruit. The physiologically of gymnosperms has evolved to allow them to withstand harsh conditions. Their needles are not as developed to harvest sunlight like broad leaves. So these trees are often out-competed in more moderate environments. However, small evergreen needles have less surface area to freeze or dry out. Therefore these cone-bearing trees are happy to call a windy mountaintop their home.
Although conifer leaves are called needles, they are just tightly folded leaves. These trees do not keep their needles indefinitely. Evergreen conifers grow (and lose) groups of needles throughout the year. This can be compared to the growth of your hair, occurring in cycles, not all at once. New growth can be denoted with a lighter green towards the end of the stem. Evergreens can keep a group of needles for multiple seasons. (The bristlecone pine has been suspected to hold onto its short needles for years! Read about it here.)
The needles have a uniquely smooth texture. This waxy coating is called cutin. Cutin is a hydrophobic compound that plays a crucial role in controlling water loss. This reserve of nutrient storage allows conifers to perform photosynthesis continuously. This process is especially vital for trees living in harsh conditions.
Evergreen trees can be found throughout the world. Cypress, pines, and firs are some of our favorites!