Why Do Evergreen Trees Keep Their Leaves in the Winter?

Evergreen trees retain their foliage all year, even in snowy winter weather.

Unlike deciduous trees that shed their leaves after the growing season, evergreen trees retain their green foliage year-round. Their leaf drop pattern differs from deciduous trees and helps them thrive during cold winters.

Misconceptions

Rather than dropping their leaves all at once as deciduous trees do, evergreens drop leaves gradually throughout the year, with plenty of foliage unaffected to keep them green in all seasons.

Adaptations

Most evergreen trees have thin needles, with little surface area for water to evaporate. This structure helps them stay hydrated year-round. Meanwhile, their dark green coloring absorbs sunlight and heat, even in winter. The pyramidal shape of many evergreens also helps them shed snow in winter.

Effects

Evergreen trees never stand naked in winter, but a tree's thickness may indicate its leaf-drop pattern. For instance, spruce trees retain their needles for several years and have a thicker appearance than pine trees, which shed their needles every three to four years, according to horticulture educator Sandra Mason on the University of Illinois Extension website.

References

• Cornell Center for Materials Research: Conifers - a.k.a. Evergreens - Do Lose Their Leaves...; Alexa Rezelman Sabanegh; May 2006
• University of Illinois Extension: Evergreens - Inside and Outside; Sandra Mason; Dec. 2010