When other trees shed their leaves and grow barren during the cold winter months, pine trees and other evergreens stay lush and green, making them a potent symbol of the persistence of life. Control over water loss explains why pine trees stay green.
Leaf drop protects deciduous plants from dehydration during the winter months. Water supplies underground may freeze in the winter and become unavailable to roots. At the same time, however, sunny winter days cause plants to lose water through their leaves. Eventually, the plant dehydrates and, lacking water for basic life functions, dies.
Pine trees possess adaptations that help them conserve water without shedding all of their leaves at once. Needles contain fewer pores through which they lose water, and a thick, waxy coating prevents further loss. The large number of evergreen needles lets them capture a lot of sunlight with relatively little risk of water loss.
Because evergreens keep their leaves, they do not need to expend energy each year to regrow a completely new set of leaves. According to the U.S. Department of Energy's Newton program, this means that evergreens can exist in areas where poor soils do not provide them with the resources for constant leaf regeneration.
- Photo Credit Roine Magnusson/Photodisc/Getty Images
Why Do Pine Trees Stay Green All Year Long?
Though we call them needles, the green of pines and other evergreens are actually leaves. They serve the same purpose as the...
Why Do Evergreens Stay Green in the Winter?
Evergreen, or coniferous, trees have special leaves that resist cold and moisture loss. They cut back on the amount of water they...
Why Do Pine Trees Not Lose Their Leaves?
While deciduous trees such as the oak and maple lose their leaves every autumn, evergreen trees like the pine tree remain green...