Have you ever wondered how pine trees stay green in winter? How can they keep their needles in the cold when leafy (deciduous) trees are barren? There is more than one reason for the winter beauty of the pines.
Water retention is one key to remaining green all year. The needles of pine trees have a waxy coating that acts as a water barrier. Their tubular shape also helps to reduce water loss, and a substance in the sap acts as antifreeze. The water that remains in the needles allows them to carry on photosynthesis, even in cold temperatures. The water and the antifreeze component are delicately balanced allowing pine trees to live in cold or hot climates.
But there is another trick pine trees use to stay green, and that is overlapping of the needles’ time on the tree. Different pine species have different time schedules. White pines (Pinus strobus) retain their needles for eighteen months. The needles of red pines (Pinus resinosa) and jack pines (Pinus banksiana) stay on duty for two-and-a-half years. Various pines are on different schedules. New needles come in the summer and needles that have finished their term of service drop off in the fall. We may not notice the transition unless we are watching closely because the pine trees stay green in winter.
Walk through a pine forest, and you will find the ground cushioned with a bed of old needles. Pine needles outlast their leafy counterparts, but like all living things they don’t live forever. We think the design of pine trees and their beauty in summer and winter is another demonstration of God’s wonderful creation.
–Roland Earnst ©2019