Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Speaker 1: I'm Lauren vogele Bomb. And this is another classic from
Speaker 1: our archives. This one details why evergreen trees like pines
Speaker 1: and many other conifers get to keep their green leaves
Speaker 1: year round, seemingly thumbing their nose at seasonal changes. Hey
Speaker 1: brain stuff, lourenvogel Bomb. Here, evergreen trees seem to thrive
Speaker 1: during the colder months, steadfastly holding on to their brightly colored,
Speaker 1: needlelike leaves as temperatures plummet, bringing welcome color and contrast
Speaker 1: to snowy landscapes. On the other hand, the wide and
Speaker 1: flat leaves of their deciduous counterparts transform into brilliant shades
Speaker 1: of red, orange and gold during the chilly and dry
Speaker 1: days of fall and early winter, only to eventually shed
Speaker 1: Their branches will remain barren until spring. So why are evergreens,
Speaker 1: which include many, but not all coniferous trees such as pines, firs, junipers,
Speaker 1: and spruces, is immune to seasonal leaf changes in shedding,
Speaker 1: while species of deciduous trees like aspens, birch, cherry, oak,
Speaker 1: and maple aren't. It mostly comes down to a little
Speaker 1: thing you might have learned about in biology class called photosynthesis.
Speaker 1: Both deciduous and evergreen trees use energy from the sun
Speaker 1: and water from the ground to turn carbon dioxide in
Speaker 1: the air into food. The difference is that shorter days
Speaker 1: brings less sun during the fall and winter, and that
Speaker 1: translates into less energy. So deciduous trees bearing broad, flat
Speaker 1: leaves go dormant or into a sort of hibernation mode
Speaker 1: and shed their leaves to help them conserve water and
Speaker 1: stay alive until spring arrives and new leaves grow from
Speaker 1: new buds. Evergreens, meanwhile, boast needles that are actually tightly
Speaker 1: rolled leaves, and the low surface area of this shape
Speaker 1: helps the needles conserve water throughout the fall and winter.
Speaker 1: A waxy coating on the needles also helps keep water
Speaker 1: from evaporating. Compared with broad delicate leaves, These dense waxy
Speaker 1: needles resist cold and stay moist, which keeps them green
Speaker 1: throughout the winter. But evergreens actually do shed their needles,
Speaker 1: just not all at once. As needles age, they turn
Speaker 1: yellow brown or a reddish tan and will fall from
Speaker 1: the tree, but usually only a handful at a time.
Speaker 1: The trees are constantly growing new needles so they can
Speaker 1: stay green year round. Evergreens greater leaf longevity means they
Speaker 1: can survive in environments that don't work for their deciduous cousins.
Speaker 1: In fact, evergreens can be found on every continent except Antarctica.
Speaker 1: The bottom line is that although those colorful deciduous trees
Speaker 1: attract their share of seasonal leaf peepers, trees that stay
Speaker 1: green year round add character to people's yards during the
Speaker 1: fall and winter, offer shelter to birds and small animals
Speaker 1: when the winter is cold, and many species are dense
Speaker 1: enough to serve as windbreaks and privacy screens. Today's episode
Speaker 1: is based on the article why evergreen trees don't shed
Speaker 1: their needle like leaves on HowStuffWorks dot com, written by
Speaker 1: Windy Bellman. Brain Stuff is production of iHeartRadio in partnership
Speaker 1: with how stuffworks dot Com and is produced by Tyler Klang.
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