Why some trees stay green all winter
The kinds of trees that people use as Christmas trees are called
“evergreens.” Evergreen trees are “ever green.” They don’t change color
and lose all their leaves in autumn as other trees do.
The leaves of an evergreen tree are its green needles. These needles do
fall off,
Arrows show water (dots) going up to an evergreen tree’s needles in
summer.Some water is lost into the air, but not as much as other kinds of
trees lose.
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but they don’t do it all at once, as other kinds of leaves do. Evergreen
needles are very tough. They don’t freeze in winter and they don’t lose
water as quickly as do other kinds of leaves. By holding on to the water
that’s in them, they stay alive and green even in winter.
No water comes up from the roots in winter. No water moves through the
tree. But the needles stay green. They live on the water that is still
in them.
