|If a tree has no leaves, how will the tree get
|Question Date: 2015-02-03|
So the trees without leaves in the winter don’t
get any sunlight. Trees need sunlight to make new
food to feed all of the living cells in the tree.
However, many trees will make all of their food
when it’s sunny, then when winter comes, they will
go into dormancy and not make any food
anymore. Trees go dormant sort of like how
bears hibernate in the winter. The idea is that
the organism makes a bunch of food before winter,
and then slows down all of its usual processes to
survive through the winter on the stored up food.
The reason the tree loses the leaves in the
winter is that it takes a lot of energy to
maintain the leaves. The tree wouldn’t get much
sunlight in the winter anyways so it makes more
sense for the tree to not waste energy maintaining
leaves and instead just go dormant for the winter.
Also leaves make it easier to lose water which
could be a huge problem for a tree in the winter.
There are trees, like cacti, that don't have any
leaves. They live in such sunny places that they
don't need extra surface area from leaves to
collect the sun. Their trunk is enough. So the
chloroplasts, the organs that take up sun and make
energy for the plants, are found on the trunk of
the tree, which is why the trunk looks green.
Other types of trees have leaves and green
photosynthetic trunks so that they can catch a
little extra sun.
There are a few trees in the desert that have
green bark, but most trees need leaves to get
sunlight. Trees in the winter often lose their
leaves to conserve energy during the winter
months, but they're burning the sugar reserves
they built up from the previous summer to stay
alive during the winter.
Good question! Some trees wait until
conditions are nicer outside before they grow new
leaves to capture sunlight. Other trees have
photosynthetic bark so they actually capture
sunlight on their trunk and branches! Aspen
trees, for example, have photosynthetic bark but
they are covered in a protective white dust that
acts like sunblock. If you go up to an aspen
tree you can wipe off the "sunblock" that was
used by native americans and see the green bark!
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