That's why these trees
drop their leaves in the
fall.
Then the snow can simply
fall between the bare branches right onto the ground.
The branches of conifers work well to shed snow,
but not so well to catch
rain.
Because conifers are
narrow at the top and their branches angle out or down
rather than up, they act like umbrellas. This means the
ground around the trunks of conifers often stays very
dry, and in the summer the trees can be very thirsty.
Being Thirsty Hurts!
ft
thirsty tree's trunk can tear when
it
tries
to such water from dry ground.
IF IT'S A
VERY
ORY
SUMMER
and
spruces
continue
to
suck water out of the
ground,
especially greedy
trees can split open along the length of their
trunks.
That's a
bad
injury for
a
tree.
Thick drops
of pitch seep out of the wound (pitch is like the
blood of the spruce tree], and the wound never
really heals. That tree will have a
long,
seeping
scar down its bark for the rest of its life.
With their wide crowns, beech trees con capture a
lot of
rain and direct
it
down their trunks
to
the ground.
A full-grown tree is very heavy. It can weigh more than five cars, and its trunk
needs to be really strong so it doesn't collapse under all that weight.
Big trees like this southern live oak need wide
trunks to support the weight of their crowns.
You can tell from these rings
how old the tree was when
it was cut down. Count the
rings from the outside to the
middle—the middle ring is the
tree when it was one year
old,
Of
course,
you can't count
the rings when a tree is still
alive because they're under
the bark—you can only see
them after the tree has been
cut down.
*
THAT'S WHY A TREE IS MADE of wood inside. Wood for
a tree is a bit like your bones are for you. You could
say that its wood is its skeleton. If you didn't have
any bones, you'd be floppy like a rag
doll,
and you
wouldn't be able to stand up. The same goes for
the tree: it needs its wood to stand up straight. And
because wood is so
strong,
it
can
support
a
tree even
when it grows really
tall.
If you take a look at a tree that's been cut down,
you'll see that its trunk is made up of
a
series of rings.
Each year a new circle of wood grows under the
tree's bark, and the trunk grows wider and wider.
Once wood
is
there,
it doesn't
go away. Because
a
trunk only
grows around the outside,
in a
thin layer between the bark and
the
