Can You Hear the Trees Talking?. Peter Wohlleben

      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

      wood,

      everything already inside the trunk

      stays

      the

      same,

      And so

      a

      tree never gets thinner, only thicker.

      That's a good thing, because the tree is also

      growing taller, and that means it's getting heavier. It

      needs a sturdy trunk to support its weight, just like

      you need

      a

      strong skeleton to support your growing

      body. That's why adults are stronger than children,

      and older trees are stronger than younger ones.

      There's something else trees have that makes them

      similar to people. Your blood flows through tiny tubes

      called arteries that run from your heart to every part

      of your body. Trees have to pump water from their

      roots

      all

      the way

      up

      to their

      crowns,

      so

      they

      have an

      extensive system of tiny

      tubes,

      too, called vessels.

      You might be able to see these water vessels if

      you

      look at the rings in

      a

      piece of wood—they look like

      small holes.

      But water only flows in the tree's outermost

      rings.

      That's why in the summer, if everything is

      working properly, a tree will be quite wet under

      its bark, Farther inside, the wood becomes drier.

      Nothing's happening there anymore, and the tree

      can't feel anything there, either. That's why it

      doesn't really matter if the inner wood begins to

      rot. Even if its trunk becomes hollowed out like an

      empty pipe, the tree will still

      be