The document discusses two main types of trees: deciduous and conifers. Deciduous trees have broad leaves that lose water and change color in the fall, while coniferous trees grow in a triangular shape with needle-like leaves that reduce water loss and are adapted to cold environments. Both types of trees have unique reproductive methods, with deciduous trees producing seeds within fruits and conifers using cones to shelter their seeds.

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TREES
By Moira Whitehouse PhD

2. Trees can be grouped as:
deciduous or conifers

3. First, we will consider:
deciduous conifers

4. Deciduous trees have
broadleaves. Broad leaves
have large surfaces so
they can gather a lot of
sunlight.
However, a tree with
flat, wide leaves also
loses a lot of water
through transpiration
where water
evaporates from the
surface of the leaf.

5. Picture of a deciduous forest in summer.

6. Deciduous tree
leaves often turn
bright colors in the
fall.

7. And most drop their
leaves in winter or
during long periods
without rain.

8. A tree drops its leaves when it is cold or dry in order
to save energy. It takes a lot of energy for a tree to
keep wide broad green and healthy.
Deciduous forest during winter

9. Deciduous trees have flowers and reproduce from
seeds.
A few have
brightly
colored
flowers in the
spring but
most do not.
Most have male and female flowers that are dull
and green, the same color as the tree so we do not
even notice them.

10. These male flowers from a
red oak are long, skinny
and green. They hang
downward from new
branches in spring
producing pollen.
When they fall off, the
male flowers sometime
look like big green worms
on the ground.
Female flowers form later than male flowers and are
not visible to the naked eye.

11. When pollen from the male flower fertilizes the
female flower, seeds develop. The seeds on a
deciduous tree usually grow inside its fruit or in a
hard shell for protection like
these acorns on a red oak tree.

12. The seeds are often dispersed when the fruits or nuts
are eaten by animals. Since the seeds inside the fruit
or shell are not digestible, the animal eventually
passes them through its droppings often away from
the parent tree. This increases the chance for a
seedling to grow in an area that is not shadowed by
its parent.

13. Lastly we will consider the:
deciduous conifers

14. Trees that grow cones are called conifers.

15. Coniferous trees grow up instead of out like a
deciduous tree and are shaped like a triangle. The
leaves are usually long, pointy needles.
Spruce Fir Pine

16. The cones of the conifers are very important to the
coniferous tree because it is there that the tree
makes and shelters its seeds.
Cones are made up of many scales that serve to
protect the seeds.

17. Female cone Most coniferous trees
have both male and
female cones. Female
cones contain eggs.
Male cones are small
and soft. They produce
(make) pollen. Once
the pollen is
released, male cones
shrivel and die.
When the egg is
pollinated a seed
Male cone
develops

18. When it's time, the
Pine cone with seeds. scales of the cone open
and the seeds fall to the
ground.

19. Coniferous trees with their long
needle like leaves thrive where
summers are short and cool and
winters long and harsh, with
heavy snowfall that can last as
long as 6 months.

20. These needles are pretty
amazing adaptations. It
is their long thin shape
and wax covering that
slows down evaporation
so the tree doesn't lose
much water. It is this
adaptation that allows
trees with needles to
grow in areas where it is
cold most of the year
and where there is little
precipitation.

21. Conifer trees do lose their
leaves but only a few at a
time and these are quickly
replaced. Since they
generally live in colder
areas of the world, they
always have some leaves
so as soon as it warms up
and the sun shines, they
can make food.

22. Coniferous trees
are triangular
shaped and the
branches are
soft and flexible.
As a result snow
slides off the
tree without
breaking its
limbs.

23. This presentation may help you
understand why forests of deciduous
and conifer trees are found in particular
regions where the climate suits their
leaves (or vice versa).