Childrens Illustrated Encyclopedia

childrens_illustrated_encyclopedia_template_US_layer_v1

530

WITHOUT PLANTS, such as trees, there could

be no life on Earth. Trees take in carbon

dioxide from the air and give off oxygen by

the process of photosynthesis, helping to

maintain the balance of the atmosphere.

Of the total amount of carbon stored

on land, 45 percent is in the forests.

Tree roots stabilize the soil so it is not

washed away by the rain, and leaves

give off vast amounts of water vapor,

which can affect the world’s weather.

Forests cover 31 percent of Earth’s land

surface. Trees vary greatly in size, from

towering redwoods to dwarf snow

willows that are only a few inches

high. They supply habitats and food for millions of

creatures, and produce wood to make buildings,

furniture, and even the pages of this book.

LEAvES

Broad-leaved trees can be recognized

by the shape of their leaves and the

pattern in which the leaves grow

on the twigs. In the winter, you

can identify a bare tree by its

bark, buds, and overall shape.

Sitka spruce cone

turns brown as

it ripens.

NEEdLES

Every conifer

has distinctively

shaped needles

that grow in a

certain pattern.

Sitka spruce

needles are

long and sharp.

Japanese

maple leaves

have deep

notches.

Rowan or mountain

ash trees have

compound

leaves.

Sweet

chestnut

leaves have

serrated edges.

Sitka spruce is an evergreen

coniferous tree often seen

in forest plantations.

Arolla pine

needles

Conifer roots

are usually

shallow but

widespread.

Pine

cone

Trees 530-

Pines, firs, cedars, and redwoods are

called coniferous trees, or conifers,

because they grow their seeds in

hard, woody cones. The long,

narrow leaves, called needles,

stay on the tree all winter.

These trees are also called

ever greens, because they

stay green all year.

Leaves of

the holly

tree are

spiky.

Scotch pine needles

grow in pairs.

CONES

Each tree has its own type of

cones. Male cones tend to be at

the top of the tree while female

cones are at the bottom.

Larch

cone

TREES

Leaves

Needle

The gingko tree has

fan-shaped leaves.

English oak

tree in the

spring and fall

Buds

Giant sequoia trees are

the largest living things— 

more than 270 ft (84 m)

high, and 2,000 tons

in weight; an elephant

weighs about 5 tons.

BrOAd-LEAvEd TrEES

Oaks, beeches, willows, and many

other trees are called broad-leaved

because their

leaves are

broad and

flat, unlike

the sharp

needles

on coniferous

trees. Most broad-leaved trees are

also called deciduous, because their

leaves die and drop off in the fall.

Acorns are the fruit of 

the oak tree; they develop

from the pollinated female

flowers during the fall.

The roots of a deciduous tree may

reach out sideways and downward to a

greater distance than the tree’s height.

Oak bark

US_530_Trees_1.indd 530 12/02/16 11:19 am