Text Leveling System

Why Do Leaves Change Color?

RDQ:	534	Max Word/Sent	21	Total Words	968		Diff Words	299
Lex	640	Ave Word/.Sent	10	Hi Freq occurs	566	58.5%	Hi freq	105	35.1%
AR	2.8	Long Sentences	1.1	Low Freq occurs	39	4%	Low freq	25	8.4%

Look at the leaves! It's autumn, and leaves are turning red and yellow,
gold and brown.
Each type of tree has its own kind of leaves. The colors of autumn
leaves differ from tree to tree. Some oak leaves may be brown or yellow,
while maple leaves may turn bright red.]]
Leaves come in different sizes and shapes as well as colors. Some leaves
are wide and others narrow. Some have points, while others may be
rounded. How many different kinds can you find?]]
Just a few weeks ago, all the leaves were green. Back in the spring, the
tiny new leaves uncurled from their buds.
The green color in the leaves helps them to absorb or hold sunlight.
Chlorophyll gives leaves their green coloring. Chlorophyll is a natural
coloring called pigment.]]
Leaves are very important to the tree. They make a kind of sugar that is
the tree's food. Leaves need sunlight, water, and air to make this food.
The leaves work to feed the tree all summer long. The sugar is used by
all parts of the tree - the leaves, branches, trunk, and roots. The food, or
sugar, helps the tree to grow. Extra sugar is stored in the leaves.]]
In the fall, many things are changing. In many places, there is a change
in the weather. There are changes in light and temperature. Inside the
leaves, there will be many changes too. All of these changes bring about
beautiful colors of fall.
In the fall, there are fewer hours of sunlight each day. The change in
light tells the tree to get ready for winter. Winter is a time of rest for the
tree. When winter comes, the tree will have to survive with less water
and sunlight.]]
The tree begins to get ready for its winter rest. It needs very little food
now, and the leaves stop their work. The life of the leaves is almost at an
end. The tree no longer needs them.
When the leaves die, they will fall from the tree. This will happen
slowly over a number of weeks. As the leaves begin to separate from the
tree, they get less water. Without water, the leaves cannot make new 
chlorophyll. The old chlorophyll begins to fade. The green color starts to
disappear.]]
Now, other colors can be seen in the leaves. Other pigments have
been in the leaves all along. But they were hidden by the dark green of the
chlorophyll. Once the green color fades, the yellow and orange pigments
can be seen.
These pigments give color to the leaves of birches, poplars, and elms.
Some food like bananas and carrots get their natural yellow and orange
coloring from these same pigments. They also give color to some flowers.
Maybe you can think of some.]]
Autumn leaves have other colors as well. The yellows and oranges have
been in the leaves all along. Other pigments are made as the leaves begin to
die. The new pigments are made from the extra sugar stored in the 
leaves.
Sunlight causes the stored sugar to change to pigment. The new
pigments make some leaves turn red, rust, or purple. The more sugar there
is, the brighter the colors will be. Bright days and cool nights seem to bring
out the best fall colors.]]
Maple leaves get their red color from these new pigments. Many 
flowers, and some foods such as beets and radishes, get their color from
these red pigments. The bright red of sumac leaves shows up only in the
fall, when these pigments form.
Some trees, like oaks, make tannin in the fall. Tannin is not a pigment,
but it does color the leaves. Some oak leaves turn a rich brown color in
autumn. See if you can find some. You may still be able to see some green
coloring too.]]
The changing color of autumn leaves is caused by changes in weather
and light. This is why the colors are not the same every year. The best leaf
colors usually come with lots of bright sunshine and crisp, clear nights.
Too much rain may make the colors dull. An early frost may kill the leaves
too soon.
Evergreen trees, like pines and spruces, keep their leaves all year. But in
cool climates, other trees must lose their leaves to survive in winter.]]
After the leaves have changed color, they are ready to separate from the
tree. When they are just barely hanging on, a little bit of wind or rain will
make them fall to the ground.
In just a short time, the tree will begin to look bare. Piles of dead leaves
collect under the tree. Some will blow away. Others will be raked up. The
leaves that are left will begin to rot. Over time, they will become part of 
the soil. Rotting leaves enrich the soil with minerals the tree needs to stay
healthy.]]
When the last of the leaves have fallen, the tree is ready for winter.
During the cold weather, the tree will be dormant, or resting. New leaf
buds have already formed. Next spring, they will open and begin to make
food for the tree.
but now, in fall, it's time to enjoy the colors of the leaves. Beautiful]]
autumn foliage cannot be seen everywhere. Only some places, such as
New England, have displays of many colors. This is because the weather
conditions there are usually just right and there are so many different
kinds of trees.]]
Fall is time to have fun with leaves. It's a time to take in the sights and
sounds of the leaves. It's a time for jumping into great piles of leaves - and
then sometimes, a time for raking them up. Fall is a time to get ready for
winter. The trees are ready - are you?]]

Subjective Criteria

Illustrations: Some support

Simple graphics, not necessary to text

Inferences: Some implications

Vocabulary: More decoding/definition issues

Language: Few descriptive words

Sentences: Simple phrases

Text structure: Oral/Natural

Complexity: Several ideas - closely related

Concepts: Abstract/Complex Environmental

Features

Topic

Trees

Changes

*Plants

Autumn

Seasons

Colors

Low Frequency Words

absorb	birches	chlorophyll	climates	differ
dormant	enrich	fewer	foliage	healthy
maple	minerals	pigment	pigments	poplars
raked	raking	rotting	rounded	separate
spruces	sumac	survive	tannin	uncurled