NATURAL VOLUME 5, NUMBER 1 • USDA FOREST SERVICE

INQUIRER

Born To

Be 

Made in the Shade

page 33

page 25

page 41

page 49

page 17

One fish

Two fish

Red fish

No fish?

One fish

Two fish

Red fish

No fish?

Made in the Shade

Where in the World

Is Carbon Dioxide?

Where in the World

Is Carbon Dioxide?

page 7

Water

Do What

You Water

Wild

Stress Test Stress Test

Facts to 

the Future

Edition

Facts to 

the Future 

Edition
Natural Inquirer

Volume 5, Number 1

Spring 2004

Facts to the Future Edition

Barbara McDonald

USDA Forest Service

Research and Development

Washington Office

Margaret Connelly

USDA Forest Service

Strategic Planning and

Resources Assessment

Washington Office

USDA Forest Service 

scientists highlighted in the

journal:

Tony Baltic

Richard Birdsey

Tom Brown

John Dwyer

Curtis Flather

John Hof

Linda Joyce

Mary Heather Noble

David Nowak

Susan Sisinni

Other scientists highlighted

in the journal:

Stephen Davies

Andy Loftus

Produced by:

USDA Forest Service

Dale Bosworth, Chief

Research and Development,

Washington, DC

Ann Bartuska, Deputy Chief

Resource Valuation and Use

Research Staff

David Cleaves, Director

State and Private Forestry

Joel Waltrop, Deputy Chief

Conservation Education Staff

Denver James, Acting

Director

With thanks to:

Jennifer Edalgo

USDA Forest Service

Athens, GA

Katrina Krause

USDA Forest Service

Athens, GA

Jessica Tanner

University of Georgia

Athens, GA

Brenda Allen

Eula Emmanuel

USDA Forest Service

Office of Communication

Washington, DC

USDA Forest Service

Southern Research Station

Athens, GA

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the

basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or

family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative

means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s

TARGET Center at (202) 720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten

Building, 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice and

TDD). USDA is an equal opportunity provider and employer.
1

Editorial Review Board:

Todd Nickelsen’s 8th grade class, 

Coile Middle School, Athens-Clarke County, GA
2

Teacher’s

Note

As teachers of

science, you want

your students to

acquire abilities that will

enable them to conduct scientific inquiry, and you want

them to gain an understanding

of the scientific inquiry

process. Scientific inquiry can

best be taught by integrating

minds-on and hands-on experiences. Over time, such experiences encourage students to

independently formulate and

seek answers to questions

about the world we live in. As

educators, you are constantly

faced with engaging your students in scientific inquiry in

new and different ways. In an

age of abundant technology,

standard teaching strategies

can become monotonous to

today’s learners. The Natural

Inquirer provides a fresh

approach to science and a

view of the outside world bigger than the classroom that

can be used while still in the

school setting.

The Natural Inquirer is a

science education resource

journal to be used with learners from Grade 5 and up. The

Natural Inquirer contains articles describing environmental

and natural resource research

conducted by USDA Forest

Service scientists and their

cooperators. These are scientific journal articles that have

been reformatted to meet the

needs of middle school and

higher students. The articles

are easy to understand and

aesthetically pleasing to the

eye, contain glossaries, and

include hands-on activities.

The goal of the Natural

Inquirer is to stimulate critical

reading and thinking about

scientific inquiry and investigation while learning about

ecology, the natural environment, and natural resources.

Science Education

Standards and Evaluations:

In the back of the journal,

you will find a matrix that

allows you to identify articles

by the national science education standards that they

address. You will also find

evaluation forms in the back

of the journal. Please make

copies of these evaluation

forms and have your students

complete them after they complete an article. Please note the

form for teachers to complete

also. Please send the evaluation forms to the address listed at the end of the forms.

You and your students may

also complete the forms online by visiting www.natural

inquirer.usda.gov.

This journal was created by

Environmental and Science

Education, an education program of the USDA Forest

Service. If you have any questions or comments, please

contact:

Dr. Barbara McDonald

USDA Forest Service

320 Green St.

Athens, GA 30602-2044

706.559.4224

barmac@bigfoot.com

Teacher’s Manual:

Please visit the Natural

Inquirer Web site at www.naturalinquirer.usda.gov. From

this site, you may read the

teacher’s manual online,

download it, or request a hard

copy.

Visit www.naturalinquirer.usda.gov for previous issues of the Natural

Inquirer, sample lesson plans, word games, the teacher’s manual,

information about the USDA Forest Service, and other resources.
Page 17

Page 33

Page 49

Contents

Teacher’s Note . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

About the Natural Inquirer . . . . . . . . . . . . . . . . . . . . . . . .4

What are Scientists? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Welcome to the Natural Inquirer

Facts to the Future Edition! . . . . . . . . . . . . . . . . . . . . . . . .5

Features

Where in the World Is Carbon Dioxide?

The Potential Impact of Rising Levels of 

Carbon Dioxide on U.S. Forests . . . . . . . . . . . . . . . . . . . .7

Do What You Water:

The Current Situation and Possible Future 

of Fresh Water in the United States . . . . . . . . . . . . . . . . .17

Born To Be Wild:

The Current Situation and Possible Future of 

Wildlife in the United States . . . . . . . . . . . . . . . . . . . . . .25

Made in the Shade:

The Current Situation and Possible Future 

of U.S. Urban Forests . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

One Fish, Two Fish, Red Fish – No Fish?

The Current Situation and Possible Future 

of Aquatic Animals in the United States . . . . . . . . . . . . .41

Stress Test:

The Condition and Possible Future of 

Forests and Rangelands in the United States . . . . . . . . .49

Sample Natural Inquirer Lesson Plan . . . . . . . . . . . . . .56

Student Evaluation Form . . . . . . . . . . . . . . . . . . . . . . . .58

Teacher Evaluation Form . . . . . . . . . . . . . . . . . . . . . . . .59

Which National Science Education 

Standards Can Be Addressed by 

the Natural Inquirer? . . . . . . . . . . . . . . .Inside back cover

What Is the USDA Forest Service? . . . . . . . . . .Back cover

Web Site Connections . . . . . . . . . . . . . . . . . . . .Back cover

The Natural Inquirer is reproduced on recycled paper with soy-based inks.

Please pass this journal along or recycle it when you have finished using it.

3
4

Scientists are people who

collect and evaluate information about a wide range

of topics. Some scientists

study the natural environment. To be a successful

environmental scientist, you

must:

• Be curious—You must be

interested in learning.

• Be enthusiastic—You

must be interested in an

environmental topic.

• Be careful—You must be

accurate in everything

that you do.

• Be open minded—You

must be willing to listen

to new ideas.

• Question everything—

You must think about

what you read and

observe.

What Are Scientists?

Scientists report their research in journals,

which are special booklets that enable scientists to share information with one another.

This journal, the Natural Inquirer, was created

so that scientists can share their research with

you and with other middle school students.

Each article tells you about scientific research

conducted by scientists in the USDA Forest

Service. If you want to know more about the

USDA Forest Service, you can read about it on

the back cover of this journal, or you can visit

the Natural Inquirer Web site at www.naturalinquirer.usda.gov. 

All of the research in this Natural Inquirer is

concerned with nature, such as trees, forests,

animals, insects, outdoor activities, and water.

In each article, you will “meet the scientist”

who conducted the research. Then you will

read something special about science and

about the natural environment. You will also

read about a specific research project. This is

written in the format that scientists use when

they publish their research in journals. Then,

YOU will become the scientist when you conduct the FACTivity associated with each article. Don’t forget to look at the glossary and the

special sections highlighted in each article.

These sections give you extra information.

At the end of each section of the article, you

will find a few questions to help you think

about what you have read. These questions are

not a test! They should help you to think more

about the research. Your teacher may use these

questions in a class discussion.

About The Natural Inquirer

Scientists at work.
5

In 1974, Congress decided

that the United States needed

an evaluation of the Nation’s

renewable (re noo uh bul) natural resources. Renewable

natural resources are environmental products and services

that can be replenished even

as they are being used.

Examples of renewable natural resources are water, minerals, and trees. Congress

believed that one of the best

ways to take care of our

renewable natural resources is

to gather the best information

that we can about them. Then,

armed with the best information, we can make good decisions about the use and

protection of our nation’s

renewable natural resources.

Congress decided that the

USDA Forest Service could

provide this kind of information. They passed legislation

(lej is la shun), called the

Resources Planning Act of

1974, or RPA for short. The

Facts to the Future Edition

of the Natural Inquirer!

Welcome to the

act requires the Secretary of

Agriculture to ensure that the

research is completed and

reported every 10 years. 

Scientists working in the

USDA Forest Service conduct

the required research about

these renewable natural

resources. (You can read

about the USDA Forest

Service on the back of this

journal, or on the Web site by

clicking on “About the Forest

Service.”) Through their

research, the scientists determine the current situation and

the probable future of renewable natural resources, 40

years into the future. 

The articles in this Natural

Inquirer include just a few of

the renewable natural

resources studied by USDA

Forest Service scientists. By

reading these articles, you will

learn about the condition of

the resources in the year 2000,

and you will learn what might

happen to them by the year

2040. In the year 2040,

how old will you be? Do you

think that the condition of the

Nation’s renewable natural

resources will be important to

our society in 2040? Why or

why not?

The articles in this journal

will help you to think about

the future of global climate

change, the Nation’s wildlife,

our fresh water, our fish, the

trees that grow in our cities

and towns, and the conditions

that tell us whether our forests

and rangelands are healthy. As

you read the articles, remember that it is hard to predict

the future. Although scientists

do the best job they can, many

things can change in the

future. One of the things that

can change is how people take

care of our renewable natural

resources. To keep our environment healthy into the

future, we need to take care of

our natural resources today!
6

Where in the World Is

Carbon Dioxide?

Where in the World Is

Carbon Dioxide?

The Potential Impact of Rising Levels of

Carbon Dioxide on U.S. Forests
7

Glossary

ecosystems (e ko sis temz):

Communities of plant and animal

species interacting with one another

and with the nonliving environment.

climate (kli met): The average condition of the weather over large areas,

over a long time, or both.

skeptical (skep tuh kul): Having or

showing doubt. 

photosynthesis (fo to sin thuh sis):

The process by which green plants

use sunlight to form sugars and

starches from water and carbon

dioxide.

carbohydrates (kär bo hi drat):

Substances made up of carbon,

hydrogen, and oxygen, including

sugars and starches.

analyzing (an uh liz): Separating

something into its parts in order to

examine them.

weather (weh thür): The temperature, wind, cloudiness, rainfall or

snowfall, and humidity of a place

for a short period of time, such as a

few days.

vegetation (vej uh ta shun): Plant

life.

coniferous (kä nif ür us): Plants or

trees that have cones.

species (spe sez): Groups of organisms that resemble one another in

appearance, behavior, chemical

processes, and genetic structure.

broadleaf (brôd lef): Plants or trees

that have flat, broad leaves.

deciduous (de sij oo us): Plants or

trees that shed their leaves every

year; not evergreen.

average (av rij): The number gotten

by dividing the sum of two or more

quantities by the number of quantities added.

elevation (el uh va shun): The height

above sea level.

Pronunciation Guide

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Accented syllables are in bold.

Meet Dr. Birdsey:

I like being a scientist

because it is exciting to be

involved in research that

could help solve climate

change, which is a global

problem. It is quite a thrill to

have the opportunity to make

a difference.

Meet Dr. Joyce:

I like being a scientist

because I can explore how

ecosystems work and use the

power of mathematics to

describe the processes in

ecosystems.

Dr. Joyce

Dr. Birdsey

Thinking About

Science

Do you think

that the climate

of the Earth is

changing?

When scientists first reported

that they had scientific evidence to show that the Earth’s

climate is changing, many scientists were skeptical. This is

a normal reaction of scientists

to new discoveries. Scientists

check the accuracy of new scientific discoveries by questioning each other. 

One way they question each

other is to do more research

that may or may not support

the other scientist’s findings.

Science is a process of learning. When something new is

discovered, it can take many

years before the discovery is

widely accepted as being true

or false.

Thinking

About the

Environment

Can you

guess what

forests have to

do with carbon dioxide in the

atmosphere? Plants use photosynthesis to take carbon

dioxide from the air and turn

it into complex carbohydrates, which are part of the

chemical makeup of plants.

When a plant dies, the carbon

in the plant goes into the soil

or returns as carbon dioxide

to the atmosphere. When

large areas of forests burn, the

carbon in the leaves, branches, and roots is released as

carbon dioxide into the
8

Earth has increased the

amount of carbon dioxide in

the atmosphere. You can see

the rising amount of carbon

dioxide in the figure. The levels of carbon dioxide in the

atmosphere are now higher

than they have been for at

least 400,000 years.

Introduction

Most scientists think that

evidence from different studies shows that our global climate is changing in many

ways, such as getting warmer,

more rain falling in shorter

amounts of time, and more

drought. These scientists have

studied the past climate by

analyzing weather observations that have been collected

over a long period of time.

atmosphere. For green plants

to take up carbon through

photosynthesis and release

carbon back into the atmosphere are normal processes. 

When plants are growing

and photosynthesis is greatest, the plants are absorbing

the greatest amount of carbon

dioxide from the air. The

plants store the carbon dioxide in their leaves and wood,

reducing the amount of carbon dioxide in the atmosphere. This reduction can be

seen in the amount of carbon

dioxide in the atmosphere

measured over Hawaii from

1959 to 1998 (figure 1, 

page 9). 

The burning of coal, oil,

and natural gas, and the clearing of forests around the
9

Other scientists are studying the possible ways that climate could continue to

change over the next 100

years by using mathematical

formulas that run on computers. The scientists in this study

used mathematical formulas

to study what kind of impact

these changes in the Earth’s

climate might have on vegetation.

Reflection

Section

• What is the

difference

between weather and climate?

• If the global climate continues to change, do you think

that there will be any

change in the type of forests

and other vegetation growing across the United

States? Why or why not?

• What was the question the

scientists were trying to

answer?

Method

The scientists focused on 10

types of vegetation in the

United States (table 1 and figure 2, pgs 10 and 11). 

Information that described

the environmental conditions

needed by each type of vegetation were entered into a

computer program. An example is the number of inches of

rainfall needed over 1 year.

Other environmental conditions included hot and cold

temperature limits. Then,

numbers representing higher

temperatures and changes in

rainfall and snowfall were put

into the formulas in place of

the current amounts. 

The results from these new

environmental conditions

described how possible climate change might cause vegetation to change across the

United States. For example, in

one formula the average temperature for the United States

was increased by 4 °C by the

year 2100. The mathematical

formulas predicted what kind

of vegetation would grow in

each area of the United States,

if everything was the same as

it is now except for the temperature and the amount of

rainfall and snowfall. 

Reflection

Section

• How would

you describe the

climate where

tundra vegetation grows? How is the climate there different from

the climate where tropical

broadleaf forests grow?

• Think about arid lands in

the United States (see table

1). What might happen to

the vegetation in arid lands

if that area receives more

rainfall in the future?

Findings

The mathematical formulas

predicted that boreal forests

and taiga-tundra vegetation

will move northward and

upward in elevation, and the

southern areas of current

boreal forests will die. For

example, the boreal forest

that now grows in Minnesota

was predicted to disappear if

the climate gets warmer.

Forests in the Pacific

Northwest and the Southeast

will initially expand in size,

then get smaller. This is

because the increased amount

of carbon dioxide will at first

enable the trees to absorb

more carbon dioxide and

carry out more photosynthesis. 

Figure 1. Amounts of carbon dioxide in the atmosphere

over Hawaii.
10

Type of Vegetation 

Tundra

Taiga-Tundra

(Ti guh-Tun druh)

Boreal (bor e ul)

coniferous forest 

Temperate (tem

pür et) evergreen

forest

Temperate mixed

forest

Tropical broadleaf

forest

Savanna 

woodland

Shrub woodland 

Grasslands

Arid lands

Table 1. The scientists examined 10 types of vegetation in the United States

and North America.

Description

Permanently frozen soils with shrubs,

mosses, grasses, and lichens.

Cold or frozen soils. Contains mosses,

grasses, lichens, dwarf shrubs, and short,

herb-like plants.

Contains few tree species, such as spruce,

fir, cedar, hemlock, and pine that can live

in intense winter cold and drought.

Contains a few broadleaf species, such as

aspen and birch.

Contains large coniferous trees such as

Sitka spruce, Douglas fir, and redwoods.

Contains some broadleaf deciduous trees,

such as oak, hickory, maple, poplar,

beech, and sycamore; and some coniferous evergreen species.

Broadleaf forest that grows where it is hot

and there is a lot of rainfall. Contains

some deciduous trees and some evergreens.

Contains scattered shrubs and small trees.

Contains dense cover of evergreen shrubs.

May also contain a few trees that can live

with little water, such as pines and scrub

oak.

Tall-grass, mixed-grass, and short-grass

prairies that contain mostly grasses.

Desert lands, with warm to cool temperatures and low amounts of rainfall.

Vegetation includes cacti and other plants

that require little rainfall.

Location in the United

States

Above the Arctic Circle in

northern Alaska

Near the Arctic Circle in

northern Alaska, and also

in the highest mountain

areas of the Western

United States

Just south of the arctic

taiga-tundra in northern

Alaska, and in the mountain areas of the Western

United States

Along the northwest U.S.

coast from Canada to

northern California

Throughout the Eastern

United States to the area

of the great plains

Puerto Rico, the U.S.

Virgin Islands, and

Hawaii

Central United States

Mostly flat areas of the

mountainous Western

United States and the

Southwest

Central United States

plains, Southwest United

States, and flat areas of

the mountainous Western

United States

Southwestern United

States and southern

California

A

B

C

D

E

F

G

H

I

J
11

Figure 2a - 2j. The 10 types of vegetation.

A

B

C

D

E

F

G

H

I

J
12

If the temperature rises and

the pattern of rain and snowfall changes, some trees

would die from too little

water. The large temperate

mixed forest would break up

into many smaller areas

because of a lack of water in

some areas. Many of the trees

would die, leaving vegetation

of a few trees and many grasses. In the Southwest, rainfall

was predicted to increase. If

that happens, the amount of

arid land would shrink, and

the area of grasslands would

increase (figure 3).

Figure 3. Current location of

4 (of the 10) vegetation types

across 48 States (Figures 3a

and 3d) and the potential

change in the range of those

vegetation types under two

different possible future climates (Figures 3b, 3c, 3e, and

3f). In Figures 3c and 3f, the

average future temperature is

higher than in Figures 3b and

3e. Rainfall and snowfall

increase in both possible

future climates, but the pattern of rainfall and snowfall is

different from what we know

today. Rainfall and snowfall

fall for shorter periods of

time, leaving periods of

drought in between.

ABC
13

Reflection

Section

• Select an area

of the United

States with

which you are

familiar. Compare the current vegetation type with

predicted changes in vegetation (see figure 3). Is there a

difference? If so, what is it?

How might that change the

environment for people

who live there?

• Do you think that these

changes will definitely

occur in the future? Why or

why not?

Implications

Although the mathematical

formulas predicted changes in

United States vegetation, the

scientists said that the results

must be considered with caution. First, these climate

futures are possible futures

and the actual future climate

may be different. It may not

be as warm or it may have

more rainfall than predicted.

Second, the predicted amount

of carbon dioxide in the

atmosphere may not be correct. Third, other effects, such

as the pattern of rainfall and

snowfall, may not happen the

way the formulas predicted.

Many other things might happen that the computer model

could not predict. 

The scientists suggest that

there are things we can do

today to lower the amount of

carbon dioxide going into the

atmosphere. For example, we

could turn some of our poorer

crop land and pasture land

DEF
14

into forests. Forests absorb a

lot more carbon dioxide than

crop or pasture land. We

could minimize the amount of

forests that we are cutting

down for other uses, such as

for agriculture or for building

homes and businesses. We can

continually improve the way

we take care of the forests

that we have. We can recycle

more paper and wood products, and we can plant more

trees in urban and suburban

areas. 

Reflection

Section

• It is hard to

predict the

future. The predictions made

by the computer model may

not be correct. How would

you recommend that people

use the computer model’s

predictions?

• The scientists identified

things that can be done now

to reduce the amount of

carbon dioxide going into

the atmosphere. Of those

things, which can you and

your classmates do? 

From: Joyce, Linda A.; Birdsey, Richard,

technical editors. 2000. The impact of climate change on America’s forests: A technical document supporting the 2000

USDA Forest Service RPA Assessment.

Gen. Tech. Rep. RMRS-GTR-59. Fort

Collins, CO: USDA Forest Service, Rocky

Mountain Research Station. 133 pp.

FACTivity

In this article, you have

learned that

different climates have

different kinds of vegetation.

The question you will

answer in this FACTivity is:

Does it take much of a

change in climate to cause a

change in the type of vegetation growing in an area? In

this FACTivity, the only measure of climate you will be

considering is temperature.

In reality, climate is composed of many other factors

in addition to temperature. 

The method you will use

to answer this question is:

Think about what scientists

have said about possible

future temperatures. In the

Methods section, you read

that “in one formula, the

average temperature for the

United States was increased

by 4 °C by the year 2100.”

According to scientists at the

Intergovernmental (in tür

guh vürn men tul) Panel on

Climate Change, the global

average temperature of

Earth’s surface may increase

by between 0.2 °C and 0.5

°C by the year 2020. (The

panel is a part of the United

Nations Environment

Program.) Thus, the average

temperature may increase

slowly for the next 20 years

or so, then the increase may

become more rapid through

the rest of the 21st century.

On the following page is a

table of yearly average temperatures for some U.S. cities.

Each of these cities lies in one

of the vegetation types from

the study. You can see that the

last five columns of the table

are empty. Your job will be to

calculate possible future temperatures for each of these

cities and complete this table.

To do this, you will first

need to convert the possible

increase in temperature from

Fahrenheit to Celsius

(Column 3 to Column 4). To

convert Fahrenheit to Celsius,

subtract 32 from the

Fahrenheit number, then multiply by 5/9 and write that

number in Column 4 for each

city. Now that you have the

temperature in Celsius, you

can add the estimated numbers to the Celsius temperature. To complete Column 5,

add 0.2 to the number in

Column 4 for the lower end

of the range, and add 0.5 to

get the higher end of the

range. To complete Column

6, add 4 to the number in

Column 4. What do the numbers 0.2 and 0.5 represent?

What does the number 4 represent?

To compare the temperature in Column 3 with the

estimated increases in temperature, you need to convert the

Celsius temperatures in
15

Column 1 Column 2 Column 3 Column 4 Column 5 Column 6 Column 7 Column 8

City and

State

Vegetation

Type

Average

Yearly

Temperature

in °F

Average

Yearly

Temperature

in °C

Possible

Average

Yearly

Temperature

Range in °C

(Year 2020)

Possible

Average

Yearly

Temperature

in °C (Year

2100)

Possible

Average

Yearly

Temperature

Range in °F

(Year 2020)

Possible

Average

Yearly

Temperature

in °F (Year

2100)

Fairbanks,

Alaska

Los Angeles,

California

Wichita,

Kansas

Honolulu,

Hawaii

Des Moines,

Iowa

Charlotte,

North

Carolina

Glenwood

Springs,

Colorado

Albuquerque,

New Mexico

Salem,

Oregon

Barrow,

Alaska

Taiga-Tundra

Shrub woodland

Grasslands

Tropical

broadleaf 

forest

Savannah

woodland

Temperate

mixed forest

Boreal coniferous forest

Arid lands

Temperate

evergreen 

forest

Tundra

26.9

63

56.2

77.2

49.9

60.1

45.7

56.2

52.1

9.42

-2.83 -2.63 – -2.33 1.17 27.27 - 27.81 34.11

Columns 5 and 6 to

Fahrenheit and complete

Columns 7 and 8. To do this,

multiply the Celsius number

by 9/5, then add 32.

Fairbanks, Alaska, is completed as an example.

Now compare the current

average temperature with the

possible future average temperatures for all of the cities.

Does the difference seem very

big? Read the Findings section again, and look again at

figure 3. Are you surprised at

the possible changes in vegetation, given the amount of

temperature change? What

does this information tell

you about the relationship

between average yearly air

temperature and the type of

vegetation growing in an

area?
16
Do What You

Water:

The Current and Possible

Future of Fresh Water in

the United States

Tom Brown

Meet Dr. Brown:

I like being a scientist

because it is challenging to figure out how to solve a problem or design the right

experiment. It is also challenging to gather good data and to

write about the study so that it

is interesting to others. I also

like being a scientist because I

have a chance to do something

useful.

Glossary

data (dat uh): Facts or figures studied in

order to make a conclusion.

reservoirs (rez ür vôrz): Places where

something, especially water, is collected

and stored for use.

aquifers (ak wuh fürz): Underground

reservoirs; Areas of sand, gravel, or

bedrock that contain a high amount of

water.

irrigation (er uh ga shun): The act of

watering by means of canals, ditches,

pipes, or sprinklers.

natural resources (nach ur ul re sôrs ez):

Things in nature that take care of a human

need, such as oil.

conserve (kän sürv): To avoid wasteful or

destructive use of something.

variables (ver e uh bulz): Things that can

vary in number or amount.

groundwater (ground wa tür): Water that

sinks into the soil and is stored in aquifers.

surface water (sur fus wat ür): Water that

does not seep into the ground or evaporate into the atmosphere.

analysis (uh nal uh sis): Separating something into its parts to examine it.

categories (kat uh gôr ez): Divisions of a

main subject or group.

livestock (liv stäk): Animals kept or raised

on farms.

census (sen sus): An official count of all

the people in a country, including other

information such as their sex, age, and

occupation.

average (av rij): The number gotten by

dividing the sum of two or more quantities by the number of quantities added.

assumptions (uh sump shunz): Things that

are taken for granted.

efficient (e fish ent): Bringing about the

result wanted with the least amount of

time, waste, or materials.

downstream (down strem): In the direction in which a stream is flowing.

analyzing (an uh li zing): Separating

something into its parts and examining

them.

Pronunciation Guide

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Accented syllables are in bold.

17

Thinking About

Science

Have you ever

said something

to someone and

had them ask

you in return, “What do you

mean?” To answer, you have

to be more specific about

what you are saying. When

scientists study something,

they answer that question

many times. 

In this study, the scientist

was studying how much fresh

water people in the United

States use every year. To do

this, he had to explain exactly

what he meant by fresh water.

He also had to explain what

kind of uses of fresh water

were included in his study: 

• Did he include the drinking

water that comes from

rivers and reservoirs? 

• Did he include swimming in

pools as a fresh water use?

When scientists decide to

study something, they have to

explain exactly what they

mean by everything that they

say and do. If they do not do
18

this, people cannot properly

understand the study’s findings. Can you think of a situation in which you have been

asked to be more specific?

Sometimes that is very hard 

to do!

Thinking 

About the

Environment

Life on planet

Earth cannot

exist without

water. Many plants and animals, including humans, need

fresh water to live. Fresh

water is water that does not

have salt in it. The oceans and

most coastal waters are made

up of salt water. Water farther

from the ocean is usually fresh

water. 

Most bodies of fresh water

are rivers and lakes, including

lakes built by humans. Fresh

water can also be found in

aquifers. Besides using fresh

water for drinking, we also

use fresh water for uses in our

homes such as washing dishes

and clothes, and for bathing.

Fresh water is also used for

irrigation; for washing away

the wastes of different kinds

of industry, including the food

animal industry; and for producing electric power. 

As you can see, plants,

humans, and other animals

must have fresh water.

Unfortunately, fresh water

may not always be available in

the amounts that humans

would like to have it. That is

why it is important to understand how much fresh water

humans will need in the

future.

Introduction

Some scientists in the USDA

Forest Service have a special

job to do. They have been

asked to predict how much of

certain natural resources people in the United States will

use in the years ahead. By predicting this, people who make

decisions about how we

should use our natural

resources will be able to do a

better job. 

For example, if scientists

predict that in the future there

will be less land available to

grow food, we can conserve

land today for growing food

in the future. In this study, the

scientist was asked to predict

how much fresh water people

living in the United States will

use from the year 2000 to the

year 2040. (How old will you

be in 2040?)

Reflection

Section

• What is one

barrier to accurately predicting how much

fresh water people will use

in the future?

• What do you think is one of

the most important variables affecting how much

total fresh water will be

used by people in the

future?

Methods

The scientist used data from

another Federal Government

agency to help answer his

Water moves from the atmosphere, to the surface of and into

the Earth, into the oceans and back to the atmosphere.
19

question. That other agency is

called the United States

Geological (ge o law juh kol)

Survey, or the USGS. Every 5

years since1950, the USGS has

estimated the amount of water

being used by Americans (figure 1). The scientist used data

about water coming from

groundwater sources and

from surface water. 

Because people use fresh

water for many reasons, the

scientist wanted to simplify

his analysis. He took all of the

uses of fresh water and divided them into water use categories. He defined water use

as any use of fresh water. This

included fresh water coming

from a steam, river, lake, or

surface reservoir. It also

included water pumped up

from a groundwater aquifer.

The water use categories he

developed include:

• Livestock—Providing water

for animals or to wash away

animal wastes.

• Home and public use—

Cooking, washing, or for

things like swimming pools

or water fountains (figure

2).

• Industrial and commercial—Using water for cooling machinery or cleaning

equipment.

• Thermoelectric (thür mo e

lek trik)—Using water to

cool power-generating

equipment.

• Irrigation—Watering agricultural fields, such as those

growing soybeans, corn, or

other plants.

To predict what might happen in the future, the scientist

examined how much water

people used in each of these

water use categories for each

year, and compared it with the

United States population for

that same year (figure 3).

Then, the scientist used predictions of population growth

to the year 2040 from the

United States census. Based on

past water use and the population for each year, he estimated how much water might be

used by a growing population

of Americans every 10 years

until the year 2040.

Do you remember the fairy

tale about Goldilocks and the

Three Bears? In that fairy tale,

there were always two Figure 1: The amount of fresh water used by Americans from

1900 to 1990.

Figure 2. Drinking water, for people or for their companion

animals, is a home water use.
20

extremes and one thing in the

middle, such as the hardness

and softness of the beds and

the temperature of the porridge. 

In this study, the scientist

looked at three estimates of

population growth to the year

2040. The first estimate

assumed the highest growth

rate, the second assumed the

lowest growth rate, and the

third was in the middle. In his

report, the scientist used the

middle estimate of population

growth (figure 4).

Reflection

Section

• Scientists

often use information that has

already been

collected by other scientists.

What are some examples of

when you use information

that had been collected by

others?

• What is the most important

variable affecting how much

fresh water will be used in

the future?

Findings

The scientist reported water

use for the five categories listed (figure 5, page 21).

After he looked at each

water use separately, the scientist wanted to present an estimate of all water use put

together. Overall, water use is

expected to rise by 7 percent

between 1995 and 2040. The

greatest amount of water will

be used for irrigation and

thermoelectric use. However,

the greatest percentage

increases are in home and

public use and in livestock

use.

Reflection

Section

• Fresh water

use is expected

to increase by 7

percent overall.

Compare this with the estimate of population growth

to the year 2040, which is

41 percent. Does this mean

that on the average and

across all uses, each person

is estimated to be using

more or less water in the

year 2040 compared with

our use today?

Figure 3: The amount of fresh water used by Americans compared with the United States population, 1900-1990.

Figure 4. The scientist used the middle series of estimates of

population growth.
21

Figure 5. Water use estimates for water use

categories from 1960 to 2040.

Table 1:

Estimates of

changes in fresh

water use from

2000 to 2040.

• Look at the percentage

increases for home and public use and for livestock use

(table 1). What other percentage is similar to those

percentages? (Hint: See the

previous reflection question.) Do you think that it is

just a coincidence (ko in suh

dens) that these percentages

are so close? Why or why

not?
22

Implications

When the scientist developed his water use estimates,

he made assumptions about

things like population growth

and the availability of water in

the future. These assumptions

may not be accurate. If the

assumptions are not accurate,

the estimates may not be accurate. 

One assumption made by

the scientist is that we will

continue to become more efficient in our use of water for

things like irrigation, in industry, and even in our homes. A

second assumption is that we

will have enough rainfall to

meet our needs for water. If

areas of the United States

experience below average

rainfall for a few years in a

row, two things could happen.

First, there may not be

enough fresh water to meet

the need, causing people to

have to conserve water.

Second, plants and animals

downstream may be affected.

When people remove water

from streams and rivers for

their use, there may not be

enough rain to make up for

the water that people take out.

Lower water levels affect the

plants and animals that live in

and around the streams and

rivers. We need to protect the

health of streams and rivers,

and to make sure people have

enough fresh water. To do

this, we need to find more

ways to conserve water now

and into the future.

Reflection

Section

• The assumptions made by

the scientist may

not be accurate.

What is one thing the scientist can do in the future to

improve our understanding

of water use into this century? (Hint: What has he

already done? Should he do

it again in 5 years and 10

years?)

• What might happen to

plants and animals living

downstream if the water

level goes down?

• What are some ways that

you could conserve water in

your home?

For more information on this study, visit

www.fs.fed.us/rm/value/docs/projecting_f

reshwater_withdrawals/. This Web site

presents a short version of the results of

this study.

From: Brown, Thomas C. 1999. Past and

future freshwater use in the United States:

A technical document supporting the

2000 USDA Forest Service RPA

Assessment. Gen. Tech. Rep. RMRSGTR-39. Fort Collins, CO: USDA Forest

Service, Rocky Mountain Research

Station, 47 p.
23

FACTivity

The question you will answer

in this FACTivity is: How much

fresh water do you use during a

typical day at home? The

method you will use to find the

answer is completing and analyzing the following questionnaire. Each person in your class

should complete the questions below. Then,

using the guide given below the questions, each

person will calculate the number of gallons of

fresh water he or she might use in a typical day

while at home. These numbers are not exact.

For example, you might turn the water off

while you brush your teeth, while your classmate might leave the water running. You might

decide to wash the car or water your flowers.

Remember that you are calculating an estimate, not an exact amount. Then, your class

will calculate an estimate of the total number of

gallons used by the whole class in a typical day,

and an estimate of the average number of gallons used by each person in the classroom.

Answer only for your own activities. Answer

the questions below for a typical day spent at

home on a Saturday. Write your answers on a

blank sheet of paper. Number your paper from

1 to 11.

• How many baths do you take? 

• How many showers do you take?

• How long is each shower in number of minutes?

• How many times do you brush your teeth?

• How many times do you wash your face

and/or hands?

• How many times do you shave your legs or

face?

• How many dishwasher loads do you run?

• How many sinks full of dishes do you wash

by hand?

• How many loads of clothes do you wash?

• How many times do you flush the toilet?

• How many 8-oz. glasses of water do you

drink?

Now, use the guide below to estimate how

much fresh water you use on a typical Saturday.

• Multiply the number of baths you took by 50

gallons.

• Add the total number of minutes you spent in

the shower, then multiply that number by 2

gallons.

• Multiply the number of times you brushed

your teeth by 1 gallon.

• Multiply the number of times you washed

your face or hands by 1 gallon.

• Multiply the number of times you shaved

your legs or face by 1 gallon.

• Multiply the number of times you washed a

load of dishes in the dishwasher by 20 gallons.

• Multiply the number of times you washed a

sink full of dishes by 5 gallons.

• Multiply the number of times you washed a

load of clothes by 10 gallons.

• Multiply the number of times you flushed the

toilet by 3 gallons.

• Multiply the number of 8 oz. glasses of water

you drank by 8. Then divide that number by

64 to calculate how many gallons of water

you drank.

Now, add the numbers you calculated using

the guide to get an estimate of your fresh water

use in number of gallons on a typical Saturday.

To find out how many gallons your whole class

used, add every student’s total gallons together.

To calculate the classroom average, divide the

classroom’s total number of gallons by total

number of students.

Now hold a class discussion about fresh

water usage. Are you surprised at how many

gallons you probably use on a typical Saturday?

Is your personal total greater or lower than the

average for the class? Can you think of ways to

reduce the number of gallons you use?

Remember, it is important to bathe regularly,

wash your hands frequently, and brush your

teeth after every meal. As you look for ways to

conserve water, do not cut out any of these

activities. 

This FACTivity was adapted from the “Water Science for Schools”

Web site: wwwga.usgs.gov/edu/sq3.html. You can do this activity

on-line by visiting the web site.
24

The Current Situation and

Possible Future of Wildlife

in the United States

Born To Be Wild: Born To Be Wild:
25

Glossary

conservation (kän sür va shun): The care

and protection of natural resources such

as forests and water.

habitats (hab uh tat): Environments

where a plant or animal naturally grows

and lives.

wildlife: (wild lif): Animals that live in

the wild.

scales (ska lz): A series of steps or degrees

based on size, amount, rank, etc.

molecular (mo lek yoo lür): Having to do

with molecules, which are the smallest

particles of a substance that can exist

alone without losing their chemical form.

populations (pop yoo la shunz): The

total number of individuals of separate

types of plants or animals occupying an

area.

ecosystem (e ko sis tem): Community of

plant and animal species interacting with

one another and with the nonliving environment.

sustain (suh stan): To keep up or maintain.

pollinate (päl uh nat): To place pollen on

the pistil of a flower, which fertilizes the

flower and causes seeds to develop.

defecate (def uh kat): To get rid of waste

matter from the bowels.

germinate (jür muh nat): To start growing or developing.

species (spe sez): Groups of organisms

that resemble one another in appearance,

behavior, chemical processes, and genetic

structure.

status (staht us): The state or condition

of something.

trends (trendz): The directions or courses

that things take.

grasslands (gras landz): Open lands with

grass growing on them.

cavities (kav i tez): Hollowed out spaces.

migrate (mi grat): To move from one

place to another.

habitat (hab i tat): Environment where a

plant or animal naturally grows and

lives.

Pronunciation Guide

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Accented syllables are in bold.

Thinking About

Science

Scientific

studies can be

carried out at a

variety of scales.

Scales can vary by size and by

time. For example, a smallscale study may be conducted

at the molecular level, or it

might only cover a time period

of a few seconds or minutes. A

large-scale study may be

focused on the stars beyond

our solar system, or it might

cover a period of years or

decades. 

The scale of this study was

large, covering the entire

United States and a time period of over 40 years. But there

Meet Dr. Flather: 

I like being a scientist

because it is essentially problem solving—and in my case,

the problems deal with the

conservation of wildlife.

Working on wildlife conservation problems can be very satisfying when their solution

leads to better management of

the habitats where wildlife

live.

Dr. Flather:

was something very different

about the long-time scale of

this study! Instead of conducting the research over a

period of years, the scientist

predicted what might happen

in the future. In this study, the

scientist was asked to

describe the current situation

and potential future of different wildlife populations, 40

years into the 21st century.

Thinking 

About the

Environment

In the natural

environment,

every living

thing has a role to play to

help keep its ecosystem

healthy. Animals do their part

to sustain their environment.

Bees, for example, pollinate

flowers. Some animals eat

fruit and later defecate the

seeds, which then germinate

in the soil. Other animals

catch seeds in their fur, and

later the seeds fall off and germinate. Animals such as

earthworms digest dead plant

and animal matter. Worm

wastes, called castings, provide nutrients for the soil.

Animals use plants for food,

shelter, and as a place to raise

their young. As you can see,

plants and animals depend

upon each other

In this study, the scientists

wanted to predict the future

of different types of wildlife.

Will the populations of different animal species go up,

down, or stay the same in the

future? By knowing something about the possible
26

future of different animal

species, we can perhaps help

those species to stay healthy,

and, therefore, help to keep

the natural environment

healthy.

Introduction

As you know from reading

“Thinking About the

Environment”(above), animals play an important role in

maintaining the health of our

natural environment. It is

important to know the status

of different kinds of animal

populations, both now and

into the future. This is important for many reasons. 

One reason is that healthy

animal populations probably

mean that the whole natural

environment is also healthy. If

some species become endangered, it might be a clue that

the environment is not as

healthy as it could be. 

Another reason is that different animal species have different values for people. For

example, some people like to

feed and watch birds in their

backyard (figure 1). For these

people, it is important to

know whether the number of

birds in their backyard might

go up, go down, or stay the

same in the future. 

One of the questions the scientist in this study wanted to

answer was: What are the

trends in different wildlife

populations? In other words,

the scientist wanted to predict

whether the population of certain animals species will go

up, go down, or stay the same

into the 21st century.

Reflection

Section

• What kinds of

wildlife live near

your home or

school? Wildlife

includes all kinds of animals

that have not been tamed by

people. Make a list of as

many different kinds of

wildlife as you can.

• How are different kinds of

wildlife important to different people? List at least four

reasons people might value

wildlife.

Method

Often, scientists like to collect their own information.

Sometimes, however, the questions they are trying to answer

cannot easily be answered by

collecting their own information. When scientists have to

collect information at a large

scale, it takes a lot of time and

money. To answer his question, the scientist in this study

asked other scientists who had

been collecting smaller pieces

of similar information. 

For example, the scientist

asked people who work for

different State governments to

share information on wildlife

populations in their State. He

also asked some of these people to predict whether the

number of animals living in

the wild would go up, down,

or stay the same in the future.

He also asked scientists working for other organizations to

share their information. By

doing this, the scientist

received information from

many different places. Then,

he put it all together to learn

what is going on with wildlife

populations nationally. 

When you prepare a paper

for a school project, you

should also collect information from many sources and

put it all together. When you

do that, you are like the scientist in this study!

Figure 1. Bird at a backyard feeder.
27

Reflection

Section

• What is one

advantage of

asking other

people to share

information that they have

collected?

• What is one disadvantage of

asking other people to share

information that they have

collected?

Findings

The scientist could not collect information on every

species of animal. Remember,

he had to rely on information

collected from other scientists.

In this article, you will learn

what the scientist discovered

about ducks, birds, turkey,

deer, bear, squirrels, and rabbits. 

The scientist found that

duck populations increased

from 1990 to 1995, ending a

period of declining populations since 1980 (figure 2).

The scientist thinks that this

increase in the numbers of

ducks is related to an increase

in wetlands available to ducks

during their breeding season.

Because the United States

experienced high amounts of

rainfall during the early

1990s, there were more wetlands available.

The scientist used information from a yearly survey of

birds to report the population

of different bird species. He

reported that the number of

species with increasing populations is about equal to the number of species with decreasing

populations (figure 3).

The scientist reported that

most of the bird species with

decreasing populations were

birds that nest in or near

urban areas, in grasslands, or

on or near the ground (figure

4). The bird species with

increasing populations were

birds that nest in wetlands or

on open water such as bays

and oceans, in tree cavities, or

birds that migrate short distances.

The scientist found that the

populations of some other

Figure 2. Changes in duck populations from 1965 to 1995.

Figure 3. The number of bird species with increasing populations is almost equal to the number of bird species with

decreasing populations, 1966-1996. There is a proportion of

bird species whose populations is staying the same.
28

species of wildlife were predicted to go up in the future,

some were predicted to go

down, and others were predicted to stay the same (figures 5-12).

You probably have heard

about threatened and endangered species. The future existence of threatened species

may be in danger if special

care is not taken to protect the

areas where they breed and

live. Endangered species are

species whose existence is

already in danger. 

The scientist wanted to find

out if there are areas of the

United States with more

threatened and endangered

species than other areas. He

discovered that the coastal

United States has a high number of threatened and endangered species (figure 13, pg. 30). 

The scientist studied predictions about the future of the

natural environment in the

United States. This included

predictions of temperature

changes, human population

growth, how much forest land

might be cleared, how many

wetlands there might be, and

other ways that the land might

change in the future. He combined this information with

what he already knew about

the areas of the United States

with a high number of threatened and endangered species

(see figure 13). From this

information, the scientist predicted which areas of the

United States will have the

greatest increases in the number of threatened and endangered species in the year 2020

(figure 14, pg. 30).

Reflection

Section

• The scientist

found that the

populations of

bird species that

nest in urban areas were

declining. He was surprised,

considering that the number

of urban areas is increasing.

What might be some of the

reasons those populations

seem to be declining? 

Figure 4. Sage grouse is a bird species that lives on the ground in grasslands.
29

Figures 5-12. The populations of some wildlife species were predicted to go up, some were

predicted to go down, and others were predicted to stay the same.
30

• The number of ducks seems

to be related to the amount

of rainfall received each

year. Think about whether

the rainfall amount in your

area this year is about normal, greater, or less than

normal. Go back and review

Figure 13. Areas of the United States with a high number of

threatened and endangered species.

Figure 14. Areas predicted to have the greatest increases in the

number of threatened and endangered species in 2020.

the list of wildlife that you

made for the first Reflection

Section. Do you think that

the amount of rainfall is

affecting the wildlife in your

area? Why or why not? If

you think that the amount

of rainfall is affecting the

wildlife, how is the wildlife

being affected?

Implications

Many wildlife species are

staying the same or are gaining in numbers. Others are

losing numbers, and the existence of some of those species

is threatened or endangered.

In some areas, the natural

environment is healthy

enough to support wildlife. 

In other areas, changes in

how we use the land are placing some wildlife in danger.

When humans make changes

to the land, we always affect

the wildlife that lives there.

Sometimes we make changes

that improve the land for

wildlife, and sometimes we

make changes that damage the

land for wildlife.

Reflection

Section

• When we

make changes in

the land that

damage it for

wildlife, do you think that

we are making the land

more healthy or less

healthy? Why or why not?

• Do you think that people

should consider the needs of

wildlife when they make

changes to the land? Why or

why not?

From: Flather, Curis H.; Brady, Stephen J.;

Knowles, Michael S. 1999. Wildlife

resource trends in the United Satates: A

technical document supporting the 2000

USDA Forest Service RPA Assessment.

Gen. Tech. Rep. RMRS-GTR-33. Fort

Collins, CO: USDA Forest Service, Rocky

Mountain Research Station.
31

FACTivity

The scientists in this study

identified areas of the United

States that may have a high

number of threatened and

endangered animal species in

the future. When an animal species becomes

endangered, it could die out and be lost forever. Some animal species, such as the Passenger

Pigeon, are already lost. The question you

will answer in the FACTivity is: What are the

advantages and disadvantages of different

ways to protect an endangered animal species

from dying out? 

The method you will use to answer this

question is: Divide your class into three equal

groups. Each of the groups will take a suggested solution on the best way to protect an

animal species from dying out. The three possible solutions are:

1. We should put some of the individuals

from an endangered species in a zoo where

they will be protected. They can breed and

live in the zoo. Then we will not have to

worry about them dying out in the natural

environment.

2. Whenever a wildlife species becomes

endangered, we should catch some of the

animals. Using the latest technology, we

should clone the animals, then release all

of the animals into the natural environment. Then we will not have to worry

about the species dying out in the natural

environment.

3. We should protect the existing habitat of

endangered species from damaging human

activity so that the endangered animals can

live on their own in the natural environment.

Members of each group should discuss the

solution as a group. Some of the questions

each group should consider are:

Group 1

1. Are animals that live in a zoo still wild animals?

2. Do you think that the land where the

endangered species used to live will become

more or less healthy if the endangered

species living there is gone?

3. Do people have the right to put wild animals in a zoo, even if one of their purposes

is to protect the animals?

Group 2

1. Would cloning individuals from an endangered species make that species healthier or

less healthy? 

2. What might be some of the effects of

cloning individuals from an endangered

species?

3. Do people have the right to clone animals?

Group 3

1. Who will pay for protecting the habitat of

endangered species? Should we spend tax

money to protect the habitat?

2. What about people who want to build

homes and businesses where endangered

species live? What should they do? Do they

have a right to live in those areas, even if by

building there an animal species might die

out?

3. Do animals have a right to live in the natural environment, even if their habitat is

wanted by people for human purposes?

Spend about 15 minutes discussing your

solution. Some group members might decide

to support the solution, while others might

decide that they cannot support the solution.

Each of the three groups should divide in two,

based on whether they support or do not support that solution. 

Your class will now be separated into up to

six groups. Each group should appoint a

spokesperson. The spokesperson of each

group will tell the group why the group supports or does not support the solution.
32
33

Made in the

Shade:

The Current Situation 

and Possible Future of 

U.S. Urban Forests

Meet Dr. Dwyer: 

I like being

a scientist

because I like

learning new

things and

sharing them

with people

who can use

them.

Meet Dr. Nowak: 

I like being

a scientist

because it

allows me to

answer questions that

have never

been

answered

before.

Meet Ms. Noble: 

I like being

a scientist

because it

allows me to

understand,

appreciate,

and take an

active role in

protecting

our beautiful natural environment.

Glossary

mammals (mam ulz): Warm-blooded animals that have a backbone;

Females have glands to produce

milk for feeding their young.

absorbing (ab zôrb ing): Attracting

and taking in another substance.

carbon dioxide (kär bun di ox id):

A gas made up of carbon and oxygen with no color or smell.

natural resources (nach ur ul re sôr

sez): Things in nature that take care

of a human need, such as oil.

status (stat us): The state or condition of something.

estimate (es tuh mat): To make a

general but careful guess about the

size, quality, value, or cost of something.

census (sen sus): An official count

of all the people in a country,

including other information such as

their sex, age, and occupation.

crowns (krownz): The top parts of

things.

average (av rij): The number gotten

by dividing the sum of two or more

quantities by the number of quantities added.

analyze (an uh liz): To separate

something into its parts in order to

examine them.

data (dat uh): Facts or figures studied in order to make a conclusion.

analysis (uh nowl uh sis):

Separating something into its parts

to examine it.

radiation (ra de a shun): The

process of sending energy out in

rays from atoms and molecules. 

Pronunciation Guide

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Accented syllables are in bold.

Meet Ms. Sisinni: 

I like being

a scientist

because my

job is defined

by my imagination. This

means I get

to explore

the world

and sometimes learn things

that no one else knew before.

Dr. Dwyer

Dr. Nowak

Ms. Noble

Ms. Sisinni

Thinking About

Science

One of the

goals of science

is to be able to

predict what

might happen in the future.

No one really knows for sure

what will happen in the

future, even with scientific

information. With accurate

scientific information, however, scientists can make a fairly

good guess. 

One of the ways that scientists predict what will happen

in the future is to examine

what has happened over time.

Let’s say, for example, that a

scientist has observed that the

number of frogs living in an
34

area between 1981 and 2003

went down every year. If you

were the scientist, would you

predict that the number of

frogs will go down over the

next 5 years or stay the same?

You can see that if scientists

are going to make useful predictions concerning the future,

they need to know what has

happened in the past over a

period of time.

Thinking 

About the

Environment

The scientists

in this study

examined a special kind of forest. This kind

of forest is probably familiar

to you, but you never guessed

that it is called a forest! 

This special forest is called

an urban forest, and it is

defined as the trees and other

plants that grow where people

live, work, and play. An urban

forest includes trees that grow

along the street, in your

schoolyard, in parks, and anywhere else in the community

(figure 1). 

An urban forest, like a rural

forest, provides homes for animals, such as birds, small

mammals, and insects. They

make places more beautiful,

reduce noise, and provide

shade. They also reduce flooding by slowing or stopping

some rain from hitting the

ground and by absorbing rainwater. Urban forests keep the

air cleaner by absorbing carbon dioxide. They also provide places for people to play

and learn about the natural Figures 1a, 1b, and 1c. Examples of urban forests.
35

environment. People don’t

always think of the trees and

other plants near their homes

as natural resources, but they

are!

Introduction

The scientists in this study

were asked to determine the

current status of urban forests

in the United States. The scientists decided to find out how

much land is covered by trees

in cities, towns, villages, and

other areas. The scientists

were also asked to predict the

future of urban forests, so they

tried to answer this question:

“Will there be more or less

urban forests in the future?”

Reflection

Section

• Do you think

that the scientists visited

every city, town,

and village where people

live across the United States

to count the number of trees

within urban forests? Why

or why not? 

• If you were the scientist,

how would you estimate the

current status of urban

forests across the United

States?

Method

The scientists could not visit

every city, town, village, and

suburban area in the United

States and count the trees.

That would have taken them

years and years! Instead, they

used information collected by

other scientists. 

First, they used information

from the United States census

to identify the areas of the

country where most people

live (figure 2). Then they used

maps created by USDA Forest

Service scientists that show

how much of the land area

where people live is covered

by the crowns of trees (figure

3).

Figure 2. Location of urban places. This map of the United States was drawn from a 

photograph taken from space at night.
36

Reflection

Section

• Do you think

that the scientists will be able

to predict what

might happen in the future,

based on the information

that they collected? Why or

why not?

Results

The scientists found that 8

out of every 10 Americans live

in cities, towns, villages, or

suburban areas. (What percentage is that? Divide 8 by 10

to find out.) The scientists

found that these areas where

people live have about 27 percent tree cover (figure 4, pg.

37). This means that a little

over one- quarter of the land

where people live is covered

by tree crowns. Surprisingly,

this is not much less than for

all lands in the United States,

which is almost 33 percent.

There is more tree cover in

cities, towns, and suburban

areas in the Eastern United

States, as compared with the

midwestern, western, and

southwestern areas of the

country. 

The scientists discovered

that the amount of land across

the United States that is taken

up by buildings, roads, and

parking lots has tripled during

the past 20 years. The rural

forests are being replaced by

buildings, roads, parking lots,

grassy areas, and trees and

other plants that are planted

around or near the built structures. If the amount of land

taken up by buildings, roads,

and parking lots continues to

increase in the future, there

will be less rural forests and

more urban forests across the

United States.

Reflection

Section

• Why do you

think there is

more tree cover

in the Eastern

United States than in the

midwestern, western, and

southwestern areas of the

country?

• Do you think that in the

future, more or less rural

forests will be replaced by

buildings, roads, parking

lots, and urban forests?

Why?

Implications

Urban forests are an important part of the places where

people live. The scientists

believe that urban forests will

become even more important

in the future. More land is

being used for buildings,

streets, and parking lots.

People will need to have urban

forests around them to provide the benefits listed in

“Thinking About the

Environment.” (Can you

name some of those benefits?)

Figure 3. Tree crown and its relationship to the measurement

of tree cover.
37

Figure 4: On the average across the United States, 27 percent of the areas where people live are

covered in trees.

Reflection

Section

• Would you

consider your

schoolyard or

local park area

an urban forest? Why or

why not?

• Think about your own use

of urban forests. What are

some of the benefits you get

from having an urban forest

near where you live or play?

From: Dwyer, John F.; Nowak, David J.;

Noble, Mary Heather; and Sisinni, Susan

M. 2000. Connecting people with ecosystems in the 21st century: An assessment of

our nation’s urban forests. Gen. Tech.

Rep. PNW-GTR-490. Portland, OR:

USDA Forest Service, Pacific Northwest

Research Station. 483 p.
38

FACTivity

Sometimes, the temperature

is too hot for people to feel

comfortable outside. Urban

forests might have an impact

on how hot or cool you feel in the warmer

months. The question you will answer in this

FACTivity is: How does being in the shade

affect how hot you feel? 

The method you will use to answer this

question is: 

Get two thermometers. Place one thermometer outside under some shade, such as

among tree branches. If there are no trees

near you, place one thermometer outside

under a bush or other vegetation where it will

receive shade. 

Date and time Temperature–In the

shade (°F or °C)

Temperature–In the

open (°F or °C)

Cloud 

conditions

(1-5)

Place the second thermometer as close as

possible to the first, but in a place where it will

receive full sun. Leave the thermometers in

place for at least 30 minutes before making

your first observation.

Record the temperature registered by each

of the thermometers. 

Have one person in your class observe and

record the temperatures at the beginning of the

class period, another person observe and

record the temperatures during the middle of

class, and a third person observe and record

the temperatures at the end of the class period. 

Also observe and record the cloud conditions at the time each observation is made. Use

the chart below as a guide for your recording.

1

2

3

4

5
39

Observe and record the temperature and

cloud conditions for at least 9 school days (or

almost 2 weeks). (How many observations will

you have? Multiply 3 X 9.) On the 10th day,

you will analyze your data. Use the following

to observe and record cloud conditions:

Cloud conditions:

1 = Clear (full sunshine, sharp shadows, no

clouds)

2 = Overcast (Hazy sunshine, fuzzy shadows)

3 = Partly cloudy (Mostly full sunshine, some

clouds over the sun at times)

4 = Partly sunny (Mostly cloudy, some periods

of full sun)

5 = Cloudy (No periods of sunshine)

Separate your recorded data into categories based on cloud conditions. For example,

place all of the 1’s (full sun) together, all of the

2’s together, all of the 3’s together, and so forth. 

Create a bar chart for each cloud condition

that occurred during your observation and

recording. Bar charts are also called histograms. See the example below.

After you have created all of your bar

charts, compare the charts with one another.

Is each cloud condition different? If so, how?

Now compute the average of all of the

temperature recordings taken in open conditions, and the average of all of the temperature recordings taken under vegetation. To

calculate the average, add all of the temperature recordings and divide the total by the

number of observations. Compare the two

averages. From your analysis, answer the

question posed at the beginning of this

FACTivity. 

Your results probably show a difference

between the temperature recorded in the sun

as compared with the temperature recorded in

the shade. Were you surprised? Probably not,

as you know that you feel hotter in the sun

than you do in the shade. Did you know that

in both cases the air temperature is actually

the same? You feel hotter in full sun because

the sun’s radiation falls on your skin and

heats it. The sun does the same thing with the

thermometer. It feels cooler under trees

because the shade keeps the sun’s radiation

from heating your skin.

6

7

8

10

9
40

The Current Situation and Possible Future

of Aquatic Animals in the United States

One Fish,Two Fish,

Red Fish—No Fish?

One Fish,Two Fish,

Red Fish—No Fish?
41

Glossary

manage (man ij): To have charge of

or direct the work of.

conservation (kän sür va shun): The

care and protection of natural

resources such as forests and water.

wildlife (wild lif): Animals that live

in the wild.

habitats (hab uh tats): Environments

where a plant or animal naturally

grows and lives.

analysis (uh nowl uh sis): Separating

something into its parts to examine it.

data (dat uh): Facts or figures studied

in order to make a conclusion.

species (spe sez): Groups of organisms that resemble one another in

appearance, behavior, chemical

processes, and genetic structure.

extinct (ek stinkt): No longer living.

populations (päp yoo la shunz): The

total number of individuals of separate types of plants or animals occupying an area.

classify (klas uh fi): To arrange by

putting into groups according to

some system.

status (staht us): The state or condition of something.

trends (trendz): The directions or

courses that some things take.

aquatic (uh kwat ik): Growing or living in or upon water.

freshwater (fresh wat ür): Having to

do with or living in water that is not

salty.

assumption (uh sump shun):

Anything taken for granted.

native (nat iv): Naturally occurring in

an area.

eroding (e rod ing): Wearing away.

emissions (e mish ens): Something

discharged or sent out.

Pronunciation Guide

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Accented syllables are in bold.

Meet Mr. Loftus: 

I like being a scientist

because it gives me a chance to

explore new things and use

what I discover to change the

way we manage the environment.

Meet Dr. Flather: 

I like being a scientist

because it is essentially problem solving—and in my case,

the problems deal with the

conservation of wildlife.

Working on wildlife conservation problems can be very satisfying when their solution

leads to better management of

the habitats where wildlife

live.

Mr. Loftus

Dr. Flather

Thinking About

Science

Scientists try

to solve problems or answer

questions by

collecting information and

doing an analysis of the information they have collected. If

they have enough time and

money, scientists usually collect their own data. If they do

not have enough time or

money, or if the kind of data

they need are already available, they will analyze (an uh

liz) data already collected by

other scientists. 

In this study, the scientists

did not have enough time or

money to collect their own

data. Instead, they used data

already collected by other scientists to help them answer

their questions. You do the

same thing when you write a

school paper on a topic not

familiar to you. You collect

information from other

sources, such as the Internet,

the library, or encyclopedias.

When you collect information

to write a paper, you are like

the scientists in this study!

Thinking 

About the

Environment

Since the pilgrims landed in

Massachusetts

in 1620, more
42

Introduction

The scientists in this study

were asked to develop information about the status of

and trends in aquatic animal

species populations across the

United States. They already

knew that there are about 800

freshwater fish species in the

United States (figure 1).

However, the scientists

found that there were few

measurements already available that would help them to

determine the status of and

trends in the populations of

these 800 freshwater fish and

other freshwater aquatic

species. The only data they

could find were collected in a

few separate areas of the

country. 

In addition, the information

was not the same from location to location. Still, the scientists collected information

that might show general

trends. From these separate

pieces of information, the scientists made an informed

guess about the status of and

potential trends in populations of freshwater aquatic

species.

Reflection

Section

• One of the

purposes of science is to use

current data or information

to predict what might happen

in the future. Scientists predict what might happen in the

future by studying trends

from the past and into the

present. Why it is important

to be able to make scientific

predictions about what might

happen in the future? (Hint:

Think about the future path

of a hurricane or about global

than 500 plant and animal

species have become extinct in

the United States. The U.S.

Fish and Wildlife Service is

charged with protecting

species from extinction (eks

tink shun). To do this, the U.S.

Fish and Wildlife Service studies the populations of animals

and plants. When they find a

plant or animal species that is

in immediate danger of

becoming extinct, they classify

it as endangered (en danj ürd). 

When the U.S. Fish and

Wildlife Service finds a plant

or animal species that is likely

to become endangered, it is

classified as threatened. Being

classified as threatened or

endangered provides the plant

or animal species with special

consideration that protects it

from human activities that

would further threaten or

endanger it. 

Figure 1. Trout are a freshwater aquatic species.
43

climate change. Is it important to be able to predict these

events? Why or why not?)

Methods

The scientists used two

types of information. To

determine the status of aquatic species populations, they

gathered data that had been

collected by other scientists.

Even though they did not

have all of the data that they

needed, they made an educated guess about the current

status of aquatic animal

species populations. 

To determine the trends in

populations, the scientists

studied examples of things

that people have done that

affected the trends in species.

If the things people do

increase the populations of

aquatic species in a particular

stream, river, or lake, this is

an example of conservation

(kän sür va shun). Conservation means taking care of the

natural environment so that it

will be both useful and protected now and in the future.

Reflection

Section

• To guess

what might

happen in the

future to some populations of

aquatic species, the scientists

made an assumption that

more and more people will

practice conservation. What

does conservation mean?

Think of an example of a conservation activity.

Remember that conservation activities can benefit

land, water, air, plants, animals, or any part of the natural environment. How many

conservation activities can

you and your class think of?

Results 

The scientists found that

there are more threatened and

endangered aquatic species

than any other type of animal

species, including those that

live on land. Of the 297 freshwater mussel species naturally

living in North America, 213

are considered threatened,

endangered, or of special concern (figure 2). (What percentage is that? Divide 213 by

297 to find out!) 

Other species are declining

but are not yet considered

threatened or endangered. In

the Chesapeake Bay, for

example, there are 99 percent

fewer oysters living there than

were living there over 100

years ago (figure 3). 

In the Pacific Northwest,

some types of salmon (sam

un) are threatened or endangered, but the population of

salmon as a whole is not considered threatened. In the

Northeast, the number of

Atlantic salmon is declining.

In the Southern Appalachian

mountains of Tennessee, the

number of miles of streams

and rivers where native trout

can be found is only about 30

percent of what it used to be.

These are just a few of the

examples that the scientists

discovered. There are many

reasons for the decline in the

numbers of fish and other

Figure 2. Freshwater mussel.
44

Agriculture—Eroding soil and washing fertilizers into waterways. This is called siltation. Silt

is the number one pollutant threatening our Nation’s waters.

Dams—Stopping the free flow of water in a stream or river.

Over-fishing—Taking more fish out of the water than the species can handle to keep their

numbers at a healthy level.

Buildings and other human development—Causing erosion and pollution.

Gravel mining—Taking gravel from stream beds for human use.

Water supply—Taking water out of streams and rivers for irrigation of agricultural land and

water supply.

Nonnative fish species—Competing with native fish species for food and habitat.

Pollution—Coming from a range of human actions, such as industrial waste products, poor

farming practices, runoff from city streets, emissions from cars, etc.

Cattle grazing near streams and lakes—Eroding soil into waterways.

Poor forestry practices—Washing soil from unpaved forest roads into waterways. 

Mining—Washing heavy metals into waterways.

Figure 4. Some causes of the decline in the number of fish and other aquatic species.

aquatic animals (figure 4).

Most of the decline is caused

by human activities.

The scientists found that

people living in different areas

of the country have been

doing things to reduce the

decline in the populations of

aquatic animal species. In

some cases, people have been

able to improve the quality of

streams, rivers, and lakes so

that the populations of aquatic animals are actually

increasing. For example, a

group of people living in the

States surrounding the

Chesapeake Bay (figure 5)

have agreed to work together Figure 3. There are 99 percent fewer oysters living in the

Chesapeake Bay now compared to 100 years ago.
45

to clean up the bay. Some of

the things they are doing are:

1. Cleaning up the water and

the land surrounding the

bay.

2. Reducing the amount of

pollution entering the bay.

3. Educating citizens about

what they can do to protect

the bay.

4. Encouraging citizens to

help make decisions about

the bay.

5. Agreeing to continue to

work together on solving

the problems of the bay. 

Figure 5. The States surrounding the Chesapeake Bay.

In another example, a

group of people from Arizona

wanted to improve Canyon

Creek for trout. One of the

problems was the rising water

temperature, caused by the

loss of green plants along the

stream’s edge. The plants had

provided shade for the

stream, keeping it cooler. The

plants had been killed by cattle that were allowed to graze

by the streambank. The people moved the cattle away

from the stream and planted

native plants along the

stream’s edge. Within 8 years,

the water temperature

dropped from an average of

21.7 °Celsius to 12.3 °Celsius

(figure 6). (To determine the

temperatures in Fahrenheit,

multiply the temperature in

Celsius by 9/5 and then add

32.) Because of the cooler

water, native trout are once

again living and reproducing

in Canyon Creek.

Reflection

Section

• Do you think

that the water

in creeks or

rivers near your home or
46

school is clean and healthy?

Why or why not?

• What do you think will

happen to the populations

of aquatic animals if conservation is not practiced?

Why? What do you think

will happen to the populations of aquatic animals if

conservation is practiced?

Why?

Implications

Although the scientists were

able to determine that the

populations of fish and other

aquatic animals have been

declining across the United

States, they do not know

Figure 6. Water temperature changes in six areas of Canyon

Creek.

exactly what the status of

these animals is nationwide.

So that better information

is available in the future, the

scientists are trying something

new. They are working with

people from six States to

develop a way to share information about fish and other

aquatic animals. They have

agreed to share the same

information, such as water

temperature; the number of

aquatic species and animals

found in streams, rivers, and

lakes; and the chemical content of the water. They are

using the Internet to share the

information. 

Using this system, the scientists will know whether populations of aquatic species are

continuing to decline, or

whether conservation activities are helping aquatic animals to survive and

reproduce. The scientists will

be able to compare the status

of one river with another

river. They hope that more

States will join the effort.

Using this system, one day scientists will know a lot more

about the status of and trends

in the Nation’s aquatic

species.

Reflection

Section

• Why do you

think that it is

important to

determine the status and possible future of the Nation’s

fish and other aquatic

species?

For water-related activities,

visit:

www.epa.gov/ow/citizen/

thingstodo.html

www.epa.gov/ow/kids.html

www.projectwet.org

From: Loftus, Andrew J. and Flather,

Curtis H. 2000. Fish and other aquatic

resource trends in the United States: A

technical document supporting the 2000

USDA Forest Service RPA Assessment.

Gen. Tech. Rep. RMRS-GTR-53. Ft.

Collins, CO: USDA Forest Service, Rocky

Mountain Research Station. 50 p.
47

FACTivity

The question you will answer

by doing this FACTivity is:

What is the status and probable

future of a current environmental condition or event? The method you will

use to answer the question will be to analyze

news articles describing the environmental

condition or event. This is similar to how the

scientists in this study determined the status

and probable future of aquatic animal species. 

As a class, decide on a current environmental condition or issue that will likely be

reported in the newspaper, TV, and in magazines for at least a few days. You may select

any environmental condition or event, such as

a recent hurricane, flood, wildland fire, or

chemical spill. You may select stories about

whether, as a society, we should drill for oil in

a national wildlife area, for example. You

may select a local, national, or international

condition or event. 

Once you have selected your topic, each

student should search for current printed

news on the topic. The stories can come from

a newspaper, magazine, the internet, or other

printed source. If the issue is national or international, be sure to check news magazines.

Each student should bring his or her printed

news article to class. 

You will need to have at least five different

stories on the same topic. They may be stories

about similar conditions or events happening

in different places, such as wildland fires

occurring in different States or countries.

Eliminate any duplicate articles. 

Divide the class into groups of five students

each. Each group should get one copy of each

of the articles. Assign one news story to each

student in the group. Each student should

study his or her article and answer the four

questions below. Then, the entire group of

five students should discuss the issue and

develop a group answer to the following questions. 

1. What caused the condition or event? For

example, if you studied a wildland fire, did

dry weather and lightening likely cause the

fire? If you studied a debate over drilling

for oil, what are the conditions that caused

the debate?

2. What is the current environmental status of

the condition or event?

3. Based on the evidence that you have, what

do you think will happen to the environment within the next 3 days? Within the

next week? Can you guess what might happen in a month, based on the information

that you currently have? What might happen within the year?

4. What are the possible implications of the

condition or event? The implications may

be environmental, personal, social, or economic.

Each group should present its analysis of

the news articles to the class. As a class, identify which groups reported similar answers,

and which groups reported different answers.

What do you think caused the analyses to be

the same? Why do you think some of the

analyses are different?

By analyzing different news stories, you are

using a similar method as the scientists in this

study. What are the advantages of using this

method? What are the disadvantages? 

Alternative: Your teacher may identify an

event or condition or even supply the articles.

Also, each group can address a different current environmental condition or event.
48

The Current and

Probable Future

of Forests and

Rangelands in

the United States

Stress Test: Stress Test:
49

Meet Dr. Hof:

I like being a scientist

because I enjoy using both

math and science to solve

problems.

Meet Dr. Flather:

I like being a scientist

because it is essentially problem solving—and in my case,

the problems deal with the

conservation of wildlife.

Working on wildlife conservation problems can be very satisfying when their solution

leads to better management of

the habitats where wildlife

live.

Glossary

conservation (kän sür va shun): The care

and protection of natural resources such as

forests and water.

habitats (hab uh tats): Environments where

a plant or animal naturally grow and live.

wildlife (wild lif): Animals that live in the

wild.

species (spe sez): Groups of organisms that

resemble one another in appearance, behavior, chemical processes, and genetic structure.

variables (ver e uh bulz): Things that can

vary in number or amount.

relationships (re la shun ships):

Connections in some fashion of two or

more things. 

rangelands (ranj lands): Open lands which

are mostly covered with grasses or shrubs. 

stressed (stresd): Strained, pressured, or

placed under tension.

indicate (in di kat): To point out or point to.

native (na tiv): Naturally occurring in an

area.

threatened and endangered species (threh

tend and en dan jürd spe shez): Species

whose numbers are so low as to threaten or

endanger its existence in the future.

cubic feet (kyoo bik fet): The summed volume of many cubes that are each 1 foot

long, 1 foot high, and 1 foot wide. 

sediment (sed uh ment): Matter set down

by wind or water, such as sand or soil.

ratio (ra she o): The relation of one thing to

another in size, amount, etc. Proportion.

breeding birds (bred ing bürds): Birds who

are also breeding and raising their young in

the area they are living.

climate (kli met): Average weather conditions of a place over a number of years.

elevation (el uh va shun): The height above

sea level.

population (pop yoo la shun): The total

number of individuals of separate types of

plants or animals occupying an area.

publicly (pub lik le): By the government, on

behalf of all citizens.

analysis (uh now luh sis): Separating something into its parts to examine it.

represent (rep re zent): To be an example of.

Pronunciation Guide

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Accented syllables are in bold.

Dr. Hof

Dr. Flather

Thinking About

Science

Scientists

often work with

things called

variables. A

variable can be anything, as

long as it can be measured or

placed into a category. Length

of hair is a variable. The number of students in a class is a

variable. Age, heart rate, and

eye color are variables too!

When scientists do their

research, they often look for

relationships between variables. Scientists find a relationship between variables

when they discover a pattern

of change between them. 

For example, there is a general relationship between the

height and weight of middle

school students. As students

get taller, they usually weigh

more. 

Scientists typically focus on

the measurement of a special

kind of variable, called a

dependent variable.

Dependent variables are called

this because their value

depends on the values of one

or more other variables. The

other variables are called independent variables. When you

write a paper, you earn a particular grade (the dependent

variable). Your grade depends

on the values of many other

independent variables, such as

the accuracy of what you

write, your grammar, sentence

structure, spelling, neatness,

and whether you turned your

paper in on time.
50

forests and rangelands, now

and into the future. Ideal

forests and rangelands have

clean water in their streams, a

variety of native animals, and

few threatened and endangered species (figure 1).

The scientists in this study

were asked to identify which

areas of forest and rangeland

in the United States might

become more stressed in the

future. To do this, they decided to identify areas across the

United States where human

activity might cause stress on

forests and rangelands.

Examples of human activities that might cause stress on

forest and rangelands include

using trees for wood products

and mining the earth for minerals. These activities can

affect the types and amount of

wildlife, the cleanliness of the

water, and whether there are a

lot of different types of plants

growing in an area.

Reflection

Section

• What is the

question the scientists were

asked to

answer?

• To determine what might

happen in the future, what

will they need to know

about the human activities

that might cause stress to

the natural environment? 

Method

The scientists identified

seven dependent variables,

which they called indicators.

The scientists called these

dependent variables indicators

because they believed these

variables would indicate how

much stress a forest or rangeland was experiencing. The

seven indicators were:

1. The number of threatened

and endangered plant

species per acre.

2. The number of threatened

and endangered animal

species per acre.

3. The amount of water flowing in streams, measured in

cubic feet per second.

4. The amount of sediment

flowing down waterways,

measured in tons per day.

5. The ratio of the number of

acres of undisturbed land to

total number of acres.

6. The number of native

breeding birds per acre. 

7. The ratio of the number of

nonnative breeding birds to

the total number of birds

(figure 2).

Thinking 

About the

Environment

The scientists

in this study

were interested

in identifying forest and

rangeland areas of the United

States where the natural environment might become more

stressed in the future. They

picked seven conditions that

indicate how stressed the natural environment is. These

conditions included things like

the number of native birds living in an area and how much

water was flowing in streams.

The scientists considered

many changes that might

affect these conditions. They

assumed that the changes that

would place the most stress on

the environment are the ones

caused by human activity.

This included things like how

many people are living in an

area, how much of the land is

built up with homes and businesses, and how much of the

land is used for cattle grazing.

Change is a normal part of

the natural environment, but

natural change usually takes a

long time to occur, and the

environment has time to adapt

to the changes. When people

make changes to the natural

environment, the change is

usually faster. If the environment does not have time to

adapt to changes, it might

become more stressed. 

Introduction

It is important to understand the condition of our

Figure 1. The Mexican wolf is

an endangered species.
51

The independent variables

included measures of the climate of an area, its elevation,

its population, how much

money had been paid for trees

to be used for wood products,

how many cows were grazing

on the land, how many mining

sites were in the area, and

whether the land was privately or publicly owned. 

Using a computer program,

the scientists did their analysis

using two steps. First, they

looked for current relationships between the indicators

and the independent variables.

For example, when human

population grows in an area,

is there a greater or lesser

number of threatened and

endangered plant species in

that area? What happens to

the amount of sediment flowing in streams when more

cows are allowed to graze in

an area? 

The scientists entered numbers into the computer program that represent what

might happen to the independent variables in the future.

For example, is the climate

expected to change? If so,

how? Is the number of cows

grazing on land expected to

increase, decrease, or stay the

same in the future?

Remember that the scientists already knew the relationship between the

indicators and the independent variables. From the

expected future changes in the

independent variables, the scientists were able to predict

how the indicators might

change in the future.

Reflection

Section

• Why were the

scientists able to

predict what

might happen to

the indicators in the future? 

Taken together, what do the

indicators represent?

• You probably know the

relationship between your

grade on a school paper and

how accurate your information was, the number of

words you incorrectly

spelled, your neatness, and

whether you turned your

paper in on time. 

If the number of incorrectly spelled words went

down, your writing or typing got neater, and you

turned your paper in early,

how would you expect your

grade to change from grades

in the past? What if the

number of incorrectly

spelled words went up, your

writing or typing got sloppier, and you turned your

paper in late? How would

you expect your grade to

change? How is your experience with grades in school

like this study?

Findings

The scientists developed

maps that show areas of the

United States where by the

year 2020 there is likely to be

the greatest concern for each

of the seven indicators of forest and rangeland stress (figures 3-9, pgs. 52-54). Then,

they combined the seven maps

and created another map that

shows areas where by the year

2020 there is likely to be the

greatest concern for stress on

forests and rangelands overall

(figure 10, pg. 54).

The scientists predicted that

by the year 2020, almost 24.6

percent of the United States

will experience a high level of

stress for at least one of the

seven indicators. The scientists

caution that this is only a prediction. What will actually

happen in the future could be

different. Their conclusions

are similar to another study

that showed the same general

locations across the United

States where stress on forests

and rangelands may be the

greatest.

Figure 2. The European starling is a nonnative breeding

bird that can be found across

the United States.
52

Figure 3. Areas of the United

States where there is likely to

be the greatest increase in

threatened and endangered

plant species by the year

2020.

Figure 4. Areas of the United

States where there is likely to

be the greatest increase in

threatened and endangered

animal species by the year

2020.

Figure 5. Areas of the United

States where there is likely to

be the greatest decrease in

stream flow by the year 2020.
53

Figure 6. Areas of the United

States where there is likely to

be the greatest increase in sediment discharge by the year

2020.

Figure 7. Areas of the United

States where there is likely to

be the greatest decrease in

undisturbed natural land by

the year 2020.

Figure 8. Areas of the United

States where there is likely to

be the greatest decrease in

native breeding birds by the

year 2020.
54

Reflection

Section

• Look at figures 3-9. Do

you see any similarities in the

location of the seven indicators? What are some of the

areas across the United

States where the most stress

is predicted to occur?

• The scientists reported that

the areas of the United

States where they predicted

a greater level of stress in

forests and rangelands are

similar to the results of

another study. Does this

give you more or less confidence in their results? Why?

Implications

Although this study identified areas in the United States

where forests and rangelands

may experience more stress by

the year 2020, this is only a

prediction. Scientific predictions are based on the best

information that scientists

have today. What happens in

the future might be different.

This study helps us to think

ahead into the future, and to

pay special attention to the

areas that need it the most. By

doing that, we might be able

to keep those areas healthier,

and possibly change what will

happen in the future.

Reflection

Section

• How old will

you be in the

year 2020?

What kind of

impact might a decline in

stream flow have on your

life in the year 2020? What

kind of impact might an

increase in the number of

threatened and endangered

animal species have on your

life?

• Do you think that people

should pay attention to the

predictions made in this

study? Why or why not?

From: Hof, John; Flather, Curtis; Baltic,

Tony; Davies, Stephen. 1999. National

projections of forest and rangeland condition indicators: A supporting technical

document for the 1999 RPA assessment.

Gen. Tech. Rep. PNW-GTR-442.

Portland, OR: USDA Forest Service,

Pacific Northwest Research Station. 57 p.

Figure 9. Areas of the United States where there is likely to be

the greatest increase in nonnative birds by the year 2020.

Figure 10. Areas of the United States where there is likely to be

the greatest increase in environmental stress by the year 2020.
55

FACTivity

The question you will answer

in this FACTivity is: What is the

environmental condition of the

land around your school? The

method you will use to answer this question

is: First, you have to decide what the best

indicators are of the environmental condition

of the land around your school. You also have

to decide what the indicators mean. To do

this, divide your class into groups of 4-5 students. Each group will hold a discussion and

submit one indicator to the class. It is okay

for more than one group to suggest the same

indicator, but if your class does not have at

least 5 indicators, assign the groups to develop more. Examples of indicators that you

might use are:

1. The number of trees per acre. More trees

indicate a better environmental condition.

2. Whether you have a bird bath, pond, or

stream on the land surrounding your

school. A source of water for birds and

other animals indicates a better environmental condition.

3. The number of bird nests on the land surrounding your school. More bird nests

indicate a better environmental condition.

After your class has developed five indicators, the class should determine the values of

each of the indicators and what the values

represent. Here are examples of the values

and what they represent for the examples

given above.

1. The number of trees per acre. (You will

have to find out how many acres of land

surround your school.) Less than 5 (<5)

trees per acre = poor condition; 6-10 trees

per acre = good condition; more than 10

(>10) trees per acre = very good condition.

2. A source of water available to birds and

other animals. No = poor condition; Yes,

we have a bird bath that is cleaned and

filled daily = good condition; Yes, we have

a pond or a stream on our school grounds

= very good condition.

3. The number of bird nests on the land surrounding your school. None = poor condition; 1-5 = good condition; >5 = very good

condition.

Select a student to write the indicators and

their values on the board. Hold a class discussion over what the indicators indicate about

the condition of the land surrounding your

school. Do the indicators tell you clearly

whether the condition of your school’s land is

good or poor? Why or why not? Hold a class

discussion about how this FACTivity is similar to the method used by the scientist in this

study. In what ways is it different?
56

Day 1 

1. Introduce topic by setting out a jar filled

with approximately 100 teaspoons

(approximately 16.7 ounces or a little over

2 cups) of water. 

2. Take a teaspoon and fill it up with water

from the jar.

3. Pour the teaspoon into the smaller jar.

4. Ask students what they think the teaspoon

of water represents.

5. Once students have started making a few

suggestions, discuss with students some of

the following facts about water. 

Sample Natural Inquirer Lesson Plan

Article: Do What You Water

Subjects Covered: 

• Science-water use, fresh water 

• Math- multiplication, addition, estimation 

• Reading- comprehension

Recommended Web Site:

U.S. Geological Survey Water Science 

for Schools at

http://ga.water.usgs.gov/edu/index.html

Objectives:

1. Students will be able to analyze and discuss

the problems with fresh water use on

Earth.

2. Students will be able to formulate solutions for problems with fresh water use.

3. Students will be able to synthesize information from a scientific magazine and discuss the information with peers.

4. Students will be able to estimate personal

water use and compare with the class.

Estimated Time for Lesson:

3-4 class periods

Materials:

Day 1

• Large glass jar

• Measuring cup

• Water

• Teaspoon

• Small glass jar

• Copies of the Facts to the Future 

Natural Inquirer

• Student science journals or notebook paper

• Pencils

Day 2

• Paper 

• Pencils

Day 3

• Factivity questions 

• Water estimation guidelines from Factivity

• Poster board or colored construction paper

• Markers, crayons, colored pencils

• Old magazines

• Scissors

• Glue

5.1. Approximately 70 percent of the

Earth’s surface is covered with water.

5.2. Out of all the water on Earth, only 1

percent is useable by humans. (The

jar with 100 teaspoons (16.7 ounces

a little over 2 cups) of water represents all the water on Earth and the

single teaspoon of water in the small

jar represents how much water is useable by humans. This is only a visual

aid. It is a loose approximation.)

5.3. Out of this 1 percent that is useable

by humans, some of the water is difficult to access because of where it is

located.

Procedure:
57

6. As a class, begin reading Do What You

Water. The teachers or student volunteers

can read aloud, the following sections:

Meet the Scientists, Thinking About

Science, and Thinking About the

Environment. 

7. After reading the Thinking About the

Environment section have students break

into pairs to read the article Do What You

Water.

8. While students are reading in pairs, they

should write down answers to the reflection questions in their science journal.

Day 2

1. At the beginning of class, have each student pair up with his/her reading buddy

from the previous class.

2. Tell students that they are going to compete in a “Quick Jot.” 

3. In order to compete in the “Quick Jot,”

students need to brainstorm a list of as

many terms, phrases, and ideas as they can

remember from the article Do What You

Water during a 2-minute time period. 

4. When the 2 minutes are up, have the students share some of the terms they came up

with. 

5. Make a list on the board of their responses. 

6. Now that students are thinking about the

article and what they learned from it, conduct a class discussion using some of the

reflection questions.

Day 3- Day 4

1. As students come into the classroom, hand

them a slip of paper with the questions

from the Factivity and the estimation procedure listed. 

2. Students should answer the questions and

then estimate their water use.

3. Once all students have finished, create a

class water use graph.

4. Discuss the results and have students think

of ways to reduce water use. 

5. Create “Water Wise” posters using the students’ suggestions and post them in the

school hallways. 

Assessment:

Students can be assessed formally and informally during this lesson. Formal assessment

can be done by creating a rubric for the

posters. For example you might require students to have some of the following: two pictures on the poster, four ideas for reducing

personal water use, correct spelling and punctuation, and a sentence or phrase about why

water conservation is necessary.

Informal assessment can be done through class

discussions, observations of group interactions, and participation. 

Modifications:

• Students that have difficulty reading can be

paired with a partner or the teacher may

want to assist while the student reads.

• Students that need an extra challenge can

work on a PowerPoint® presentation for

the class that uses the Natural Inquirer, as

well as other sources to create an informational slideshow on water use and the

water cycle.
1. The article I read was entitled:

n Where in the World Is Carbon Dioxide?

n Do What You Water

n Born To Be Wild

n Made in the Shade

n One Fish, Two Fish, Red Fish – No Fish?

n Stress Test

Circle the answer that best describes how you

feel about the article you just read.

2. The article was:

Easy to understand

Hard to understand

Very hard to understand

3. The article was:

Very interesting to read

Somewhat interesting to read

Not interesting to read

4. Did you learn something from reading 

the article? n Yes n No

5. Did you try to answer the 

Reflection Questions? 

n Yes n No n Some of them

If you read and tried to answer any of the

reflection questions, did they help you to

think about the article? n Yes n No

6. Would you like to read another article?

n Yes n No

7. How old are you? (Circle)

9 10 11 12 13 other age: _____

8. What grade are you in? (Circle)

4th 5th 6th 7th 8th 9th

9. Are you a girl or a boy?

n Girl n Boy

Now write in your answer:

10. What did you learn from reading 

the article?

11. What is your favorite subject in school?

Along with your class or by yourself, 

please send this form to:

Dr. Barbara McDonald

USDA Forest Service

320 Green St.

Athens, GA 30602-2044

Thank you!

TEACHERS, PLEASE COPY THIS FORM BEFORE DISTRIBUTING.

STUDENTS,

Tell Us What You Think About The Natural Inquirer

58
59

For each article that you read, please answer

the following:

Name of Article:________________________ 

1.Would this article help you meet any of

the required statewide science curriculum

standards? n Yes n No

2.How close to the appropriate reading and

comprehension level for your students is this

article written?

n Very close

n Somewhat close

n Not close

3.If the article is somewhat close or not close

to the appropriate reading and comprehension

level, is it:

n Too hard

n Too easy

4.Would or did you use this article in your

classroom as an educational resource?

n Yes n No n Why or why not? 

5.Please rate the article sections on a scale of 

1 to 5. One means the section was not useful

at all, five means the section was very useful.

Not Very

useful useful

Sidebars 1 2 3 4 5

Glossary 1 2 3 4 5

Introduction 1 2 3 4 5

Methods 1 2 3 4 5

Findings 1 2 3 4 5

Graphs, figures, photos 1 2 3 4 5

Reflection Questions 1 2 3 4 5

FACTivity 1 2 3 4 5

6. For any of the sections you rated with either

a “one” or a “two” in question 5, please indicate why the section was not useful or how it

can be improved:

Sidebars

Glossary

Introduction

Methods

PLEASE CONTINUE THIS EVALUATION ON THE NEXT PAGE +

PLEASE COPY THIS FORM BEFORE COMPLETING.

The Natural Inquirer—Teacher Evaluation
60

Findings

Graphs, figures, photos

Reflection Questions

FACTivity

7.Was the “Note to the Teacher” useful 

to you?

n Yes n No n Somewhat

8.What grade(s) do you teach? ______

9.What subject(s) do you teach?

10. Other comments or suggestions:

Please send this evaluation, along with your students’ evaluations, to:

Dr. Barbara McDonald

USDA Forest Service 

320 Green St. 

Athens, GA 30602-2044

Thank you! Your evaluations will help us to continually improve the Natural Inquirer.
Which National Science Education Standards* Can Be Addressed by the Natural Inquirer?

Science Education

Standards*

Where in the WorldIs Carbon Dioxide?One Fish, Two Fish,Red Fish – No Fish?Do What You Water

Made in the Shade

Born To Be WildStress Test

*National Research Council, Content Standards, Grades 5-8

Articles

61

Science as Inquiry

Abilities necessary to do scientific inquiry X X X X X X

Understandings about scientific inquiry X X X X X X

Physical science

Properties and changes in properties in matter X

Motions and forces

Transfer of energy

Life science

Structure and function in living systems X X

Reproduction and heredity X

Regulation and behavior X

Populations and ecosystems X X X

Diversity and adaptations of organisms X X

Earth and space science

Structure of the Earth system X X

Science in personal and social perspectives

Personal health X X

Populations, resources, and environments X X X X X X

Natural hazards

Risks and benefits X X X X X

Science and technology in society X X X X X

History and nature of science

Science as a human endeavor X X X X X X

Nature of science X X X X X X

History of science
The U.S. Department of

Agriculture (USDA) Forest

Service is part of the Federal

Government. It is made up of

thousands of people who care

for the Nation’s forest land.

The USDA Forest Service

manages over 150 national

forests and almost 20 national grasslands. These are large

areas of trees, streams, and

grasslands. National forests

are similar in some ways to

national parks. Both national

forests and national parks

provide clean water, homes

for animals that live in the

wild, and places for people to

do fun things in the outdoors.

National forests also provide

resources for people to use,

such as trees for lumber, minerals, and plants used for

medicines. Some people in the

USDA Forest Service are scientists, whose work is presented in this journal. USDA

Forest Service scientists work

to solve problems and provide

new information about natural resources so that we can

make sure our natural environment is healthy, now and

into the future.

What Is the Forest Service?

United States Department of Agriculture

Forest Service

FS-798 • March 2004

Visit these Web sites for more information:

USDA Forest Service:

www.fs.fed.us

The Natural Inquirer:

www.naturalinquirer.usda.gov

Conservation Education:

www.fs.fed.us/outdoors/nrce/

USDA Kid’s Page:

www.usda.gov/news/usdakids/index.html

Agriculture in the Classroom:

www.agclassroom.org

NatureWatch:

www.fs.fed.us/outdoors/naturewatch/defaul

t.htm

Woodsy Owl:

www.fs.fed.us/spf/woodsy

National Forest Information:

www.fs.fed.us/links/forests/shtml

National Forest Recreation:

www.fs.fed.us/recreation/recreation.shtml