Dear Friend:
Trees shade and cool our homes, bring songbirds
close by, and mark the changing seasons. Children
can climb them or build a tree house in their
branches. For all of us trees are a source of lumber,
food, and countless products—and they beautify our
communities and the countryside.
But equally important, trees keep our water
clean, reduce soil erosion, clean the air we breathe,
and fi ght global warming.
If trees are to provide all these benefi ts, we need
to care for the trees we have and plant more. Planting
and caring for trees is something each of us can do to
improve our community and help the environment.
If we are to have trees in abundance, it is
important to be able to identify them so we will know
how to care for them and plant the right trees in the
right place.
And it’s just plain fun to be able to identify trees,
either those in your neighborhood or on a trip far
from home.
To help you learn to identify trees, the Arbor
Day Foundation has prepared this key for your use.
I hope you will use this guide regularly to help
you appreciate trees—one of nature’s great wonders.
Best regards,
John Rosenow
Chief Executive
Arbor Day Foundation
211 N. 12th Street
Lincoln, NE 68508
www.arborday.org
Copyright © 2009 by Arbor Day Foundation
All rights reserved. No part of this book may be reproduced
or transmitted in any form or by any means electronic or
mechanical, including photocopying, recording, or by any
information storage or retrieval system – except by a reviewer
who may quote brief passages in a review to be printed in a
magazine, newspaper or on the web – without permission
in writing from the publisher, for more information please
contact the Arbor Day Foundation.
Although the publisher has made every e ort to ensure the
accuracy and completeness of information in this book, we
assume no responsibility for errors, inaccuracies, omissions, or
any inconsistency herein.
First printing 2009
Printed in Canada
LIBRARY OF CONGRESS CATALOGING-IN-
PUBLICATION DATA
ISBN: 978-0-9634657-5-7
What Tree Is That?
Category 1: Nature Category 2: Garden
LCCN: #2008939816
Inside Flap: Common Words to Know
Page 3: Arbor Day Hardiness Zone
Page 4: Trees Identifi ed
in This Book
Page 5: Start Here
Page 6: Eastern Guide Start
Page 67: Eastern Invasive Species
Page 68: Western Guide Start
Page 141: Western Invasive Species
Page 142: Index
Page 149: Online Resources
Page 150: Field Notes
Table of
C
ontents
This book is intended to be used as a fi eld guide to assist you in iden-
tifying trees by their leaves. In some cases, fruiting bodies, seeds,
bark or other parts are helpful in making an identifi cation.
1. Examine several leaves or needles from the same tree. Choose
typical ones to identify. Avoid choosing oddities or rarities.
Also observe fruiting bodies, fl owers, seeds, and bark.
2. Beginning on page 6 with Box 6A, there is a series of questions
about the leaves and other tree parts. Each answer leads to
another question until the identity of the tree is discovered.
Each featured tree is listed alphabetically in the index, pages
142–148, for quick reference. The words printed in CAPITAL
LETTERS are defi ned in context when they fi rst appear and in
alphabetical order in the Glossary on the inside fl ap.
How to Use This Book
2
It is helpful to know where in the country a tree is most likely
to grow. Hardiness zones in the U.S. are noted with the leaf
art for each species. For example, zones 4-9 means that a
tree is “hardy” in zones 4,5,6,7,8, and 9, according to the
arborday.org Hardiness Zone map above, based on the most
recently compiled average annual minimum temperatures
recorded by U.S. weather stations. Suitable hardiness means
a tree can be expected to grow in the zone’s temperature
range. However, local variations such as moisture, soil, winds,
and other conditions might a ect a tree’s adaptability to a
particular locale.
It is helpful to know where in the country a tree is most likely
It is helpful to know where in the country a tree is most likely
Arbor Day Hardiness Zones
3
Go to arborday.org
to fi nd the zone for your zip code.
Zone Avg. Annual Low
2 ■ -40°F through -50°F
3 ■ -30°F through -40°F
4 ■ -20°F through -30°F
5 ■ -10°F through -20°F
6 ■ 0°F through -10°F
7 ■ 10°F through 0°F
8 ■ 20°F through 10°F
9 ■ 30°F through 20°F
10 ■ 40°F through 30°F
© 2006 by the
Arbor Day Foundation
®
4
This tree key was written for use in the colored area in the
United States and Canada. Only the more common trees
are identifi ed. Cultivars (special selections of a species),
uncommon species, and palm trees have not been included.
Trees Identifi ed
in This Book
5
1. In each box there are two or more questions. Each yes
answer is followed by a GO TO direction which indicates
a page number and box identifi er.
2. Read each question in the box. Follow the directions by
the question most correctly answered yes, moving to the
page and box number indicated.
3. By repeating this process and turning to the pages indi-
cated, the yes answer will direct you to the box that names
the tree. The color of the box will match the color
of the tree’s box identifi er. Compare the leaf drawing with
your leaf sample.
10
A
Are the needles mostly 3–6"
(7.6–15.2 cm) long?
OR
Are the needles mostly
3
⁄
4
–4"
(1.9–10.2 cm) long?
10
B
YES
GO TO
10
C
YES
GO TO
If you have some idea about the tree’s name, you may also look it up
in the index, which lists the page where each species is shown.
START HERE
Box
identifi er
Questions
to answer
If answer is YES, turn to this
page and box
How to use this key:
YES
GO TO
5
A
6
A
YES
GO TO
68
A
YES
GO TO
Do you live east of the Rocky Mountains or in
the blue shaded area of Canada or Alaska?
OR
Do you live west of the Rocky Mountains or in
the green shaded area of Canada or Alaska?
6
6
A
Does the tree bear cones and have
leaves that are needle-like? CLUE:
These trees are called CONIFERS (cone-
bearing) and most are EVERGREEN
(tree with needles or leaves that remain
alive and on the tree through the winter
and into the next growing season).
OR
Does the tree bear cones that are
sometimes berry-like and have
leaves that hug the twig and are
scale-like or awl-shaped? CLUE:
These trees are called CONIFERS (cone-
bearing) and most are EVERGREEN.
OR
Does the tree have leaves that are
fl at and thin? CLUE: These trees
are called BROADLEAF, (a tree with
leaves that are fl at and thin) and bear
a variety of fruit and fl owers. Most
are DECIDUOUS (shedding all leaves
annually).
7
D
YES
GO TO
16
B
YES
GO TO
7
A
YES
GO TO
EASTERN
START HERE
7
Are the leaves SIMPLE (one
BLADE attached to a stalk or
PETIOLE)?
OR
Are the leaves COMPOUND
(more than one BLADE attached
to a single stalk or PETIOLE)?
OR
Are the uniquely fan-shaped
leaves mostly attached, in
clusters, to short, SPUR-like
branches? It is a ginkgo.
7
A
Are the SIMPLE leaves
OPPOSITE (2 leaves that
are directly across from
each other on the same
twig)?
OR
Are the SIMPLE leaves
ALTERNATE (leaves that
are staggered, not opposite
each other on the twig)?
7
B
Are the COMPOUND leaves
OPPOSITE?
OR
Are the COMPOUND leaves
ALTERNATE?
Are the trees EVERGREEN
with needles arranged in clusters
of 2–5? These are pine trees.
OR
Are the trees DECIDUOUS,
with needles arranged in clusters
of many on short, SPUR-like
branches? These are larches.
OR
Are the trees EVERGREEN
with needles arranged singly?
OR
Are the trees DECIDUOUS
with singly attached needles of
uneven length fl attened along
the twig, the cone a 1" (2.5 cm)
diameter green or brown wrin-
kled ball? It is a baldcypress.
7
C
7
D
7
B
YES
GO TO
7
C
YES
GO TO
25
B
YES
GO TO
18
A
YES
GO TO
24
B
YES
GO TO
20
D
YES
GO TO
58
B
YES
GO TO
8
A
YES
GO TO
12
A
YES
GO TO
12
B
YES
GO TO
14
D
YES
GO TO
8
Are the needles clustered in groups of 5
and the cones long with thin scales? It is
an eastern white pine.
OR
Are the needles clustered in groups of 2
or 3, and the cone scales thick and often
tipped with spines?
Are the needles clustered in groups
of 3?
OR
Are the needles clustered in groups
of 2?
OR
Are the needles clustered in groups of 2
and 3 on the same tree?
Are the needles 3–5" (7.6–12.7 cm)
long, somewhat twisted, often sprouting
in tufts from the trunk; cones 2–3
1
⁄
2
"
(5.1–8.9 cm) long? It is a pitch pine.
OR
Are the needles 8–18" (20.3–45.7 cm)
long, cones 6–10" (15.2–25.4 cm) long?
It is a longleaf pine.
OR
Are the needles 6–9" (15.2–22.9 cm)
long, cones 3–6" (7.6–15.2 cm) long?
It is a loblolly pine.
8
C
8
B
9
A
YES
GO TO
8
B
YES
GO TO
8
C
YES
GO TO
10
A
YES
GO TO
10
D
YES
GO TO
9
B
YES
GO TO
9
C
YES
GO TO
9
D
YES
GO TO
8
A
loblolly pine.
9
9
A
The fabled tree
eagerly sought
by the fi rst wave
of loggers in
America. The
provincial tree of
Ontario.
9
B
The fi re resilient
conifer of the East,
even producing
new branches and
needles after fi re
kills the green
foliage
Pitch Pine
Pinus rigida
Zones 4–7
9
C
A tall, stately pine
of the South long
sought by loggers
Longleaf Pine
Pinus palustris
Zones 7–10
9
D
Our most important
and widely cultivated
timber species in the
southern United States
Loblolly Pine
Pinus taeda
Zones 6–9
Eastern White Pine
Pinus strobus
Zones 3–8
