Dendrology 101 & Tree Identification

Techniques

Presented by

Craig Hensley,

Park Interpreter

Guadalupe River State Park

Saturday, October 21

Texas Master Naturalist 18th Annual Meeting

Step 1: Purchase a Field Guide Field Guide to Texas Trees by Benny J. Simpson

Texas Trees Field Guide by Stan Tekiela

Texas, Shrubs, and Vines of the Texas Hill Country by Jan Wrede

Texas Trees: A Friendly Guide by Paul W. Cox & Patty Leslie

Native and Naturalized Woody Plants of Austin & the Hill Country by Brother Daniel Lynch, C.S.C.

Step 2: Become Familiar with itReview the Book – particularly the coverage range and the

descriptions/terminology

Keep in mind that Texas has more than 5,000 vascular plants within its borders

If you are going to get serious, a good jeweler’s loupe will come in handy – 10x is recommended

Dendrology: The Scientific Study of Trees and other Woody Plants

Woody plants include trees, shrubs, bushes, sub-shrubs and vines

The definition of a tree, according to Utah State University is a “woody plant having one erect perennial stem (trunk) at least three inches in diameter at a point 4.5 feet above the ground, a definitely formed crown of foliage, and a mature height of at least 13 feet.

The Tree as a System*

ENVIRONMENT

Carbon DioxideLight

WaterNutrients

TREE

FUNCTION STRUCTURE

Photosynthesis Leaves

Support

Tran

spo

rt

Uptake

Branches

Stems

ShootSystem

Woody Roots

Fine Roots

RootSystem

*From “The Growing Tree by Brayton F. Wilson

Stability

Tree Growth

Trees are dynamic systems

Trees grow through using materials they produce leading to changes in thickness and length of each branch

For trees to grow they must produce more photosynthate than they need to maintain themselves

The difference in fast- vs. slow-growing trees or those of different species result not from different processes, but different rates of those processes

Keys to Identification of Woody Plants:

1. Deciduous vs. Evergreen

2. Bark

3. Silhouette

4. Twig Morphology

5. Flowers

6. Fruit

7. Leaf Characteristicsa. Shapeb. Marginc. Venationd. Pubescence/lack ofe. Lobing/lack off. Simple/Compound

Deciduous vs. Evergreen

Bark Characteristics

Basswood Elm Maple

HickoryWalnut

Burr/Post Oak

Live Oak

Tree Buds

Leaves, flowers, and/or stems emerge from the apical meristem deep inside a bud

Tree buds are useful tools for tree identification, particularly during winter months for deciduous trees

The orientation of the buds help determine the growth direction and thus shape of a tree

By counting the bud scale scars on a branch, you can determine the age of that branch

Twig Morphology

Leaf Basics

LeafMargins

Let’s Practice

Dichotomous (Taxonomic) Keys

Used to sort out species of similar living things

Design consists typically of couplets of choices, for example:

1: Plant with deciduous leaves; 1’: Plant with evergreen (needle-like) leaves

Choosing one or the other leads to a new couplet for each

Following this path leads you to the identification of the specific organism or thing

1 Plant evergreen or feathery and thin, fruit a cone…………………………………………2

1’ Plant deciduous…………...……………………………………………………………….3

2 Leaves tiny, sharp, scale-like; fruit a bluish cone (berry-like)………….……Ashe Juniper

2’ Leaves feathery, alternate to ¾ inches long; cone green turning brown……..Bald Cypress

3 Leaves opposite one another on branch or stem...………………………………………...4

3’ Leaves arranged alternately along branch or stem……………………………………….14

4 Leaves compound…………………………………………………………………………5

4’ Leaves simple……………………………………………………………………………..9

5 Leaves palmately compound; 5 leaflets all attached at central location….Yellow Buckeye

5’ Leaves pinnately compound; not as above………………………………………………..6

6 Leaflets 3, entire, strong odor when crushed………………………Wafer Ash (Hop Tree)

6’ Leaflets 3 or more, if three leaflets, not entire…………………………….………………7

7 Leaflets 3 to 5, coarsely toothed above middle, stems green…………………....Box Elder

7’ Leaflets 5 or more…………………...…………………………………………………….8

8 Leaflets 9-10 pairs, leaflets toothed………………………………………….…Elderberry

8’ Leaflets 5, margins entire………………………………………………….……Green Ash

9 Leaves in whorls of three, margins entire………………………….………..…Buttonbush

9’ Leaf opposite in pairs………………………………………………………………….…10

10 Leaves oval, finely toothed, rusty hairs on lower central vein……………Rusty Blackhaw

10’ Leaves not as above……………………………………………………………………...11

11 Leaves with coarse teeth, upper surface rough……………………………..Texas Lantana

11’ Leaves entire……………………………………………………………………………..12

12 Leaves small, diamond-shaped, entire, stems at 90-degree angle from stem…..Elbowbush

12’ Stems and leaves not as above………………………………………………………...…13

13 Leaves small, entire, oval, sometimes clustered…….……………Whitebrush (Bee Brush)

13’ Leaves larger, rough on upper surface, veins parallel or nearly so…Rough Leaf Dogwood

14 Leaves compound….…………………………………………………………………….15

14’ Leaves simple……………………………………………………………………………27

15 Leaves twice compound………………………………………………………………….16

15’ Leaves only once-compound……...……………………………………………………..18

Virginia Creeper

Basswood or Linden

Rough-leaf Dogwood

Mexican Buckeye

Slippery or American Elm

Box Elder

Poison Ivy

Sycamore

Cedar Elm

Sugarberry Hackberry

Blackjack Oak

Spanish or Texas Red Oak

Shin Oak

Walnut

Redbud

Escarpment/Black Cherry

HoneyMesquite

Ashe Juniper

Thank you