1. Fundamentals of Dendrology
Prepared By:
David Mercker
Extension Associate
University of Tennessee
Department of Forestry, Wildlife, Fisheries

2. Dendrology = That field of botany dealing with the identification/classification of trees and shrubs
What tree is this?
(den•drol´• •jē) e

3. process of elimination. Using a dicotomous key,
Proper tree
identification is a
process of elimination.
Using a dicotomous key,
a series of if – then questions
are asked, which carries the
reader to the next series of
questions. In a broad
sense, trees
can first
be broken
into group
A or group B.

4. Group A Coniferous, Evergreens, Softwoods
Green leaves present during winter
Have either needles or scales
Trees that bare cones: Pines, Spruces, Firs, Henlock

5. Group B Deciduous, Broad -leaves, Hardwoods
Green leaves absent in winter
Provide most of fall color
Exception – Bold Cypress is an example of a “deciduous Conifer”

6. Needles Single Bundles Single = firs, spruce Bundles = pines
Needles are bound together in a “fasicle” and identification is determined by the # of needles per fasicle.

7. Arrangement
Group B
Node = the point at which the leaf petiole attaches to the stem. Petiole = Leaf Stalk.

8. Types
Simple
Singular leaf with one petiole attaching to twig.
Compound
Several smaller “leaflets” each attached to a petiole which is then attached to a twig

9. Types
= Simple
One leaf, attached to one petiole, attached to the stem

10. Types Compound = How many leaves are in this picture?
The peticle is very long; leaflets are without stalks and their base is directly attached to peticle. All portions break off together and fall to the earth in Autumn.
How many leaves are in this picture?

11. Shapes Lobed Entire Southern Magnolia
The Southern Magnolia is an example of a “simple and entire leaf.”
Southern Magnolia

12. Leaf Margins Cottonwood Serrated Yellow Poplar Smooth
Serrations can be tiny or large, pointed or hooked and sometimes doubly-serrated (serrations on serrations).
Is the yellow poplar lobed or entire?
Cottonwood
Serrated
Yellow Poplar
Smooth

13. Sinus - Scarlet oak has deep sinuses
Northern red oak has shallow sinuses
Sinus = an indentation that protrudes inward on a leaf toward the midrib (vein)
Sinus depth is particularly important for identifying oak species

14. (opposite sides proportional)
Leaf Base Symmetry
Symmetrical
(opposite sides proportional)
Asymmetrical
(not proportional)

15. Bristle – Tipped Lobes Lobes with Bristles Lobes Smooth
A characteristic of the red oak group is that they have bristle-tips; the white oak group does not.

16. Leaf Base Shape
Flattened
Obtuse
Wedge-shaped

17. Pith Comparison Walnut Hickories
Sometimes leaf differences are subtle so an analysis of the “3 B’s” is necessary . . .Branches, Buds & Bark.
Hickories

18. Conifers – Group A Leaves scale–like = cedars Leaves needle–like
Single needles
Clusters of 2
Clusters of 2 & 3
Clusters of 3
Clusters of 5
= cedars
= spruce, fir, hemlock
= Virginia pine, scotch pine
= shortleaf pine
= loblolly pine
= white pine
Scotch pine is mostly grown in Christmas tree plantations

19. Example #1 – Group B Leaves needle or non needle-like?
Opposite or alternate arrangement?
Simple or compound?
Lobed or entire?
Serrated or smooth?

20. Example #2 – Group B Leaves needle or non needle-like?
Opposite or alternate arrangement?
Simple or compound?
Lobed or entire?
Serrated or smooth?
With or without bristle-tips?

21. References
Harrar and Harrar. Guide to Southern Trees. Dover publications
Mohlenbrock, Robert H. Forest Trees of Illinois. Southern Illinois University
U.S. Forest Service. Important Forest Trees of the Eastern United States