1. 1103 Jennifer Woods PowerPoint 1 - Leaves
Tree Identification
1103
Jennifer Woods
PowerPoint 1 - Leaves

2. Tree Identification Characteristics
In order to correctly identify trees in nature it is important to know certain characteristics used in tree identification.
Looking at characteristics other than leaves of a tree will help to identify it. This helps when there are no leaves on a tree or they are too high to see properly.
These are just some of the techniques used in tree identification.

3. Tree Identification Characteristics
Some of these characteristics that should be looked at when identifying a tree are:
Leaf shape
Twigs and buds
Bud scars
Fruit
Flowers
Bark
Tree form/Branching pattern
Where the tree is growing and what other plants and trees it may be growing around.

4. Leaves
Leaves are the best and often the easiest way to identify a tree.
Needles and scale of evergreens are also considered leaves.
Questions to consider when identifying leaves:
Are the leaves:
simple or compound? 
margins smooth or margins rough? 
any sinuses or lobes?
What is the size, shape, texture, and color variation of the leaves?

5. Leaves – Simple or Compound
Simple leaves only have one leaf blade.
Compound leaves are made up of several separate leaflets attached to a common leaf stem.

6. Leaves - Margins
Margins are the edges of the leaves, which have different patterns.
Examples of margins are:
Smooth
Serrate or Doubly serrate
Dentate
Crenate
Undulate
Sinuate
Lobed

7. Leaves – Sinuses or Lobes
A sinus is the indentation between two lobes.
A lobe is a division of a leaf blade that is broadly attached.

8. Leaves - Shapes Leaves can come in many shapes.
Some examples of leaf shapes are triangular, oval, or elliptical.

9. Leaf Arrangements
Leaf arrangement refers to the leaf arrangement on the stem of the tree.
Leaves are arranged in three different ways:
Opposite – Buds form in pairs on either side of the twig.
Alternate – Buds are arranged singly at intervals along the twigs.
Whorled – Buds are arranged in circles around the twig.

10. Leaf Arrangements
Most trees have alternate branching.

11. Tree Identification 1103 Jennifer Woods
PowerPoint 2 – Twigs, Buds, Fruit, Bark, Tree Forms

12. Twigs and Buds A twig is the current year’s growth on a tree.
A bud is where the leaves will eventually grow from and is located on a twig. Buds can be pointy, blunt, shiny, dull, smooth, hairy, and come in many colors.
A bud scar is where last year’s leaves fell off. Bud scars are unique for every species.

13. Twigs and Buds Terminal buds are on the end of a twig.
The marks inside a leaf scar are called bundle scars.

14. Fruit and Flowers
Fruit is the matured ovary of a flowering plant – the seed bearing product of the plant. In conifers the fruit is called a cone.
Select fruit types:
Drupe
Berry
Acorn
Samara
Pome
Legume
It is easier to identify a tree by its fruit because it is on the tree longer than flowers.

15. Fruit and Flowers
Many trees do not have perfect flowers, most have imperfect flowers.
Flower and fruit clusters are termed inflorescences.
Types of inflorescences:
Spike
Raceme
Panicle
Corymb
Umbel
Cyme

16. Bark
Bark is a helpful for identification in the fall and winter when leaves are not available.
Bark is the outer layer of the tree that covers the inner layers of the tree that move nutrients upward to the foliage.
Main bark characteristics are thickness, degree of roughness (smooth, scaly, furrowed), color of outer and inner bark, depth and breadth of fissures, width of fissures, and length of plates.

17. Tree Forms
A tree form is basically the silhouette that a tree makes. It is the general overall shape of a tree.
Trees of the same species will not all have the same silhouette.
Tree forms differ by the tree specie, age of tree, whether it is in an open or forested area.
When using tree forms for identification do not use trees in a forested area because they may not have had optimal growth due to light and water requirements.

18. Tree Forms Some examples of tree forms are: Conical (Balsam Fir)
Pyramidal (White Spruce)
Slender (Black Spruce)
Vase-shaped (American Elm)
Oblong (Shagbark Hickory)
Drooping (Weeping Willow)

19. Tree Identification 1103 Jennifer Woods
PowerPoint 3 – Taxonomic Keys, Evergreen Identification, Scientific Names, and Michigan Trees

20. Taxonomic Key Use
When identifying trees it is also helpful to be able to use tree identification guides and taxonomic keys.
The key works by distinguishing differences among a group of trees by various physical characteristics until only one specie is left.
A taxonomic key is used to identify trees and shrubs by using leaf shape, twigs and buds, seeds, fruit, and cones to narrow a sample down to a specific specie of tree.
Taxonomic keys usually start with a leaf sample.

21. Angiosperms vs. Gymnosperms
Angiosperm – A flowering plant.
Gymnosperm – young seeds naked at the time of pollination, the mature seeds never borne in an ovary or fruit.
Angiosperms are also considered flowering plants. These trees lose their leaves in the winter with the exception of evergreen angiosperms.
The major group of gymnosperms in Michigan are conifers and the major group of angiosperms are the broad leafed trees.

22. Evergreen Identification
Evergreens or conifers are identified differently than deciduous trees.
In evergreens needles or scales do not fall off in the winter except in a few species like the tamarack.
Conifers have either needles like a white pine or scales like a cedar.
Cone shape, size, and color can also be used in evergreen identification.

23. Evergreen Identification
Needles occur in three ways on evergreens:
Needles grow in clusters of two or more (ex. true pines).
Needles grow in clusters of 10 or more in short lateral shoots (ex. Tamarack).
Needles grow solitary along the branch (ex. spruce).

24. Evergreen Identification
When identifying evergreens count the number of needles that occur in a group and then length of the needles.
Needles that occur singularly may either be flat or round and have different numbers of white lines on the bottom of the needles.
Needles that are flat may be all scale like as in cedar trees or junipers.

25. Scientific and Common Names
Scientific names are used for standardization so everyone will know what tree is being discussed since common names change from one area to another.
Scientific names are either italicized when typed or underlined when hand written.
The genus of a scientific name is always capitalized and the species is always lowercase.

26. Michigan Trees
The following are some examples of common Michigan trees. Included are the common and scientific names of these trees.

27. Michigan Trees Examples
Largetooth Aspen – Populus grandidentata
Basswood – Tilia americana
Beech – Fagus grandifolia
White Birch – Betula papyrifera
White Cedar – Thuja occidentalis
Black Cherry – Prunus serotina
Box Elder – Acer negundo
American Chestnut – Castanea dentata
Flowering Dogwood o Cornus florida
American Elm – Ulmus americana
Balsam Fir – Abies balsamea
Hemlock – Tsuga canadensis

28. Michigan Trees Examples
Shagbark Hickory – Carya ovata
Ironwood – Ostrya virginia
Black Locust – Robinia pseudoacacia
Black Maple - Acer nigrum
Norway Maple – Acer platanoides
Red Maple – Acer rubrum
Silver Maple – Acer saccharinum
Sugar Maple – Acer saccharum
Mountain Ash – Sorbus spp.
Red Oak – Quercus rubra
White Oak – Quercus alba
Jack Pine – Pinus banksiana

29. Michigan Trees Examples
Red or Norway Pine – Pinus resinosa
Scotch Pine – Pinus sylbestris
White Pine – Pinus strobus
Austrian Pine – Pinus nigra
Sassafras – Sassafras albidum
Black Spruce - Picea mariana
Norway Spruce – Picea abies
White Spruce – Picea glauca
Sycamore – Platanus occidentalis
Tamarack – Larix Laricina
Black Walnut – Juglans nigra
Black Willow – Salix nigra
Witch-Hazel – Hamamelis virginiana

30. References
Barns, Burton V., Wagner, Warren H. Jr., Michigan Trees The University of Michigan Press, Ann Arbor
Burnie, David., Tree Alfred A. Knopf, New York
Petrides, George A., A Field Guide to Trees and Shrubs Houghton Mifflin Boston, 1972.
Smith, Norman F., Trees of Michigan and the Upper Great Lakes Thunder Bay Press, Lansing
Pictures taken from: