Download Tree Basics

Tree Identification
1103
Jennifer Woods
PowerPoint 1 - Leaves
Tree Identification Characteristics
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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.
Tree Identification
Characteristics
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Some of these characteristics that should be
looked at when identifying a tree are:
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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.
Leaves
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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:
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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?
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Leaves – Simple or Compound
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Simple leaves only have one leaf blade.
Compound leaves are made up of several
separate leaflets attached to a common leaf
stem.
Leaves - Margins
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Margins are the edges of the leaves, which have
different patterns.
Examples of margins are:
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Smooth
Serrate or Doubly serrate
Dentate
Crenate
Undulate
Sinuate
Lobed
Leaves – Sinuses or Lobes
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A sinus is the indentation between two
lobes.
A lobe is a division of a leaf blade that is
broadly attached.
Leaves - Shapes
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Leaves can come in many shapes.
Some examples of leaf shapes are
triangular, oval, or elliptical.
Leaf Arrangements
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Leaf arrangement refers to the leaf arrangement
on the stem of the tree.
Leaves are arranged in three different ways:
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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.
Leaf Arrangements
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Most trees have alternate branching.
Tree Identification
1103
Jennifer Woods
PowerPoint 2 – Twigs, Buds, Fruit, Bark,
Tree Forms
Twigs and Buds
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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.
Twigs and Buds
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Terminal buds are on the end of a twig.
The marks inside a leaf scar are called
bundle scars.
Fruit and Flowers
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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.
Fruit and Flowers
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Many trees do not have perfect flowers, most
have imperfect flowers.
Flower and fruit clusters are termed
inflorescences.
Types of inflorescences:
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Spike
Raceme
Panicle
Corymb
Umbel
Cyme
Bark
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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.
Tree Forms
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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.
Tree Forms
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Some examples of tree forms are:
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Conical (Balsam Fir)
Pyramidal (White Spruce)
Slender (Black Spruce)
Vase-shaped (American Elm)
Oblong (Shagbark Hickory)
Drooping (Weeping Willow)
Tree Identification
1103
Jennifer Woods
PowerPoint 3 – Taxonomic Keys,
Evergreen Identification, Scientific Names,
and Michigan Trees
Taxonomic Key Use
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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.
Angiosperms vs. Gymnosperms
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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.
Evergreen Identification
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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.
Evergreen Identification
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Needles occur in three ways on evergreens:
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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).
Evergreen Identification
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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.
Scientific and Common Names
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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.
Michigan Trees
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The following are some examples of
common Michigan trees. Included are the
common and scientific names of these
trees.
Michigan Trees Examples
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Largetooth Aspen –
Populus grandidentata
Basswood – Tilia
americana
Beech – Fagus
grandifolia
White Birch – Betula
papyrifera
White Cedar – Thuja
occidentalis
Black Cherry – Prunus
serotina
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Box Elder – Acer
negundo
American Chestnut –
Castanea dentata
Flowering Dogwood o
Cornus florida
American Elm – Ulmus
americana
Balsam Fir – Abies
balsamea
Hemlock – Tsuga
canadensis
Michigan Trees Examples
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Shagbark Hickory –
Carya ovata
Ironwood – Ostrya
virginia
Black Locust – Robinia
pseudoacacia
Black Maple - Acer
nigrum
Norway Maple – Acer
platanoides
Red Maple – Acer
rubrum
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Silver Maple – Acer
saccharinum
Sugar Maple – Acer
saccharum
Mountain Ash – Sorbus
spp.
Red Oak – Quercus
rubra
White Oak – Quercus
alba
Jack Pine – Pinus
banksiana
Michigan Trees Examples
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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
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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
References
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Barns, Burton V., Wagner, Warren H. Jr., Michigan Trees The
University of Michigan Press, Ann Arbor. 1985.
Burnie, David., Tree Alfred A. Knopf, New York. 1988.
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. 1995.
Pictures taken from:
 http://www.usoe.k12.ut.us/curr/science/sciber00/7th/classi
fy/sciber/taxokey.htm
 http://www.dsisd.k12.mi.us/mff/TreeBasics/TreeIDkeys.ht
m