TO BE SUCCESSFUL IN IDENTIFYING TREES, THERE ARE SOME BASIC FACTS AND
CHARACTERISTICS THAT YOU SHOULD BECOME FAMILIAR WITH
THESE CHARACTERISTICS INCLUDE:
•common leaf shapes
• parts and positions of parts of leaves
• leaf margins
IN ADDITION TO LEARNING THESE ABOVE LISTED TOPICS, THE UNDERSTANDING
OF SOME FREQUENTLY USED TERMS IS NECESSARY IN THE PROCESS OF TREE IDENTIFICATION
Alternate - One leaf attached at each node. See opposite and whorled.
Capsule - A dry fruit which contains more than one seed and splits open when ripe.
Deciduous - Refers to trees which drop their leaves in autumn.
Leaflet - A leaf-like portions of the blade of a compound leaf.
Leaf Scar - The impression in a twig at the point where a leaf was attached.
Petiole - The stalk attaching a leaf blade to the stem.
Lobe - A division or projecting part of the blade of a leaf.
Opposite - Two leaves attached at each node. See alternate and whorled.
Whorled - Three of more leaves or other parts attached to a stem at the same point.
THIS SLIDE ILLUSTRATES IMPORTANT
ASPECTS OF LEAVES THAT ARE ALWAYS
USED WHEN IDENTIFYING A TREE
MIDRIB
LEAFLET
PETIOLE
BLADE
ALTERNATE
OPPOSITE
PETIOLE
CONTINUE
•CLICK ON ANY PHOTO TO VIEW
IDENTIFICATON DETAILS ABOUT EACH OF
THESE COMMON PA TREE SPECIES
SASSAFRAS, UNLIKE OTHER SPECIES OF TREES, HAS THREE VARIATIONS OF LEAVES
EACH TYPE HAS DIFFERING LOBES
THIS PARICULAR SPECIES CAN ASLO BE IDENTIFIED BY ITS “MINTY” SCENT THAT IS
EVIDENT WHEN ITS STEM IS SPLIT
ITS LEAF STRUCTURE IS SIMPLE
SASSAFRAS IS ALSO RELATIVELY UNIQUE IN THE FACT
THAT IT CAN RELEASE A CHEMICAL THAT CAN
PREVENT OTHER PLANTS FROM GROWING WELL,
HELPING TO ELIMINATE SOME OF ITS COMPETITION
SASSAFRAS TWIGS ARE DISTINCTLY GREEN AND ITS
FRUIT, REFERRED TO AS DRUPES, CAN VARY FROM
DARK BLUE TO DEEP PURPLE
IN ADDITION TO THESE MULTIPLE DEFINING
CHARACTERISTICS, THE FLOWER IS YELLOW-GREEN
Sugar maples are large, deciduous trees
Typically 30‘ - 90' tall.
Leaves are simple, and opposite, with triangular
lobes and doubly toothed edges
Leaves are usually 2½“ - 4" long and nearly as wide
Bark is very smooth and grey, darkening and becoming
furrowed in narrow ridges with age
Flowers tend to be small, fragrant clusters of red and orange flowers that hang from the
reddish twigs of the Sugar Maple
This particular species grows in low, rich woods, along the margins of lakes, marshes, and
swamps, in wet thickets, and on floodplains and stream terraces
The fruit of the Sugar Maple is a paired, red, pink, or yellow, winged samara, about ¾" long
• Magnolia acuminata is one of about
210 species of Magnolia
•The fruit is green and cylindrical like a small
cucumber that then turns bright pink in
autumn before ripening to a dark red and
opening to release its seeds.
•The leaves of this species are pointed at the ends as its name dictates.
Acuminate means tapering to a fine point as the leaf of this species does
The bark of the Red Maple is similar to that of other maples
as it is smooth and grey when young and then gradually
matures and receives darker, shaggy, peeling flakes
Fruit is regularly less than 1” long and spreads at a narrow angle
Maturity is reached by this reddish brown fruit in May or June
Twigs are quite glossy and slender and are at first green but eventually fade to red
Leaves, as represented by the photo above, are opposite and simple with 3 -5 shallow
lobes that are coarsely toothed
They are pale or light green the majority of the time with a whitish underside and
turn to a brilliant red / orange in the fall
The leaves of the Catalpa are opposite or whorled, simple, heart-shaped, 6"-10" long and
have a 6" wide; margin
They are always entire or wavy; smooth above, and hairy beneath
The twigs of this tree have numerous defining characteristics. Not only are they stout, but
they are also yellow-brown with no buds at the ends
The side buds are small and appear to be hidden in bark.
Large, nearly round, depressed leaf scars are also common on this leaf
The fruit can easily be described as bean-like, up to 15" long, ½"
wide, their halves separating when ripe, and may persist on
tips of branches all winter
Flowers appear in July, and are arranged in terminal clusters
about 10" long; each showy flower white with yellow and
purple spots, 2" in diameter
The Box Elder thrives in low, moist areas, floodplains, and stream banks
This medium – sized tree is most abundant in eastern and southern Pennsylvania
Leaves are noted as opposite and compound, with 3-5 coarsely and irregularly toothed
leaflets, each 2"-4" long and 2"-3" wide
Twigs are almost always stout, purplish-green or green, and sometimes smooth but often
have a whitish coating and scattered raised lenticels or an airy aggregation
of cells on the roots or stem
The fruit has wings about 1 and 1/2” - 2” long that
are parallel or in curved and mature in September
and as many fruits do, exist in drooping clusters
And although the fruits mature in September, fruit
stalks persist far into winter
Young Box Elders have smooth, greyish – brown trunks
and branches then become distinctly narrow ridged
These leaves are opposite, simple, 3-lobed, and rounded at the base
They also boast finely toothed margins and rusty pubescence on the lower surface.
As are the leaves of the Red Maple, the twigs of the Striped Maple are originally a shade of
green and then later become red
Each season of growth is then marked by 2 or 3 lines encircling the twig
The winged fruit of the Striped Maple has extremely divergent wings that are about
¾” long and mature in September in drooping clusters
Seeds are also marked on one side with a depression
Bark is smooth and greenish or reddish brown
It is conspicuously marked with vertical white streaks;
older trunks rougher, darker and less streaked.
The twigs of this tree are stout, as are many othe species, but are reddish brown with buds
that are glossy red with green at the base.
Leaves are opposite, simple, and coarsely 5-lobed
They are approximately 4"-7" wide and milky sap exudes from the broken leaf-stalk
The fruito f the Norway Maple have wide wings spreading to nearly horizontal that
mature in autum
The bark is commonly smooth and light broen on young trees
but darkens and evelops fissures with age
The Norway maple can be distinguished from other maples by the
larger leaves as well as the previously mentioned milky sap from
the petiole and the horizontal fruits
Leaves are opposite, simple, deeply 5-lobed, and coarsely
toothed. They are on average 5” long
The leaves are almost always green above, silvery-white beneath
and their fall color is a greenish-yellow.
Twigs tend to be slender and glossy green in spring and later turn
chestnut brown.
The Silver Maple’s lower branches have a distinctive upward curve at the end.
And its fruit ids the largest of the native maples with wings 2" long, widely spreading, maturing
in spring.
The bark is similar to that of other trees being as it is smooth and grey when young and in
comparison, the older trunks are broen and furrowed with plates that curl out on the ends.
These are commonly found in moist woods and on stream banks throughout Pennsylvania,
usually reaching 50'-60' high.
TREE RINGS ARE AN EASY WAY TO SEE A TREE’S LIFE SOTRY
IT SHOWS WHEN AND FOR HOW LONG A TREE MAY HAV BEEN DEPRIVED OF SUNLIGHT,
WATER, OR SUFFICIENT NUTRIENTS
THESE TREES HAVE NUMEROUS ROWS OF TINY RINGS TO SHOW THE LACK OF GROWTH
OVER THE YEARS
STUDYING TREE RINGS CAN ALSO TELL YOU IF A TREE HAS EXPERIENCED A FIRE OR EVEN A
BLIGHT WHICH CAN BE SHOWN BY THE EXISTENCE OF SCARS AND THE PREVIOUSLY
MENTIONED NARROW RINGS
THE SAPWOOD IS THE AREA OF THE TREE THAT CONTAINS THE GROWTH RINGS
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THE OTHER LAYERS ARE AS FOLLOWS:
COMBIUM CELL LAYER
HEARTWOOD
THE OUTER BARK
THE INNER BARK