Dendrology, Tree Identification Techniques, & Important ... · Different tree families and species take on distinct forms and exhibit typical silhouettes in a natural setting. Like

© Christopher Ebling 2008-2019 All rights reserved.

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Dendrology, Tree Identification

Techniques, & Important

Blackland Prairie Trees

Chris EblingTexas Master Naturalist

© Christopher Ebling 2008-2019. All rights reserved.

Any redistribution or reproduction of part or all of the contents in any form is prohibited. You may,

with express written permission of the author, reproduce, extract portions of, and/or reuse the

content for educational purposes only, provided that you credit the author as the source of the

material.

© Christopher Ebling, 2008-2011. All rights reserved.

Tools to Aide in Identification

◼ Identification books and field guides

◼ Web sites

◼ Mobile applications

◼ Botanical descriptions are often highly

technical

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The Purpose of This Talk is to Explain These Terms

TWIGS and BUDS: pubescent light brown twigs with corky wings or ridges; ovoid light

brown to gray buds, smooth 1⁄4 inch (6 mm) long. LEAVES: alternate; simple; petiole 5⁄8

- 1 inch (16 - 25 mm) in length; leaf blade is obovate to narrowly elliptical in outline, 2 3⁄4

- 6 inches (70 - 152 mm) long, 2 - 5 inches (51 - 127 mm) wide, 5 - 7 lobed with center

sinuses nearly reaching midrib, base rounded to cuneate, rounded apex; dark green

above, grayish-green with finely dense pubescence below.


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Tools of the Trade


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What is a Tree?

◼ A “woody plant” is a plant with persistent woody parts that do not die back in adverse conditions❑ Wood = Cellulose structures on

a Lignin framework.

❑ Most woody plants are trees or shrubs.

◼ A tree is a woody plant with a single erect perennial trunk at least 3 inches in diameterat breast height (DBH).

◼ Most trees have definitely formed crowns of foliage and attains heights in excess of 13 feet.

All trees are woody plants, but not all woody plants are trees.

Source: US Forest Service


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All trees are woody plants, but are all woody plants trees?


Tree or Not a Tree?

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Tree or Not a Tree?

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Tree or Not a Tree?

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Trunk Cross Section

◼ Bark ❑ The outer protective covering of tree

trunks.

❑ Most of the total thickness of bark consists of outer bark, which is made up of dead cells.

❑ Outer bark may be very thick, as in the cork oak, or quite thin, as in young birches and maples.

❑ Openings in the outer bar (lenticels) allow the movement of carbon dioxide and oxygen to and from the inner tissues.

◼ Phloem (sapwood) ❑ A thin layer of living cells that act

together to transport food in the form of sugars, which are made in the tree’s leaves, through the trunk and stems to other parts of the tree.

❑ As old layers of outer bark are sloughed off, new ones are constantly being added from the inside, where new phloem is always being created..

Source: Microsoft Encarta


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Trunk Cross Section◼ Cambium

❑ Separates the living xylem cells from the phloem.

❑ As the tree grows and develops, the cambium forms new phloem and xylem cells.

❑ The layers of xylem cells form rings; these rings can be counted to determine the age of the tree in areas with distinct growing seasons

◼ Xylem (Sapwood - heartwood)❑ Consists almost entirely of dead cells.

❑ The living xylem cells, however, act as the tree’s plumbing system by transporting water and dissolved food through the trunk and stems.

◼ Pith ❑ Serves as a storage tissue for sugars

and as a reservoir for wastes in young trees.

❑ In older trees the pith is crushed by the xylem’s woody tissue, and wastes are simply deposited in the wood cells near the center of the trunk.

Source: Microsoft Encarta


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Tree Classes

◼ Angiosperms

❑ A plant whose seeds are enclosed in an ovary.

❑ “Deciduous”, “hardwood”

◼ Gymnosperms❑ Literally means “naked seed”

❑ A plant whose seeds are not enclosed in an ovary.

❑ “Conifer”, “evergreen”, “softwood”

❑ Other minor tree families◼ Ginko, Cycad, etc.

◼ Beware!❑ Not all Angiosperms are deciduous

◼ Live Oak

❑ Not all Gymnosperms are evergreen◼ Bald Cyprus, Larch

Bur Oak

White Pine


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How do we identify trees?

◼ Location

◼ Form

◼ Leaves

◼ Twigs

◼ Fruit

◼ Wood

◼ Bark

◼ Flowers

Tree identification is a “holistic” activity, often involving multiple

identifying characteristics which will vary by time of year.


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Location◼ Trees are highly adapted to their

environment❑ Temperature range

❑ Total rainfall and annual distribution

❑ Soil type and chemistry

◼ Understanding the local environment can help you narrow the range of choices

◼ For example, in a natural environment:❑ Will you ever see a long-leaf pine on

the Blackland Prairie?

❑ Will you ever see a Bur Oak in the Trans-Pecos?

◼ Beware! Altitude can mimic colder, wetter climate conditions!❑ Guadalupe National Park

◼ Relic forest of Douglas Fir, Ponderosa Pine, SW White Pine, & Aspen forest surrounded by desert

◼ Maintains climatic conditions from 15,000 years ago.


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Form◼ Different tree families and

species take on distinct forms and exhibit typical silhouettes in a natural setting.

◼ Like location, the form of a tree can be used to narrow the list of possible choices.

◼ Beware!❑ Forms can vary widely in

response to local conditions!◼ Location i.e. edge of range,

altitude

◼ Tree density

◼ Microclimate

American Elm

Longleaf Pine


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Leaf Characteristics◼ Leaf characteristics are a very good indicator of tree type.

◼ Leaves are described by their:❑ Arrangement on twig

❑ Overall shape

❑ Complexity◼ Simple, pinnate, bi-pinnate

❑ Margins

❑ Apices

❑ Bases

❑ Venation pattern

❑ Surface features

❑ Petioles◼ Shape

◼ Presence of stipules

◼ Problem – leaves only available during the growing season on deciduous trees

◼ Beware!❑ Leaf shapes can vary widely from tree to tree and even on a single tree (i.e. top to

bottom)

❑ Why?


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Leaf Arrangement

◼ A preliminary indicator on dormant twigs.

◼ Alternate❑ Leaves not paired on twig

❑ Eg. Elm

◼ Opposite❑ Leaves paired on twig

❑ Eg. Ash

◼ Whorled❑ Leaves arranged in a whorl on

twig

❑ Eg. Catalpa

◼ Are leaves arranged in ranks along a branch?❑ What is the most ubiquitous

form in the universe?


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An Interesting Digression…

◼ All plants, including trees,

spiral as they grow

❑ Why?

◼ The number of leaves in a

given spiral sequence is a

Fibonacci number.

❑ 0,1,1,2,3,5,8,13,21…

◼ The ratio of leaves in the

spiral to the number of turns

in the spiral is a sequence

of Fibonacci numbers!© Jill Britton, 2005


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Deciduous Leaf Characteristics

Source: Wikipedia


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Coniferous Leaf Characteristics

◼ Short, blunt, curved

and needle-shaped leaf

❑ Juniperus

❑ Picea

❑ Abies

◼ Bundles of long needle-

shaped leaves

❑ Pinus

◼ Flattened, overlapped

and scale-like leaves

❑ Thuja

New Growth Mature

Chris Evans, River to River

CWMA, Bugwood.org


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Twig Characteristics

◼ Key features (see notes)

❑ Terminal bud

❑ Axial bud

❑ Leaf scar

❑ Bundle scar

❑ Stipule scar

❑ Lenticels

❑ Pith

Source: US Forest Service


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Fruit Characteristics

◼ Cone

❑ An organ on conifers that

contains the reproductive

structures

❑ Male

◼ Pollen bearing

◼ Similar across species

❑ Female

◼ Seed bearing

◼ vary widely across species

◼ Excellent for identification

purposes

Male Cones

Pine

Red Cedar

Bald CypressYew

Pine Seed


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Female Pine Cones – A Closer Look

◼ Two general types

❑ Haploxylon – white pines

◼ Umbo generally unarmed

❑ Diploxylon – yellow pines

◼ Umbo generally armed

◼ Three major parts

❑ Peduncle/rachis

❑ Seed scale/umbo

❑ Seed

◼ Vary in size from 1.5” to 28”

◼ See notes page for more

detail


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◼ Nut

❑ A dry, one seeded fruit with

a thickened and hardened

wall.

◼ Oak, walnut, hickory, pecan

Pecan

Pin OakBur Oak

Hickory

Black Walnut


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◼ Samara

❑ A one- or two-seeded dry

fruit in which part of the fruit

wall grows out into a wing.

◼ Elm, maple, ash. American Elm

Green Ash

Red Maple


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◼ Drupe

❑ A one-seeded simple fruit in

which the innermost part is

hard and stony, the

outermost part is a

relatively thin skin, and the

middle part between the

skin and the stone becomes

either fleshy or fibrous.

◼ Choke cherry, Poison Ivy,

Dogwood

Choke Cherry

Poison Ivy

Dogwood


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◼ Berry

❑ A simple fruit in which the

ovary wall or at least its

inner portions become

enlarged and usually juicy.

◼ Persimmon

Persimmon


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◼ Pome

❑ A fruit with fleshy outer

tissue and a papery-

walled inner chamber

containing the seeds.

◼ Apple, Pear

Apple

Pear


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◼ Pods

❑ A long narrow outer case

holding the seeds of a

plant

◼ Locust

◼ Catalpa

◼ Coffeetree

Honey LocustCatalpa

Kentucky Coffeetree


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Bark Characteristics

◼ Bark can be used as a secondary source of identification

◼ In some cases, bark characteristics alone can identify a tree

❑ Sycamore

◼ Bark types:

❑ SMOOTH (Sycamore, Crape Myrtle)

❑ FURROWED (Black Walnut)

❑ SCALY (Longleaf Pine)

❑ PLATED (like scaly but scales much larger)

❑ WARTY (Toothache-tree, Zanthoxylumssp.)

❑ SHAGGY (Shagbark Hickory)

❑ FIBROUS (like furrowed but furrows themselves furrowed)

❑ PAPERY (Paper Birch)

◼ Beware! Bark characteristics vary widely between young and mature trees!

Sycamore


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Wood Characteristics

◼ Wood grains vary

widely across species

◼ Distinctions not often

obvious to the naked

eye

❑ Often requires a

magnifying lens and a

very sharp knife to aide

in identification

Black Walnut Red Oak

White Pine

Ring PorousDiffuse Porous

Non-PorousSpringwood

Summerwood

Pores

Springwood

Summerwood

Resin Canals

Rays

© Christopher Ebling 2008-2019 All rights reserved.

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Important Blackland Prairie

Trees


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A Word About Taxonomy

◼ Why use scientific nomenclature?❑ Precisely identify a unique species

❑ Common names vary widely:

◼ Quercus shumardii

◼ Red Oak

◼ Spanish Oak

◼ Shumard Oak

◼ Spotted Oak

◼ Texas Red Oak

❑ Communicate relatedness across family, genus, and species◼ Family: Fagaceae

❑ Genus: Castanea - Chestnuts

❑ Genus: Fagus - Beeches

❑ Genus: Quercus - Oaks

▪ Species: Quercus Alba

▪ Species: Quercus Rubra


Taxonomic Family: Ebling

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Genus: Chris Genus: Donald Genus: Robert Genus: Ian

Can you identify the characteristics that convey relatedness?


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Common Blackland Prairie Trees

◼ Juglandaceae ❑ Pecan

❑ Black Walnut

◼ Fagaceae❑ Bur Oak

❑ Chinquapin Oak

◼ Ebenaceae ❑ Persimmon

◼ Oleaceae ❑ Green ash

◼ Moraceae ❑ Bois D’ Arc

◼ Ulmaceae ❑ Cedar Elm

◼ Cupressaceae ❑ Eastern Red Cedar

◼ Salicaceae ❑ Cottonwood

◼ Pinaceae ❑ Longleaf

❑ Loblolly


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Pecan

Juglandaceae: Carya illinoinensis

◼ Form: A large tree (can reach heights well over 100 feet) with spreading crown when in the open.

◼ Leaf: Alternate, pinnately compound with 9 to 15 finely serrate and often curved leaflets, 12 to 18 inches long.

◼ Twig: Moderately stout, light brown, fuzzy (particularly when young); leaf scars large and three lobed; buds are yellowish brown to brown, hairy, with terminal buds 1/4 to 1/2 inch long.

◼ Fruit: Large, oblong, brown, splotched with black, thin shelled nuts, 1 1/2 to 2 inches long, husks are thin, usually occur in clusters on trees, mature in fall.

◼ Bark: Smooth when young, becoming narrowly fissured into thin broken strips, often scaly.


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Black Walnut

Juglandaceae: Juglans nigra

◼ Form: A medium to large tree up to 100 feet in height that developes a straight, clear bole with a narrow crown under competition, twigs and branches quite stout.

◼ Leaf: Alternate, pinnately compound, 12 to 24 inches long with 10 to 24 leaflets (poorly formed or missing terminal leaflet), leaflets are ovate-lanceolate, finely serrate, and 3 to 3 1/2 inches long, rachis is stout and somewhat pubescent; yellow-green to green above, slightly paler below.

◼ Twig: Stout, light brown, with a buff-colored chambered pith; buds are tan, and large with a few pubescent scales; leaf scars are 3-lobed, resembling a "monkey face".

◼ Fruit: Round, 2 to 2 1/2 inches across, with a thick, green indehiscent husk. The husk contains an irregularly furrowed, hard nut that contains sweet, oily meat (edible), mature in late summer to fall.

◼ Bark: Brown on surface, darker brown when cut, ridged and furrowed with a rough diamond pattern.


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Bur Oak

Fagaceae: Quercus macrocarpa

◼ Form: A large tree that often reaches over 100 feet tall with a long clear bole. In the open it becomes a very wide, spreading tree.

◼ Leaf: Alternate, simple, 6 to 12 inches long, roughly obovate in shape, with many lobes. The two middle sinuses nearly reach the midrib dividing leaf nearly in half. The lobes near the tip resemble a crown, green above and paler, fuzzy below.

◼ Twig: Quite stout, yellow-brown, often with corky ridges; multiple terminal buds are small, round, and may be somewhat pubescent often surrounded by thread-like stipules; laterals are similar, but smaller.

◼ Fruit: Acorns are quite large (1 1/2 inches long) and 1/2 enclosed in a warty cap that has a long-fringed margin, maturing in one growing season in late summer and fall.

◼ Bark: Ashy gray to brown in color and quite scaly, but noticeably ridged vertically on large trees.


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Chinquapin Oak

Fagaceae: Quercus muehlenbergii

◼ Form: Medium sized tree to 60 feet, with a rounded crown.

◼ Leaf: Alternate, simple, obovate or oblong, large coarse gland tipped teeth on margin, 4 to 7 inches long, dark, shiny green above, much paler below.

◼ Twig: Slender to moderate, orange-brown, buds cluster at branch tips, terminal buds 1/8 inch long, pointed, chestnut brown, individual scales with frosted edges.

◼ Fruit: Acorn, nut 1/2 to 1 inch long, broadest below the middle, thin bowl-shaped cap covers about 1/3 of acorn and forms a tattered fringe on the margin of cap, dark brown when mature.

◼ Bark: Thin, light gray, rough and flaky.


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Persimmon

Ebenaceae: Diospyros virginiana◼ Form: A small to medium sized tree to 60

feet with a round-topped crown of crooked branches. In forest stands the stem may be straight, tall, and slender.

◼ Leaf: Alternate, simple, oblong to oval, 2 1/2 to 5 inches long, pinnately-veined, margin entire, lustrous green above and paler or whitened below.

◼ Twig: Slender, light brown to gray, maybe scabrous or pubescent; no true terminal bud and twig scar is often very prominent, buds are dark red to black with 2 bud scales, triangular in shape, appressed; leaf scar has one, oval vascular bundle trace.

◼ Fruit: A plum-like berry that is green before ripening, turning orange to black when ripe, 3/4 to 2 inches in diameter, leafy bracts on top of fruit. The fruit is very astringent and mouth numbing when green, sweet and edible when ripe after a hard freeze; matures in mid to late fall.

◼ Bark: When young gray-brown with orange in fissures, later becoming much darker, breaking up into square scaly thick plates; reminiscent of charcoal briquettes (very unique).


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Green Ash

Oleaceae: Fraxinus pennsylvanica

◼ Form: A medium sized tree to 70 feet tall with a poorly formed bole and an irregular to round crown.

◼ Leaf: Opposite, pinnately compound with 7 to 9 serrate leaflets that are lanceolate to elliptical in shape, entire leaf is 6 to 9 inches long, green above and glabrous to silky-pubescent below.

◼ Twig: Stout to medium texture, gray to green-brown and either glabrous or pubescent, depending on variety; leaf scars are semicircular to flat across the top, with lateral buds sitting on top of leaf scar (not down in a in notch as with white ash).

◼ Fruit: A single-winged, dry, flattened samara with a slender, thin seed cavity, maturing in autumn and dispersing over winter.

◼ Bark: Ashy gray to brown in color, with interlacing corky ridges forming obvious diamonds; older trees may be somewhat scaly.


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Bois D’Arc

Moraceae: Maclura pomifera

◼ Form: A medium sized tree with a short trunk. The crown is irregular, with stiff, spiny branches.

◼ Leaf: Alternate, simple, pinnately veined, 2 to 5 inches long, oblong to ovate with an acuminate tip, margins entire, upper surface shiny.

◼ Twig: Moderately slender, zigzag, green changing to buff or orange-brown. Twigs are armed with stout, unbranched thorns at each leaf scar. A milky sap is exuded when cut.

◼ Fruit: A large, round multiple of drupes 4 to 5 inches in diameter, with a very distinctive citrus smell; the outer surface looks like "brains"; when crushed, a white, milky juice is exuded, maturing in early fall.

◼ Bark: Orange-brown, developing scaly ridges with irregular furrows.


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Cedar Elm

Ulmaceae: Ulmus crassifolia

◼ Form: Medium sized tree to 60 feet with rounded crown of drooping branches.

◼ Leaf: Alternate, simple, narrowly ovate to nearly lanceolate, 1 to 2 inches long, inequalateral base, coarsly toothed margins with somewhat rounded teeth, thick and slightly leathery, dark green and rough above with soft hairs beneath.

◼ Fruit: Single-seeded flat football-shaped samara, notched at tip, 3/8-1/2 inch long, covered with soft white hair, ripens in the fall.

◼ Twig: Slender, often with corky ridges, zig zaged, brownish; buds small ovate and pointed, reddish brown.

◼ Bark: Light brown, furrowed into scaly ridges.


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Cottonwood

Salicaceae: Populus deltoides

◼ Form: A large tree with a clear bole and an open spreading crown resulting in a somewhat vase-shaped form.

◼ Leaf: Alternate, simple, pinnately veined, 3 to 6 inches long, triangular (deltoid) in shape with a crenate/serrate margin. The petiole is flattened and glands are present at the top of the petiole.

◼ Twig: Stout, somewhat angled and yellowish; buds are 3/4 inch long, covered with several brown, resinous scales. Has a bitter aspirin taste.

◼ Fruit: Cottony seeds, 1/4 inch long borne in a dehiscent capsule, maturing over summer.

◼ Bark: Smooth, gray to yellow-green when young. Later turning gray with thick ridges and deep furrows.


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Eastern Red Cedar

Cupressaceae: Juniperus virginiana

◼ Form: A small tree with a dense ovoid or columnar crown reaching up to 60 feet tall.

◼ Leaf: Evergreen, very small, with two types of leaves (often on the same tree), scale-like leaves 1/16 inch long, dark green, with 4 sides held tightly to twig and longer (1/4 inch), dark blue-green needle-like leaves that are more common on young trees and fast growing shoots.

◼ Twig: Green for several years, covered in scales, later turning brown.

◼ Fruit: Berry-like cones, light green in spring, turning dark blue and glaucous at maturity, about 1/4 inch in diameter, appearing in spring and maturing in the fall.

◼ Bark: Red-brown in color, exfoliating in long, fibrous strips, often ashy gray where exposed.


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Longleaf Pine

Pinaceae: Pinus palustris

◼ Form: A medium sized to large tree capable of reaching over 100 feet in height, with a straight trunk, coarse branches and tufted needles at ends of branches.

◼ Leaf: Evergreen needles, very long and feathery (8 to 18 inches long), with three dark green needles per fascicle; tend to be tufted at branch tips.

◼ Twig: Very stout, gray-brown; buds large, ovoid, silvery-white.

◼ Fruit: Very large (largest cone in the Eastern U. S. --6 to 10 inches long), ovoid to conical in shape, sessile, red-brown, umbo is armedwith a curved prickle, maturing in the fall.

◼ Bark: Quite scaly, orange-brown to gray, eventually developing flat plates.

◼ Not found on Blackland Prairie


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Loblolly Pine

Pinaceae: Pinus taeda

◼ Form: A medium to large tree can reach well over 100 feet tall, self-prunes well and develops a fairly straight trunk and an oval, somewhat open crown.

◼ Leaf: Evergreen needles, 6 to 9 inches long, with (usually) three yellow-green needles per fascicle.

◼ Twig: Orange-brown in color, fine to moderately stout; buds are narrowly ovoid, light reddish brown.

◼ Fruit: Ovoid to cylindrical, 3 to 6 inch red-brown cones; umbo is armed with a short spine, maturing in early fall.

◼ Bark: Initially red- to gray-brown and scaly; older trees are ridged and furrowed, with somewhat rounded scaly plates; very old trees have red-brown, flat scaly plates.

◼ Not found on Blackland Prairie

Documents

Dendrology, Tree Identification Techniques, & Important ... · Different tree families and species take on distinct forms and exhibit typical silhouettes in a natural setting. Like