Tree Identification Techniques

Massachusetts Qualified Tree Warden Course Learning Objectives

• Recognize why tree ID is important • Recognize principles of ID and classification, including binomial nomenclature • Identify common tree parts Importance of Tree ID

• Communicate with staff and contractors • Understand species responses to stresses (drought, damage, construction, etc.) • Insect & disease susceptibility Binomial Nomenclature

Acer saccharum

Acer saccharum

Genus Species (plural genera) (specific epithet) Binomial Nomenclature sugar maple Acer saccharum hard maple rock maple common name Latin name • Lower case • Italics (unless proper noun) • When talking about • Many common names plants, also called “botanical name” Binomial Nomenclature

• Variety – within a species, there may be groups of plants that retain certain characteristics

Genus Species Variety Name of Variety Acer rubrum var. drummondii

• Common name: Drummond red maple Binomial Nomenclature

• Cultivar (short for ‘cultivated variety’)

Genus Species Cultivar Acer rubrum ‘Columnare’

• Common name: red maple ‘Columnare’ Tree ID – general tips

• Start broad and narrow down possibilities • Use all parts of the tree available to you Leaves

Broadleaf Needle-like Scale or awl-like Leaf Arrangement Alternate vs. Opposite

Image: massnrc.org Alternate or Opposite?

Image: treeschool.myspecies.info/ Alternate or Opposite?

Image: treeschool.myspecies.info/ MAD-CAP-HORSE

Pneumonic to remember opposite plants. Many opposite plants fall under this pneumonic.

Maple – Ash – Dogwood

Caprifoliaceae (honeysuckle) family

Horsechestnut white ash Image from Iowa State University Looking at Leaves Parts of a Leaf

Leaf blade

Image from Norton-Brown Herbarium, University of Maryland Leaf Types

Simple Compound

Images: Butler.edu Simple vs. Compound Leaves

Simple leaf Compound leaf

Images: Butler.edu Simple Leaf

Image from Norton-Brown Herbarium, University of Maryland Compound Leaf

Image from Norton-Brown Herbarium, University of Maryland Leaf Venation

Pinnate venation

American elm Image from Northern Forest Atlas, http://northernforestatlas.org Leaf Venation

Palmate venation

sugar maple

Image from Northern Forest Atlas, http://northernforestatlas.org Leaf Margins Leaf margins may be entire (smooth), toothed, or lobed Leaf Margins Leaf Margins Leaf Shapes What to look for…

Entire

Simple or Serrate compound? Leaf margin

Leaf Shape Opposite or Palmate or alternate Lobes and sinuses Pinnate? arrangement ? Other things to look for

• Form/Habit • Bark • Flowers • Fruits and Seeds • Twigs • Buds and leaf scars Form

Image: Mollie Freilicher

Image: Bates.edu Form

Image: Mollie Freilicher Bark Old Young

Image: Mollie Freilicher Image: Chris Bersbach Bark

Old Young Images: Mollie Freilicher Looking at Twigs Twigs

Image: Mollie Freilicher Leaf Scars

Image: Mollie Freilicher Leaf Scars

Tree of heaven (Ailanthus altissima) Leaf Scars

Image: Minnesotawildflowers.com Image: Mollie Freilicher Buds Flowers

Red maple (Acer rubrum) Norway maple Serviceberry (Acer platanoides) (Amelanchier sp.)

Images: Mollie Freilicher Fruit

Honeylocust Red oak Crabapple (Gleditsia triacanthos (Quercus rubra) (Malus spp.) var. inermis) Ash Tree ID Fraxinus spp.

Opposite

Compound leaf Ash Tree ID Ash Tree ID

• Furrowed bark

• Fruit is a one-winged samara Green Ash and White Ash • Green Ash – common street tree –Average 5% of street tree population • White ash – often naturally growing Woodpecker- damaged ash • Know what looks “normal” bark(symptom Normal ash bark of eab) Putting it all together

Dichotomous key Use all Parts of the Tree Available • Form/Habit • Bark • Flowers • Fruits and Seeds • Twigs • Buds and leaf scars • Habitat – street tree or natural area? • If you are totally unsure, use a key.

September 25 TREE IDENTIFICATION – SESSION 2 Norway maple Acer platanoides

• Leaves like sugar maple, but are usually larger, usually with 5-7 lobes. • Snap petiole for white milky sap • Bark - gray to brown and furrowed • Samaras of a Norway maple have a wide angle Sugar maple Acer saccharum • Opposite • 5 lobes, fine teeth along margin • Pointy buds • Samara 80-90 degree angle • No milky white sap from petiole • Furrowed bark Eastern white pine Pinus strobus • Evergreen needles, 3-5 inches long • Needles in bundles of 5

Northern • Cones 4-7 inches long, Forest Atlas resinous • Bark, smooth when young, becoming ridged and furrowed • Large tree (100+ feet), Northern Forest Atlas horizontal branch habit Northern red oak Quercus rubra • Leaves are large, thin, and papery (not glossy), with shallow sinuses small bristles on the lobe tips. • Leaf tips are pointy • Red oak can be identified by the “ski trail” lines on bark. • Acorn is larger than most other oaks. Acorn cap is flat, like a saucer, covers about a quarter of the nut. American elm Ulmus americana • Vase-shaped habit • Leaves have unequal bases • Leaf margins are doubly- serrate

Northern Forest Atlas • Fruit is a round samara • Buds flattened against twig • State tree of Massachusetts

Northern Forest Atlas

October 23 TREE IDENTIFICATION – SESSION 4 Cherry Prunus spp. • Small tree • Recognized by its most distinctive feature- smooth, shiny, red-tinted bark with red horizontal stripes • Alternate leaves, finely toothed • Spring flowers, white, pink Oregon State Ginkgo Ginkgo biloba

• Easily distinguished by small, 2-3 inch long, fan-shaped leaves

• Gawky, irregular shape with large branches London planetree & sycamore Platanus spp. • Large tree • Alternate, simple leaf, reminiscent of maple leaf, up to 9 inches wide • Bark-blocky and exfoliating, showing light inner bark • Fruit: ball-shaped, hang down, singly or in pairs White oak Quercus alba • Large tree, rounded form in open • Alternate, simple leaf with rounded lobes Northern Forest Atlas • Acorn: elongated, cap Northern Forest Atlas covers ¼ of acorn • Bark: whitish, ashy,

Northern Forest Atlas sometimes blocky on older trees

Wikipedia Littleleaf linden Tilia cordata • Distinct uneven heart- shaped leaf, smaller than leaf of American linden • Fragrant flowers • Fruit has a leaf-like bract • Canopy shape often resembles a tear drop

Joseph OBrien, USDA Forest (triangular in shape) Service, Bugwood.org Richard Webb, Bugwood.org November 6 TREE IDENTIFICATION – SESSION 5 Silver maple Acer saccharinum • Opposite • Leaf has 5 deeply cut

T. Davis Sydnor, The Ohio State University, Bugwood.org lobes, bright green above, silver below • Red petiole, red buds

Tom DeGomez, University of Arizona, Bugwood.org • Mature bark shaggy, Rob Routledge, Sault College, Bugwood.org furrowed

Paul Wray, Iowa State University, Bugwood.org Honeylocust Gleditsia triacanthos var. inermis • Pinnately-compound leaves • Hardy and common street tree • 6-8 inch long fruits, resemble large, brown bean pods. • Bark is gray-brown to bronze, smooth with horizontal lenticels, later breaking into long, narrow, curling plates Pear Pyrus spp. • Medium-dark green shiny leaves with symmetrical curves ending at petiole. • Small brown fruits, appear during summer and remain into fall. • Grows very upright, with a conical, narrow shape and narrow branching angles Pin oak Quercus palustris

• Distinct habit – low branches droop, middle are horizontal, upper branches point upward • Leaf 5-7 deeply cut, U-shaped lobes • Acorn: Shallow cap, covers ¼ of nut Northern Red Oak vs Pin Oak

• Shallow V-shaped • Deep U-shaped sinuses sinuses

• 1” long acorn • ½” long acorn

• Bark: Smooth • Bark: Smooth when young, when young, thin wide ridges when ridges when old old “ski trails” Zelkova Zelkova serrata

• Vase-shaped habit • Alternative to American elm • Leaf with scalloped margin • Bark- as tree ages, becomes gray-brown and peely • Requires proper pruning; poor branch attachments Cherry vs. Elm vs. Zelkova

• Smooth shiny • Criss-cross ashy • Smooth reddish red bark with grey-brown brown bark, horizontal bark exfoliates with stripes age Cherry vs. Elm vs. Zelkova • Shiny, finely- • Uneven base, • Dark green toothed oval doubly-toothed leaves with leaves sharp teeth scalloped teeth November 20 TREE IDENTIFICATION – SESSION 6 Serviceberry Amelanchier spp.

• 6-20 feet tall, often multi-stem • Alternate, simple elliptical leaf, fine-toothed • Bark: Gray, striated, green pith Crabapple Malus spp.

• Short and stout, rounded • Leaf shape can vary greatly, typically ovate. • Bark: Variable, generally smooth when young, older- thin and scaly. • Flowers: white to red Cottonwood and Poplars Populus deltoides and Populus spp.

• Alternate, simple, triangle- shaped leaf with rounded teeth • Flat petiole (all poplars)

Northern Forest Atlas • Big stem, big buds • Bark: gray, blocky with furrows and fissures • Seeds are cottony Red maple Acer rubrum • Leaf differs from the sugar and Norway maple--has a narrower form and less prominent teeth. • Leaf is typically 3-lobed, sometimes weakly 5-lobed. • Also characterized by red petiole —although other maple petioles may have a red tinge Distinguishing Between Common Maple Leaves 5 or 7 sharp-toothed lobes. Norway Smooth margins, milky sap

3 or 5 toothed lobes. Red Reddish petiole

Silver 5 thin lobes, deep sinuses

Sugar 5 lobes, blunt points A few common trees that we didn’t have time to include in our class sessions, but that you likely encounter in your communities TREE IDENTIFICATION Eastern Hemlock Tsuga canadensis • Flat needles, white dots on sides of midrib, finely toothed toward tip • Bark becomes gray and furrowed • Small cones Arborvitae Thuja occidentalis

• Form: Upright, conical • Scale-like, flattened Richard Webb, bugwood.org leaves • Bark is thin, brown, shredded

Northern Forest Atlas Horsechestnut Aesculus hippocastanum

• Opposite, palmately Bugwood.org Richard Webb,Richard compound leaf with 5-7 leaflets Chris Evans, University of Illinois, Bugwood.org

, Maine Forest Forest Maine , • Habit-branches slope Kanoti Service, Service, Bugwood.org down, then up at tips Keith Keith • Bark—gray, blocky, Richard Webb., Bugwood.org exfoliating to show orange Hybrid inner bark with pink Paul Wray, Iowa State flowers • Large, sticky terminal bud University, Bugwood.org (Aesculus x carnea) • Panicles of white flowers Colorado Blue Spruce and Picea pungens Other Spruces • Needles ¾ to 1 ¼ inch long, blue- green, 4 sided, resin smell • Leaves attached to twig by leaf Richard Webb, Bugwood.org peg

Tom DeGomez, • Long cones, up to 4” long, University of Arizona, Bugwood.org flexible scales Leaf pegs • Bark: Gray-brown, becoming Elmer Verhasselt, visible (on Bugwood.org black flaky with age spruce) Northern Forest Atlas

Norway spruce, Keith Kanoti, Maine Forest Service, Bugwood.org Hawthorn Crataegus spp.

• Small tree, rounded form • Alternate simple lobed leaves, finely toothed • Thorned and thornless varieties Northern Forest Atlas • Spring flowers: white, pink, red

Northern Forest Atlas

Northern Forest Atlas