Question of the Question of the Day:Day:

How can you tell one How can you tell one tree from another? tree from another?

What characteristics do What characteristics do you use to identify a you use to identify a

tree?tree?

DendroloDendrologygyWhat is dendrology?What is dendrology?

Dendrology is the scientific Dendrology is the scientific study of trees and other woody study of trees and other woody plants.plants.

Trees vs. ShrubsTrees vs. Shrubs Tree = one, main woody stemTree = one, main woody stem Shrub = small, woody, Shrub = small, woody, branched branched

from basefrom base

2 Major Tree 2 Major Tree DivisionsDivisions DeciduousDeciduous

aka: Hardwoods aka: Hardwoods & Broadleaf& Broadleaf

Sheds leaves Sheds leaves seasonallyseasonally

Broad leavesBroad leaves HardwoodHardwood Examples: Oaks, Examples: Oaks,

Maples, Tulip Maples, Tulip Poplars, etc.Poplars, etc.

ConifersConifers aka: Softwoods & aka: Softwoods &

EvergreenEvergreen Bear conesBear cones Needle or scale-Needle or scale-

like leaveslike leaves SoftwoodSoftwood Examples: Pines, Examples: Pines,

Cedars, Firs, etc.Cedars, Firs, etc.

Tree Tree IdentificationIdentification

Trees may be identified by Trees may be identified by various means including:various means including: LeavesLeaves BarkBark Tree ShapeTree Shape Flowers and FruitFlowers and Fruit Etc.Etc.

Let’s focus on leavesLet’s focus on leaves

LeavesLeaves Leaves are often the easiest/best way Leaves are often the easiest/best way

to identify a tree.to identify a tree.

Needles and scale of evergreens are Needles and scale of evergreens are also considered leaves.also considered leaves.

Some questions to consider when Some questions to consider when identifying leaves:identifying leaves: Simple or compound?Simple or compound? Margins smooth or rough?Margins smooth or rough? Arrangement on twig opposite or Arrangement on twig opposite or

alternate?alternate? Veins pinnate (like a feather) or palmate?Veins pinnate (like a feather) or palmate?

Important Vocab:Important Vocab: Blade = whole leafBlade = whole leaf Petiole = stemPetiole = stem Margin = outer edgeMargin = outer edge

Leaf Leaf PartsParts

Leaves– Simple or Leaves– Simple or CompoundCompound

Simple leaves only have one leaf Simple leaves only have one leaf blade.blade.

Compound leaves are made up of Compound leaves are made up of several separate leaflets attached to several separate leaflets attached to a common leaf stem.a common leaf stem.

SimpleSimple

Source: Ohio State University– Biology of Source: Ohio State University– Biology of Horticulture WebsiteHorticulture Website

Compound Compound Leaves Leaves Important to remember:Important to remember:

Compound leaves have leaflets Compound leaves have leaflets which are attached to the leaf stalk which are attached to the leaf stalk ((not the twignot the twig))

Leaflets can be attached to the Leaflets can be attached to the leaf stalk in several ways:leaf stalk in several ways:

Pinnately CompoundPinnately Compound

Bipinnately CompoundBipinnately Compound

Palmately CompoundPalmately Compound

Compound Leaves Compound Leaves (Cont.)(Cont.) Pinnately Pinnately

CompoundCompoundThe leaflets are The leaflets are attached across attached across from each from each otherother

Resembles a Resembles a “feather”“feather”

Ex: White AshEx: White Ash

PPIINNNNAATTEE

Source: Ohio State University– Biology of Horticulture WebsiteSource: Ohio State University– Biology of Horticulture Website

Compound Leaves Compound Leaves (Cont.)(Cont.)

Bipinnately or Bipinnately or Twice CompoundTwice Compound The primary The primary

leaflets are leaflets are divided into divided into secondary leaflets, secondary leaflets, also written 2-also written 2-pinnatepinnate

Ex: HoneylocustEx: Honeylocust

Source: Ohio State Source: Ohio State University– Biology of University– Biology of Horticulture WebsiteHorticulture Website

BipinnatBipinnatee

Compound Leaves Compound Leaves (Cont.)(Cont.)

Palmately Palmately CompoundCompoundThe leaflets are The leaflets are arranged in a arranged in a pattern that looks pattern that looks like fingers on the like fingers on the palm of a handpalm of a hand

Ex: Horse ChestnutEx: Horse Chestnut

PPAALLMMAATTEE

Source: Ohio State University– Biology of Source: Ohio State University– Biology of Horticulture WebsiteHorticulture Website

Quick Check for Quick Check for Understanding: Simple? Understanding: Simple?

Compound?Compound?

Leaves– How Leaves– How arranged on twig? arranged on twig?

(Leaf Arrangement)(Leaf Arrangement) OppositeOpposite When leaves are arranged directly When leaves are arranged directly

across from each other on the twig.across from each other on the twig. AlternateAlternate

When leaves stagger up the twig When leaves stagger up the twig and are NOT located directly across and are NOT located directly across from each other.from each other.

WhorledWhorled 2 or 3 leaves attached at the same 2 or 3 leaves attached at the same

point on the twig and “whorl” point on the twig and “whorl” around the twig (think of circle)around the twig (think of circle)

Leaf Arrangement Leaf Arrangement (Continued)(Continued)

Alternate

Opposite

Whorled

Leaf Arrangement Leaf Arrangement (Cont.)(Cont.) Most trees have Most trees have

alternatealternate branching.branching.

Think to yourself Think to yourself “MAD Horse” “MAD Horse” (Maple, Ash, (Maple, Ash, Dogwood, and Dogwood, and Horse Chestnut) Horse Chestnut) to remember to remember those with those with opposite opposite branching.branching.

Leaf Arrangement Leaf Arrangement (Continued)(Continued)

It is important to remember…It is important to remember…The opposite vs. alternate The opposite vs. alternate vs. whorled arrangement vs. whorled arrangement refers to the way the refers to the way the LEAVES are arranged on LEAVES are arranged on TWIG, TWIG, notnot the way the the way the leaflets are arranged on leaflets are arranged on the leaf stalk.the leaf stalk.

Quick Check for Quick Check for Understanding: Alternate? Understanding: Alternate?

Opposite? Whorled?Opposite? Whorled?A B

C

Leaves– MarginsLeaves– Margins The margin of the leaf is The margin of the leaf is

the leaf edge.the leaf edge. 3 major types:3 major types:

Entire MarginEntire MarginLobed MarginLobed MarginToothed MarginToothed Margin

Leaves– Margins Leaves– Margins (Cont.)(Cont.)

Entire Margin = smooth edgesEntire Margin = smooth edges

Ex:Ex:

EasternEastern

RedbudRedbud

Leaves– Margins Leaves– Margins (Cont.)(Cont.)

Lobed margin = projections that Lobed margin = projections that shape theshape the

edge of the leafedge of the leaf

Ex: White Ex: White

OakOak

Leaves– Margins Leaves– Margins (Cont.)(Cont.)

Toothed Margin = saw-like edge Toothed Margin = saw-like edge on the leafon the leaf Serrated edgeSerrated edge

Example:Example:

SycamoreSycamore

Leaves– VeinsLeaves– Veins Pinnately veinedPinnately veined

means that there means that there is only one main is only one main vein.vein.

Palmately veinedPalmately veined means that there means that there are several main are several main veins originating veins originating from the petiole.from the petiole.

Leaves– Veins Leaves– Veins (Cont.)(Cont.) Pinnate Veins (Ex: Dogwood)Pinnate Veins (Ex: Dogwood)

Palmate Veins (Ex: Sweetgum)Palmate Veins (Ex: Sweetgum)

Leaves– Veins Leaves– Veins (Cont.)(Cont.)

ConifersConifers Conifers bear cones and have Conifers bear cones and have

needles.needles. Needles can be Needles can be singlesingle & flat, & flat,

blunt, round or sharp.blunt, round or sharp.

Needles can be Needles can be groupedgrouped together in tufts or bundles.together in tufts or bundles.

Spruce needles are sharp and

individually attached to the stem.

Pine needles are attached to twig in “bundles” of 3-5,

depending on species