Illinois Chapter ISA Certification Workshop TREE BIOLOGY

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Illinois Chapter ISA Certification WorkshopTREE
BIOLOGY

• Chapter 1
• Jennifer Hitchcock
• jenflwr_at_gmail.com

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What is Tree Biology?

• The Study of Structure and Function of Trees
• And the Relationships between the two

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Lecture Summary

• Tree Anatomy Morphology
• The studies of the component parts of the tree
• (inside out)
• Tree Physiology
• Study of the biological and chemical processes
  within the tree

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What is a Tree?

• Long lived perennial
• Woody
• Compartmentalizing organism

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Types of Trees

• Hardwoods
• e.g. oaks, maples, poplars, ash, beech, magnolia,
  locust, sycamore, sweet gum, willow, etc.
• Conifers (gymnospermsnaked seed)
• e.g. cypress, pines, spruces, firs, larches,
  junipers, yews
• Gingko

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• Excurrent tree
• Strong central trunks (leaders)
• Most young trees
• Conifers, sweet gum

Graphic Urban Tree Foundation
Photo Missouri State University
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• Decurrent tree
• Lateral shoots outgrow original terminal shoot
• Round-headed tree
• Typical of mature trees
• Oaks, elms

Graphic Urban Tree Foundation
Photo Duke University Winged elm
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Trees

• Main functions
• Grow
• Reproduce
• Maintain/ protect themselves

Photo North Carolina State University
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Tree Anatomy

• Heartwood (darker)
• Non-water conduction
• Non-living xylem
• Sapwood
• Water conduction
• Living xylem
• Cambiumgrowth
• Thin layer of active Xylem Phloem
• Bark

Graphic Colorado State University Extension
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Build a Tree
Photo Goshen College
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Plant Growth

• Cell growth
• A. Mitosis - cell division
• B. Cell differentiation
• Cells change structure to specific function
• Arranged tissues organized into organs (leaves,
  stems, roots, flowers and fruit)
• Organs organized to function as an organism-tree!

Photo University of
Wisconsin
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Tree Anatomy Vocabulary

• Cells Tissues (GROWTH)
• Meristems Cells that produce other cells
• Differentiation Change in the cells structure
  to assume a needed function
• Apical meristems Meristems located at the ends
  of shoots/buds and roots (primary growth)
• Cambium Lateral Meristems that produce the
  trees vascular system (secondary growth)
• Cork Cambium lateral meristem that produces bark

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Tree Growth

• Meristem is the tree growth zone
• 1.Primary meristem
• Responsible for elongation of roots and stems
• Located in the tips of roots and stems (buds)

Graphic Michigan State University Extension
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Tree Growth

• 2. Secondary or lateral meristem increase in
  diameter
• Vascular cambium produces xylem or phloem
• Cork cambium - produces bark
• Palms lack secondary or lateral growth
• (no increase in diameter size)

Photo UF Herbarium
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Tree Anatomy Vocabulary

• Cells Tissues (GROWTH)
• Cambium produces Xylem and Phloem
• Xylem Is produced on the inside of the Cambium,
  it is the wood of the tree. Moves water and
  minerals up to the leaves. Supports the tree.
  Stores sugars for future use. Made up of vessels
  (soda straws)
• Phloem Is produced to the outside of the
  Cambium (next to the bark). It moves sugars down
  from the leaves

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Growth Tissue Cambium

• Where growth occurs
• (Growth rings seasonal cambium)
• Cambium produces
• Phloem (outside)
• Xylem (inside)

Graphic UF Horticulture
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Vascular Tissue - Xylem

• XylemWood of trees
• Functions
• Conduction of water dissolved minerals
• Support weight of tree
• Storage of carbohydrate reserves
• Defense against spread of disease decay

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Vascular Tissue - Xylem

• Composed of dead living cells
• Xylem
• Tracheids water conduction support
• Fibers mechanical strength
• Parenchyma cells-help maintain water balance
  store carbohydrates(example ray cells)
• Vessels hardwood trees only ( no gymnosperms)

Graphic Sonoma State University
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Vascular Tissue - Xylem

• Transportation of water and minerals
• Transpiration is the loss of water through leaves
• Water molecules are pulled in long,
  hydrogen-bonded chains from root to leaf

Graphic University of Washington
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Vascular Tissue - Xylem

• Water conduction occurs in sapwood
• Conifers 2-12 rings may conduct water
• Hardwoods outermost 1 or 2 rings especially elm
  trees
• Non-water conduction heartwood (darker in color
  than sapwood)

Graphic University of Minnesota Extension
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Build a Tree
Photo Pacific Union College
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Vascular Tissue Phloem

• Food transport (requires energy)
• Cells are living
• Sieve tube cells
• Companion cells
• Parenchyma cells
• only sieve cells in gymnosperms

Graphic Pacific Union College
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Vascular Tissue - Phloem

• Translocation conduction of sugars produced in
  the leaves to other parts of the plant
• Photosynthate moves from source to sink
• Sinks plant parts that use more energy than
  they produce
• All plant parts at one time are sinks
• Most photosynthate is either utilized or stored
  closed to manufacturing site

Graphic UF Horticulture
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Vascular Tissue

• Axial transport materials flow up and down
• (longitudinally)
• Rays parenchyma cells that extend across
  (radial) xylem and phloem
• Transport sugars
• Store starch
• Restrict decay

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Tree Bark
Photo East Tennessee State University

• Outer, protective covering
• Function
• Moderates interior temperature
• Reduces water loss
• Protects against injury
• Composition
• Nonfunctional phloem corky tissues
• Contain wax and oil to minimize water loss
• Lenticels small openings that permit gas
  exchange

Photo Colorado State Extension
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Tree Organs

• Leaves
• Stems
• Roots
• Flowers
• Fruits-dry or fleshy

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Terminal Bud
Flower
Lateral Bud
Shoot
Leaf Axil
Leaf Blade
Node Internode
Petiole
Vascular System
Primary Root
Root
Lateral Root
Root Hair
Root Cap
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Leaf Anatomy

• Cuticle
• Vascular bundles
• Parenchmya cells
• -chloroplasts
• -chlorophyll
• Stomata
• Guard Cells
• Petiole

Graphic Butler University Herbarium
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Leaves

• Primary Purpose
• Photosynthesis
• Carbon dioxide
• Water
• Light
• Yields
• Carbohydrates/sugar(Photosynthates)
• oxygen

Graphic Butler University Herbarium
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Leaves

• Stomata openings
• Control loss of water vapor (transpiration)
• Control gas exchange
• Guard cells open and close stomata in response
  to
• Light, temperature, wind and humidity
• Open-day
• Close-night

Photo University of Hawaii at Manoa
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Antitranspirant Sprays

• Artificially close stomata cells to prevent water
  loss during drought or dormant times
• Reduces photosynthesis, cooling of leaves, and
  carbon dioxide uptake

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Modified Leaves

• Arid regions
• Thick cuticle, leathery leaves and few stomata
• Succulent, water retaining leaves or dense hairy
  coverings

Photo Texas AM
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Modified Leaves

• Tendrils
• Spines reduce water loss and protect

Photo FL Exotic Plant Pest Council
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Leaves

• Deciduous - trees that shed their leaves every
  year
• Leaves lost are the result of cell changes and
  growth regulators
• Abscission zone at stem
• Enable leaf drop in fall
• Protect leaf area against desiccation pathogen
  entry

Graphic University of California Davis
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Leaves

• Fall foliage color
• Triggered by short, sunny days with cool nights
• Sugar accumulates chlorophyll breaks down
• Other pigments show
• Anthocyanins reds purples
• Carotenoids yellows, oranges reds
• Evergreen trees that hold their leaves form
  more than one year

Photo USDA
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Branches

• BudsStemsBranches
• strongly attached underneath but weakly attached
  above
• Branch collar layers of tissue, bulge around
  branch base
• Autonomous-function on own

Photo University of Florida (Horticulture)
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Stem Anatomy

• Node-gives rise to
• leaves buds
• Internode-distance between nodes
• Terminal bud-primary growth
• Terminal bud scale scar- start of new growth of
  current year

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Buds

• 1. Terminal or apical buds - located at the end
  of a shoot
• 2. Lateral or axillary buds - located on the
  sides of the stems.
• often dormant because of
• apical dominance

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Stems

• 3. Adventitious buds arise from loss of primary
  bud
• 4. Epicormic shoots-When dormant buds sprout and
  grow
• Environmental stress can trigger response
• Can grow from
• Internode of the stem
• Edge of a leaf
• At the cut on a stem or root

Photo by Joseph OBrien, USDA Forest Service
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Modified Stems

• Spur a compressed stem with short internodes,
  usually bearing leaves, flowers and/or fruit.
  Many fruit trees such as apples, pears, cherries
  and ginkgo
• Thorn pyracantha, locust

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Roots

• 4 Main Functions
• Anchorage
• Storage
• Absorption (sm roots)
• Conduction
• Roots need water air for optimal growth

Photo Louisiana State University
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Roots

• Absorbing roots
• Small, fibrous
• Grow at ends of roots
• Found in top foot of soil
• Lateral or horizontal roots near surface
• Sinker roots
• Grow vertically downward off lateral roots
• Found w/in few feet of trunk

Photo University of Texas
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Roots

• Most roots found in upper 1-12 of soil
• Taproot is a downward growing root in young trees
• Roots may extend 2-3 times the tree crown/canopy
• Root extent and directional growth is the result
  of the trees environment rather than genetics

Wrong
Correct
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Roots

• Mycorrhizae (fungus roots) - the symbiotic
  relationship of roots with certain fungi
• Symbiosis both organisms benefit from the
  living arrangement
• Fungi get food in turn aid roots in absorption
  of water and minerals

Photo Iowa State University Extension
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Roots

• Water enters young roots or mycorrhizal roots by
  osmosis
• Osmosis requires fluid transport from higher
  concentration to lower concentration
• Reverse Osmosis water movement from out of
  roots into soil
• Example de-icing roads with salt increases
  (higher concentration in soil)

Photo Forestry Department South Australia
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Allelopathy

• Production and release of chemical substances by
  one species that inhibit the growth of other
  species of plants
• Reduced seed germination and seedling growth
• Examples Walnut, red maple, swamp chestnut oak,
  sweet bay, red cedar

Photo Texas AM
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Flowers Fruit

• Flower is reproductive structure of plant
• Once pollinated give rise to the fruit or seed
• Most seeds are protected with an ovary or capsule

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Tree Physiology

• Plant growth limited by
• Genetics
• Environment
• Plant hormones
• Auxin
• Produced in shoots
• Alters crown growth
• Involved in tropisms
• Cytokinin
• Produced in roots
• Shoot initiation and growth

Photo University of Nottingham, UK
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Plant Hormones regulate Growth

• Hormones signal
• Cell Division
• Cell Elongation
• Flowering
• Fruit Ripening
• Leaf Drop
• Dormancy
• Root Development

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Plant Response to Environment

• Tropisms
• Geotropism-gravity response
• Phototropism-light response
• Hydrotropism-water response

Photo University of Wisconsin
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Photosynthesis

• Converting light into sugar for food
• Chlorophyll is the green/leaf pigment that
  absorbs sunlight
• Chlorophyll is stored in chloroplast cells of
  leaves
• (Chloroplasts is where Photosynthesis takes
  place)
• ENERGY IS STORED

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Respiration

• Energy made from photosynthesis is used
• (Sugar or carbohydrates /starch)
• Oxygen is needed
• Carbon dioxide and water are given off
• Tree able to survive in these situations?
• 1. Flooded roots (tree roots cannot
  respiredeath)
• 2. Defoliated leaves by caterpillars (reserved
  foodlives)
• ENERGY IS RELEASED

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Plant Growth and Development
Photosynthesis Respiration
Produces Food Uses food for plant energy
Stores energy
Releases energy
Cells containing chloroplasts All cells
Releases oxygen
Uses oxygen
Uses water
Produces water
Uses carbon dioxide
Produces carbon dioxide
Occurs in sunlight
Occurs all the time
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Transpiration

• Loss of water through stomata (openings) of
  leaves
• -similar to perspiration in people
• Helps cool leaf during hot times and aids water
  uptake in xylem
• (Dependent on water, temperature, humidity)
• 90 water absorbed from roots are lost in leaves

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Tree Physiology

• Compartmentalization is a system of defense
• CODITCompartmentalization Of Decay In Trees

Graphic USDA Forest Service
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Tree Physiology

• Shigos model is 4 barrier walls
• Wall 1 resists vertical spread, plugs up xylem
• Wall 2 resists inward spread, plugs latewood
  cells
• Wall 3 inhibits lateral spread, activates rays
  cells to resist decay
• These 3 walls form reaction zone

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Tree Physiology

• Shigos model
• Wall 4 is the next layer of wood to form after
  injury
• Strongest of all 4 walls
• Protects from outward decay
• Barrier zone

Photo Colorado State Extension
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Palms

• Monocots
• Have no cambium layer
• Have no growth ring of xylem
• Have vascular bundles of xylem phloem

Photo Smithsonian Marine Station, Ft. Pierce
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Helpful Websites for Tree ID

• ISA Tree List Exam Study Guide
• http//www.isa-arbor.com/certification/exams.aspx
  
• http//wp.nres.uiuc.edu
• http//urbanext.uiuc.edu/treeselector
• http//utgardens.tennessee.edu/ohld220/
•  http//www.noble.org/webapps/plantimagegallery/Pl
  antList.aspx?PlantTypeID3IndexTypeCommonName
•  http//www.hort.uconn.edu/Plants/

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Illinois Chapter ISA Certification Workshop
Series

• Jennifer Hitchcock
• jenflwr_at_gmail.com
• 847-826-8763

Photo University California Berkeley