Download Trees

ISA
Int. Society Arboriculture
Certification Workshop
TREE BIOLOGY
What is Tree Biology?
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The Study of Structure and Function of Trees
Relationships between the two
Tree Anatomy
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?
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Long lived perennial
Woody plant
Usually single stemmed
Compartmentalizing organism
Types of Trees
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Deciduous
oaks, maples, poplars, ash, beech, magnolia,
locust, sycamore, sweet gum, willow, etc.
Conifers (Evergreens)
cypress, pines, spruces, firs, larches, junipers,
Evergreen:
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Strong central trunks
(leaders)
Conifers
Grows one “layer” each
year
Tamarack????
Graphic: Urban
Tree Foundation
Deciduous trees:
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Lateral shoots
outgrow original
terminal shoot
Oaks, elms, many
others
Photo: Duke University
Winged elm
Graphic: Urban
Tree Foundation
Leaves
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Deciduous – shed
leaves every year
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Leaves lost are result of
cell changes and growth
regulators
Abscission zone at stem:
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Enable leaf drop in fall
Protect leaf area against
desiccation & pathogen
entry
Graphic: University of California Davis
Trees
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Main functions
Grow
 Reproduce
 Maintain/
protect
themselves
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Photo: North Carolina
State University
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Heartwood (darker)
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Water conduction
Living xylem
Cambium=change=
growth
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Non-water
conduction
Non-living xylem
Sapwood
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Tree Anatomy
Thin layer of active
Xylem & Phloem
Bark - Protection
Graphic: Colorado State University Extension
Build a Tree
Photo: Goshen College
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Cell growth:
A. Mitosis - cell division
B. Cell differentiation
1. Cells change structure
to specific function
2. Arranged tissues
organized into organs
(leaves, stems, roots,
flowers and fruit)
3. Organs organized to
function as an
organism-tree!
Plant
Growth
Photo: University of
Wisconsin
Tree Anatomy Vocabulary
Cells & Tissues (GROWTH)
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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 tree’s
vascular system (secondary growth)
Cork Cambium – lateral meristem that produces bark
Tree
Growth
Meristem is the
tree growth zone
1.Primary
meristem–
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Responsible for
elongation of
roots and stems
Located in the
tips of roots and
stems (buds)
Graphic: Michigan State University Extension
Tree Growth
2. Secondary or lateral
meristem – increase
in diameter
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Vascular cambium –
produces xylem or
phloem
Cork cambium produces bark
*Palms lack secondary
or lateral growth
(no increase in diameter
size)
Photo: UF Herbarium
Tree Anatomy Vocabulary
Cells & Tissues (GROWTH)
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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
Growth
Tissue:
Cambium
Where growth occurs
(Growth rings –
seasonal cambium)
Cambium produces:
 Phloem (outside)
 Xylem (inside)
Graphic: UF Horticulture
Vascular Tissue - Xylem
Xylem=Wood of trees
 Functions:
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Conduction of water
& dissolved
minerals
Support weight of
tree
Storage of
carbohydrate
reserves
Defense against
spread of disease &
decay
Vascular Tissue Xylem
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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
Vascular Tissue
- Xylem
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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
Build a Tree
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Translocation:
conduction of sugars
produced in the leaves
to other parts of the
plant
Vascular Tissue Phloem
Rays – cells that
extend across
(radial) xylem and
phloem
 Transport
sugars
 Store starch
 Restrict decay
Graphic: UF Horticulture
Tree Bark
Photo: East Tennessee
State University
Outer, protective covering
Function:
 Moderates interior
temperature
 Reduces water loss
 Protects against injury
Composition:
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Nonfunctional phloem & corky
tissues
Contain wax and oil to minimize
water loss
Lenticels – small openings that
permit gas exchange
Photo:
Colorado State
Extension
Tree Physiology
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Compartmentalization is a system of defense
CODIT:
Compartmentalization Of Decay In Trees
Graphic:
USDA Forest
Service
Tree Physiology
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Shigo’s model is 4
barrier “walls”
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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
Tree Physiology
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Shigo’s model
Wall 4 is the next
layer of wood to
form after injury
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Strongest of all 4
walls
Protects from
outward decay
Barrier zone
Photo: Colorado State Extension
Tree Organs
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Leaves
Stems
Roots
Flowers
Fruits
-dry or fleshy
Shoot
Terminal Bud
Flower
Lateral Bud
Leaf Axil
Leaf Blade
Node
Internode
Petiole
Vascular System
Primary Root
Root
Lateral Root
Root Hair
Root Cap
Leaf Anatomy
Cuticle
Vascular bundles
Parenchmya cells
-chloroplasts
-chlorophyll
Stomata
Guard Cells
Petiole
Graphic: Butler University Herbarium
Leaves
Primary Purpose:
Photosynthesis
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Carbon dioxide
Water
Light
Yields:
 Carbohydrates/sugar
(Photosynthates)
 oxygen
Graphic: Butler University Herbarium
Leaves
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Stomata – openings
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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
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Photo: University of Hawaii at Manoa
Antitranspirant Sprays
Artificially close stomata cells to prevent water
loss during drought or dormant times
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Reduces photosynthesis, cooling of leaves, and
carbon dioxide uptake
Modified Leaves
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Arid regions:
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Thick cuticle,
leathery leaves and
few stomata
Succulent, water
retaining leaves or
dense hairy
coverings
Photo: Texas A&M
Modified Leaves
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Tendrils
Spines – reduce water loss and protect
Photo: FL Exotic Plant Pest Council
Branches
Buds=Stems=Branches
 strongly attached
underneath but
weakly attached
above
 Branch collar – layers
of tissue, bulge
around branch base
 Autonomousfunction on own
Photo: University of Florida (Horticulture)
Stem Anatomy
Node-gives rise to
leaves & buds
Internode-distance
between nodes
Terminal bud-primary
growth
Terminal bud scale scarstart of new growth of
current year
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
3. Adventitious buds
arise from loss of
primary bud
Stems
4. Epicormic shootsWhen dormant buds
sprout and grow
 Environmental stress
can trigger response
 Can grow from:
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Internode of the stem
Edge of a leaf
At the cut on a stem or root
Photo by Joseph O’Brien,
USDA Forest Service
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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
Modified Stems
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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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
Roots
Photo: University of Texas
Roots
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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 tree’s
environment rather than
genetics
Wrong
Correct
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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
Roots
Photo: Iowa State University Extension
Roots
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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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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
Allelopathy
Photo: Texas A&M
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
Tree Physiology
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Plant growth limited by
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Genetics
Environment
Plant hormones
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Auxin:
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Produced in shoots
Alters crown growth
Involved in tropisms
Cytokinin –
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Produced in roots
Shoot initiation and growth
Photo: University of
Nottingham, UK
Plant Hormones regulate Growth
Hormones signal:
 Cell Division
 Cell Elongation
 Flowering
 Fruit Ripening
 Leaf Drop
 Dormancy
 Root Development
Plant Response to Environment
Tropisms:
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Geotropism-gravity response
Phototropism-light response
Hydrotropism-water response
Photo:
University of
Wisconsin
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
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 respire=death)
2. Defoliated leaves by caterpillars (reserved food=lives)
ENERGY IS RELEASED
Plant Growth and Development
Photosynthesis
Respiration
Produces Food
Stores energy
Cells containing chloroplasts
Releases oxygen
Uses water
Uses carbon dioxide
Occurs in sunlight
Uses food for plant energy
Releases energy
All cells
Uses oxygen
Produces water
Produces carbon dioxide
Occurs all the time
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
Palms
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Monocots
Have no cambium
layer
Have no growth ring
of xylem
Have vascular
bundles of xylem &
phloem
Photo: Smithsonian Marine
Station, Ft. Pierce
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?PlantTypeID=3&IndexType=CommonN
ame
 http://www.hort.uconn.edu/Plants/
Illinois Chapter ISA
Certification Workshop Series
Jennifer Hitchcock
[email protected]
847-826-8763
Photo: University
California Berkeley