forest trees structure and fucnction.pdf

forest trees

1. Kenneth Williams

Fisheries Extension Specialist
Langston University Aquaculture
Extension Program

2. Trees

© Longest lived organisms on earth.

© Heights of 100 meters diameters
meters.

e Due to longevity, trees must withstan
extremes of climate.

© Trees allocate much of their energy to
diameter growth. Not so in other plants.

e Physiology of trees a young science.

3. 3 TISSUE SYSTEMS OCCUR IN
PLANTS

e Dermal Tissue System N
— Function: Protection from the enviro:
water loss.

e Vascular Tissue System
— Function: Conduction of water, nutrients, sug
and hormones throughout the plant.
e Ground or Fundamental Tissue System
— Function: Storage, support, filler tissue and site of
photosynthesis.

4. Dermal Tissue System
© Function: Protection from the.
environment and water loss.
o Tissues:
e a) epidermis - single layer of cells on
primary (herbaceous ) plant parts.
e b) periderm or bark - a corky tissue tha
replaces epidermis on secondary (woody
plant parts.

5. Vascular Tissue System

S

N

e Function: Conduction of water, nutrients,
sugars and hormones throughout the pk

e Tissues:

© a) xylem - conducts water and nutrients up
roots, stems and leaves.

© b) phloem - conducts water, sugar, hormones,
etc. primarily down roots, stems and
leaves, but also can move up at times.

6. Ground or Fundamental Tissue
System_
e Function: Storage, support, |
and site of photosynthesis.
e Tissues:

© a) cortex - outer region of stems and
roots.

e b) pith - center of stems.

© c) mesophyll - middle of leaves and
flower petals

7. c. ....

PLANT ORGANS, TISSUE SYSTEMS, TISSUES AND CELL TYPES

3 TISSUE SYSTEMS OCCUR IN PEANTS
Dermal Tissue System i
Function: Protection from the environment and water loss.
Tissues: N
a) epidermis - single layer of cells on primary (herbac

b) periderm or bark - a corky tissue that replaces epide
(woody) plant parts.

2) Vascular Tissue System

Function: Conduction of water, nutrients, sugars and hormones
plant.

Tissues:
a) xylem - conducts water and nutrients up roots, stems and leaves.

b) phloem - conducts water, sugar, hormones, etc. primarily down roots,
and leaves, but also can move up at times.

3) Ground or Fundamental Tissue System

Function: Storage, support, filler tissue and site of photosynthesis.
Tissues:

a) cortex - outer region of stems and roots.

b) pith - center of stems.

€) mesophyll - middle of leaves and flower petals

) plant parts.
is on secondary

8. + MERISTEMS AND GROWTH
MN (

e Primary Growth - growth in leng
primary (herbaceous) tissues called t
body.

e Apical meristem or apex - the growing poi
located at the tips of stems and roots

e

that gives rise to
rimary plant

e Secondary Growth - growth in width or diamete
that gives rise to secondary (woody or corky) tissu
called the secondary plant body.

9. Leaf
primordia

Apical meristem

10. | 3 Year Old Shoot

Shoot diagram

-«—— Terminal Bud

Lateral Bud

#— Bud Scale Scar
+ Leaf Scar

Node —»>
Internode
Terminal Shoot »-
| <— Terminal
| Lateral Bud Bud
a Lateral Shoot
| Node—» Bundle Scar

-«— Bud Scale Scar

| Lenticels

11. Shoot growth

~

e Fixed shoot growth — 1 perio
growth, often over quickly. Ex. Do;

e Free shoot growth — continual grow
throughout season (most in spring) ex.
Cottonwood

e Recurrent flushing — several periods of
growth throughout season. Ex. White oak

12. Shoot growth

Free growth — fast growing hardwoods —

14. Root growth

N

e Similar to shoots de

e Taproot is the 1* root to grow. Bra f
form off of it. Taproot may not persis

© Root growth depends on soil and moist
conditions/ Ex. Red maples on upland sit
have large taproots but have a shallow rot
system in poorly drained soils.

15. Root growth

© Most growth in length occurs inthe long
roots. h

e Most surface area is in the short of fi
roots. The fine roots are also called fee
roots. They take up nearly all the water
nutrients.

e Larger roots provide a conduction path an
mechanical support.

16. Fine roots, the mycorhizae
4
© Most of the fine roots are actual y a fungus
called mycorhizae plus tissues frc
tree root.

e Mycorhizae increase root surface area,
increase water and nutrient uptake and
increase resistance to pathogens and
nematodes.

17. Fine roots, the mycorhizae

~

e The mycorhizae receive most of its food
from the host tee.

e This is a very important fungal/tree
partnership and crucial to tree survival.

e All trees are mycorhizal

e Without this fungus trees will stunt and ma
die.

18. Protoxylem Pole

Metaxylem

Pericycle
Endodermis
Cortex
Epidermis
Lateral Root
Growth
Apical
Meristem
Root Cap

Endodermis
Metaxylem

Protoxylem
y Cortex

Pole

4 A Meristematic Tissue
Epidermis

Quiescent Center

Root Cap
Lateral Root Emergence

19. Flowering and reproduction

~

© Flowers develop as vegetative shoot apical
meristem transforms into a reproducti
meristem.

e Flower shoots have a determinate grow
pattern, they grow, flower and meristem
disappears.

20. Conifer reproduction

e Male and female cones are borne
separately on the same tree.

© Male cones are usually lower than
female cones to reduce self
pollination.

© Male cones are small (1-2 cm)
release pollen in spring 1 year after
forming.

e Female cones large, seeds released 2
years after pollination.

e Conifers are wind pollinated

21. Angiosperm reproduction

e Pollination may be by wind, inBects, birds
or bats. a

e Flower and seed development may b
few weeks ex. Poplars or several years
Some oaks.

e Male and female reproductive parts may
in the same flower or male and female
flowers on separate trees.

22. Angiosperm reproduction

e Many trees disperse seeds in fall Ad win
These seeds remain dormant until spring
Ex. Some oaks

© Some seeds can remain in the soil for year
until conditions are right for germination.

23. Secondary growth

Xx

e Diameter growth occurs In the
cambium, the large sheet of cells
bark.

o It ensheaths the entire plant body in a s
layer of cells..

e During growth cambium divides to produc
xylem to the inside and phloem to the
outside of this tissue.

24. Secondary growth

~

e Cambium activity is greater in spring than
summer making the cells at this ti

e This results in annual rings. Usually
per year.

e Rings may be missing or incomplete or
sometimes more than 1 per year.

25. CAMBIUM LAYER

OUTER BARK

WILDFIRE DAMAGE BELOW
DASHED HIGHLIGHT LINE

ANNUAL GROWTH RINGS

1929 THE TREE IS A
SEEDLING

AT 36 YEARS OLD
THE TREE IS +34"
IN DIAMETER,

NOTE THE BREAK IN THE
GROWTH RINGS WHERE THE
DAMAGE OCCURRED AND THE
DURATION OF TIME IT TOOK THE
TREE TO CLOSE-UP THE WOUND
AND AGAIN BEGIN PRODUCING
CONTINUOUS GROWTH RINGS

Figure 1: In 1987 the tree was harvested at
age 58 and had a diameter of 6 %4”.

26. £
=]
2
£
3
Ú

Cork cambium

28. Xylem

N

e 3 functions:

e Conduction of water by cells ca ed.
vessels. These cells are dead.

e Support by thick walled vessel cells.
e Storage — parenchyma cells transport ant
store starches. These cells may be in rays.
e Hardwoods more efficient than conifers in
moving water due to structural differences.

29. Heartwood

Sapwood (living
parenchyma cells)
an be

Healthy
heartwood (dead
parenchyma cells)

Fungus rotted heartwood

30. Phloem

© Cells form sieve tubes — vertically arranged
files of living cells with end walls that are
porous.

e Phloem transports sugars and organic
substances formed in leaves to other pa
the tree and roots.

e Phloem is only functional a few years
before the cells are crushed in tree growth

31. epidermis

cortex

pith
cambium

Xylem and
phloem

|

|
|
xylem !

\
\
\phloem
L : J JL i
xylem , phloem
cambium
Elizabeth Morales}

32. Tracheids

Similar function as xylem in
hardwoods, support and conduction

33. Cork cambium and bark

Xx

e Periderm or outer bark formed from the cork
cambium which originates in the epidermi

e Cells to the outside of the cork cambium
thick layer of a waxy substance called sube

e Suberin is water repellant and resistant to bact
and fungus.

e New periderms are continuously formed.
e Cork cells are dead at maturity.

34. Camolurn

Heartwood

Sapwood

Vascular cambium

Living phloem

Cork cambium
Periderm
Cork

Copyright © Pearson Education, Inc., publishing as Benjamin Cummings.

36. poa sa) upper epidermis

palisade parenchyma
cheroplasts

cullcle

mesophyll

xylem

phloem

lower epidermis
spongy mesophyll

Figure 12a. Leaf cross section

37. Gas movement:

Stomata (open)

Guard Cell (turgid)

| |

Parenchyma

Stomata (closed)

ard Cell (flaccid)

‘TT
| Parenchyma

—_— ww

38. Photosynthesis

Ingredients Product

@ Sunlight +
H,O + CO, + Nutrients —> “CH, O” +0,

H

Water Carbon Nitrate NO, ' “Organic Oxygen
dioxide Phosphate PO, ; matter”
Iron 1
Silica

Same rule applies to marine life that
Earhguide ttp:slerthoude ced ade applies to terrestrial life.

39. Respiration

N
© Respiration provides energy >
maintenance and the construction 0!
cells.

e Respiration is the opposite of
photosynthesis. The oxidation of sugars
carbon dioxide and water, releasing usabl
chemical energy.

40. Respiration

e The chemical equation for respiration is:

e (CH,0), +60, —+ 6CO,+6H,0

e Photosynthesis occurs mostly in leaves.

© Respiration occurs in all living cells.\

e Carbohydrates not used in respiration
stored as starches. An important tree
reserve.

e Many trees have enough stored starch to r
foliate the tree 3 times. This allows the tree
to recover from insect, weather and disease
damage.

41. PHOTOSYTHENSIS

WATER + LIGHT « CHEMICAL ENERGY,

1. Chloroplasts trap light energí

2. Water enters leat #

=— Light energy

Action spectri

for Anacharis

Relative rate of
photosynthesis

—— 3. Carbon dioxide
enters leaf through
stomata

a

0 i 1 i
400 450 500 550 600 650 700 750
Wavelength in nm

” 4 Sugar leaves leat
CHEMICAL ENERGY + CARBON DIOXIDE = SUGAR

42. Growth
substances or
plant
hormones

Effects very
complex and
not always
understood.

Table 32.1 Main Plant Hormones and Some Known

(or Suspected) Effects

Promote cell elongation in coleoptiles and
stems; involved in phototropism and
gravitropism

Gibberellins Promote stem elongation; might help br
dormancy of seeds and buds; stimulate '
breakdown of starch

Cytokinins Promote cell division; promote leaf expan:
and retard leaf aging

Abscisic acid Promotes stomatal closure; promotes bud
and seed dormancy

Ethylene Promotes fruit ripening; promotes abseissi
of leaves, flowers, and fruits

Florigen (?) Arbitrary designation for as-yet unidentified’
hormone (or hormones) thought to cause
flowering

43. Secondary compounds

e 1000’s of chemicals produced
many with no known function.

e Some may be defensive.

e Many have commercial value, ex. The
terpenoids.

44. e Single most important factor i
and survival.

e Water makes up 80% of living cells.

e Most water in trees lost through
transpiration.

e There is a continuous column of water fro
soil to roots to leaves in trees. This is calle
the soil-plant-atmosphere continuum.

45. Outside air Y
=-10.010
-100.0 MPa

Leaf 'Y (air spaces)
=-70MPa

Leaf Y (coll walls)
= -1.0 MPa

Copyright © Pearson Education, Inc., publishing as Benjamin Cummings.

812. [eto
H le;

Cohesion and
adhesion in

from soil

46. Tonic Form

Element Funetions Up by Tree

Macronutrients

Nitrogen Ñ Component of amino acids, proteins, NH, NO:
uneleie acids, chlorophyll

Phosphorus Pp Component of high energy compounds HPOZ LPO
eg. ATP), nucteic acids, phospholiprls

Potassium K Enzyme activator, counterion for K°
osmoregulation, stomatal function

Calcium Ge Cell wall stabilizer, enzyme activator, Cr
regulator of cell membrane functions

Magnesium Mg Enzyme activator. Component ot Mg"
chlorophyll

Sulfur 5 Component of some mino acids and Mar

pres

47. | Micronutrients
Tron

Chlorine

Copper
Manganese:

Zinc

Molybdenum
Boron

Cobalt

Fe
cl
Cu
Mn
Za
Mo
B
Co

Election transport protein component

Osmotegulation and ion balance

Ename activator

Enzyme activator

Enzyme activator

Nitrate reduction. nitrogen fixation

Phloem transport activater?

Required by nitrogen Bxing symbionts of
legumes

wer
ct
ie?
Mu
Ay
MO,
BO.
cor

ae

48. | Light A

e Shade tolerance — ability of a
in the shade of other trees.

e Photoperiod — duration of daylight.
Provides signals for bud set and leaf fa
other physiological functions.

49. Temperature

o Trees grow between OC — 40C \

e They become dormant when temp
begin to drop.

50. Tree forms

e Excurrent growth form — singles
ex. Pine tree.

e Decurrent growth form — multiply ste
ex. Elm tree.

51. Tree forms

( “a growth) Decurrent growth

wi Y

53. Tree longevity

© Growth rate slows as trees age.

© They become less resistant to pest
disease.

© May be killed from storms , fungal rot

e Physiology of tree longevity poorly
understood.

54. Largest trees

Giant sequoia over 300 ft. hi