Download 03411-07.6 Physiology of a Tree

Course:
Unit 7:
03.411
Natural Resources Conservation
Forest Resource Management
Lesson 6: Physiology of a Tree
QCC: ................................................................................................. 168, 389, 412
Objectives:
1.
2.
3.
4.
Describe the physiological processes of tree growth.
Explain tree growth.
Explain tree diameter.
Describe the methods of reproduction.
Teaching Time:
1.5 hours
References:
Holland, I.I., Rolfe, G.L. Forests and Forestry. 5th Edition. Interstate Publishers,
Inc. Danville, IL. 1997.
Union Camp Corporation. Union Camp Corporation Agricultural School Forest
Lesson Guide. Lesson IV. Central Region Agricultural Office.
Materials and Equipment:
Increment bore
Diameter cutting of pine logs
Overhead projector
Transparency 7.6.1 and 7.6.2
TEACHING PROCEDURE
Course 3.411 Natural Resources Conservation
Revised August 2000
Unit 7, Lesson 6
1
Georgia Agriculture Education Curriculum
Introduction and Mental Set
Show students various photographs of trees and ask them to guess the age
of the tree. Record their guesses on the board. Ask them what criteria they
can use to determine the trees= age. What is the distinguishing mark on a
tree that allows us to know its age? Lead the students to the fact that the
annual ring is the answer.
Discussion
1.
How is an annual ring formed?
A.
By division of the cambium
B.
Each ring is composed of two cell walls:
Summerwood - a darker-colored area of small, dense, heavy
walled cells.
Springwood - a lighter-colored area of large, thin-walled cells
C.
The difference between the summerwood and springwood cell
walls creates the ring. Show the transparency AThe Trunk@
from the SFLG Lesson IV.
2.
Distribute a pine wood cross section and have the students
count the age of the specimen.
3.
Why do annual rings vary in width?
A.
Closeness to other trees (the closer to other trees; the closer
the rings)
B.
Rainfall amount (the more rain, the further the rings are apart)
C.
Drought
D.
Natural disasters - fires, insect damage, etc.
4.
Activity
Have students do several increment borings on several trees at
different heights. Determine the age of the tree.
5.
Why do you get different ages for the same tree?
A.
The level of the boring is crucial to getting an accurate age
reading.
B.
Readings are truer the lower on the tree they are taken.
How do trees reproduce?
A.
Seed - Most trees reproduce by this method
B.
Sprouts
C.
Suckers
6.
Course 3.411 Natural Resources Conservation
Revised August 2000
Unit 7, Lesson 6
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Georgia Agriculture Education Curriculum
7.
What are the parts of a monocot and dicot seed?
A.
Display and discuss transparency 3.2.1
B.
Seed coat
C.
Embryo
D.
Stored food
$ Endosperm
$ Cotyledons
8.
What is a complete flower?
A.
Display and discuss transparency 3.2.2
B.
Contains the pistil, stamen, sepals, and petals
C.
Identify the plant=s reproductive parts
$ Stigma, style, ovary for the pistil
$ Anther and filament form the stamen
9.
What is an incomplete flower?
A flower that lacks either a pistil, stamen, sepals (calyx) or petals
(corolla)
10.
What are monoecious and dioecious flowers?
A.
Monoecious flowers contain both the male and female
reproductive parts.
B.
Dioecious male and female flowers are produced on separate
trees.
11.
How are seeds dispersed?
A.
Wind
B.
Birds and other animals
C.
Water
D.
Man
Course 3.411 Natural Resources Conservation
Revised August 2000
Unit 7, Lesson 6
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Georgia Agriculture Education Curriculum
SUMMARY
How are trees reproduced?
Explain how trees grow.
Review how to determine the age of a tree
Evaluation
Laboratory activity - increment boring
Written quiz
Course 3.411 Natural Resources Conservation
Revised August 2000
Unit 7, Lesson 6
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Georgia Agriculture Education Curriculum
3.2.1
PARTS OF THE SEED
Two Basic Types
Course 3.411 Natural Resources Conservation
Revised August 2000
Unit 7, Lesson 6
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Georgia Agriculture Education Curriculum
3.2.2
PARTS OF THE FLOWER
Course 3.411 Natural Resources Conservation
Revised August 2000
Unit 7, Lesson 6
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Georgia Agriculture Education Curriculum
Ways that Tree Stands Regenerate
a. Seeding (natural or direct)
b. Stump sprouting
c. Planting of seedling
Photosynthesis
 The leaves of a plant use sunlight, carbon dioxide,
chlorophyll, and water to produce carbohydrates.
 Oxygen is given off as a by-product
 Carbohydrates, including sugars and starches, are
later converted to fat and proteins.
 Fats and proteins are used as food for growth and
respiration or are stored in the plant for later use.
Course 3.411 Natural Resources Conservation
Revised August 2000
Unit 7, Lesson 6
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Georgia Agriculture Education Curriculum
Growth of a Tree
 Trees begin growth in the spring when the temperature is
warm enough.
 Growth is slower in the summer because of the hot, dry
weather.
 Cells are the building blocks of trees.
 Root tips, twigs, and branches increase in length when
cells become longer.
 The tree increases in diameter when cells under the bark
divide.
 New growth from under the bark forms the annual ring.
 One ring is produced each year.
 The age of a tree can be determined by counting the
Course 3.411 Natural Resources Conservation
Revised August 2000
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Georgia Agriculture Education Curriculum
number of rings from the center out to the edge of the tree.
 The width of the growth ring indicates the tree’s growing
conditions that year.
Forest Stratification and Life Zones
 Emergent- a tree that grows above the general level of the forest canopy.
These tallest trees of the forest are exposed to stronger sun and winds than
trees in the sheltered levels below.
 Canopy- the level just below the emergent level. It forms the roof of the
forest with the crowns of the dominant trees and other vegetation. Life at
the canopy, is host to a broad spectrum of animals including birds, small
mammals, and insects.
 Understory- the area below the canopy, which comprises shrubs, snags, and
small trees. This level receives little light. Many of these plants tolerate
shade and will remain at this level; others will grow and replace older trees
that fall. Th understory life zone provides shelter and habitat for larger
mammals including foxes, raccoons, deer, and bears as well as many species
of birds, insects, and spiders.
Course 3.411 Natural Resources Conservation
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Georgia Agriculture Education Curriculum
 Forest floor- the lowest level of the forest, which is made up of tree
seedlings, dead leaves and needles, grasses, ferns, flowers, fungi, and
decaying plants and logs. The forest floor is home to a multitude of
organisms, especially small mammals (mice, voles, rabbits, etc.), frogs,
turtles, newts, salamanders, insects, grubs, maggots, spiders, other
invertebrates, and microorganisms that support decomposition. Groundnesting birds, such as winter wrens, ovenbirds, and quail may also be found
here.
Course 3.411 Natural Resources Conservation
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A Look at Competition
Trees complete with each other and with other plants in the forest. They vie for
sunlight, water, nutrients, and space to grow. Trees occupy the forest canopy, the
understory, and the forest floor (as seedling), with roots that can be deep or spread widely
across the forest floor. The forest canopy is formed by the branches and leaves from the
tallest trees. The understory is the middle layer where shorter trees and shrubs grow. The
third layer, the forest floor, is made up of seedlings, grasses, ferns, fungi, decaying plants
and logs, and surface- and below- ground- dwelling animals and microorganisms.
Trees can be classified according to the position they occupy in the forest canopy or
understory. Such a system measures how well a tree has grown relative to its closest
competitors. Generally, trees that get the most sunlight will grow fastest.
The five classes of forest are:
Dominant- Dominant trees have crowns (tree tops) that rise above the general canopy level.
They get full sunlight from above and from all sides.
Co-dominant- Co-dominant trees make up the canopy level. Their crowns receive overhead
light, but dominant and other co-dominant trees restrict some side sunlight.
Intermediate- Intermediate trees also occupy the canopy level, but receive sunlight only
from above.
Suppressed- Suppressed trees receive no direct overhead or side sunlight. They usually are
slow growing and may be weak.
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Dead trees (snags)- These can be found in the canopy, understory, or forest floor.
Not all trees require direct sunlight to grow. Some trees, called shade tolerant, grow
well underneath other trees. Often, they will be the second forests growing under an
established forest. Many common trees, such as maple, beech, some oaks, hemlock, and
firs, are shade-tolerant.
Shade-intolerant species grow in direct sunlight. Often, they are the first trees to
grow in an area following disturbance. Many common trees, such as pines and aspen, are
shade-intolerant.
The five classes of forest are:
 Dominant- Dominant trees have crowns (tree tops) that rise above the
general canopy level. They get full sunlight from above and from all sides.
 Co-dominant- Co-dominant trees make up the canopy level. Their crowns
receive overhead light, but dominant and other co-dominant trees restrict
some side sunlight.
 Intermediate- Intermediate trees also occupy the canopy level, but receive
sunlight only from above.
Course 3.411 Natural Resources Conservation
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 Suppressed- Suppressed trees receive no direct overhead or side sunlight.
They usually are slow growing and may be weak.
 Dead trees (snags)- These can be found in the canopy, understory, or forest
floor.
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