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Introduction to Forestry
Hoyt Ponder
Submitted October 20, 2005
Objectives
Upon completion of this course, the student should be
able to:
1. Describe the forest resources of Louisiana and our
region.
2. Explain primary and secondary growth of a tree.
3. Define and explain techniques used for the
management of a forest including: soil, water,
and wildlife.
4. Understand basic economic concepts of the
forestry industry.
What makes up forest?
 In terms of woody
plants, the two main
types are trees and
shrubs.
 What are the main
differences in a tree
and a shrub?
Trees and Shrubs
 A tree is a woody plant, typically large with a
well-defined stem and a more or less defined
crown.
 A shrub is a woody plant, seldom exceeding
10 ft. in height, usually having several
persistent woody stems branching from the
ground.
Types of Seeds
 Angiosperms – trees which produce seeds
that are encased in a hull, shell or fruit.
(Oaks, Fruit Trees, and Grasses)
 Gymnosperm – trees which produce seeds
that are naked. (Pines)
Types of Seeds (cont.)
 Angiosperms (two kinds)

Monocotyledons-embryo with one leaf.


Palm trees and grasses
Dicotyledon-embryo with more than one leaf.


Oaks, maples, and magnolias
Broadleaved or hardwoods
 Gymnosperms


Conifers-pines, junipers, spruces, firs, and cypress
Softwoods
Types of Trees
 Evergreens


Retains leaves year round
Often a synonym for conifers (except cypress)
 Deciduous


Trees that loose their leaves every year
Often a synonym for hardwood (oaks)
Energy/Food
 2 Types of Sugars


Starch – source of energy, excess is converted
into wood
Cellulose – structural, makes up 70% of wood
Energy/Food
 Photosynthesis

Co2 + water in the
presence of light =
sugar
 Respiration

Oxidation of Carbon

Sugar in the presence of
Oxygen = CO2
Secondary Chemicals
 Lignin – functions as a glue that glues cells
together, second most abundant chemical in
wood
 Tannins, terpenoids, and alkinoids all protect
trees from insects, fungi and bacteria
Three Types of Tissue
 Ground – biochemistry
 Dermal – epidermis or skin
of plant (bark)
 Vascular – transport system
Xylem – transports water
and mineral salts
 Phloem – transports
organic food and sugars

Growth
 Primary Growth – elongation (height)
 Secondary Growth – diameter (width)


Each year a tree gets
a new growth ring
The growth ring can
tell you a great deal
about a tree
Growth (cont.)
 Meristems

Refers to points of growth that are actively
dividing
Apical meristems – tips of limbs and trunks (primary
growth – deals with elongation)
 Cambium meristems – single cell layer wide
(secondary growth – gets bigger in diameter)

Plant Hormones
 Auxins

Hormones that are made in the shoot tips, and
controls phototropism (ability to grow towards
the light)
 Apical Dominance


Control of auxins in the tips of the limbs and
shoots
Suppresses elongation of lateral branches
Symbiosis with Fungi
 Symbiosis – both plant and fungi benefit
 Mycarhizae – fungi that surround the roots

increases uptake of nutrients, increases the
surface area of the roots
 Rhizobium – bacteria that is symbiotic with
legumes (mimosa, black locust) and

fixes atmospheric nitrogen
Tolerance
 Tolerance is the ability
to grow in low light
conditions
Tolerance
 Intolerant grow best in
full sunlight (bald
cypress, pines, oaks)
 Tolerant has relatively
equal growth with
different levels of
sunlight (southern
magnolia, beech)
 Many of the important
commercial and
wildlife species are
intolerant trees. Much
of forest management
has focused on
maintaining
communities of
intolerant species.
Gap Dynamics
 Small scale disturbances – small openings in
a forest where advanced regeneration occurs



Fugitive – easily distributed seeds (pines)
Buried seeds – seeds remain viable for a long
time (oaks)
Sprouting – roots and stumps sprout to form a
new forest
Competition through Chemistry
 Allelopathy – condition when some plants
produce chemicals that inhibit, retard, or kill
other plants

The black walnut produces juglone which is a
phenolic compound that kills most plants.
Prescribed Burning
 Uses:






Reduction of logging debris
Preparation of seed beds
Reduction of fuels in forests
Control understory vegetation
Improvement of wildlife habitat
Improvement of forage for livestock
Prescribed Burning
 Limitations:




Must be controllable (fuels, weather,
topography)
Preparation of fire breaks
Smoke management (air quality, liability)
Cost $7-$20 per acre
“Let It Burn” Policy
 Managing Natural
Fires

Put out the fire or let it
burn?
 Yellowstone Park is
this policies biggest
challenge (contains 2.2
million acres)
“Let It Burn” Policy
 In 1988 45% of Yellowstone burned (approx.
1 mil. Acres)
 ½ were only surface fires
 25-30% burned under constant suppression
 Much of the problem was caused by fuel
build up due to prior fire suppression
Regeneration
 Follows harvesting or small scale disturbance


Natural Regeneration – seeds produced in area
sprout and regenerate.
Artificial Regeneration – can be accomplished
by either Direct Seeding or Planting nursery
grown seedlings
Natural Regeneration
 Advantages:



Usually produces a
thick stand
No bed preparation is
required
Requires no costs
 Disadvantages:





Unknown species
Unknown genetics
Bad seed year
Drought
Seeds may be eaten by
rodents
Natural Regeneration
 Methods:



Seed tree method – superior
trees are left to provide seed
and are removed after
regeneration.
Shelter wood method –
similar to seed tree method,
but deals with species where
shelter is required
Coppice method – using
stump and root sprouts.
Artificial Regeneration
 Advantages:





Control seed supply
Increases prompt
reforestation
Greater control over
species and genetics
Control tree spacing
Regenerate in optimal
weather conditions
 Disadvantages:

Can be costly

Bed prep

Cost of seedlings

Cost of planting
Succession
 The orderly replacement of species through
time in a given location eventually leading to
a stable community
 Two types of Succession:


Primary – initial invasion of a bare site
Secondary – orderly replacement of species over
time
Harvesting Timber
 2 Main ways



Clear cutting – all trees
are removed at one time
High grading – best
quality and largest trees
are removed, only poor
quality and small trees
are left
Thinning – age,
corridor
Clear Cutting
 Advantages:



Easy site preparation
Max profits
Natural and artificial
regeneration can be
used
 Disadvantages:



Soil erosion
Takes time to
regenerate
Negative view
High Grading
 Advantages:



Biggest tallest trees are
harvest
Species can be selected
for a market
Highest dollar per board
foot
 Disadvantages:



Appearance
Smaller trees and
poorer quality is left
Regeneration has
genetics that are inferior
Siviculture
 Manipulation of forest vegetation to
accomplish a specific set of objectives
controlling forest establishment, composition
and growth

Even aged stand – stands in which relatively
small differences exist between individual trees


Usually develop after a large scale disturbance (intol.)
Un-even aged stand – lack of disturbance (tol.)
Un-even Aged Stand
 Dominant – project above canopy, direct sun from
above and part of the sides
 Co-dominant – top of canopy, direct sun from
above only
 Intermediate – crowded into canopy, sun only
directed to the top of the crown
 Suppressed – completely overtopped,no constant
direct sun (some plants will die)
Review
 What is the difference between a tree and a
bush?
 How does fungi work together with trees?
 What is the controversy over the “Let it burn
policy”?
 What are advantages and disadvantages of
clear cutting and high grading?
Tomorrow’s Lesson
 Commercial Forest Land
 NIPF – Non-industrial Private Forests
 Land Expectation Value (LEV)
 Mean Annual Increment (MAI)
 Harvest Scheduling