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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: Describe the forest resources of Louisiana and our region. Explain primary and secondary growth of a tree.

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Introduction to forestry l.jpg

Introduction to Forestry

Hoyt Ponder

Submitted October 20, 2005

Objectives l.jpg

Upon completion of this course, the student should be able to:

  • Describe the forest resources of Louisiana and our region.

  • Explain primary and secondary growth of a tree.

  • Define and explain techniques used for the management of a forest including: soil, water, and wildlife.

  • Understand basic economic concepts of the forestry industry.

What makes up forest l.jpg

In terms of woody plants, the two main types are trees and shrubs.

What are the main differences in a tree and a shrub?

What makes up forest?

Trees and shrubs l.jpg
Trees and Shrubs 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 l.jpg
Types of Seeds shrubs.

  • 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 l.jpg
Types of Seeds (cont.) shrubs.

  • 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 l.jpg
Types of Trees shrubs.

  • 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 l.jpg
Energy/Food shrubs.

  • 2 Types of Sugars

    • Starch – source of energy, excess is converted into wood

    • Cellulose – structural, makes up 70% of wood

Energy food9 l.jpg

Photosynthesis shrubs.

Co2 + water in the presence of light = sugar


Oxidation of Carbon

Sugar in the presence of Oxygen = CO2


Secondary chemicals l.jpg
Secondary Chemicals shrubs.

  • 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

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Three Types of Tissue shrubs.

  • 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 l.jpg
Growth shrubs.

  • 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 l.jpg
Growth (cont.) shrubs.

  • 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 l.jpg
Plant Hormones shrubs.

  • 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 l.jpg
Symbiosis with Fungi shrubs.

  • 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

Tolerance17 l.jpg

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.


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Gap Dynamics oaks)

  • 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 l.jpg
Competition through Chemistry oaks)

  • 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.

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Prescribed Burning oaks)

  • 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 burning21 l.jpg
Prescribed Burning oaks)

  • 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 l.jpg

Managing Natural Fires oaks)

Put out the fire or let it burn?

Yellowstone Park is this policies biggest challenge (contains 2.2 million acres)

“Let It Burn” Policy

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“Let It Burn” Policy oaks)

  • 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 l.jpg
Regeneration oaks)

  • 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 l.jpg

Advantages: oaks)

Usually produces a thick stand

No bed preparation is required

Requires no costs


Unknown species

Unknown genetics

Bad seed year


Seeds may be eaten by rodents

Natural Regeneration

Natural regeneration26 l.jpg

Methods: oaks)

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.

Natural Regeneration

Artificial regeneration l.jpg

Advantages: oaks)

Control seed supply

Increases prompt reforestation

Greater control over species and genetics

Control tree spacing

Regenerate in optimal weather conditions


Can be costly

Bed prep

Cost of seedlings

Cost of planting

Artificial Regeneration

Succession l.jpg
Succession oaks)

  • 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 l.jpg

2 Main ways oaks)

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

Harvesting Timber

Clear cutting l.jpg

Advantages: oaks)

Easy site preparation

Max profits

Natural and artificial regeneration can be used


Soil erosion

Takes time to regenerate

Negative view

Clear Cutting

High grading l.jpg

Advantages: oaks)

Biggest tallest trees are harvest

Species can be selected for a market

Highest dollar per board foot



Smaller trees and poorer quality is left

Regeneration has genetics that are inferior

High Grading

Siviculture l.jpg
Siviculture oaks)

  • 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 l.jpg
Un-even Aged Stand oaks)

  • 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 l.jpg
Review oaks)

  • 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 l.jpg
Tomorrow’s Lesson oaks)

  • Commercial Forest Land

  • NIPF – Non-industrial Private Forests

  • Land Expectation Value (LEV)

  • Mean Annual Increment (MAI)

  • Harvest Scheduling