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

dividingApical 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 treesUsually 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