Presentation on theme: "Introduction to Forestry Hoyt Ponder Submitted October 20, 2005."— Presentation transcript:
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