SILVICULTURE

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SILVICULTURE

• Manipulation of Forest Stands Under Management

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Silviculture

• Definition The theory and practice of
  controlling the establishment, density,
  composition, and growth of forests for the
  production of desired outputs.

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Silviculture (contd).

• OBJECTIVES
• 1. Control of stand composition
• 2. Control of stand density
• 3. Stocking and restocking of unproductive
  areas
• 4. Control length of rotation
• 5. Protection and salvage of timber
• 6. Protection of site and other benefits

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Silviculture (contd)

• Basic Ecological Principle A given acre of land
  is capable of the production of a given amount of
  biomass.
• Silvicultural applications, for the most part,
  change the form of biomass.

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Silvicultural Tools or Techniques

• 1. Harvesting (Cutting)
• A. Regeneration harvests.
• B. Intermediate treatments.
• Thinning
• Cleaning
• etc.
• 2. Prescribed fire

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Silvicultural Tools or Techniques

• 3. Chemical treatments
• Herbicides
• Insecticides
• Fungicides
• Used primarily to accomplish various objectives
  of intermediate treatments.

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Silvicultural Tools or Techniques

• 4. Seeding or planting
• 5. Pruning
• 6. Girdling
• 7. Fire prevention and control

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Reproduction Systems

• Procedures by which the forest (stand) is
  renewed or established, either naturally or
  artificially.
• Types
• High Forest vs. Low Forest
• Even-Aged vs. Uneven-Aged

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Regeneration Harvest Systems

• Even-Aged
• Clearcutting
• Shelterwood
• Seed Tree
• Uneven-Aged
• Selection

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Clearcutting

• Advantages
• - May be best for over-mature stands
• - Avoids logging damage to residual and
  reproduction
• - Minimizes concerns for windthrow
• - Often provides bare seedbed
• - Facilitates type conversion
• - Economies of operation
• Concentrates logging activity
• Reduces road building

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Clearcutting

• Disadvantages
• - Poor site protection
• - Poor aesthetics
• - Possible losses of site fertility
• - Inappropriate for many species
• Heavy seeded
• Tolerant some situations
• - Requires diversified markets
• Size
• Species

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Seed Tree

• Advantages
• - Good for intolerant, lighter-seeded species
• - Possibility of species control for
  regeneration
• - Concentration of logging activity
• - Can harvest large areas with good regeneration

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Seed Tree

• Disadvantages
• - Poor site protection
• - Poor aesthetics
• - Seed source subject to windthrow
• - Requires wind distribution of seed
• - Timing of harvest is critical
• - Competition may hinder regeneration

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Shelterwood

• Advantages
• - Provides reasonable site protection
• - Prepares site for seed germination
• - Proper distribution of light
• - Timing of regeneration cut for good seed
  production
• - Good for heavy seeded species

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Shelterwood

• Disadvantages
• - Potential for logging damage to residual and
  regeneration.
• - Risk of windthrow, fire, etc.
• - Higher degree of administrative skill and time
  commitment

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Selection

• Advantages
• - Maximum of site protection
• - Selectivity of product outputs
• - Minimizes risks of windthrow, fire, etc.
• - Most aesthetic
• - May be best for small woodlots

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Selection

• Disadvantages
• - High logging costs
• - Potential for logging damage to residual
• - Limited to shade tolerant species
• - Requires greatest degree of administrative
  skill

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Intermediate Practices

• Treatments that occur between the time of stand
  establishment and the time of regeneration
  harvest.
• Objectives
• - Improve quality of stand
• - Protection control of mortality
• - Shorten rotation

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Intermediate Practices

• Cleaning (Weeding)
• - Primary purpose is control of stand
  composition by removal of undesirable
  individuals.
• - Done in immature stands, not beyond sapling
  stage, usually first to twentieth year.

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Intermediate Practices

• Thinning
• - Modifying stand structure to achieve desired
  spacing.
• - Purpose is to increase rate of growth of
  residual stand and shorten rotation.
• - May be done at any age, usually poletimber
  stage or beyond.

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Intermediate Practices

• Improvement Cutting
• - Removal of undesirable individuals to
  improve overall quality of the stand.
• - Normally done in stands beyond sapling stage.
• - Most needed practice for previously unmanaged
  stands.

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Intermediate Practices

• Salvage Cutting
• - Made for purposes of removing trees killed or
  damaged by various agents, (fire, disease,
  insects, etc.).
• - Generally done when damaged material is
  marketable.

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Intermediate Practices

• Pruning
• - Removal of a portion of the limbs or crown.
• - Purposes of improving form or quality of
  individuals or for stand protection.

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Intermediate Practices

• Sanitation
• - Removal of potential disease or insect
  infested trees for stand protection.
• - Marketability not a significant concern.

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Integrated Pest Management