SILVICULTURAL PRACTICES

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SILVICULTURAL PRACTICES
Forestry Committee May 2007
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SILVICULTURE

• The application of various treatments such as
  tree planting, pruning, intermediate cuttings and
  harvest cuts.

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• The forest manager must analyze each timber stand
  for the biological economic factors that bear
  upon it, then devise the silvicultural
  practices which will best meet their management
  objectives.

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FACTORS TO BE CONSIDERED

• Timber production Practices selected to produce
  the highest value products as well as volume that
  was feasible for the site available markets.

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• Timber production wildlife habitat Practices
  aimed at the highest return possible still
  accomplish both goals in a profitable manner.

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• Timber production watershed protection
  Practices used to areas adjacent to streams,
  ponds or lakes that require special techniques to
  protect the areas still accomplish the
  management objectives.

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BEST MANAGEMENT PRACTICESBMPS

• Require avoiding the following practices
• Using wheeled or tracked vehicles
• Leaving trees or tops in the water
• Roads or trails of any kind, unless absolutely
  necessary
• Fire

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• Any type of mechanical site preparation or
  machine planting
• Portable sawmills and log decks
• Aerial application of any pesticides or
  herbicides

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STREAMSIDE MANAGEMENT ZONES (SMZs)

• Areas near creeks streams that are protected to
  prevent erosion pollution.
• Distance from the edge of the streambed
• Region Primary SMZ Secondary SMZ
• Lower Coastal Plain 20 0
• Upper Coastal Plain 40 40
• Piedmont Mountain 80 80

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• Timber production recreation areas Practices
  used to keep both timber production and
  recreation activities profitable.

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• Always keep in mind that the practice of
  silviculture is tailored to each forest stand

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CUTTING OPERATIONS

• The principle most beneficial silvicultural
  treatments used in the southeast.
• The majority of timber is managed for maximum
  production.
• Intermediate cuttings cuttings of the timber at
  any time from reproduction stage to timber
  maturity or final harvest.
• Rotation the time from when the stand is
  established until the final harvest cut.

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INTERMEDIATE CUTTING OBJECTIVES

• Improvement of the existing stand
• Regulation of tree stand growth
• Early financial returns
• Reduction of conditions favorable to insects
  disease
• To create conditions favorable to reproduction

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THINNING

• A form of intermediate cutting in young stands to
  improve the yield of the stand at final harvest
  to provide the owner with early financial return.
• The objective is to leave better trees so future
  growth is concentrated on the higher value trees
  to utilize all merchantable material produced
  by the stand during its rotation.

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THINNING TECHNIQUES

• Low thinning taking out overtopped small trees
  in the understory
• Crown thinning removing trees from the middle
  upper levels, opening the canopy for maximum
  growth of dominant co-dominant trees in the
  stand

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• Selection thinning removes the dominant trees to
  concentrate growth on the lower crown classes.
  Not recommended unless immediate income is top
  priority. Considered high-grading.
• Mechanical thinning based on spacing with little
  or no regard for tree vigor, form or position in
  the canopy.

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MECHANICAL THINNING

• Two methods most often used are row thinning
  fixed intervals.
• Row thinning-taking out rows of trees at a time.
  (example every 3rd or 5th row)
• Fixed interval-strips cut throughout the stand.

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CLEANING

• Treatments in young stands past the sapling stage
  to free the desired species from competition by
  regulating the composition of mixed stands.

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METHODS OF CLEANING

• Prescribed burning-using fire under very closely
  controlled conditions the most economical tool
  used in young pine stands
• Cuttings-removing the undesirable trees by
  cutting
• Basal spraying-using chemicals sprayed at the
  base of trees to reduce competition reliable but
  expensive
• Foliage spraying-spraying hardwoods with
  herbicides is effective for broadcast control
  methods widely used

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LIBERATION CUTTINGS

• Used to free young stands, up to sapling size
  from competition of older, overtopping,
  individual trees.
• Accomplished by
• Girdling-cutting through the bark cambium
  layer to kill the stem leave it standing in
  place.
• Basal spraying-spraying herbicides around the
  stump or injected into the tree to kill it, used
  for large trees

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IMPROVEMENT CUTS

• Intermediate cuts to stands larger than saplings.
  They are done to improve the stand competition,
  quality, condition or form by removing inferior
  trees.

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TYPES OF IMPROVENENT CUTS

• Sanitation cut-removing trees infested with
  insects or attacked by disease.
• Salvage cut-removing trees that are dead, damaged
  by insects, disease, wind, lightning or various
  other factors.
• Pruning-removal of side branches from standing
  trees to produce knot-free lumber from logs of
  higher quality. No more than 1/3 of the tree
  crown should be removed.

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• LIVE CROWN RATIO-generally considered the best
  indicator of condition of the stand in relation
  to the optimum growth financial returns to the
  owner. Calculated by the amount of live crown
  divided by the overall height of the tree.

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STAND CONDITION INDICATORS

• Live crown ratio-sapling size to larger trees
  should have a live crown ration of 1/3 of their
  total height for proper growth ratio.
• Overcrowding-causing the crown to recede to ¼ or
  even less of the total height. Stands should be
  thinned to get optimum growth.

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STAND CONTITION INDICATORS

• Increment boring-taking a core sample of the tree
  to determine the trees growth rate. A reduction
  in the width of the annual rings indicates the
  need for thinning.
• Basal area-an excellent indicator of the degree
  of stocking in the stand the need extent of
  thinning required. Measured in square feet,
  taken with a wedge prism.

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• The general tendency for forest managers is to
  thin timber too lightly. This can cause a delay
  in the rotation of the forest resulting in an
  economic loss for the landowner.

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HARVEST CUTTING OBJECTIVES

• Removal of the mature timber.
• Establishment of reproduction.
• Supplementary treatments of the timber-growing
  site to develop favorable conditions for seedling
  growth.

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HARVEST METHODS

• Clear cutting Virtually cutting all of the trees
  in a stand, both large small. When clear
  cutting is used, artificial reforestation is the
  primary method of establishing a new stand.
• Seed tree cutting a form of clear cutting,
  except 4-10 trees are left dispersed throughout
  the area to provide for reproduction.

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• Shelterwood cutting a harvest cutting method
  where 25-40 trees per acre are left to supply
  seed for regeneration. Sometimes as many as 3
  cutting stages are used in a shelterwood cut.
• Selection cutting a complex method of cutting
  removing individual trees throughout the stand
  based upon maturity, growth rate, diameter
  vigor.