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FOREST MANAGEMENT WORKSHOP MANUAL

TIMBER STAND IMPROVEMENT


1.  DEFINITION - Timber Stand Improvement (TSI) consists of 
practices designed to produce more and better quality wood 
products off a given area by improving the quality and species 
composition of the stand and by increasing, or at least 
preventing a decrease in, the rate of growth of the residual or 
crop trees in the stand.  This is usually done through a process 
of cutting or deadening undesirable vegetation which is 
competing for sunlight or other elements necessary for growth 
with the desired or crop trees in the stand, or which has a 
degrading effect on the stand.  Timber stand improvement may be 
commercial in which salable products of value at least equal to 
the cost of the practice are harvested, or it may be non-
commercial in which there is no harvest of products or such 
harvest is not sufficient to pay the cost of the practice.  
Essentially, the purpose of TSI is to make available the proper 
growing space for the best trees in the forest by favoring them 
and limiting competition.  A side benefit is salvage of trees 
which might otherwise be lost through mortality.

2.  Conditions necessary for successful TSI:

    a.  There must be a residual stand which is suitable for 
        economical production of wood products.
    b.  The benefits of increased quality or growth derived from 
        removing competing vegetation must be significantly 
        greater than the cost of carrying out the practice.
    c.  Only that vegetation (usually trees or vines) competing 
        with crop trees is removed.
    d.  The stand must be protected from wildfire and grazing by 
        livestock.

3.  TSI may include:

    a.  Release of crop trees from overtopping or undesirable 
        trees or vines.
    b.  Thinning overcrowded stands by cuttings designed to 
        regulate stand density.
    c.  Pruning of branches off the butt log of the tree to 
        improve lumber quality.
    d.  Cleaning young stands to insure a higher proportion of 
        more desirable species as the stand matures.
    e.  Sanitation cuts removing diseased or insect infested 
        trees to prevent infection of other trees in the stand.

4.  Methods of TSI:

    a.  Felling of undesirable stems-cut trees must not be left 
        lodged in crop trees.
    b.  Girdling-by cutting a ring at least 2 inches wide, 
        through the bark and into the wood completely around the 
        stem to be deadened.
    c.  Frill girdling with chemical-by cutting a frill of 
        overlapping axe cuts completely around the stem and 
        treating the frill with a chemical mixture.
    d.  Basal Spray-for stems under 4 inches in diameter by 
        spraying the lower 18" to 24" of the stem to the point 
        of run-off with a chemical mixture.
    e.  Foliage Spraying-applied during the growing season when 
        leaves are fully developed (usually June 15th to August 
        15th) foliage is thoroughly wet with a mist spray of brush killer.
    f.  Pruning-cut lower limbs off with a saw as close to the 
        trunk of the tree as is practical without damaging the 
        trunk.  Trees should be pruned to a height of 9, 11, 13, 
        15, or 17 feet.  100 to 150 crop trees per acre should 
        normally be pruned to be economically justifiable except 
        in the case of high value trees such as black walnut 
        where it is practical to prune even a single tree per 
        acre.  This should be done during winter but may be done 
        at other seasons during the year.  In no case should 
        more than 1/2 the living crown be removed during any 
        pruning operation.  At least 1/3 the total tree height 
        should be left in living crown.

        Methods "a"through "d" may be applied at any time during 
        the year.

5.  Pesticide Application:

    a.  In cases where pines are cut in pine stands, stumps 
        should be treated by sprinkling with borax to prevent 
        infection by root rotting fungi.
    b.  Since herbicides are very difficult to remove from spray 
        containers, any sprayer which has been used to apply 
        herbicide should NOT later be used to apply pesticides 
        to desirable crops.
    c.  All pesticides should be applied in strict accordance to 
        label directions.
    d.  Commercial applicators of pesticides must be licensed.

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Last revised December 25, 1998.

Please send comments to: Duane Bristow (oldky@webcom.com)