Forestry

timber STAND IMPROVEMENT

Image by Street Donkey
Image by Markus Spiske
Image by Markus Spiske

Timber Stand Improvement (TSI) consists of practices designed to produce more and better quality wood products by improving the quality and species of the stand and by increasing 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 is most often a non-commercial activity in which there is no harvest of salable timber or such harvest is not sufficient to pay the cost of the practice. In very few cases it may be a commercial practice in which salable products of a value at least equal to the cost of the practice are harvested.

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.

Conditions necessary for successful TSI:

  • There must be a residual stand which is suitable for economical production of wood products (i.e. between 25-40 years old with favorable soils)

  • The benefits of increased quality or growth derived from removing competing vegetation must be significantly greater than the cost of carrying out the practice.

  • Only that vegetation competing with crop trees is removed.

  • The stand must be protected from wildfire and grazing by livestock. (i.e. fenced from cattle and pasture)


TSI practices include:

  • Release of crop trees from overtopping or undesirable trees.

  • Thinning overcrowded stands by cuttings designed to regulate stand density.

  • Cutting and removing grapevines from the stand

  • Pruning of branches off the butt log of the tree to improve lumber quality.

  • Sanitation cuts removing diseased or insect-infested trees to prevent infection of other trees in the stand.


Methods of TSI:

  • Felling of undesirable stems. Cut trees must not be left lodged in crop trees.

  • Girdling-by cutting a ring through the bark and into the wood completely around the stem to be deadened.

  • Cutting grapevines once at eye level and again at ground level. Treatment with a herbicide may be necessary.

  • Pruning-cut lower limbs off with a saw as close to the trunk of the tree as is practical without damaging the trunk.

  • This should be done during winter but may be done at other seasons during the year. In no case should more than 1/2 of the living crown be removed during any pruning operation. At least 1/3 the total tree height should be left in the living crown.