Timber Stand Improvement
Definition:
Timber stand improvement (TSI) is the process of improving the quality of a woodland over time.
How is TSI Accomplished? Click here for TSI Diagram & TSI Photos
1. By deadening or cutting down poor quality or "cull" trees.
2. By removing low-value tree species that are competing with higher value species.
3. By thinning dense young stands to promote larger and healthier trees on the same growing space.
3. By cutting grape vines growing in future crop trees.
4. By eliminating non-native or invasive plants from woodlands that can hinder growth or regeneration.
When is TSI Typically Done?
1. During a timber harvest operation.
Some TSI can be done during a selective timber harvest assuming that the stand of trees was marked prior to harvest by a professional who used good judgment. This means marking not only large mature trees for harvest, but also some smaller diameter trees of poor form or quality and cull trees (>50% defective). Beware that many stands of trees marked for harvest by timber buyers on behalf of landowners are not done with improvement as the main objective, but rather the removal of the largest and most valuable trees.
2. Immediately after or between harvest operations.
Right after a timber harvest is a good time to carry-out TSI. Trees that were partially damaged or knocked over by logging operations can be cut down, coppiced at the stump, or deadened in place. Cull trees that were not taken during the harvest can also be deadened. By performing this immediately after the harvest, you will gain the maximum growth benefits to the future stand and the work will be easier to perform due to less undergrowth.
With a young even-aged stand of trees, the timing of TSI will depend on the age and growth of the stand. For example, in southern Indiana a dense stand of bottomland timber will need a thinning at 20 to 25 years in age. Slower growing upland timber may not require such a thinning until the trees approach 30 years of age.
Finally, light TSI that consists of cutting down or deadening cull trees and cutting grape vines can be carried out anytime in the life cycle of a forest.
What Does it Cost to Perform TSI?
The cost of performing TSI will depend on who does the work. The first aspect of TSI is to determine which trees need to be cut down or deadened. This can be accomplished by a trained forester or by a landowner who has knowledge of tree identification, tree health, timber quality, and stand growth. The trees that need to be removed can be marked with paint to assist the landowner who wants to do his or her own work. The second aspect of TSI is the more difficult work of cutting down and/or deadening the trees and vines. The cost of hiring a forester to perform such work will typically vary from $30-$50 per acre, depending on the stand conditions and the number of trees or vines to be treated.
What are the Returns from Performing TSI?
1. Studies carried out by universities have demonstrated the financial returns associated with TSI. Here is one example:
2. TSI also improves the health and vigor of the trees in a forest. Crowded stands of trees are generally slow growing and are more susceptible to insect attack or disease outbreak. After TSI is performed, the remaining trees are more dominant, grow faster, and are more resistant to attack.
3. TSI can favor certain wildlife species in a forest. For example, increased understory growth following a thinning in a dense young forest will promote more browse for deer or more insects for quail.
Safety Precautions:
Please beware that cutting down and/or deadening trees in a forest can be dangerous work. If you decide to perform TSI in your own woods, please use all safety precautions and be sure to sound any cull trees to determine the amount of defect in the stem before cutting. A large and hollow tree can fall over with as little as a 1" deep chainsaw girdle made around the trunk.
Copyright 2006, Dwyer Forestry Consulting