Timber Processing I: Pruning Techniques

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Questions and Answers

What is a consequence of delayed pruning on tree health?

Increased production of timber

Easier stacking of branches

Reduced competition between trees

Thicker branches lowering production (correct)

What is the ideal season for pruning trees to avoid stress?

Summer, to prepare for winter

Fall, before the leaves shed

Winter, during the dormant season (correct)

Spring, during active growth

Which of the following tools is NOT commonly used for pruning?

Screwdrivers (correct)

Chainsaws

Pruning shears

Pole pruning saw

What factor influences the healing process of a pruned tree branch?

Ambient temperature and humidity Signup and view all the answers

What type of pruning is described as a slow natural process?

Natural pruning (Cladoptosis) Signup and view all the answers

What is the primary aim of a correct pruning schedule?

Limit knots to the knotty core section Signup and view all the answers

Which pruning regimen is recommended for a 9-meter dominant tree aged 8-9 years?

5 meters Signup and view all the answers

What diameter pruning method is suggested for a 10.5 m tree?

Prune to 5-6 m height Signup and view all the answers

What is a negative effect of over pruning on trees?

Bark scorch Signup and view all the answers

The recommended removal percentage of the living crown that does not restrict growth is:

25% Signup and view all the answers

What adverse effect is associated with heavy pruning?

Epicormic shoots Signup and view all the answers

What is the recommended action when pruning a 14.5 m tree?

Prune to 8 m Signup and view all the answers

What is the result of a 70% removal of living crown from a tree?

Reduction in height and diameter growth Signup and view all the answers

What is the primary objective of pruning trees?

To prevent dead knots and improve timber quality Signup and view all the answers

What is a key factor influencing timber quality according to knot characteristics?

The size of the knots and their type Signup and view all the answers

Which of the following is NOT a primary reason for pruning trees?

Enhancing visual appearance Signup and view all the answers

What type of knot is more likely to fall out as wood dries?

Dead knot Signup and view all the answers

What is a potential consequence of having tight knots in timber?

They reduce the overall strength of the wood Signup and view all the answers

What should be carefully considered when creating a pruning schedule?

The optimal time for pruning each type of tree Signup and view all the answers

Which of these options is listed as a secondary reason for pruning?

Fire protection Signup and view all the answers

What type of knot is formed when a living branch is overgrown by the main stem of the tree?

Tight knot Signup and view all the answers

Study Notes

Definition of Pruning

Removal of live, dead, or dying branches from trees to achieve specific objectives.
Pruning is a costly operation and requires justification, as pruned logs can sell for a higher price.

Primary and Secondary Reasons for Pruning

Main goals include preventing dead knots and general knot formation.
Secondary benefits encompass fire protection, improved health of the compartment, better accessibility, and enhanced timber value.

Knot Influence on Timber Quality

Knots significantly affect timber quality and selling price.
They reduce structural strength, cause lateral distortion, and lead to issues like cracking and poor processing.

Types of Knots

Tight/Live Knots:
- Do not fall out upon drying; formed from living branches overgrown by the main stem.
- Still reduce wood strength but are stronger than dead knots.
Loose/Dead Knots:
- Can fall out when dried; occur with dead branches overgrown by main stem.
- Not integral to the stem, leading to possible structural weaknesses.

Pruning Schedules

Designed to optimize financial gains in commercial forestry.
Requires careful planning on when and how to prune to limit knot formation and maximize clear timber around the knotty core.

Fixed Lift Pruning Regime

Specific pruning heights based on tree size and age, designed to maintain tight knots and promote healthy growth:
- Dominant tree height of 3.5m requires pruning to 1m at age 3-4.
- Dominant tree height of 12m requires pruning to 7m at age 10-12.

Diameter Pruning Regime for P.patula and P.taeda

Trees are pruned to a diameter of 10cm or 50% of the crown around varying dominant tree heights to manage knotty cores effectively.

Effects of Over Pruning

Can lead to bark scorch, epicormic shoots, and cambium damage resulting in disease.
Removal of:
- 25% of living crown: No growth restriction.
- 50%: Temporary effect on diameter but not height.
- 70%: Reduces both height and diameter growth.

Consequences of Delayed Pruning

Increased knotty cores and thicker branches lead to lower production and higher costs.
Difficulty in managing heavier branches and potential for more significant bark damage.
Greater competition among trees results in more and larger knots, decreasing overall timber quality.

Correct Pruning Practices

Should be conducted in winter during the dormant season to avoid tree stress and minimize pest incidence.
Proper silvicultural practices are essential to maintain tree health.

Natural Pruning (Cladoptosis)

A slow process where lower branches are naturally removed by environmental factors.
Occurs more frequently in eucalyptus species than in pine, influenced by factors like fungal activity and growing conditions.

Pruning Equipment

Essential tools include pole pruning saw, pruning shears, chainsaws, and rich pruning tools designed for effective branch management.
Use of diameter gauges assists in achieving correct pruning specifications.

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Description

This quiz covers the fundamental concepts of pruning in timber processing, emphasizing the definition, objectives, and importance of this technique. Learn about the primary and secondary reasons for pruning, including cost-effectiveness, fire protection, and enhancing timber quality.