What Is The Difference between Compression Wood and Tension Wood?

So, what is the main difference between compression wood and tension wood? The former is formed on the lower side of the trunk while the latter on the upper side of the trunk. 

Mature wood usually has unique growth patterns and reaction properties. The reaction wood occurs due to environmental factors like wind, pressure, climate, the force of gravity, and more.  These unique growth patterns are witnessed on tree trunks and branches. Changes in these environmental factors result in compression and tension wood. 

This article provides detailed insight into the differences between compression wood and tension wood. The purpose is to provide deeper insight and understanding. 

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Difference between Compression Wood and Tension Wood (With Table)

Basic Term

Compression Wood

Tension Wood

Description

Develops on the lower side of the leaning part trunk

Develop on the upper side of the leaning trunk.

Amount of Cellulose

30%

60%

Found

Softwood like pines

Hardwoods like oaks

Reaction of Wood

Conifers

Dicots

Function

Lengthening and straightening bends

Prevent branch from bending or drooping due to pulling force

Examples of Wood

Pinewood

Mango woods

Type of Plants

Gymnosperms

Angiosperms

What Is Compression Wood?

Compression wood is a specialized type of wood that forms in response to mechanical stresses, particularly compression forces, acting on the lower side of leaning or inclined stems, branches, or trunks of trees. It is a structural adaptation developed by trees to counteract gravitational pull and maintain stability in response to tilting or bending. This unique wood type exhibits distinctive anatomical features compared to normal wood.

In terms of structure, compression wood is characterized by thicker cell walls, smaller cells, and a higher density of fibers. These anatomical modifications contribute to the wood’s enhanced strength and support properties, making it well-suited for its role in providing mechanical support in response to compression forces.

Compression wood is commonly found in coniferous trees, where its presence can affect the quality and characteristics of the wood. The wood often appears darker in color compared to normal wood, making it visually distinguishable. Its formation is a dynamic response to environmental and mechanical cues, emphasizing the tree’s ability to adapt to its surroundings and maintain structural integrity in the face of external pressures.

Understanding compression wood is essential in various contexts, including forestry, wood processing, and the study of tree biomechanics. Recognition of its unique properties aids in the assessment of wood quality and the development of effective strategies for wood utilization in industries such as construction and manufacturing.

What Is Tension Wood?

Tension wood is a specialized type of wood that develops in response to mechanical stresses, particularly tension forces, acting on the upper side of leaning or inclined stems, branches, or trunks of trees. It is a structural adaptation that helps trees counteract the forces of gravity, maintain an upright position, and resist bending or tilting. Tension wood possesses distinctive anatomical features that distinguish it from normal wood.

One prominent characteristic of tension wood is the presence of gelatinous fibers. These fibers, observable under a microscope, are elongated cells containing a gelatinous material. Notably, this gelatinous material contracts upon drying, contributing to the characteristic properties of tension wood. The contraction of these fibers aids in the tree’s response to tension forces, providing a mechanism for the adjustment and maintenance of its structural integrity.

Tension wood is often found in hardwood trees, and its presence influences the overall quality and characteristics of the wood. The anatomical modifications in tension wood make it particularly suitable for resisting tension forces and maintaining the tree’s stability in response to external mechanical stresses.

Understanding tension wood is essential in forestry, wood processing, and the study of tree biomechanics. Recognizing its unique features and properties helps researchers and industry professionals assess wood quality, optimize the utilization of wood resources, and gain insights into the dynamic responses of trees to their environmental and mechanical conditions.

Differences Between Compression and Tension Wood

  1. A compression wood reaction occurs in conifers of the lower side of the trunk while tension wood occurs on the upper side of the leaning trunk.
  2. Compression wood has a little amount of cellulose when compared to tension wood cellulose.
  3. Tension wood is quite common in gymnosperms while compression wood in angiosperms.
  4. Compression wood is quite common in conifers like pines while tension wood in mango plants.
  5. Tension wood help to prevent the branch from drooping due to pulling force while compression wood offer lengthening and straightening effects on bends.

Similarities Between Compression and Tension Wood

  1. Both are reaction wood
  2. Both happen in trees
  3. Both contain cellulose 

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Conclusion

Compression wood and tension wood are two distinct types of wood that develop in response to mechanical stresses in trees. These woods exhibit contrasting characteristics in terms of structure, composition, and function within the tree.

Compression wood forms on the underside of leaning or inclined stems, branches, or trunks of trees. It is a response to compression forces and gravitational pull, typically developing on the lower side to provide additional support. In terms of structure, compression wood has thicker cell walls, smaller cells, and a higher density of fibers. It often appears darker in color compared to normal wood.

Tension wood, on the other hand, develops on the upper side of leaning stems in response to tension forces. Its primary function is to counteract the mechanical stress and help the tree maintain an upright position. Tension wood is characterized by the presence of gelatinous fibers, which have a distinct appearance under a microscope. These fibers are elongated and contain a gelatinous material that contracts upon drying, contributing to the characteristic reaction wood properties.

In summary, compression wood forms on the underside of inclined tree stems, exhibiting thicker cell walls and increased density to provide mechanical support against compression forces. Tension wood, which develops on the upper side of inclined stems, is characterized by gelatinous fibers that contract upon drying, helping to counteract tension forces and maintain the tree’s upright position. Understanding these differences is crucial for various applications, including wood processing and the study of tree biomechanics.

More Sources and References

  1. Lignification and Tension Wood. Research Gate

  2. Reaction Wood. Landscape Plants 

  3. Reaction Wood. Wikipedia 

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