Certified Forester Practice Exam

What is compression wood?

1. Wood that shrinks under pressure

2. Wood produced by increased cambial activity on a leaning stem

3. Wood that grows faster due to optimal conditions

4. Wood produced exclusively on the upper side of a tree

The correct answer is: Wood produced by increased cambial activity on a leaning stem

Compression wood refers to the specialized type of wood that develops in response to mechanical stress experienced by trees, particularly in leaning or tilted conditions. When a tree leans, the cambium—the layer of actively dividing cells that produces new wood—behaves differently on either side of the stem. On the side of the lean that is under compression, the cambial activity increases, leading to the formation of compression wood. This wood is characterized by different structural properties, including higher density and more pronounced growth rings, which helps the tree maintain stability and strengthen its structure against the forces of gravity and wind. This phenomenon is an important adaptation mechanism for trees, allowing them to better harness their resources and continue growing effectively even in challenging conditions. Other options relate to different wood characteristics, but only the option describing increased cambial activity on a leaning stem captures the essence of what compression wood is and its role in a tree's response to environmental stressors.