Certified Arborist Practice Exam

Which of the listed options is NOT a diffuse porous tree species?

1. Planetree

2. Maple

3. Poplar

4. Oak

The correct answer is: Oak

The correct choice identifies oak as a tree species that is not classified as diffuse porous. In the context of tree anatomy, diffuse porous species have a uniform distribution of pores (vessels) throughout the growth rings, allowing for a more consistent texture and appearance across the wood. Species such as planetree, maple, and poplar fit this description because they typically exhibit a more even distribution of vessels in their wood. In contrast, oak is categorized as a semi-porous or ring-porous species. This means it has distinct growth rings with larger pores formed early in the growing season (earlywood) and smaller pores formed later (latewood). This variation creates a characteristic pattern in the wood, leading to differences in texture and density. Understanding these classifications helps in various fields, such as woodworking, forestry, and botany, as they affect the properties of the wood, its workability, and its uses.