ISA Tree Biology & Physiology

Question 1

What is the role of xylem in a tree?

Accepted Answer

Transferring water from roots to leaves

Answer

Xylem is one of the two main transport tissues in vascular plants, including trees. Its primary function is to transport water and dissolved mineral nutrients from the roots, up through the stem, and to the leaves. This upward movement is crucial for photosynthesis and maintaining turgor pressure within the plant.

Question 2

What is photosynthesis in trees?

Accepted Answer

The conversion of sunlight into energy

Answer

Photosynthesis is the vital process by which green plants, including trees, convert light energy into chemical energy. Using chlorophyll, carbon dioxide from the air, and water from the soil, trees produce glucose (sugar) for food and release oxygen as a byproduct. This process is fundamental for tree growth and survival.

Question 3

How does tree bark protect the tree?

Accepted Answer

Protects from pests and environmental damage

Answer

Tree bark serves as the tree's protective outer layer, shielding the delicate inner tissues from various threats. It acts as a barrier against insect infestations, fungal diseases, and physical damage from animals or weather extremes. Bark also helps regulate the tree's internal temperature and prevents excessive water loss.

Question 4

What is the function of phloem in trees?

Accepted Answer

Transferring sugars and nutrients from leaves

Answer

Phloem is the other main transport tissue in trees, working in conjunction with xylem. Its primary role is to transport sugars (produced during photosynthesis in the leaves) and other organic nutrients to all parts of the tree where they are needed for growth or storage. This movement can be both upwards and downwards, depending on the plant's needs.

Question 5

How do trees adapt to drought conditions?

Accepted Answer

Reduce leaf growth

Answer

Trees adapt to drought conditions by implementing strategies to conserve water. Reducing leaf growth, shedding leaves, or developing smaller, thicker leaves are common adaptations that minimize the surface area available for transpiration (water loss through leaves). This helps the tree retain precious water during periods of scarcity.

(ISA) ISA Certified Arborist Practice Test

(ISA) ISA Certified Arborist Practice Test

ISA Tree Biology & Physiology