ISA Tree Biology and Physiology Questions and Answers — Questions and Answers
Question 1: An arborist observes a mature oak tree with a large, older wound on its trunk. New growth has formed around the edges of the wound, but the exposed wood in the center appears dark and decayed. This response, where the tree forms barriers to resist the spread of decay, is best described by which of the following concepts?
- Photosynthesis
- Transpiration
- CODIT (Compartmentalization of Decay in Trees) (Correct answer)
- Apical dominance
Correct answer: CODIT (Compartmentalization of Decay in Trees)
CODIT, which stands for Compartmentalization of Decay in Trees, is the process by which trees form defensive barriers to wall off decay and prevent its spread into healthy wood. This involves a four-wall system that resists the spread of pathogens. The new growth around the wound is Wall 4, the strongest barrier.
Question 2: Which of the following correctly pairs a tree tissue with its primary function?
- Phloem - transports water and minerals from the roots to the leaves.
- Xylem - transports sugars from the leaves to the rest of the tree.
- Cambium - a layer of cells responsible for secondary growth (thickening). (Correct answer)
- Pith - primary site of photosynthesis.
Correct answer: Cambium - a layer of cells responsible for secondary growth (thickening).
The cambium is a lateral meristem, a layer of actively dividing cells between xylem and phloem, responsible for the secondary growth that thickens stems and roots. Xylem transports water and minerals up the tree, while phloem transports sugars (produced during photosynthesis) from the leaves to other parts of the tree. The pith is the central core of the stem.
Question 3: A client is concerned about a newly planted maple tree that is losing water vapor from its leaves, especially on hot, sunny days. The arborist explains this is a normal process. What is the correct term for this process of water vapor loss through the stomata of leaves?
- Respiration
- Transpiration (Correct answer)
- Photosynthesis
- Guttation
Correct answer: Transpiration
Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems, and flowers. Water is primarily lost as vapor through small pores on the leaf surface called stomata. This process also helps pull water and minerals up from the roots.
Question 4: The primary growth of a tree, which results in the elongation of its shoots and roots, originates from which type of meristematic tissue?
- Vascular Cambium
- Cork Cambium
- Lateral Meristems
- Apical Meristems (Correct answer)
Correct answer: Apical Meristems
Apical meristems are located at the tips of shoots and roots and are responsible for primary growth, which increases the length of the plant. Lateral meristems, such as the vascular cambium and cork cambium, are responsible for secondary growth, which increases the girth or thickness of the tree.
Question 5: Which of these processes is essential for converting stored sugars into usable energy for a tree's growth, maintenance, and defense, and requires oxygen to occur?
- Photosynthesis
- Respiration (Correct answer)
- Translocation
- Absorption
Correct answer: Respiration
Respiration is the metabolic process where trees break down sugars (produced during photosynthesis) to release energy for various life processes. This process requires oxygen, which is why soil aeration is critical for root health, as roots must also respire. Photosynthesis creates sugars, while respiration consumes them to produce energy.
Question 6: An arborist is evaluating the root system of a large tree in a confined urban space. Which type of roots are primarily responsible for absorbing water and mineral elements from the soil?
- Tap roots
- Woody structural roots
- Absorbing roots (nonwoody) (Correct answer)
- Sinker roots
Correct answer: Absorbing roots (nonwoody)
Nonwoody, absorbing roots, often called feeder roots, are the primary structures for the uptake of water and essential mineral elements. They have a large surface area, often increased by root hairs, to facilitate absorption. Woody structural roots provide anchorage and transport, while tap roots and sinker roots are primarily for anchorage and storage.
ISA Tree Biology and Physiology Questions and Answers
An arborist observes a mature oak tree with a large, older wound on its trunk.
New growth has formed around the edges of the wound, but the exposed wood in the center appears dark and decayed.
This response, where the tree forms barriers to resist the spread of decay, is best described by which of the following concepts?