LARE LARE Prep Section 3 — Questions and Answers
Question 1: Which plant hardiness zone system is most commonly used in the United States to guide plant selection?
- Köppen Climate Classification
- USDA Plant Hardiness Zone Map (Correct answer)
- Sunset Western Garden Zones
- Ecoregion Level III Classification
Correct answer: USDA Plant Hardiness Zone Map
The USDA Plant Hardiness Zone Map, based on average annual minimum winter temperatures, is the standard reference for plant selection in the US.
Question 2: A landscape architect specifies a tree with a 'caliper' measurement. Caliper refers to the trunk diameter measured:
- At the base of the trunk at grade
- At 6 inches above grade for trees up to 4-inch caliper (Correct answer)
- At breast height (4.5 feet) for all trees
- At the narrowest point of the trunk
Correct answer: At 6 inches above grade for trees up to 4-inch caliper
Per ANSI Z60.1, caliper is measured at 6 inches above grade for trees up to 4-inch caliper, and at 12 inches for larger trees.
Question 3: What is the primary function of a 'root barrier' installed along a sidewalk adjacent to a large-caliper tree?
- To prevent roots from absorbing sidewalk irrigation water
- To direct root growth downward and away from pavement (Correct answer)
- To protect roots from damage during sidewalk construction
- To prevent disease transmission between adjacent trees
Correct answer: To direct root growth downward and away from pavement
Root barriers redirect tree root growth downward rather than horizontally, preventing pavement heaving while keeping the tree in place.
Question 4: Allelopathy in the context of planting design refers to:
- The sensitivity of plants to air pollution
- Chemical inhibition of one plant's growth by another plant's secretions (Correct answer)
- A symbiotic relationship between a tree and mycorrhizal fungi
- The phenomenon of plants leaning toward light sources
Correct answer: Chemical inhibition of one plant's growth by another plant's secretions
Allelopathy describes the biochemical inhibition or stimulation of one plant species by chemicals released by another, affecting planting compatibility.
Question 5: When developing a plant palette for a public plaza in a high-pedestrian urban environment, which characteristic is LEAST important to prioritize?
- Salt and compaction tolerance
- Fruit or seed messiness
- Seasonal wildlife habitat value (Correct answer)
- Resistance to vandalism and mechanical damage
Correct answer: Seasonal wildlife habitat value
In a high-pedestrian urban plaza, wildlife habitat value is less critical than tolerance to urban stresses, maintenance, and safety concerns.
Question 6: The term 'xeriscape' refers to a landscape design approach that primarily emphasizes:
- Use of only native plant species
- Water-efficient landscaping through plant selection and design (Correct answer)
- Zero-maintenance landscape installation
- Elimination of all irrigated turf areas
Correct answer: Water-efficient landscaping through plant selection and design
Xeriscape is a water-efficient landscaping philosophy that uses drought-tolerant plants, efficient irrigation, and improved soil to reduce water use.
Question 7: A landscape architect's planting plan calls for plants on 'center' spacing. Plants specified at 24" o.c. in a triangulated pattern will cover ground more efficiently than a grid pattern because:
- Individual plants grow larger in triangulated arrangements
- Triangulated spacing reduces the effective square footage per plant
- Each plant covers approximately 15% more area due to offset rows (Correct answer)
- Triangulated patterns require less irrigation coverage
Correct answer: Each plant covers approximately 15% more area due to offset rows
Triangulated (staggered) planting allows rows to offset, reducing gaps and allowing approximately 15% better ground coverage than a square grid at the same spacing.
LARE LARE Prep Section 3
Which plant hardiness zone system is most commonly used in the United States to guide plant selection?