Soil and Water Management Flashcards
6 cards from real ISA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Soil and Water Management flashcards as text
What is the primary concern with overwatering established landscape trees?
Answer: It saturates the root zone, displacing oxygen and creating anaerobic conditions that lead to root suffocation and disease
Overwatering fills soil pore spaces with water, displacing the oxygen that roots need for aerobic respiration. Extended saturated conditions lead to root death, root rot diseases (particularly Phytophthora), and progressive decline.
How does a perched water table form and why is it problematic for tree root health?
Answer: It occurs at the interface between two soil layers of different texture, trapping water above the finer-textured layer and saturating roots in that zone
A perched water table forms when water moving downward through soil encounters an abrupt textural change (e.g., sand over clay), causing water to accumulate at the interface. This saturated zone suffocates roots growing at that depth.
What is the recommended method for irrigating newly transplanted trees during their establishment period?
Answer: Deep, infrequent watering that moistens the entire root ball and surrounding soil, gradually reducing frequency as roots establish
Newly transplanted trees should receive deep watering that thoroughly moistens the root ball and surrounding backfill soil. Frequency should be higher initially (2-3 times per week) then gradually reduced to encourage root exploration into surrounding soil.
How does road salt (sodium chloride) damage trees growing along roadways?
Answer: It increases soil sodium levels causing clay dispersion and poor drainage, draws water from roots through osmosis, and direct spray causes foliar desiccation
Road salt damages trees through multiple pathways: soil sodium causes clay particles to disperse (destroying structure), salt in soil water draws water out of roots through osmosis, and salt spray on foliage causes desiccation and tissue death.
What is the relationship between soil texture and plant-available water holding capacity?
Answer: Loam soils hold the most plant-available water because they balance drainage and retention better than sand or clay
Loam soils (balanced mix of sand, silt, and clay) hold the most plant-available water. While clay soils hold more total water, much of it is held too tightly for roots to extract. Sandy soils drain too quickly to retain much available water.
Why is the concept of the 'critical root zone' important during construction near trees?
Answer: It defines the minimum area around a tree that must be protected from soil compaction, grade changes, and root severance to maintain tree health and stability
The critical root zone (CRZ) represents the minimum root area necessary for tree survival and structural stability. Damage within the CRZ from compaction, root cutting, or grade changes frequently leads to post-construction tree decline and potential failure.