ISA Certified Arborist Practice Exam 2025 – All-in-One Resource for Comprehensive Exam Success!

Water quality plays a significant role in tree health, and one of the primary reasons is that contaminated water can negatively impact growth. Trees require clean, pollutant-free water to thrive because contaminants such as heavy metals, pesticides, and excess nutrients can inhibit their development. Poor water quality can lead to various physiological stresses in trees, affecting their nutrient uptake, root function, and overall vitality.

Additionally, if trees are exposed to contaminated water, they may struggle to absorb the necessary elements for healthy growth, which can lead to stunted growth, reduced flowering, and increased susceptibility to diseases. In essence, clean water is fundamental for trees to perform essential biological functions effectively.

While other factors relating to water quality are also important—like its impact on photosynthesis and pollutant absorption—they do not directly address the harmful consequences of contaminated water on growth as clearly as the correct choice does.