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

Excessive nitrogen application to trees primarily stimulates leaf and stem growth, leading to lush foliage. This phenomenon occurs because nitrogen is a critical nutrient that promotes vegetative growth; however, when provided in excess, it can disrupt the balance between above-ground growth and root development. As a result, trees may develop dense canopies with extensive leaf area, but their root systems may not grow proportionately to support this increased biomass.

Without sufficient root development, the tree may struggle to uptake water and nutrients effectively, making it more susceptible to stress, drought, and other environmental factors. Furthermore, an overabundance of nitrogen can lead to weaker trees that are more prone to disease and pest problems due to shallow root systems, which lack stability and resilience.

In contrast, enhanced root development, sufficient water retention, and increased flower production are not typically direct consequences of excessive nitrogen application. This imbalance in growth priorities can ultimately compromise the overall health and longevity of the tree.