ISA Certified Arborist Practice Exam

What is the importance of mulch for trees?

1. It enhances the beauty of the garden.

2. It helps retain soil moisture and regulate soil temperature.

3. It increases the number of insects around trees.

4. It prevents trees from growing too tall.

The correct answer is: It helps retain soil moisture and regulate soil temperature.

Mulch plays a crucial role in the health and well-being of trees by helping to retain soil moisture and regulate soil temperature. This is particularly important for young trees or newly planted specimens, as they can be more susceptible to fluctuations in moisture levels and temperature extremes. Retaining soil moisture with mulch reduces the frequency of watering required, which not only conserves water but also establishes a more stable environment for root growth. Additionally, by regulating soil temperature, mulch helps to keep roots cool during hot weather and warmer during cold spells, promoting optimal conditions for growth and minimizing stress on the tree. While the aesthetic enhancement of a garden is certainly a benefit of using mulch, its practical advantages related to moisture retention and temperature regulation are vital for the long-term health and vitality of trees. The other options, such as increasing insect populations or preventing tall growth, do not reflect the fundamental ecological benefits that mulch provides to trees.