Why should mulch be kept away from the base of tree stems?

Why should mulch be kept away from the base of tree stems?

• A. To prevent moisture accumulation and disease at the collar and trunk; can also harbor pests.
• B. To improve nutrient uptake at the stem.
• C. To promote root growth directly at the trunk.
• D. To increase soil pH around the trunk.

Answer: (A)

Keep mulch away from the base of tree stems to prevent a damp, sheltered area at the trunk. When mulch rests against the bark, it traps moisture and limits airflow, creating a perfect environment for fungal diseases, trunk/ collar rot, and pests. The recommended practice is a ring of mulch around the root zone with a gap of several inches between the mulch and the trunk so air can circulate and moisture can dry. The other statements don’t fit because mulch won’t improve nutrient uptake at the stem (nutrients are taken up by roots in the root zone, not the trunk), it doesn’t promote root growth directly at the trunk, and it isn’t used to reliably change soil pH around the trunk.

Keep mulch away from the base of tree stems to prevent a damp, sheltered area at the trunk. When mulch rests against the bark, it traps moisture and limits airflow, creating a perfect environment for fungal diseases, trunk/ collar rot, and pests. The recommended practice is a ring of mulch around the root zone with a gap of several inches between the mulch and the trunk so air can circulate and moisture can dry. The other statements don’t fit because mulch won’t improve nutrient uptake at the stem (nutrients are taken up by roots in the root zone, not the trunk), it doesn’t promote root growth directly at the trunk, and it isn’t used to reliably change soil pH around the trunk.