Urban Forest Drought Tip – Mulch

To provide trees with the best chance of survival during drought, apply mulch on the soil surface within the drip line of the tree. According to the International Society of Arboriculture, mulching, when done correctly, is one of the most beneficial practices for tree health.

Benefits of mulching include the following:

• Conserves soil moisture by increasing water infiltration and slowing evaporation.
• Improves soil structure, fertility, and aeration as it decomposes.
• Moderates soil temperature, protecting roots from extreme summer and winter temperatures.
• Eliminates potential tree damage from mowers and trimmers.
• Prevents soil compaction by reducing foot and vehicle traffic.
• Impedes growth of weeds and grass that compete with tree roots for water and nutrients.

Steps for Proper Mulching

• Mulch can be applied at any time of the year.
• Apply mulch on top of drip line irrigation system.
• Mulch as much of the area under the drip line of the tree as possible. Drip line is the area underneath the trees canopy. Preferably to the outermost edge of the tree's canopy.
• Apply a 2- to 4-inch layer of mulch. Applying more than 4 inches may harm the tree's root system.
• Keep all mulch material approximately 6- inches away from the trunk. This will prevent root rot.
• Organic based mulch is ideal. This includes wood chippings, grass clippings, pine needles, leaf litter, etc.
• Stay away from non-organic mulch products, such as plastic sheeting, recycled rubber-based products, rocks, etc.