Mulch is valuable for a tree’s health and care. Mulch insulates the soil helping to provide a buffer from extreme temperatures, retains water helping to keep the roots moist, keeps weeds out to limit root competition, prevents soil compaction, and reduces lawn mower damage. Organic mulch such as wood chips or bark pieces is best as inorganic mulch can lead to a variety of problems. For example, rocks will heat up in the summer sun.
Place 2 to 3 inches of organic mulch around the tree, being sure to keep the mulch from touching the trunk of the tree. Mulch should be at least 3 inches away from the trunk and should extend out 3 to 10 feet depending on the size of the tree. Piling 6 to 12 inches of mulch at the base of the tree trunk is called volcano mulching This causes CO2 to build up and prevents the tree from completing respiration. As oxygen is depleted the tree will decline.
Tree watering is an essential part of tree care. New trees should be watered immediately after the tree is planted. During the first two growing seasons, new trees expend a lot of energy establishing their roots and have a difficult time dealing with heat and drought. For this reason, mulching and regular watering are important. Unless it rains 1 inch or more, rain water is not enough for newly planted trees.
While not enough water is harmful to trees, too much water is bad as well. Over-watering is a common tree care mistake. As a rule of thumb, soil should be moist, not soggy. A damp soil that dries for a short period will allow adequate oxygen to permeate the soil.
Tree Gator Bags hold 15 to 20 gallons of water, depending on bag setup and tree trunk diameter, and are helpful for maintaining moist soil around the tree. They should be filled every 7 to 10 days during the first two growing seasons (May to November). After two years, the tree’s roots will be established and the tree will be able to withstand a wider range of water conditions on its own because it has a proper root structure.
Aeration involves perforating the soil with small holes to allow air, water, and nutrients to penetrate deeper into the soil. Aeration can help add nutrients to depleted soils and alleviate soil compaction.
Large trees saturate the ground with feeder roots and can deplete the soil of nutrients. Compacted soils reduce the growth of shallow feeder roots and can lead to tree decline. Even foot traffic in populated areas can cause soil compaction. Soil aeration is recommended once every 5 years for large trees, for trees located in areas with compacted soils, or for trees planted in clay soils.
Trees that are planted properly and in the right location do not need fertilization and micronutrients. However, trees planted in urban environments, or clay or sandy soils, may need some help. To minimize future maintenance and care, always plant the right native tree in the right place.
To develop a tree with strong and desirable form, it is important to properly prune a tree. Ideally, branches should be at an angle between 30 degrees and 60 degrees and should be spaced every 12 to 18 inches. If trees are pruned properly when they are young, they will require less corrective pruning when they are mature. Other common reasons for pruning a tree include removing dead branches, removing crowded or rubbing branches, and eliminating hazards.
If pruning is not done properly, it can cause damage that will last a tree’s entire lifetime, stressing the tree and often weakening its structure. Know the purpose before making a cut on a tree because each cut can change the tree’s entire growth pattern.
Follow these guidelines for proper maintenance pruning:
- Prune only broken, damaged, or diseased branches on newly planted trees.
- Beginning at 2 to 3 years after a tree is planted, prune every 3 to 5 years until the tree is 10 feet clear above the ground. After that time, a tree can be pruned every 5 to 10 years.
- Do not remove more than 10% to 15% of the canopy on small trees, and more than 25%^ of the canopy on large trees.
- Large trees should be pruned by a professional trained in arboriculture.
Proper pruning involved making cuts just outside the branch collar. The branch collar should not be damaged or removed because it contains trunk/parent branch tissue. Cuts should not be made between buds and lateral branches because it may lead to sprout production, stem decay, and misdirected growth. If a permanent branch needs to be shortened, a cut should be made at a lateral branch with a diameter at least one-third the size of the parent branch.
When removing large limbs, it is important to first reduce limb weight. An undercut should be made approximately 12 to 18 inches from the point of attachment. A top cut should then be made several inches farther out on the limb. This will cause the limb to break off, significantly reducing it’s weight. Finally, the 12 to 18 inch stub can be removed by cutting back to the branch collar. To prevent tearing the bark, make an undercut near the branch collar and then make a top cut on the 12 to 18 inch stub at a 45 degree angle.
Along with proper pruning cuts, it is important to use the right pruning tools. For small trees, most cuts can be made with hand pruning shears. Cuts larger than one-half inch in diameter should be made with a pruning saw or loppers. Read the label when purchasing pruning tools to determine appropriate use, and keep all tools clean and sharp.