3 minute read
Take Care of Landscape Trees Today for a Greener Tomorrow!
By Janet Hartin
Trees are likely the most highly valued plants in your HOA’s landscape. They provide shade, reduce temperatures in hot urban heat islands, add beauty, and even help clean the environment by storing carbon dioxide. Prune trees correctly. Taking care of your trees is an important way to maximize these benefits.
HERE ARE SOME WAYS YOU CAN HELP ENSURE A HEALTHY TOMORROW THROUGH PROPER TREE CARE TODAY:
• Prune trees following recommended practices and never top them! Topping a tree is the process of giving a tree a virtual crewcut by making one or more horizontal cuts across the top of the tree to shorten it. Why is topping trees harmful? Topping trees results in unstable, unsafe, and unattractive trees. It also reduces the ability for trees to reduce high temperatures and provide adequate shade in urban heat islands, sequester (store) carbon produced by fossil fuels, and provide wildlife habitat. In some cases, trees are topped because a tall tree that should not have been selected in the first place is growing into utility lines. In other cases, topping occurs due to a lack of knowledge about the dangers of topping and/or simply wanting to save money by going with the lowest bid. In all cases, topping should be avoided. The combination of improper balance and weak, poor-quality growth following topping creates a much higher likelihood of personal injury and property damage than occurs from properly pruned trees. For detailed information on proper pruning visit the International Society of Arboriculture's (ISA) consumer website: www.treesaregood.org). Contact a Certified Arborist (https://www.isa-arbor.com/Credentials) who is trained in tree health and care if you are in doubt about caring for your landscape trees. S/he will determine the proper pruning and thinning procedures and otherwise assess the overall health of your tree.
• Remove any tree ties that are cutting into the trunk or branches of your trees. If trees must be staked due to windy conditions, make sure that the ties are loose enough to allow trees to gently flex in the wind. This helps trees develop the necessary lower trunk strength and stability to support the tree as it matures. Over time, you may be able to completely remove the ties and stakes once the lower trunk becomes stronger and self-supporting.
• Keep all plants and mulch several inches away from tree trunks.
• Keep tree trunks dry. They should not come into contact with water from sprinklers or hoses.
• Water mature trees infrequently and deeply. Watering too often reduces the level of oxygen in the rootzone and can lead to waterlogged soils prone to crown and root rots. During fall, trees require only about 15% of the water they required in the summer.
• Identify and correct problems due to diseases, insects, or non-living (abiotic) disorders early. Most of the time, these problems are due to poor drainage or other soil/water management issues rather than pests. Watch out for borers, weevils, and root and crown-rot forming pathogens common to our desert.
• Ensure adequate space for a new tree. Large growing shade trees liker ficus and rosewood require up to 3,000 cubic feet of underground space and should not be planted under power lines. Smaller drought resistant trees are better choices under these conditions.
• Add mulch around trees (but avoid contact with trunks) to prevent damage from mowers and weed trimmers. Mulch also reduces soil evaporation and weed seed germination.
• Avoid soil grade changes. Grade changes from construction activities should be kept several yards from trees. Even small changes in the depth of the soil can result in serious root system injury. As little as four to six inches of soil applied on top of the root zone of a mature tree can dramatically reduce the amount of oxygen available to roots and can kill a tree over time. Lowering the grade can cause lower trunk and root injury and reduce the nutrient and moisture supply to the roots.
Janet Hartin is the Area Environmental Horticulture Advisor for the UC Cooperative Extension programs in San Bernardino, Los Angeles, and Riverside Counties and County Co-director for San Bernardino County. She can be reached at (951) 313-2023 or by email at Jshartin@ucanr.edu.
