Though we may not be able to fathom a time when the ground is fully thawed and we need to worry about drought, irrigation is fundamental to the health and success of your landscape plants. In ground irrigation systems already in place should be checked for proper functioning and repaired where and if necessary, while being careful not to damage or greatly disturb vegetation. Similarly, if you plan to install an irrigation system, be sure to have your arborist consult with the irrigation professional; together they can map out where irrigation is needed, places where it may not be as beneficial and areas to avoid digging so as not to injure vegetation.
The use of underground irrigation systems is on the rise, these systems not only increase possible plant diversity which can thrive on a site but assist in addressing the seemingly cyclical drought patterns occurring regionally. Lack of moisture is one of the top stressors facing landscape and urban trees, and extended stress from drought conditions makes plants more susceptible to pests and disease. Proper irrigation of trees with a customized and modifiable irrigation plan and system can help your landscape plants resist infestation or infection, improve vigor and help to ensure lasting beauty.
However, while these systems provide vast benefits, installation or improper usage can lead to serious tree damage. Overwatering and root damage are common problems associated with the use of in ground irrigation systems whether they were installed for the turf or trees. Trenching too close to a tree while installing a system can cause long term damage to its root system. Remember that roots extend quite a ways, a general rule of thumb is that root systems can be over 2 1/2 times the height of the tree and the majority of the growth is within the top 18 inches of soil. It is in these areas that damage is incurred or roots entirely severed while installing underground piping required for an irrigation system. Trenching, vibratory plowing or earth sawing methods may make 20 inch cuts vertically through soil destroying any roots in their path. Damage may not be instantly visible, but usually within months dieback and decline will become apparent.
Your arborist can develop a tree protection plan to advise and inform the irrigation professional on minimizing damage to trees during the installation process. Proposed layout, installation and operational plan should be reviewed by your arborist prior to beginning this type of project. Without a plan in place to protect inhabiting trees root damage is likely to occur. Prior to choosing a contractor research “trenchless technology” and “horizontal drilling” to find more information about tree friendly methodologies of landscape irrigation installation. Today there are many available options for affordable, versatile, easy-to-use, green technologies which leave a small environmental footprint. Root system damage is something you want to avoid where feasible, physical damage provides easy access for disease and pests to an already stressed tree, recovery is possible but it can a tough road, fraught with hardships.
