Water and oxygen are the two most important factors that trees need to survive. Trees are just like humans they need these nutrients to survive. When these resources are limited trees begin to decline, and, when a tree declines you begin to see dieback of leafy material in the upper portions of a tree’s crown. Water is one of the biggest reasons for this. During the summer, drought typically occurs and leaves begin to wilt and dry up. Irrigation systems can fix this issue and keep a tree healthy, and help it to live longer. However poor irrigation planning can have the complete opposite effect and can kill a tree. Planning for your irrigation system is the best way to keep a tree alive. Simple measures can be taken to ensure healthy trees for the future.
More times than not, improper irrigation installation occurs. Most installers use trenching methods to put in irrigation lines. Most of the tree’s roots are located within the top 12 inches of soil; however, irrigation lines are typically put in about 20 inches deep. This type of method severally damages a tree’s root system causing issues to arise such as: absorption of nutrients, desiccation (drying out of roots), and infestation of pests and disease. These issues stress out a tree which causes decline and ultimately death. If a root system is damaged within the dripline, the best remedy is to keep the tree adequately watered to prevent drying out and to limit stress.
There are two alternative methods of irrigation installation that can keep a tree healthy. One method is to trench outside of the tree’s dripline. This ensures the majority of the tree’s roots stays intact allowing an easier ability to fight off pests and disease. The second method method involves tunneling underneath the roots, limiting root damage. Once the tunnels have been made the irrigation lines can be pulled through.
Once the irrigation lines are installed, another issue arises, over watering. This is an issue we see on a regular basis. Just as too little water can kill a tree, too much water can do the same thing. As stated earlier trees need air in order to survive, if there is to much water the roots can not breath, which causes disease to occur, root rot and water molds. These fungi and bacteria are present in the soil and are out competed by other healthier bacteria; however, these pests strive in wet environments, and when the environment favors them they can cause many problems. The roots will look black and tear apart easy. Healthy roots are white and fleshy and won’t pull apart easy. The upper branches will begin to have dieback in the tips and the crown will look very sparse.
Many times irrigation is used on a daily basis, even during wet seasons. Limiting the amount of water in the environment will help to keep the trees healthy. Applying 1-3 inches of water a week is adequete for good growth and developments. If the root systems were damaged during installation increasing the amount of water would be beneficial. Placing a layer of mulch 2-4 inches thick will help to keep moisture in the soil. Mulch will also help relieve compaction and competition.