You need proper water drainage. It’s necessary to protect your trees. Without good water drainage, a tree can slowly drown. It can take just a few days or maybe a few years, but it will happen. The tree without good water drainage will die from a lack of oxygen and nutrients. Waterlogged soils prevent aeration of plant roots and create susceptibility to diseases such as root rot. If you can correct your water drainage problems during lawn installation or tree planting, then you may just save your tree.
Before you plant a tree, you should evaluate the proposed planting area by performing a percolation test. What’s that you may ask? Well, percolation refers to how quickly water drains through the soil. To test your lawn’s percolation, dig a few holes within the potential root area of the mature tree – generally inside of and just beyond the canopy of the tree. Measure the rate of water drainage. You should make the holes between 18 to 36 inches deep and 6 to 12 inches wide. About three holes will provide thorough evaluation of the site. Fill the holes with water and allow the water to completely drain out of the holes before refilling with water to the tops of the holes. Measure the water drainage every hour. Percolation at the rate of 1 to 2 inches per hour indicates good water drainage.
Lawns around new construction are often shallow and compacted from foot traffic and heavy equipment. You should amend your soil to improve tilth and water drainage by incorporating 1 to 2 inches of organic matter such as peat moss or compost into the top 4 to 6 inches of soil. Cultivate your soil prior to and after the addition of these amendments to facilitate mixing them with the existing soil. Organic matter provides both moisture retention and better water drainage through the creation of larger soil pores.
When poor water drainage is due to a hardpan or impervious layer under your topsoil, drainage chimneys can correct the problem. With a posthole digger, dig 8 to 12 inches wide holes that are deep enough to break through the compacted layer into the porous soil. Fill the holes with gravel. The spacing of the drainage chimney is site-specific and depends on the degree of waterlogging you find. Begin with evenly spaced chimneys just outside the dripline of the tree. Add more drainage chimneys until you’ve corrected the problem.
You can install a French drain to move water away from a low-lying area. You don’t want your trees to get waterlogged as this can lead to diseases such as root rot. Begin building the French drain within the dripline of your tree and dig deep enough to get below the root area. You will then excavate a trench leading away from the tree to a lower level, using a slope of 3 inches per 25 linear feet. The width of the trench should be at least 6 inches. You can put 4-inch-diameter permeable pipe in the bottom of the trench to help with water drainage. Then, fill the trench with gravel and rock.
Of course, we hope you don’t need to take extreme measures to ensure that your tree has proper water drainage. We encourage you to think before you plant and to know your soil and your situation. A tree has the best chance of surviving when its environment provides for proper water drainage naturally. If you need help in deciding where to plant your tree, we are happy to provide it. Give us a call at 512-341-8888 today for more information. We’re Austin Tree Service and we want all your trees to be healthy.