By Ralph E. Mitchell
Beyond broken branches, one of the most common hurricane-related tree damage issue was uprooted trees. Trees bent and listing, some partially uprooted, and even some with their root balls totally exposed, were indications of poor root development and anchorage problems. Irresistible force winds aside, some blow-overs were unavoidable, but some could have been prevented with proper planting techniques from the get-go.
Most tree roots are in the upper three feet of soil, but grow well beyond the reach of the branches out into the landscape. This is generally sufficient to stabilize and anchor the tree from day to day winds and even the occasional severe wind storm. In some areas our water table is so high that roots can be pruned off by the water compromising stability to the point where wind will blow the whole tree over exposing a mat of shallow roots. Some trees may have even been planted in confined planting beds where roots were deflected and solid anchorage was not achieved. Trees planted with circling roots are also in danger of blowing over.
If you were to plant a tree, proper planting techniques are essential to future stability and wind resistance. Start with conducting a site assessment and choosing the correct tree – right plant in the right place. How big will the tree get, hardiness, soil conditions, overhead barriers, etc. all need to be considered. Call 8-1-1 before you dig – this is essential! Dig the hole wide and shallow. Now comes the most important part in tree installations that many people forget – the root ball preparation. If it is in a plastic container, carefully remove it and examine the root ball. Find what is called the “root flare” – the juncture between the roots and the base of the trunk. Next, find the “top-most root” – this is one to several large roots that are either exposed or within two inches of the soil surface. If the root flare and the top-most roots cannot be found, this can mean that the tree is set too deep in the pot and some soil will have to be removed until you find these important cues. Any circling roots will need to be cut with pruners. You can also cut the roots with a sharp spade by slicing the outer edge of the root ball essentially shaving off kinked or defective roots.
If the root ball comes wrapped in natural burlap (also called balled and burlapped) untie it at the top and spread if underground so that no part is exposed and can wick away moisture. Also untie any strings. The natural burlap will rot away over time. Some large burlapped root balls may also come with a wire cage to help stabilize the root mass. After it is carefully set into the hole, simply cut the wire cage up in place as soil is packed around it – it will rust away in time. If the burlap and the twine is synthetic, it must all be removed as it will not break down and can girdle the roots in the future.
At this point, place the root ball in the hole with about ten percent of it above the soil surface. This is to allow for settling. It is important that the root ball is not planted too deep. Fill in the soil (with no amendments) and firm it around the root ball. The add ten to twenty gallons of water over the root ball and backfill for the first watering. Apply a two to three inch layer of mulch up to the sides of the root ball , but keep it away from the trunk. If you need to form a berm around the root ball to hold water, use mulch and not soil to create it. Eliminate the berm after the tree is established. You can stake a tree for no more than a one year if needed.
Water is the final critical ingredient needed. As an example, a tree with a less than two-inch trunk caliper will need to be watered daily for two weeks, every other day for two months, and then weekly until established. It will take three to four months for a one-inch caliper tree to become established. Irrigation amounts applied should be about two gallons per inch trunk caliper. It is frequency of irrigation that makes the biggest impact, not so much the volume.
The simple act of proper planting will go a long way in establishing a tree that is better apt to weather a wind storm. Better established roots are a true anchor in the storm! For more information on all types of questions related to trees, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer. Don’t forget to visit our other County Plant Clinics in the area. Please check this link for a complete list of site locations, dates and times – http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.
Gilman E. F & Laura P. Paterson (2017) Chapter 11—Planting and Establishing Trees. The University of Florida Extension Service, IFAS.