Article by: Jessica Warren, ANR Agent, Camden County
Basic Tree Health and Management
Most of us have and enjoy trees in our landscapes, but often little thought is given to those trees until something is terribly wrong. Usually by the time a homeowner calls me about a tree, it is already dead or dying and the damage done to it cannot be undone. Tree care is one area where an ounce of prevention is worth more than a pound of cure.
Many tree issues can be prevented by proper planting. Before planting a tree, it is important to make sure that you are putting it in an appropriate site. The sun/shade needs, drainage requirements, and salt exposure of the tree should match the site that you are planting it in. Understory trees shouldn’t be planted in full sun locations as this can lead to more disease and environmental stressors on the tree.
Drainage is an especially important consideration in our area. Though we often have a sandy topsoil, our subsoil drains poorly and our water table is high. If the planting hole holds water for 24 hours, only water loving trees should be used.
Many tree health issues are caused by improper planting techniques and it’s hard or impossible to correct these errors. The most common error is planting too deep. The root flare of the tree should always be exposed and a tree should never look like a pole sticking out of the ground. Planting holes should be bowl-shaped and 2-4 times as wide as the root ball and/or container.
When planting it is also important to consider the mature size of the tree. The tree should be planted in adequate space for what it will grow to be, not what size it is when you buy it. For example, think how large the live oaks in St. Marys are — that’s how much space you need to allocate them in your landscape. Trees should be given adequate space for root growth with out running into driveways, sidewalks, roads, fences, powerlines, and housing foundations. Plan for root space twice the diameter of the mature canopy.
For optimal tree health, mulch under trees and don’t plant anything – including grass – within the dripline. Turfgrass, groundcovers, and other ornamentals compete with trees for water, oxygen, nutrients, and space. Mulch can also reduce the need to mow or weed eat under or close to the tree, reducing the risk of mechanical entry which can be an entry point for pests and disease. Mulch reduces erosion, runoff, competition and compaction while conserving soil moisture and maintaining more moderate soil temperatures. Mulch should be applied 3-4 inches thick and should extend at least to the dripline of the tree. Make sure to pull mulch away several inches from the trunk of the tree. Mulch piled against the trunk (also known as volcano mulching) can cause rot, disease, and insect issues. Organic mulches break down and improve soil quality, structure, and nutrition over time. Conveniently, the best mulch (and fertilizer) for a tree is its own leaves.
Compaction is another common culprit of tree decline. Tree roots need air from soil pore spaces. In an ideal soil, half of the volume of the soil is pore spaces filled with water or air. Once these pore spaces are lost they cannot be regained, and adding fill soil around existing trees prevents oxygen and water movement to the roots. This is a very important consideration when trying to maintain trees in construction sites. It may take several years for the impacts of compaction to become obvious, but they can’t be undone. Compaction may be caused by construction equipment, lawnmowers, or vehicles driving over the root zone. Sometimes it can even be caused by repetitive foot traffic. It’s like death by a thousand paper cuts – each bit of traffic over the root zone accumulates to suffocate the tree.
Luckily, most of the most damaging impacts to trees can be prevented with a little planning and forethought. If you have concerns about trees in your landscape send me a picture of your concerns at jkwarren@uga.edu following the instructions on our website https://extension.uga.edu/county-offices/camden/agriculture-and-natural-resources/sending-photos-to-anr-agent-for-diagnosis-id.html.