Q: I have a friend who has a sloping piece of property with bald cypress at the low end. The intention is to build a house and level the property. How close to the bald cypress can we get with fill dirt and not cause a problem for the tree? Can I build a well around the tree and fill in the whole area?
A: I am so glad you asked me this question before you filled in the area with dirt. The ideal scenario would be to imagine a circle 2-3 times the drip line and add no fill dirt within that circle. The drip line is the point where the tips of the branches end. But since that area is probably the whole yard we should consider other choices.
Try to keep as wide a berth around the tree as possible; adding no fill dirt to that area. Consider a circle from the trunk out to the drip line as a minimum area. Roots require soil full of air (about 50%) and adding fill dirt to the landscape greatly reduces the amount of air available to the roots. The roots in turn suffocate resulting in the tree eventually dying. The process is slow; it may take 3-7 years for the tree to totally succumb to the loss of roots. In the mean time, the tree may develop a fungal disease on the branches or borers will suddenly appear. These pests are really only opportunists and they come in once they sense the tree in dying. Some people may fault the fungus or the insects but the root of the problem (excuse the pun) is the fill dirt. This problem is true of almost all trees, not just bald cypress.
Well structures have been constructed around trees particularly those of special interest to property owners. Building the well is expensive and labor intensive, however research did not indicate it was especially beneficial. Ultimately you must decide if the trees are important enough to keep and then grade the property accordingly. Just one more hint about building and trees, keep all heavy vehicles away from the tree roots because soil compaction from constant foot and vehicle traffic can kill the tree too. By the way, Bald Cypress is not only a great tree near water sources, but it makes a terrific landscape plant too. It is drought tolerant once it is established and can live in a variety of soil environments.
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