| For the Times-Union
Sometimes we take trees for granted. We see them as the pillars in our landscape and sometimes forget that they are living things that need the same conditions to live and thrive as our favorite flower, shrub or groundcover.
Often, we think because they are larger and live longer, they do not need as much care, or they are more tolerant of neglect. In some cases, this is true. A leaf disease that would doom our prized rose is barely a minor nuisance to a maple tree.
However, the origin of most landscape tree decline, and eventual death can be traced back to something that was done in the past (sometimes years) by someone not knowing that it would harm the tree. In the horticultural world, these practices that cause tree decline are called cultural causes and most of the time can be avoided.
Let’s explore some of the most common cultural decline causes and how to avoid them.
Giving trees enough space: I recently drove through a new subdivision. The developers had planted live oaks about 2 feet from the edge of the curb, in between the street and the sidewalk. I am sure the intention was that some day the trees would be part of a beautiful street tree canopy. It would have been better to plant the live oaks in the middle of the yard where they had plenty of space or plant a smaller tree in the space between the sidewalk and the street.
Before you plant a tree do some quick measurements to see how much room you have. A small maturing tree with less than a 20-foot crown spread needs about 200 square feet of space. A medium-sized maturing tree with a 30-foot crown spread needs 400-500 square feet of rooting space. A large maturing tree needs a minimum of 900 square feet of rooting space.
Planting too deep: The number one cause of tree decline for a young tree is the practice of planting too deep. If you look at trees in natural areas such as parks, you will notice that the part of the trunk where the roots flare out from the trunk is above ground. This zone where the roots begin is called the root flare. When we plant a tree the root flare should be visible and located slightly above the soil grade. If you take a look at the base of your tree and it looks like a fence post in the ground, it is more than likely planted too deep. A wise forester once told me, “Plant it high and it won’t die.”
Deep planting is a mistake performed by homeowners and landscape professionals alike. Deep planting encourages roots that will choke the trunk of the tree, as well as encourages disease and decay at the base of the tree by prolonging the time the trunk stays wet after rainfall or irrigation. It also reduces the amount of oxygen that tree roots