by Area Forester Lisa Deaton
Those Hidden Roots
This loblolly pine (above) is located on the shore of a tidal creek that flows into the Chesapeake Bay. The needles and branches in the top of the tree have been dying for the past several months. We initially thought that the harsh growing conditions of a saltwater shoreline and repeated flooding had finally taken its toll on this tree. Then we found out that the tree’s roots had suffered through the construction of a home addition and the installation of a lawn irrigation system. The homeowners thought that as long as the taproot directly under the tree was undisturbed then the tree would be fine.
While pine trees do have a central taproot, evident in the two tree stumps on the right, (below) they also have a large network of smaller roots and fine root hairs like the stump in the center of the photo.
The fine roots of live trees are located in the first few feet of soil. Just driving over them with heavy equipment can compact the soil enough to damage those roots. Cutting through tree roots for irrigation systems or utilities (electric wire, cable, etc.) eliminates part of the original root system and creates wounds where diseases can enter the tree.
A general rule of thumb during home construction is to leave the ground underneath a tree undisturbed for at least the breadth of its canopy. A tree’s roots can extend away from the tree a distance of 1 to 3 times its height, which is a consideration for landscape planning, also.
These photos (below) provide a glimpse of the underground root system of hardwood trees.
Here are a few more photos from an eroded shoreline on the York River (Most of the fine root system of these dead pines has weathered, decayed and fallen off).
Last, but not least, this is an interesting look at root competition.