Everything Else . Trees produce several different kinds of roots, he said. The feeder roots, which explore the soil for nutrients and surface water, grow close to the surface and spread out from the trunk, Laurence said. Another kind, called coarse roots or water roots, grow both down and out, he said, trying to tap into a reliable source of water. The upper layers of soil generally provide the most nutrients but also dry out the fastest so the coarse roots look beyond and below the trunk area, he explained.
Some trees have a taproot that is sent straight down for water and also provides support.
The overall root pattern, including whether there is a taproot, can be determined by considering the tree's species and the underlying soil structure where the tree is growing, Laurence said. The loblolly pine, for example, has a big taproot because it tends to grow in areas where the soil is deep and loosely packed. The spruce, on the other hand, tends to grow in thin soil and does not bother with a taproot, Dr. Laurence said. New questions are answered on the site every Tuesday and Thursday.