Chestnut Root Zones

How many times have you heard someone say "Those trees have deep tap roots. They don't need to be watered." There are two parts to this statement that makes it both correct and wrong.

The correct part is that many types of trees have tap roots that extend down into the earth below the topsoil. Trees need water during the entire growing season to have a good year where they are able to generate new seeds for future trees.

The incorrect part of the above statement is that the tap roots are a core part of the trees root sturcture. In a tree's root structure the tap roots purpose is primarly for bringing in water. A tree needs a complex mixture of nutrients and minerials to be able to sustain its life and grow. Trees have most their roots in the first 18" into the soil. The reason for the high concentration of the roots in the topsoil is that is where the availability of the nutrients are. Because of this concentration of the roots, the calculations for amending the soil with nutrients is calculated only to a depth of the first 12" of the top soil.

Let us take a look at a real example. In the picture below a tree had been blown down by gale force winds. This process also cause a uprooting of the tree's roots in the top soil.

The roots still have a lot of the top soil embedded around them. This photograph shows where the concentration of the roots for this tree were before it was blown down. You can see some of the roots were broken when the tree went down. These roots extended out past the primary root mass to access additional nutrients to support its increasing size. The roots left in the gound usually die and decompose. Some variety of trees, such as chestnut trees, will send up new trees from the roots left in the soil. These new trees are called suckers

There are some commercial growers that propagate their trees using the roots to send up new trees. There are two chalenges with propagating chestnut trees using the roots. The first problem is that most commercial nuseries start their chestnut trees from seed and graft the desire variety to the seedling. So trees started from the roots are not true to type of the grafted top. The other problem is removing the "sucker" from the soil is they are likely attached to a large root and do not have good root structures of their own. The process of propagating trees from roots is called layering. The nice thing about layered trees is there is no chance of loosing the top graft (graft failure) and ending up with some unknown tree with unwanted nut size or quality.

Chestnut tree roots do not like heavy/clay soils. The more clay in the soil the less likely the chestnut tree will survive year after year. The soil also has to be deep. If a clay or rock subsoil structure exists this can also make life difficult for a chestnut tree. If the soil has a lot of rocks a chestnut tree will do ok but will need soil amendments to increase the available nutrients. When planting a chestnut tree always water it when you plant it. The roots have to have active contact with the soil and only water can provide the contact sufficient enough to transfer nutrients.