We are gradually clearing an old agricultural field that was once abandoned and we want to clear it again. We are using this field for multiple purposes, planting food plots, a vegetable garden, an orchard and nut trees. In order to get more sunlight into our field we keep culling trees on the edges of the field. We have been using girdling to do this.
A few years ago we started culling unwanted trees by girdling them. Girdling is the process of cutting the cambium layer or outer bark, down to the wood. In our method we use a chainsaw and make a shallow cut around the circumference of the tree in 2 places, usually about 4 inches apart; one upper; one lower, about one to two feet above the ground. It is important that the cut is made all the way to the wood specially in uneven areas of the bark. We usually do not cut more than 1/2 inch into the wood, because we want the tree to maintain its strength and remain upright until it is dead. We do not want to weaken the tree so that wind will blow it over easily.
Why does this work to kill the tree and how long does it take the tree to die? Trees have two types of vascular tissue. The Xylem (wood) which carries water and nutrients up the tree and the Phloem (inner bark) which carries sugars (sucrose) down the tree to the roots. The stored energy in the roots in deciduous trees is essential to new leaf generation each spring. When this source of energy to the roots is cut off, the tree will die. Sometimes death will take several years, but usually by the third year the tree is dead. This method can also be used to thin trees in a forest. In a forestry situation, you can come back and cut the tree down or just let it die and let nature fell the tree as it decays.
One of the benefits of girdling trees is that the wood can be used for firewood and it is kept dry naturally while the tree is still standing. If cut within the second to fifth years, when the tree is dead or near dead, the wood is dry but has not yet had time to begin to decompose. This drying while standing minimizes the time that firewood needs to “season” prior to being burned.
Why not just cut the tree down in the first place? The best time to cut an remove a deciduous tree is when the leaves are off the tree. We are not always available to cut the trees at this time of year, or we do not have enough time to cut down as many trees as we would like. By girdling the trees, we immediately stop further growth of the tree above ground and at the roots. The leaves will start to fall off after girdling, and will start letting in more light. You can girdle a tree in under 10 minutes. This allows us to stop the growth of a quantity of trees and still have the flexibility to remove them at our convenience. Since we are clearing a field, we do not want the cut trees creating clutter in our field and limiting our ability to mow or till.