Transplant shock will remain a planting problem until the natural balance between the root system and leaves of the transplanted tree is restored. Of all the newly planted trees that do not survive, most die during this important period of root establishment. When digging a tree for transplanting, more than ninety-five percent of the absorbent roots are cut. With less than five percent of its root system remaining, the newly transplanted tree suffers water stress.
The crown is able to lose water faster than it can be absorbed by the limited root mass. Water stress, in turn, can reduce the ability of leaves to produce carbohydrates (energy), slow the growth of all parts of the tree, and subject the tree to many other environmental and pest-related problems. Combined, all these problems contribute to the “transplant shock” that can kill the tree. You may have identified the problem accurately.
I saw trees on the back of trucks that were driving on the road at high speed. If the root ball is exposed, it is very subject to drying out. If the leaves and twigs are not protected from air and sun during transport, this may cause the leaves to dry out and fall off. It is important to keep the roots moist and, as far as possible, to protect the leaves from drying air at high speed during transport.
However, there are other factors that could be involved. The roots of trees and shrubs normally grow far beyond the volume of soil that can be moved. To keep most roots within a small area, prune roots in spring or fall before transplanting. Plants that move in autumn (October or November) should be pruned roots in March, and plants that move in spring (March) should be pruned roots in October.
Prune roots only after leaves have fallen from deciduous plants in autumn or before buds sprout in the spring. Plants can suffer serious damage if done at other times. The roots within the pruned area develop many branches and form a strong root system within a confined area. If the root is not pruned, the plant may die from transplant shock due to root loss.
Important factors to consider when relocating a tree to a new environment are the ratio of root ball mass to trunk diameter, soil conditions, sunlight, and a constant watering schedule for at least one growing season after transplantation (this varies by species and time of year). Top pruning should be limited to removing broken and damaged branches and developing a good structure of the tree. Most newly planted trees are subject to stress-related problems due to the enormous loss of roots when excavated in the nursery. Although it looks like the tree is dying, a quick scratch with your thumbnail to reveal the tissue just below the bark of a small twig will provide evidence that the tree is still trying to grow.
To provide some protection to the roots, move the tree with “semi-naked” roots, leaving some soil attached to the fibrous roots. During this time, root damage and changing environmental conditions are the two main sources of stress (or shock) for a tree. Therefore, a tree with a caliber (measured at 6 above ground) of 9 can be easily moved with a shovel of 80. For example, a ten-inch tree would need at least 13 seasons after transplanting to restore the root system to its pre-transplant size.
The vigorous growth of the upper part does not return until the root system is replaced, after the fifth season with the example four-inch tree. Experts agree that a newly planted tree normally needs one year for every inch of trunk diameter to recover a normal root system. Except for the year following transplantation, when the growth of twigs is influenced by shoots formed the previous year, the amount of twig growth is closely related to the amount of root system that is present. Shrubs less than 3 feet tall and deciduous trees less than an inch in trunk diameter (measured 6 inches above the ground) can move barefoot.
Dead trees and trees in shock may look deceptively similar, but there is an easy way to differentiate. Regardless of size, newly planted trees experience a period of transplanted shock during which they are very vulnerable to stress. However, you can take steps before and after planting to minimize its impact and help your tree recover and establish faster. As long as the roots and tops of the tree are unbalanced, the roots cannot supply enough water and nutrients to the upper parts of the tree for vigorous growth.