A tree cannot be transplanted by simply uprooting it and placing it in a pit dug elsewhere. The process involves multiple steps and requires significant expertise. First, the soil around the tree is dug up to isolate the roots.
The guidelines recommend the following procedures for transplantation:
- Digging and root pruning: Sometimes root pruning is needed before transplant; in that case, sufficient time should be given for new roots to develop, before the tree is lifted. The guidelines mention digging and pruning to be done in multiple stages.
- Creating the root ball: A root ball (a mass formed with tree roots and the soil surrounding it) of reasonable size should be achieved before the tree is lifted. Larger, more mature trees need a bigger root ball for regrowth and stability.
- Trimming of tree roots: Before the tree is lifted, the roots underneath will have to be trimmed. The cuts must be clean so as to avoid the tearing and breaking of roots. Any torn root should be trimmed cleanly back up to the healthy tissues.
- Root treatment: The roots should be treated with anti-termite, anti-bacterial and anti-fungal chemicals as well as root hormones. The guidelines specify the quantity of these materials to be used.
- Cleaning tree crown: While the tree branches are commonly cut off during transplant, the TEC says such pruning of the crown reduces the tree’s ability to make food and build reserves. But the crown can be cleaned to remove damaged, diseased and crossed branches, so as to minimise susceptibility to pests and diseases.
- Preparing the new site: Before the tree is lifted, the new site should be fully prepared. The guideline specifies the pit size for different tree sizes. Vermicompost should be added in the trenches and watered, to maintain soil moisture and for easy establishment of roots.
- Lifting the tree: Damp hessian sacks (gunny bags) should be placed around the root ball and pinned to it. This ball should be kept moist until the transplant is completed. Tree lifting should be timed so as to enable direct delivery to the new site. The tree should be lifted by its root ball, and not by the trunk as this can cause serious injury. The tree should be watered before lifting and after transplant.
- Replantation: Any branches damaged in transit should be trimmed back. A soil saucer can be formed around the root ball circumference, for water retention and conserving soil moisture. Mulch can also be added. Fertilisation isn’t needed unless the tree has nutrient deficiency.
How is a tree transplanted?
A tree cannot be transplanted by simply uprooting it and placing it in a pit dug elsewhere. The process involves multiple steps and requires significant expertise.
First, the soil around the tree is dug up to isolate the roots. The big branches are lopped off, leaving only small shoots for regeneration. This is done to make transportation of the tree to the new location easier.
The root system is covered with wet gunny bags to protect the roots and to keep the tree hydrated. The tree has to be first sent to a nursery to acclimatise to a new kind of soil, and to regenerate. Once new shoots start sprouting, the tree is lowered into a pit created in its new spot.
What factors determine the success of a transplant?
Even after all steps are meticulously followed, a lot depends on luck. Dr Babu said the survival rate of a transplanted tree is about 50%. If it survives, the tree may take up to 10 years to grow a full canopy similar to what it originally had.
Not all trees can be transplanted. While peepal, ficus, semal and sheesham are tolerant to transplantation, trees such as dak, palash, arjun, shahtoot and jhilmil are not. Any tree that has a tap root system cannot be transplanted, as the root goes deep into the soil, and it is not possible to isolate it without damage.
In agriculture and gardening, transplanting or replanting is the technique of moving a plant from one location to another. Most often this takes the form of starting a plant from seed in optimal conditions, such as in a greenhouse or protected nursery bed, then replanting it in another, usually outdoor, growing location. This is common in market gardening and truck farming, where setting out or planting out are synonymous with transplanting. In the horticulture of some ornamental plants, transplants are used infrequently and carefully because they carry with them a significant risk of killing the plant.
Transplanting has a variety of applications, including:
- Extending the growing season by starting plants indoors, before outdoor conditions are favorable;
- Protecting young plants from diseases and pests until they are sufficiently established;
- Avoiding germination problems by setting out seedlings instead of direct seeding.
What do the tree transplantation guidelines say?
As per the guidelines, transplantation is recommended only for healthy, structurally sound trees, so that the tree has a higher chance of survival and the operation is cost-effective. The committee also recommends transplantation for trees with particular significance and high conservation value, but not for invasive exotic species. Transplantation can’t be done to a location with poor soil or during summers. Distance and accessibility to the new site is another factor.
Overall, the guidelines say many factors like the tree’s condition, size, species, conservation status, environmental and cultural factors, engineering conditions, cost-effectiveness, should all considered when deciding on transplantation. The High Court, while hearing the PIL, had also clarified that transplantation should be considered only if the tree can’t be retained at its location.