One of the biggest challenges facing prospective macadamia farmers is the long wait for return on investment. In a traditional orchard it typically takes around four or five years to harvest and some seven years to pay for the capital cost of establishing the orchard.
Due to the long wait many farmers opt to plant trees at a reduced spacing to ensure a greater yield per hectare during the first ten years, and then the excessive trees are thinned out for optimal spacing. The discarded trees usually end up as fire wood. But Shane Davies, a macadamia farmer in the Alkmaar area in Nelspruit has found a way to reduce this waste and ensure a faster return on investment for his newly established orchards.
Davies had a nine year old orchard due for thinning. Although it is common practice to simply chop down the extra trees, he wasn’t happy with the inefficiency of investing in trees that end up being productive for a fraction of their lifespan. He decided to experiment by carefully removing the mature trees and transplanting them into a new field. This would save him the expense of buying in new trees for his new orchard and would also keep the thinned out trees productive.
The cost benefit was further increased when Davies harvested a crop from the replanted trees far sooner than he would have had he planted new, two-year-old trees.
The trees were transplanted six years ago when they were nine years old. Within four years the new orchard already produced a yield of 4kg dry-nut-in-shell (DNIS) per tree. If Davies had planted two year old trees instead, he would have had to wait at least five years to get a crop and around seven years to achieve the 4kg DNIS crop he received from these trees. Today the yield is on par with the original trees of the same age on the farm.
Davies admits that the trees do lag behind the original orchard with the same aged trees in productivity but the benefit of replanting is still evident. “A normal four year old tree will give you about 5kg – 7kg DNIS, so you forfeit a bit on the yield on the replanted trees because they go into shock when replanted. But the outcome is still better because it reduces the waiting time for a crop by three years.”
The trees were initially planted at a five metre by five metre spacing. After nine years that space was reduced to ten metres by five metres, resulting in 200 trees per hectare.
Every second tree in the orchard that needs to be removed is first marked with north and south markers. A basin is then created around the trees and they are thoroughly watered every day for two weeks. After that the tree is dug out using a mechanical tree spade and the taproot is cut off. The tree is then carefully relocated to the new field. Here a deep hole is dug and filled with water to remove the oxygen from the soil, so as not to over expose the trees roots to oxygen. The tree is placed in the hole and then filled with sand. The relocated trees are watered twice a week for four to six weeks after which normal irrigation resumes.
Davies says that when the trees are replanted all foliage is removed to discourage the trees from producing a crop. “The crop is dependent on the foliage so it is a gamble how much foliage to leave on the tree. You want the tree to focus its energy on establishing itself and creating a strong root system, before it starts being productive. For this reason I don’t boost the fertiliser either and only after six months do I start with the normal fertiliser cycle. After that I leave the leaves to grow out normally.”
Because the foliage is removed it is important to protect the bark from sun damage, since the trees were shielded from the sun previously. Shane paints the bark of the trees with regular white PVA paint. Added into the paint is the fungicide Aliette that protects the tree from fungi and root diseases.
Davies achieved a remarkable success rate with the relocated trees. On 2,5 hectares only 12 trees did not survive the transplant. “It has turned out to be a very successful and profitable experiment. Everything was trial and error. I don’t know what the maximum age is that one can replant a tree and we are still working out the correct ratio of foliage to leave on the trees when we replant. But I am very happy with the results and my crop in the new orchard has come in a lot quicker than if I had followed the traditional route,” Shane said.
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