The processes of tea tree oil farming at Codrington
Tea tree cultivation processes for oil is a small industry located predominantly on the North Coast of NSW with a small group in Northern Queensland. The farming and processing of tea tree for its oil under plantation conditions has evolved from the small scale operators harvesting naturally grown “bush” stands which, until the 1980’s, was the nature of the industry.
Tea tree oil is a natural product with antiseptic and antimicrobial properties which has been used in Australia, Europe and North America for decades for treating cuts, warts, insect bites, minor burns and mould. It is steam distilled from the leaves of melaleuca alternifolia, a tree native to Northern NSW and is increasingly an ingredient in cosmetic products such as toothpaste, cleansers, acne treatments and insect repellants.
During the 1980’s the then NSW Department of Agriculture undertook a plant breeding program for the purpose of selecting high oil yielding strains of melaleuca alternifolia. Over the years since, this program has continued with industry financial support with positive results in terms of yield increase. The importance of this work is quite relevant to any plantation for the following reasons –
- it is an expensive crop to establish,
- the propagation, maintenance, harvesting and processing costs for a well managed plantation are the same irrespective of the oil yield, and
- it is a tree crop with an indefinite commercial life, due largely to the economic barriers associated with replanting a moderately yielding plantation.
One of the unusual aspects of the industry is that the saleable commodity is a liquid but at the bulk farmgate level it is quoted and sold by the kilogram. At the retail level it is marketed and sold by the millilitre or litre.
Plantation Farming at Codrington, New South Wales
The land selected for this tea tree growing business comprises three adjoining farms of 90 hectares located at Codrington on the banks of the Richmond River near Coraki on the Far North Coast of New South Wales.
This fertile black soil land is well suited to tea tree growing as it will produce superior yields of high quality oil. Whilst the plants can cope with wet conditions, management of the plantation requires effective drainage as the black soil can easily become waterlogged in this high rainfall area and this in turn can be counterproductive to effective weed and pest control. To achieve good drainage the area to be planted is firstly cleared of all obstacles such as fencing, water troughs and rocks and then levelled to an effective slope by GPS/laser equipped earthmoving scrapers.
Once this profiling is complete the land is deep ripped, cross ripped and finally rotary hoed to establish a fine tilth seedbed ready for planting.
Whilst the land preparation is underway the plants are grown from seed in a specialist nursery. It takes 4 months to grow a suitable seedling from seed and this is best done in the warmer months between August and March. The optimum planting window is between August and March as there will be no paddock growth of the plantation outside this period.
The planting out density in rows 1 metre apart and at intervals of 280mm along the row equates to 33,000 seedlings per hectare. Once planted their root ball must be kept damp for at least a month to overcome transplant shock and this can be achieved through rainfall, by irrigation or by tractor drawn water cart.
Assuming the seedlings are planted, watered and established successfully they require 2 years growth before the first harvest. Industry experience shows that cutting trees too early can kill young trees and at the very least hamper their development and subsequent yield potential. The 2 year rule is not exact in that the planting usually occurs in the summer whereas the harvest is conducted in late winter which can be a bit more than 2 years later.
Notwithstanding tea tree is a native plant, it is susceptible to regular insect attack on its leaf foliage – that portion of the plant which holds the valuable oil. This requires a high level of vigilance in pest monitoring as a plantation would be decimated if insects are not controlled. Weed control is also important to facilitate vigorous plant growth and to guard against tainting the quality of harvested oil.
Organic nutrients are returned to the plantation in the form of mulch, chicken manure and composted tea tree cuttings.
Harvesting tea tree oil
Harvesting the oil is a completely mechanized process. Oil is harvested annually from grown trees and the ideal harvest window is July to September. An earlier harvest risks frost damage to the plant regrowth which occurs 5-6 weeks after harvest. A later harvest limits the new growth potential and resultant next season’s oil yield. The optimal growing time is between the warmer months of October and March, after that there is little new growth.
The two row purpose built harvesters are very efficient and cut the established trees off at ground level.
A new plantation grows out to its long term annual yield potential over a period of 3 harvests as the plants tiller or sprout multiple new limbs from the primary cut stem and thus produce additional oil bearing leaf.
The completely shredded tree (leaf and stem) is transported in the harvester hopper to bulk bins located around the plantation perimeter and these are duly hauled onto a semi-trailer for transport to the off farm distillery for steam processing within 24 hours.
The cut material is steam distilled in 10 tonne stainless steel bins for 2 hours and the resultant oil stored in stainless steel vats for later decanting to 200 litre stainless steel drums which is the usual form of packaging for sale and consignment to end users.