| According to a
conversation I had with a bloke, Melaleuca alternifolia
will grow just about anywhere, except Antarctica, and he
wasn't sure it wouldn't grow there. In its natural
environment, Melalauca alternifolia will survive with
its roots under water, and will continue to survive through a
drought - there will be leaf drop, but the tree will survive
in most cases. Melaleuca alternifolia will survive a
bush fire - doesn't leave much leaf, but will come back nicely
for next years harvest.
Commercial plantation Melaleuca
alternifolia is cultivated at anything from 5000 to 40000
trees per hectare, and plantations in Australia are now found
in along the coastal regions from Port Macquarie in central
NSW north to Bundaberg in Queensland, with a large number of
growers on the Atherton Tableland in northern Queensland.
Plantation growing dates from 1977, with an explosion of
plantings in the 1990's.
First harvest can be as soon as 12 months
from planting, but 15 to 18 months is better.. Usually
harvested once a year in summer, needs irrigation when young,
can be subject to pest attack, is relatively easy to distil
and is well known in the world market. Plantation harvesting
is mechanical, with the trees cut at near ground or waist
height, mulching the entire tree into a purpose built `pot' or
distillation vessel, which is driven or towed back to the
distillation unit, and steam distilled. Mechanical harvesting
at ground level can be difficult, and if the roots are
disturbed, the tree will often die.
Distillation times vary, but in a large
commercial operation, speed is of the essence. Bush gathered
or wild harvested Melaleuca alternifolia requires
cutting non-cultivated trees, bagging the biomass (leaves and
branchlets), and transporting the bags back to the
distillation unit. Bush harvesters used to gauge distillation
times by the time taken to drink a carton of beer, but that
was the good old days. Yields of 5% have been claimed, but 1%
is a good yield for this tree - 1 kg (2.2 lbs) of oil from 100
kg (220lbs) of biomass. In a commercial operation, this can
drop to around 0.5 to 0.7% - depends on the amount of woody
material contained in the total biomass.
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The quality of oil,
in terms of the percentages of T-4-Ol and cineole, can be
varied by altering the distillation times, which is handy if a
client wants a particular percentage of components. It's
tricky, but it can be done. Most distillers don't bother - if
the plants come from good seed, and horticultural practices
are adequate, then the oil will be OK. The discussion (or
argument) on high cineole versus low cineole, is in our view,
a marketing ploy devised by people who found they had a bucket
of oil that needed to be sold. Certainly, high cineole Melaleuca
alternifolia oils can be harsh in scent, but the efficacy
is not affected, and may, in fact, be enhanced.
Lemon scented Tea Tree - Leptospermum
petersonii - is a shrub or small tree (2-10m) (7-33 ft)
which grows in rocky, inhospitable country, or along
watercourses.
Leptospermum petersonii is
chemically very different from Melaleuca alternifolia.
The chemotype most commonly grown and harvested for essential
oil is characterised by 50% or higher amounts of citral and
around 20% citronellal. The total aldehyde content can go as
high as 90%. Leptospermum petersonii has a fresh lemon
scent, with tones of citronnella candles. Yields of up to 3%
have been claimed, but commercially and realistically, around
1% is a good rule of thumb. Some trees will yield as low as
0.1%. This oil we would not use in pure form direct onto the
skin. It is used as fragrance raw material, as a natural
insect repellent, as a cosmetic preservative and as a natural
anti-microbial against a number of fungal infections. There
are even teas made from the dried leaves.
CONTINUE
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