Other Effects

Tea trees are harvested by cutting the main stem near ground level, leaving a bare stump that will produce the coppice regrowth. However it takes time to produce a new canopy and during the first 3 months after harvest, the growth rate was 46% of that during months 4-6, the most efficient stage (Murtagh 1996). After 6 months, new shoots were less vigorous than before and the growth rate declined to 71% of the stage two rate. The relative rates were calculated with all other conditions remaining constant. The best yields of biomass were obtained by timing harvests so that the second and third regrowth stages coincided with the best environmental conditions for growth. The analysis of the effect of water stress on yield provided a good example of the gains from following this approach. Across all harvest times, water stress reduced biomass yields by an average of 24%. However, an October harvest that matched the first stage of regrowth to the driest period, had only a 7% reduction in yield due to water stress. This result reflected in part the assumption, supported by the functional analyses, that there is no water stress soon after harvesting because of the large root to shoot ratio (Blake and Tschaplinski 1986).

Melaleuca species are reputed to be very tolerant of water logging. Gomes and Kozlowski (1980) found no effect of 30 days flooding in stagnant water on the growth of M. quinquenervia, but longer periods did reduce growth. Bolton and Greenway (1996) obtained good growth from M. alternifolia growing in 100-150mm deep, flowing sewage effluent over 20 months, but it is unlikely if the same tolerance would be present in stagnant water with a higher oxygen tension. Colton and Murtagh (1990) noted that growth was depressed on waterlogged soil.

OIL YIELD

Because the two are not closely related, the combined effect of oil concentration and leaf yield gives a wide range in potential oil yield. Colton and Murtagh (1990) indicated that the oil yield could range from a low of 43kg/ha/yr to a high of 392kg/ha/yr, with a yield of 150-200kg/ha/yr representing a realistic target for most plantations in northern NSW.

Since these projections were recorded in 1990, there has been no confirmed advance in the potential oil concentration on a plantation scale, but the situation could change in the near future. Doran et al. (1996) recorded a 60% increase in oil concentration in plants grown from seed from a selected provenance, over the concentration in plants from selected lines used in commercial nurseries. Williams (1995) has developed clones that produced more than twice the oil yield of unselected trees. Efforts are proceeding to confirm that these gains can be achieved in commercial plantations, but at this stage it would be premature to use either set of work to adjust the projected oil yields. Apart from the use of genetic improvement to increase the oil concentration, it might be possible to use preharvest treatments to increase the concentration, but little work has been done in this regard.

Some progress has been made since 1990 towards producing higher leaf yields by fine-tuning the agronomic procedures in growing a crop (Murtagh 1998). The expected yields in Table 3 were obtained by increasing the previous estimates of leaf yield (Colton and Murtagh 1990) by 5%, and using the leaf: twig and twig: biomass ratios in Murtagh (1996), and a mean dry matter content of 40% to calculate the other plant yields. In addition to the above gain, more growers are producing crops in the higher yielding categories, so the industry average has increased by more than 5%. A realistic yield target would be 170-220kg oil/ha.

Table 3 Typical yields of tea tree under three growing conditions

Growing Conditions

Growing Conditions

Table 3 Typical yields of tea tree under three growing conditions

Poor

Good

Excellent

Leaf yield (t DM/ha)

1.7

3.6

5.1

Twig yield (t DM/ha)

2,5

5.3

7.5

Biomass yield (t DM/ha)

3.6

8.9

13,6

Biomass yield (t GW/ha)

9.0

22.3

34.0

Oil yield (kg/ha) @ low cone.*

51

108

153

@ medium conc.

94

198

281

@ high conc.

136

288

408

*Representative oil concentrations are 30mg/g (low), 55mg/g (medium), and 80mg/ g (high). See text for explanation of plant fractions.

*Representative oil concentrations are 30mg/g (low), 55mg/g (medium), and 80mg/ g (high). See text for explanation of plant fractions.

SUMMARY

Tea tree oil is produced from trees grown as a row crop. The cultural aim is to maximise the oil concentration in leaves and the yield of leaf at harvest time.

The oil concentration follows a seasonal trend, with the highest concentration in summer and the greatest amplitude between seasons in the cooler localities. Additional short-term variation is superimposed on the seasonal trend and is more marked in plants with a high oil concentration. The rapid recovery in concentration following a short-term loss indicates that new oil is obtained either from direct synthesis or interconversion from another chemical form. The oil concentration increases with increasing temperature and humidity, but was not altered by irrigation on a site with subsoil moisture. The observed changes in oil concentration are consistent with a double pool conceptual model where some oil is held in a stable storage, and the remainder in an organ that is subject to gains and losses of oil.

The yield of leaf is primarily determined by the total biomass yield of a tree. Trees grow best at high temperatures, and the effect of water stress on growth is most marked in the post-flush stage of growth. Growth is most efficient during 4-6 months after harvest when a new canopy has developed and the shoots are relatively young. Timing a harvest to synchronise this optimum growth stage with the best seasonal conditions for growth gave the highest biomass yields.

REFERENCES

Baker, G.R. (1995) NSW Agriculture, unpublished results.

Baker, G.R., Lowe, R.F. and Murtagh, G.J. (1995) NSW Agriculture. Unpublished results. Banthorpe, D.V., Charlwood, B.V. and Francis, M.J.O. (1972) The biosynthesis of monoterpenes.

Chem. Rev., 72, 115-163. Barz, W. and Köster, J. (1981) Turnover and degradation of secondary (natural) products. In E.E.Conn, (ed.), The Biochemistry of Plants, vol 7. Secondary Plant Products, Academic, New York, pp. 35-84.

Blake, T.J. and Tschaplinski, T.J. (1986) Role of water relations and photosynthesis in the release of buds from apical dominance and the early reinvigoration of decapitated populars. Physiol. Plant, 68, 287-293.

Bolton, K.G.E. and Greenway, M. (1996) A feasibility study of Melaleuca trees as candidates for constructed wetlands, SE Queensland, Australia. Proc. 5th Int. Conf. Wetland Systems for Water Pollut. Control, Vienna, Sept. 1996.

Brophy, J.J. and Lassak, E.V. (1983) The volatile leaf oils of Melaleuca armillaris, M. dissitiflora and M. trichostachya. J. Proc. Roy. Soc. NSW, 116, 7-10.

Brophy, J.J. and Lassak, E.V. (1992) Steam volatile leaf oils of some Melaleuca species from Western Australia. Flav. Frag. J., 7, 27-31.

Butcher, P.A., Doran, J.C. and Slee, M.U. (1994) Intraspecific variation in leaf oils of Melaleuca alternifolia (Myrtaceae). Biocbem. System. Ecol., 22, 419-430.

Charles, D.J. and Simon, J.E. (1990) Comparison of extraction methods for the rapid determination of essential oil content and composition of basil. J. Amer. Soc. Hort. Sci., 115, 458-462.

Colton, R.T. and Murtagh, G.J. (1990) Tea-tree oil—-plantation production. Agfact P6.4.6, NSW Agriculture & Fisheries, 1990.

Cornwell, C.P., Leach, D.N. and Wyllie, S.G. (1995) Incorporation of oxygen-18 into terpinen-4-ol from the H218O steam distillates of Melaleuca alternifolia (tea tree). J. Essent. Oil Res., 7, 613-620. 2

Cowan, I.R. and Milthorpe, F.L. (1967) Resistance to water transport in plants—a misconception misconceived. Nature, 213, 740-741.

Croteau, R. (1988) Catabolism of monoterpenes in essential oil plants. In B.M.Lawrence, B.D.Mookherjee and B.J.Willis, (eds.), Flavors and Fragrances: A World Perspective, Elsevier, Amsterdam, pp. 65-84.

Curtis, A. (1996) Growth and Essential Oil Production of Australian Tea Tree (Melaleuca alternifolia (Maiden and Betche) Cheel), Master of Agricultural Science Thesis, The University of Queensland.

Curtis, A. and Murtagh, G.J. (1989) NSW Agriculture. Unpublished results.

Cutter, E.G. (1978) Plant Anatomy, Pt 1, Cells and Tissues, 2nd edit, Edward Arnold, London, pp. 214-241.

Dawkins, A.E. (1915) The calculation of the oil content of foliage from measurements of the number and size of the oil glands. Proc. Roy. Soc. Victoria, NS27, 153-154.

Dement, W.A., Tyson, B.J. and Mooney, H.A. (1975) Mechanism of monoterpene volatilization in Salvia mellifera. Phytochem., 14, 2555-2557.

Doran, J.C., Baker, G.R., Murtagh, G.J. and Southwell, I.A. (1996) Breeding and selection of Australian Tea Tree for improved oil yield and quality. Final Report on Project No. DAN-87A, Rural Industries Research and Development Corporation, Canberra, October 1996.

Doran, J.C., Caruhapattana, B., Namsavat, S. and Brophy, J.J. (1995) Effect of harvest time on the leaf and essential oil yield of Eucalyptus camaldulensis. J. Essent. Oil Res., 7, 627-632.

Drew, J., Russell, J. and Bajak, H.W. (1971) Sulfate Turpentine Recovery, Pulp Chemicals Association, New York, pp. 30-44.

Drinnan, J.E. (1997) Development of the North Queensland Tea Tree Industry. Final Report on Project No. DAQ-184A, Rural Industries Research and Development Corporation, Canberra, 1997.

Dussourd, D.E. and Denno, R.F. (1991) Deactivation of plant defence: correspondence between insect behaviour and secretory canal architecture. Ecology, 72, 1383-1396.

Etherington, R.J. (1989) Essential Oils in Australia and Environmental Effects on Short Term Variation in Oil Yield of Tea Tree (Melaleuca alternifolia). Bachelor of Rural Science (Honours) Thesis, University of New England.

Flück, H. (1963) Intrinsic and extrinsic factors affecting the production of secondary plant products. In T.Swain, (ed.), Chemical Plant Taxonomy, Academic, London, pp. 167-186.

Gaff, D.F. and Carr, D.J. (1961) The quantity of water in the cell wall and its significance.Aust. J. Biol. Sci., 14, 299-311.

Gershenzon, J. (1984) Changes in the levels of plant secondary metabolites under water and nutrient stress. Recent Adv. Phytochem., 18, 273-320.

Gershenzon, J. and Croteau, R. (1991) Terpenoids. In G.A.Rosenthal and M.R.Berenbaum, (eds.), Herbivores: Their Interactions with Secondary Plant Metabolites, vol. 1. The Chemical Participants, Academic, San Diego, pp. 165-219.

Gershenzon, J., Lincoln, D.E. and Langenheim, J.H. (1978) The effect of moisture stress on monoterpenoid yield and composition in Satureja douglasii. Biochem. Syst. Ecol., 6, 33-43.

Gershenzon, J., Murtagh, G.J. and Croteau, R. (1993) Absence of rapid terpene turnover in several diverse species of terpene-accumulating plants. Oecologia, 96, 583-592.

Gomes, A.R.S. and Kozlowski, T.T. (1980) Responses of Melaleuca quinquenervia seedlings to flooding. Physiol. Plant, 49, 373-377.

Guenther, E. (1948) The production of essential oils. In E.Guenther, (ed.), The Essential Oils. vol. 1, van Nostrand, New York, pp. 85-226.

Guenther, E. and Althausen, D. (1949) The Essential Oils. vol. 2, van Nostrand Reinhold, New York, pp. 7-137.

Harborne, J.B. and Turner, B.L. (1984) Plant Chemosystematics, Academic, London, pp. 216236.

Hojmark-Andersen, J. (1995) Investigations into the yield of essential oil from Melaleuca alternifolia (Maiden and Betche) Cheel. Fourth Year Report, Bachelor of Applied Science (Hort Tech), The University of Queensland, Gatton College, Lawes, October 1995.

Janson, R.W. (1993). Monoterpene emissions from Scots pine and Norwegian spruce. J. Geophys. Res., 98 D2, 2839-2850.

Jones, H.G., Lakso, A.N. and Syvertsen, J.P. (1985) Physiological control of water status in temperate and subtropical fruit trees. Hort. Rev., 7, 301-344.

Juuti, S., Arey, J. and Atkinson, R. (1990) Monoterpene emission rate measurements from a Monterey pine. J. Geophys. Res., 95, D6, 7515-7519.

Kawakami, M., Sachs, R.M. and Shibamoto, T. (1990) Volatile constituents of essential oils obtained from a new developed tea tree (Melaleuca alternifolia) clone. J. Agric. Food Chem., 38, 16571661.

Koedam, A., Scheffer, J.J.C. and Svendsen, A.B. (1979) Comparison of isolation procedures for essential oils. II. Ajowan, caraway, coriander and cumin. Z. Lebensm. Unters. Forsch., 168, 106-111.

Lawrence, B.M. (1986) Essential oil production. In T.H.Parliament, and R.Croteau, (eds.), Biogeneration of Aromas, American Chemical Society, Washington DC, pp. 363-369.

List, S., Brown, P.H. and Walsh, K.B. (1995) Functional anatomy of the oil glands of Melaleuca alternifolia (Myrtaceae). Aust. J. Bot., 43, 629-641.

Loomis, W.D. and Croteau, R. (1973) Biochemistry and physiology of lower terpenoids. Recent Adv. Phytochem., 6, 147-185.

Lowe, R.F. and Murtagh, G.J. (1995) NSW Agriculture. Unpublished results.

Lowe, R.F. and Murtagh, G.J. (1997) NSW Agriculture. Unpublished results.

Lowe, R.F., Murtagh, G.J. and Baker, G.R. (1996) NSW Agriculture. Unpublished results.

McKey, D. (1979) The distribution of secondary compounds within plants. In G.A.Rosenthal and D.H.Janzen, (eds.), Herbivores, Academic, New York, pp. 55-133.

Mihaliak, C.A., Gershenzon, J. and Croteau, R. (1991) Lack of rapid monoterpene turnover in rooted plants: implications for theories of plant chemical defense. Oecologia, 87, 373-376.

Murtagh, G.J. (1988) Factors affecting the oil concentration in tea tree. Proc. 4th Australasian Conf. Tree Nut Crops, Lismore, August 1988, pp. 447-452.

Murtagh, G.J. (1991a) Tea tree oil. In R.S.Jessop and R.L.Wright, (eds.), New Crops, Inkata, Melbourne, pp. 166-174.

Murtagh, G.J. (1991b) NSW Agriculture, unpublished results.

Murtagh, G.J. (1992) Irrigation as a management tool for production of tea tree oil. Final Report on Project No. DAN-19A, Rural Industries Research and Development Corporation, Canberra, May 1992.

Murtagh, G.J. (1996) Month of harvest and yield components of tea tree. I. Biomass. Aust. J. Agric. Res., 47, 801-815.

Murtagh, G.J. (1998) Tea tree oil. In K.W.Hyde (ed.), The New Rural Industries, Rural Industries Research and Development Corporation, Canberra, pp. 272-278.

Murtagh, G.J. and Baker, G.R. (1994) Factors affecting Oil Yield in Tea Tree. Final Report on Project No. DAN-58A, Rural Industries Research and Development Corporation, Canberra, November 1994.

Murtagh, G.J. and Curtis, A. (1991) Post-harvest retention of oil in tea tree foliage. J. Essent. Oil Res.,

Murtagh, G.J. and Etherington, R.J. (1990) Variation in oil concentration and economic return from tea-tree (Melaleuca alternifolia Cheel) oil. Aust. J. Exp. Agric., 30, 675-679.

Murtagh, G.J., Gershenzon, J. and Croteau, R. (1993) Washington State University, unpublished results.

Murtagh, G.J. and Smith, G.R. (1993) NSW Agriculture. Unpublished results.

Murtagh, G.J. and Smith, G.R. (1996) Month of harvest and yield components of tea tree. I. Oil concentration, composition, and yield. Aust. J. Agric. Res., 47, 817-827.

Penfold, A.R. and Morrison, F.R. (1950) "Tea Tree" oils. In E.Guenther, (ed.), The Essential Oils. vol.

4, van Nostrand Reinhold, New York, pp. 526-548.

Penfold, A.R., Morrison, F.R. and McKern, H.H.G. (1948) Studies in the Myrtaceae and their essential oils. Part 1. The seasonal variations in yield and cineole content of Melaleuca alternifolia Cheel. In Researches on Essential Oils of theAustralian Flora, vol. 1, Museum of Applied Arts and Sciences, Sydney, pp. 5-7.

Reilly, T.L. (1991) The economics of tea tree. Reports: Tea Tree Marketing & Planning Conference, Ballina, NSW, 31 Oct-2 Nov. 1991.

Salisbury, F.B. and Ross, C.W. (1992) Plant Physiology, Wadsworth Publishing, Belmont, Calif.

Schonherr, J. and Bukovac, M.J. (1978) Foliar penetration of succinic acid-2,2-dimethylhyrazide: Mechanism and rate limiting step. Physiol. Plant, 42, 243-251.

Schonherr, J. and Riederer, M. (1989) Foliar penetration and accumulation of organic chemicals in plant cuticles. Rev. Environ. Contam. Toxicol., 108, 1-70.

Small, B.E.J. (1981) Effects of plant spacing and season on growth of Melaleuca alternifolia and yield of tea tree oil. Aust. J. Exp. Agric. Anim. Hush., 21, 439-442.

Southwell, I.A. and Stiff, I.A. (1989) Ontogenetical changes in monoterpenoids of Melaleuca alternifolia leaf. Phytochem., 28, 1047-1051.

Southwell, I.A. and Stiff, I.A. (1990) Differentiation between Melaleuca alternifolia and M. linariifolia by monoterpenoid comparison. Phytochem., 29, 3529-3533.

Stahl-Biskup, E. (1987) Monoterpene glycosides, state-of-the-art. Flav. Frag. J., 2, 75-82.

Tingey, D.T. (1981) The effect of environmental factors on the emission of biogenic hydrocarbons from live oak and slash pine. In J.J.Bufalini, and R.R.Arnts (eds.), Atmospheric Biogenic Hydrocarbons, vol. 1, Ann Arbor Scientific Publishing, Ann Arbor, Michigan, pp. 53-73.

Tingey, D.T., Turner, D.P. and Weber, J.A. (1991) Factors controlling the emissions of monoterpenes and other volatile organic compounds. In T.D.Sharkey, E.A.Holland and H.A.Mooney, (eds.), Trace Gas Emissions by Plants, Academic, San Diego, pp. 93-119.

Waring, R.H. and Schlesinger, W.H. (1985) Forest Ecosystems, Academic, Orlando, pp. 7-37.

Welch, M.B. (1920) Eucalyptus oil glands. J. Roy. Soc. NSW, 54, 208-217.

Whish, J.P.M. and Williams, R.R. (1996) Effects of post harvest drying on the yield of tea tree oil (Melaleuca alternifolia). J. Essent. Oil Res., 8, 47-51.

Wiermann, R. (1981) Secondary plant products and cell and tissue differentiation. In E.E.Conn, (ed.), The Biochemistry of Plants, vol. 7. Secondary Plant Products, Academic, New York, pp. 85-115.

Williams, L.R. (1995) Selection and breeding of superior plants of Melaleuca to increase the production and antimicrobial activity of tea tree oil. In K.H.C.Baser, (ed.), Flavours, Fragrances and Essential Oils, vol. 2, AREP Publ, Istanbul, pp. 408-417.

Williams, L.R. and Home, V.N. (1988) Plantation production of oil of Melaleuca (tea tree oil)—A

revitalised Australian essential oil industry. Search, 19, 294-297. Zimmermann, M.H. and Milburn, J.A. (1982) Transport and storage of water. In O.L.Lange, P.S. Nobel, C.B.Osmond and H.Ziegler, (eds.), Physiological Plant Ecology, vol. 2, Springer-Verlag, Berlin, pp. 135-151.

Zrira, S. and Benjilali, B. (1991) Effect of drying on leaf oil production of Moroccan Eucalyptus camaldulensis. J. Essent. Oil Res., 3, 117-118.

Was this article helpful?

0 0
Aromatherapy Aura

Aromatherapy Aura

This powerful tool will provide you with everything you need to know to be a success and achieve your goal of breaking into the mighty wellness arena. All the same the issue with getting hold of all that content is the huge expense. If you don't have time to compose all that content yourself, you're going to have to pay somebody to do it for you. And not only that, but if you've done outsourcing before, then you'll know that quality may often be 'questionable'.

Get My Free Ebook


Post a comment