Why do we need plantations of Leptospermum?
The short answers are supply and demand for medicinal grade honey, and superior genetics. The global demand for medicinal honey has grown considerably in recent years which has led to high prices being paid for this honey in comparison to other types. Medicinal honey is now becoming more accepted in the medical community as a tool to slow the development of antibiotic resistance in bacteria, especially golden staph, as well as usage as a topical dressing for wounds. As research continues in this area, more uses for this honey are being discovered, further increasing demand. Medical honey can also be used in the veterinary industry as a wound dressing, and has been for many years, particularly with horses. This combination of factors suggests that there is unlikely to be an oversupply issue for many years. The wild resources of Leptospermum in Australia and New Zealand are finite resources, and these are being fully stocked with hives to maximise production. There are now signs that overstocking is happening in some areas and honey yields could start to decrease per hive if overstocking increases. The obvious solution is to increase the resource through plantations.
Plantation stock, if it has been tested, should have higher DHA levels than the wild resource. This is because in any given area in nature, there is genetic variation of DHA levels in the nectar of plants, with some being low, and others high. Through testing, only the plants with superior DHA (and sugar for bee attraction, nutrition and honey production) are used for propagation. In this way, more nectar is collected from high DHA plants, which results in superior levels of MGO in the honey. In a plantation, the majority of the plants that the bees forage from will be Leptospermum. This reduces "nectar contamination" from other sources which in turn, reduces the DHA levels in the honey (a bit like adding water to cordial, the more water added, the weaker it gets). Nectar contamination is difficult to control in natural sites. These factors suggest that the highest grade honey (and most valuable) will come from Plantations.
The importance of a "nectar gap"
A nectar gap is a period of the year in your location when there is a low supply of nectar. Such a time is ideal to find a Leptospermum species to fill the gap so that the highest grade honey can be produced. Any nectar from a plant other than the selected Leptospermum that bees forage will dilute the honey produced. The more monofloral the honey is, the higher MGO levels will be in the extracted honey. Most seedling suppliers are growing only one or two species. Grand Ridge Propagation has ten species and cultivars that have been nectar tested and propagated. The total flowering period of these species is up to a consecutive NINE MONTH period, all with high DHA levels. This is possibly a world first! In this way, we can help you select the best species for your individual situation, climate, microclimates, rainfall pattern and nectar gaps.
Plantation construction and spacings
The first consideration for any plantation is your desired goal from the plantings. The two most common scenarios are windbreaks and specialist honey production plantings. Windbreaks that consist solely of Leptospermum plants should be planted at 2m spacing, with a similar gap between rows. In this way, the plants will "lock in" together and provide support from strong winds, without being too close so as to compete for moisture and nutrients. For mixed species windbreaks, firstly ensure that the other species wont overlap their flowering times with the Leptospermum as this will dilute the nectar being foraged. For a low growing windbreak consisting entirely of shrubs, plant at 2m spacing. When Eucalypts or other large trees are to be incorporated for shade and height, plant at three metre spacing with a zig zag pattern between rows. If your site has good moisture levels and fertility, you could plant the Leptospermum row at 2m apart, with the gums remaining at 3m.
Specialist honey production plantations are designed so that maximum surface area of plant is produced, therefore maximising flower production. A plant spacing of 3m (1150 plants/hectare) will achieve this goal. This density allows the shrubs to grow to their full size without growing into each other to any large extent. It also allows maximum sunlight to reach each individual plant (there is a direct correlation between sunlight exposure, foliage density and flower production). Each plant will also be far enough away from each other so as to be not competing for nutrients and moisture. Planting at higher densities will in fact decrease flower production as each plant will be competing for light and other resources, resulting in spindly and weak plants. Planting at lower densities will allow weeds and other plants to establish strongly (potentially diluting nectar), as well as leaving large areas unproductive for Leptospermum flower production. Consideration should be given at the planning stage for access tracks so that hives can be strategically placed in the plantation, as well as other plantation management tasks.
Stocking rates and honey yields
Most yield data comes from the New Zealand honey industry and is based on Leptospermum scoparium. Stocking rates per hectare are stated as 1 hive/hectare in "wild" sites, with plantations ranging from 1 to 4 hives/hectare. Plantation stocking rates will vary with plantation age, density and seasonal variations. A plantation in its first year of flowering (on average three years from planting) would be best stocked lightly. With further experience and maturity of the plantation in coming years, the stocking rate can be gradually increased. Peak production can be expected after six years from planting, with a plantation lifespan of thirty years expected based on Leptospermum scoparium. It is likely some Australian species will exceed thirty years (I have seen 50 year old Leptospermum petersonii planted as street trees in Melbourne still flowering prolifically). From my experience testing flowering plants of many Leptospermum species, some Australian species could also be more prolific nectar producers than Leptospermum scoparium, which offers the potential for higher stocking rates than have been achieved in New Zealand. Yield of honey per hive ranges from 20kg/hive up to 40kg/hive, once again based on New Zealand information. These figures could vary in the Australian situation. With Australia having so many species available over extended flowering periods when compared to New Zealand, the potential for a highly productive and profitable industry is an exciting prospect.
The economics of Manuka honey production is the true driver for the development of this industry. At a wholesale level where the honey is sold to packers, prices paid range from $20/kg to over $100/kg. These prices are based on tested honey, with the higher prices paid for premium products. There is I believe also great potential for small scale producers to market their own product direct to consumers. I am yet to meet a beekeeper selling at a market that isn't consistently asked about the availability of Manuka honey. It would not be unreasonable to expect a 250g jar of tested honey of 300MGO to retail for $25 ($100/kg) when sold at a Farmer's market or similar. The direct marketing of such premium honey would make the planting of a couple of hectares of Leptospermum for a small number of hives an attractive proposition. (The picture to the right was taken at Melbourne's Tullamarine Airport. The 250g jar of 400MGO honey was selling for $59.95, most likely marketed at international customers!)
Genetic improvement programs
The challenge to produce extremely high levels of DHA in our Leptospermum species will be an ongoing process for our business. Scientific research in New Zealand indicates that the level of DHA in a plant is inherited in its progeny. Genetic theory suggests that any plant will produce seedlings for DHA in a bell curve, ie, most around its level, with some much lower and some much higher. Only through nectar testing can those superior plants be found. We are currently growing several hundred Leptospermum scoparium and Leptospermum polygalifolium plants for testing in an attempt to find these individuals. This is already providing great results, as we have tested Leptospermum scoparium with DHA 14691 ppm (MGO 1998)! Such plants can then be cloned to rapidly increase the amount of superior genetics. This process will be replicated with all of our species to produce lines that are genetically superior. Consider the potential of plantations flowering for nine months of the year with over 15000 DHA. Watch this space!