TRUFFLE INOCULATED TREES
A taste sensation.
Southern Woods is excited to take the propagation and inoculation of truffles to the next level in the New Zealand edible fungi market.
Our growing and testing procedures have been thoroughly revised to set new industry benchmarks in New Zealand, and to provide the best possible product to our discerning customers.
We have combined our knowledge and experience of growing trees with the scientific expertise of a local research Institute for inoculation and testing. Southern Woods can now confidently supply our customers with the highest quality seedlings of truffle inoculated oaks, pines and hazels, inoculated with one of three truffle species.
Trees are typically available around spring and autumn each year, with the final testing happening in August/September.
For larger orders we have a lead in time of at about 18 months, with planning starting in autumn. To guarantee the supply, we would appreciate your order before July.
What are Truffles?
Truffles are the fruits of perennial soil fungi that live in symbiosis with certain trees.
The truffle mycelium colonize roots and transform them into mycorrhizae (from Greek, ‘fungus-root’), real root organs resulting from the intimate merger between plant and fungal tissues. The fungus supplies the tree with water and nutrients while the tree provides the fungus with soluble sugars from photosynthesis. Through the mycorrhiza connection, both the truffle and the tree help each other to grow. The powerfully scented fungi are a culinary delicacy in many parts of the world and are a sought-after product in New Zealand and many world markets. The tree species provided by Southern Woods are proven hosts of specific truffles and are already successfully grown in New Zealand.
The accurate identification of the truffles species at each stage of the seedling production process, i.e. inoculation and testing, is crucial for the successful initial establishment of these valuable fungi. The identification relies on the use of both morphology (i.e.microscopy) and DNA techniques. These tools combined with current knowledge, enable confirmation of the presence of a target species on a tree. Morphology also enables trained eyes to estimate the abundance and the development of the desired species. Well-developed mycorrhizae start to branch, forming mycorrhizal clusters which are only detectable through morphology. Southern Woods is proud to be at the forefront of industry innovation and truffle testing procedures, to ensure customers have the best possible chance of establishing a successful truffière.
Matching the tree & truffle species to your site is crucial, as is site preparation and ongoing orchard management. If climate and other environmental conditions are not suitable, the truffle crop may not be successful. The first harvest can be expected, on average, from about four years upwards after planting. Bianchetto can start fruiting on pines as early as three years after planting.
Périgord Black Truffle
The Périgord truffle is one of the most commercially valuable truffles in the world because of its powerful, sweet aroma. The dark brown, warty-skinned fruiting bodies can reach up to the size of a grapefruit. Truffles become ready for harvest in mid-winter, and grow best in high alkaline limestone soil with either an Oak or Hazelnut host tree.
The Bianchetto or ‘Little White’ truffle is also known as the ‘pine forest truffle’ or the ‘truffle of March’ and is grown for its excellent flavour and aroma. The Bianchetto truffle is very variable. Its diameter can be up to 5 cm or more, it has a smooth skin and a pale-yellow to reddish-brown appearance. The Bianchetto truffle prefers sandy limestone soils, and associates with a variety of host trees, including oaks, hazels, conifers and others. Harvest is typically from winter to spring.
Tuber aestivum syn. T. uncinatum
This truffle has an intense aroma reminiscent of hazelnut. Its size varies, can be up to 10 cm or more in diameter. It has a black warty skin. Warts can often be larger than those of the Périgord Black truffle. Tuber aestivum partners best with oaks and hazels, although it can be found on many other species. It favours organic soils and is typically harvested between spring and autumn.
An edible investment.
Prices for first grade fresh black truffles in the French market are currently about 1200 Euros per kilogram.
Elsewhere in the world prices paid by those very few top-class restaurants, which are able to source the product, are in excess of $3,600 NZ per kilogram. In New Zealand, black truffles sell between $2 and $3 per gram.
European truffle production is limited by the lack of large-scale farms, relatively low levels of technical skill and business expertise within the farming community, and enormous competition from other forms of land use.
Total truffle production is expected to vary from 50 to 70 tonnes annually.
Truffle Growing in Australasia
Partly following on from the developments in France but also as a consequence of successes with other new crops, there has been growing interest from New Zealand and Australia in establishing a black truffle industry. Both countries have been growing black truffles for a number of years.
The soil and climate conditions required by truffles and their host trees exist in both countries, and both have the high technical and management skills required to make black truffle growing a success.
In New Zealand, the industry gained impetus from the efforts of Plant & Food Research that developed a system of inoculating the roots of young trees with black truffle spores.
Truffles were first produced in a Gisborne truffière in 1993, and there are now a few productive plantations from the Bay of Plenty to Canterbury. At present there are about 40,000 trees on more than 100 sites, most of which have fewer than 600 trees.
This includes well producing truffières in Canterbury. Because of the relatively small size of the existing truffières it is difficult to extrapolate precise production data but yields equivalent to well over 100kg/hectare have already been achieved. These yields are reputed to be the highest in the world for cultivated truffles.
The nursery where the trees are inoculated and grown is operated under strict quarantine and hygiene conditions to ensure a high standard of quality control. The actual inoculation process is based on a French system, modified to meet local hygiene and quarantine requirements.
Trees are grown from seed for 12 to 18 months up to approximately 20 cm in height in carefully managed conditions to ensure a high level of mycorrhization (establishment of the fungi on the root). They are sold with every chance of producing truffles, given correct, and on-going, management.
PLANTING YOUR TREES
Choosing and Preparing the Site
A number of key conditions must be satisfied in order to successfully grow the Perigord black truffle in a plantation setting.
- Correct soil pH (add natural lime and/or dolomite to achieve optimum 7.9)
- Friable, well-aerated, and well-drained soil (drain if required, and cultivate prior to planting)
- Sufficient moisture at key times (install a mini-sprinkler irrigation system)
- An absence of competing fungi (see table below)
- Absence of competing weeds (maintain a weed-free spot around the tree)
- A relatively dry climate (more so for Holm oaks)
- Warm summer temperatures (mean daily 16.5 to 22C)
- Cool winter temperatures (mean daily 1 to 8C)
- Easy contour (for ease of machinery operation)
Plant in autumn or spring into weed-free and well-cultivated ground. Use a non-residual herbicide like ‘Buster’ but don’t use ‘Glyphosate” e.g. RoundUp, as it is detrimental to soil fungi. Autumn and winter planting can also be successful with larger seedlings and/or more cold-hardy species (e.g. Common oak and Hazelnuts).
Plant at 5m x 4m spacing i.e. 500 trees per hectare. DO NOT over-fertilise the soil at planting as you risk killing off the truffle fungi. Avoid salt-based fertilisers such as DAP, Nitrophoska etc. Blood and bone would be a good choice.
Disturb the roots as little as possible. Ensure that the potting mix is well covered with soil. Water in well. Put a 60cm tall triangular Tuff Guard shelter with a stake on each tree. This will help to protect against frost, pests, wind and sprays.
Truffle fungi are ectomycorrhizal fungi and for them to establish well it is important that your truffière is not positioned within 20m of other trees that could harbour competing ectomycorrhizal fungi. Most trees form arbuscular mycorrhizas – the other main form of mycorrhizal fungi. These are all suitable for use as windbreak or companion trees close to your truffière.
Put a 40cm diameter mulch mat (or similar) around each tree.
PLANTING WITH TRUFFLES
Suitable (and unsuitable) Companion Trees.
Suitable companion/windbreak trees (these form arbuscular mycorrhizas)
NZ Natives (most are suitable so just the key species have been listed below)
Akeake (Dodonaea and Olearia species), Broadleaf (Griselinia littoralis), Coprosma species (C. lucida, C. robusta. C. propinqua), Corokia species, Flax (Phormium tenax, P. cookianum), Lacebark (Hoheria species, Kowhai (Sophora species), Pittosporum species (P. See the native shelter designs in the Southern Woods catalogue.tenuifolium, P. eugenioides, P.ralphii), Ribbonwood (Plagianthus regius), Totara (Podocarpus totara)
Ash (Fraxinus species), Deciduous fruit trees (Prunus and Malus), Himalayan Cypress (Cupressus torulosa) Japanese cedar (Cryptomeria japonica), Lawson cypress (Chamaecyparis lawsoniana), Leyland cypress (Cupressus leylandii), Maples (i.e. Acer negundo, A. pseudoplatanus), Macrocarpa (Cupressus Macrocarpa), Mexican Cypress (Cupressus lusitanica), Olives (Olea cultivars e.g. Frantoio, Leccino, Pendolino), Redwoods (Sequoia sempervirens, Sequoiadendron giganteum), Rowan (Sorbus aucuparia), Viburnum (e.g. V. tinus ‘Lucidum’).
Unsuitable windbreak and companion trees (within 20m of the truffière)
Alders (Alnus species), Beech (Fagus and Nothofagus species), Birch (Betula species), Cedar (Cedrus species), Chestnuts (Castanea), Douglas Fir (Pseudotsuga menziesii), Eucalyptus (all species), Firs (Abies species), Hazelnuts (Corylus species), Hornbeam (Carpinus), Kanuka (Kunzea ericoides), Larch (Larix species), Lime (Tilia species), Manuka (Leptospermum scoparium), Oaks (Quercus species), Poplars (Populus – all cultivars), She-oaks (Allocasuarina species), Spruces (Picea species), Willows (all cultivars and species)
Approximate Setup Costs
Set-up costs vary depending on factors including topography, soil type, climate and infrastructure. Indicative establishment costs per hectare are:
Reticulated spray irrigation system
Liming and soil rectification
Planting, tree guards, stake, mulch mat
400 trees @ $53+GST
Total - Excluding GST
MAINTAINING YOUR TREES
On-going costs include weed spraying, tree maintenance, watering and soil maintenance. On average these will be around $1,200/hectare/annum. Harvesting silage or hay from between these rows may offset some of these costs.
LONG TERM RETURNS
Returns for Perigord Black Truffles
It is almost impossible to get verifiable income data from a fully developed, mature truffière anywhere in the world. This is partly due to the very high prices received for the product, and the fact that the European producers are very secretive about methodologies and systems and the consequent returns.
Experience from Tasmania has shown that, given the right conditions, truffles around Holm Oak trees can be found four years after inoculation, though it would be wise to use 7 or more years in your financial projections. Naturally, a small tree in the early years is not going to have a large root system on which to harbour many black truffles.
In New Zealand, there have been instances of yields in excess of 90kg/ha. One plantation in the Bay of Plenty has achieved a yield of more than 400g/tree.
Once a tree starts producing it seems to then continue to produce on a regular basis. Several mature plantations in France have reported individual trees consistently producing 150-200g grams of truffles per year. Assuming correct inoculation, appropriate on-going management and that each tree is producing, estimates can be made regarding yield.
Production can be projected from an initial 2 to 4kg/ha at year 6, up to a potential of 40kg/ha over a subsequent 5-year period. After 11 years, on-going production is estimated at 20 to 40kg/ha/year
SELLING YOUR TRUFFLES
During June, July and August, when “down under” black truffles can be supplied fresh, France’s population of 55 million almost doubles to about 100 million thanks to an influx of tourists. Europe is on summer holiday, and restaurants throughout France do a roaring trade. Local people in the European market believe that if they can access fresh black truffles in their summer it will increase the overall awareness and result in increased demand.
Currently the small volume of NZ produced truffles are mostly sold locally to top-end restaurants. As volumes increase more truffles will be air freighted to overseas markets. Contact should be made with the NZ Truffle Association for an update of current industry marketing initiatives.
NZ Truffle Association, PO Box 351, Wellington 6140; www.nztruffles.org.nz
Hills Laboratories, Ph 03 377 7176, Web www.hill.laboratories.com
Soil Amendments – Contact your local farm supply merchant or fertiliser representative. Note that natural lime or dolomite is better than pelletized products
Taming the Truffle – The history, lore, and science of the ultimate mushroom. Ian Hall, Gordon Brown & Alessandra Zambonelli, 2007. www.timberpress.com
The Black Truffle – Its History, Uses and Cultivation. Ian Hall, Gordon Brown & James Byars. NZ Crop & Food Research, 2001. www.crop.cri.nz/books
Edible Mycorrhizal Mushrooms and their Cultivation. Proceedings of the 2nd International Conference on Edible Mycorrhizal Mushrooms, Christchurch, July 2001. Editors: Ian Hall, Wang Yun, Eric Danell, & Alessandra Zambonelli. www.crop.cri.nz/conferences/em-mushroom
Edible and Poisonous Mushrooms: an introduction. Ian Hall, P. Buchanan, Yun Wang, & A. Cole. NZ Crop & Food Research, 1998.
The Truffle Book. Gareth Renowden. Email firstname.lastname@example.org, Web www.limestonehills.co.nz, Ph 021 790 070
Factors affecting the fruiting of the Perigord black truffle: a comparison of productive and non-productive Tuber melanosporum truffieres in NZ. NZ Crop & Food Research, 2002
In defence of truffles – Guerin-Laguette A, Wang Y 2015. Quarterly journal of the New Zealand Tree Crops Association (Inc.) TreeCropper 82: 10–13
Mycorrhiza analyses in New Zealand truffières reveal frequent but variable persistence of Tuber melanosporum in co-existence with other truffle species. –Guerin-Laguette A, Cummings N, Hesom-Williams N, Butler R, Wang Y. 2013. Mycorrhiza 23: 87-98. DOI 10.1007/s00572-012-0450-2
Successes and challenges in the sustainable cultivation of edible mycorrhizal fungi – furthering the dream. Guerin-Laguette A. 2021. Mycoscience 62:10-28. Free to download from: Successes and challenges in the sustainable cultivation of edible mycorrhizal fungi – furthering the dream (jst.go.jp)