Why has production of the black truffle (Tuber melanosporum) declined in France?

Natural production in France declined from over 1000 tons to under 100 tons over the past 100 years and continues to decline annually. There are many causes, the most significant being deforestation, climatic change, conversion of land to non-agricultural use and the late development of scientific technology for commercial production. Nevertheless, market demands, and therefore prices, have remained high.

At what depth do truffles grow?

Truffles are generally found in the top 150 mm, but can be down to 350 mm on rare occasions and emerging from the surface in certain conditions.

What happens if the truffles are not harvested?

If the truffles are not harvested, they will rot. However the spores will remain in the soil and if ingested by another animal may be transported to another host tree where they may give birth to new mycorrhiza.

What animals are used to hunt for truffles?

Pigs were the traditional animal used to locate the mature truffle, but in essence it is difficult to train a pig to sit, stop or stay, and not to eat the truffle, which is a natural thing for a pig to do. As a result, commercial plantations use specially trained dogs to identify the location of the truffles. Any dog will find truffles if it has a good relationship with its trainer and enjoys the game. Springer spaniels, Labradors and a lagotos, which is a traditional European truffle hunting dog, are used on the Tasmanian plantations and all have their good and bad points.

Where does your base stock come from?

Our stock comes from many black truffle farms in the truffle heartland of France. It is microscopically checked using technology developed by the French National Institute for Agricultural Research (INRA). We only select the best breeding stock from our nursery.

Do you guarantee that your saplings will grow?

We check the health of all saplings before delivery. Healthy saplings that are planted into well prepared land and are properly maintained should grow. However, we cannot guarantee this since we do not have control over these factors.

Do you guarantee a truffle harvest?

We sell trees that are mycorrhized with truffle but we cannot guarantee that they will produce truffles as there are too many variables. However, in our experience, all growers who have followed all the recommended procedures have produced truffles from their plantations.

What risks are there in growing truffle plantations?

The black truffle (Tuber melanosporum) is vulnerable to competitive fungi, some of which are also grown commercially but have significantly less value. While we take every precaution to ensure that our trees are only inoculated with the intended truffle spore, contamination of black truffle trees has posed serious risks in France and very recently New Zealand. Our advice on where and how to plant the inoculated trees is also important to reduce the risk of contamination from indigenous fungi once the saplings are planted out.

Do I need to fertilize truffle trees?

Once soils have been corrected prior to planting, it should not be necessary to add additional fertilizers. However, we would recommend an annual soil test to see if periodic applications of lime or fertilizer may be necessary.

How old are the saplings that you sell?

They are sold between 12-18 months.

What kind of tree species do you use?

We use the two species of oak most commonly used in truffle orchards, namely Quercus ilex (Holly oak) and Quercus robur (English oak).

Are truffle trees on the alien species control list?

The control of alien plant species is in terms of Department of Agriculture and Environment legislation. There are different categories of alien plant species, some of which have to be removed and destroyed. The factors affecting the department's decision about whether or not to list a plant include water use and invasiveness. Neither the Quercus ilex (holly oak) nor the Quercus robur (English or common oak) are on any category of this list.

The black truffle itself is a non-invasive fungus and is approved for import for agricultural production by the Department of Agriculture.

Am I allowed to plant oak plantations?

There are restrictions on growing trees for timber in terms of Department of Water Affairs and Forestry (DWAF) legislation. However, a truffle plantation does not fall under DWAF legislation because it is not a timber crop but an agricultural crop. Therefore you may grow oak plantations in order to produce truffles. However, other agricultural use regulations may apply to particular sites. Growers are advised to obtain information from the local Department of Agriculture on any relevant and applicable controls.

Are truffles an environmentally friendly crop?

Although the most frequently used host trees in commercial plantations are exotics, there is minimal use of fertilizers, herbicides and pesticides and fungicides are prohibited since they would kill the truffle. The land, once planted, is not regularly tilled, which allows natural soil organisms to thrive. In addition, the truffle plantation is a carbon sink and not a carbon user.

What is the truffle's life cycle?

The fungus requires a warm moist period in early spring to trigger initiation of the fruiting body. It requires specific water management and in Europe irrigation is not possible on many plantations, so they need to rely on summer storms to develop their truffles. Here we choose sites with irrigation potential if possible to eliminate the risk of a long dry period which may starve the truffle of moisture causing it to either abort or be small and contorted. They will normally reach their full size around April if conditions are optimal and then take about another three months to reach harvesting age.

How do I market my truffles?

There are two main markets for fresh truffles: top South African restaurants situated mainly in Jo'burg and Cape Town and restaurants and wholesale markets in Europe, America and Asia. South African growers can either attempt to develop their own markets for their truffles or enter into agreements with us in terms of which we will guarantee to purchase minimum truffle harvests of 2kg or more.

Will heavy liming damage my land if I decide not to grow truffle trees?

Liming binds certain minerals, making them unavailable to plants. However, the effects of liming can be reversed so they need not be permanent. It is recommended that farmers seek advice from an agronomist, which is likely to include soil testing, to make adjustments to soil prior to planting any crop.

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