- The following paper is an objective view on the viability of growing the truffle
Tuber melanosporum in the Willamette Valley. Included in this study are the history of
the truffle, biological cycle, habitat description, method of cultivation and an enterprise
budget for commercial production in the Willamette Valley.
The truffle, a fungus that grows naturally underground, has long been a delicacy in
European culture and it continues to appear in expensive restaurants around the world.
The cultivation of T melanosporum was established first in Europe, but is gaining
popularity in other parts of the world. Farms are appearing in Israel, Australia, The
United States, New Zealand, and other nations. North Carolina and California also have
operating truffle farms. Several species are currently cultivated in Europe, but the most
prevalent and the only species cultivated outside of Europe is the Perigord (Black) truffle,
Truffles are the fruiting bodies of various fungi. Spores produced within fruiting
body germinate into tiny hair-like filaments (mycelia) that eventually attach themselves
to the root tips of a host species and form mycorrhiza. After about six years, secondary
mycelia emanating from the mycorrhizae grow together into a knot and form the fruiting
body or carpophore. Host trees vary according to the location and species of truffle,
however oak and hazelnut trees are most commonly used. Host trees that have been
mycorrhized with truffles can be purchased from reputable growers for about $15 each.
The climatic characteristics of the Willamette Valley are similar to those of major
truffle growing regions in Europe. In addition, soils in the Willamette Valley may have
an advantage because potentially competitive ectomycorrhizal fungi are adapted to acidic
soils. T. melanosporum is grown in soils with high pH. Raising the soil pH for T.
melanosporum could reduce the competition from native fungi adapted to acidic soils.
Although few attempts have been made to cultivate truffles in Oregon, the Willamette
Valley could be an ideal habitat for growing Tuber melanosporum.
Establishment of a truffle farm takes 7 to 12 years depending on the species and the
condition of the plot. Land must be free of plants that support ectomycorrhizal fungi,
have evenly mixed sand, silt and clay (or well drained soils) and have an alkaline pH.
An irrigation system should be installed in case of drought. After the trees are planted,
maintenance of the truffle plot involves tilling the soil once a year, liming to maintain pH
and pruning the host trees. Production typically begins after about six years and full
production after about 10 years. Yields are difficult to estimate because truffle
production is heavily influenced by weather conditions. In Europe, typical yields range
from 50-150 kg per hectare (50-150 pounds per acre) in different plantations.
The enterprise budget for a truffle farm in the Willamette Valley considers the costs
and returns for a newly established farm. The budget is, by design, only a guide and does
not consider individual differences among farmers. For example, it is expected that
truffle cultivation will be an enterprise added to an existing farm, however the included
budget includes costs of renting machinery for tilling. For a farmer that already owns
his/her machinery, the budget must be altered accordingly.
Truffles are expensive to produce. Profit and loss depend greatly on yield and price
per pound. Also, commercial cultivation of truffles has not been achieved in Oregon and
results are unpredictable. In good years, however some farms yield more than 100 kg per
hectare (100 pounds per acre). Market prices fluctuate and may depend heavily on
reputation as well as quality of truffles. In 2001, fresh truffles of the variety Tuber
melanosporum were available on the Internet for about $225/kg ($500/pound). Other
truffle species such as T. magnatum sell for about $765/kg ($1700/pound). The truffle
industry is virtually unexplored in Oregon and there is potential to grow T.
melanosporum in the Willamette Valley. This is a high risk crop due to the initial
investment, a 10 year establishment period and fluctuations in yield and market values.
Still, truffles are a low maintenance crop, can be sold worldwide and are highly
acclaimed among gourmets. Also, truffle supply is limited, resulting in extreme high
price. Socially and economically it appears that Tuber melanosporum could be a viable
enterprise in the Willamette Valley.