Some of my favorite foods are truffles, and perhaps the best tasting truffle – in my humble opinion – is the famous Périgord Black Truffle, also known as Tuber melanosporum, which is known as a prized delicacy capable of fetching a pretty penny.
Tuber melanosporum is an important ectomycorrhizal fungus that can be cultivated with crop trees such as Hazelnut, and other truffles can be cultivated with other nut trees such as Pecan. Despite a concerted effort to understand the biology of T. melanosporum, both through a genome sequence and other molecular tools to understand population biology – as well as government efforts to promote cultivation with nut trees – harvests of the Périgord Black Truffle have been declining since the 1970s. There has been no agreement in what has been causing this decline from a community of researchers.
In a brief report entitled “Drought-Induced Decline in Mediterranean Truffle Harvest” in the journal Nature Climate Change, Büntgen et al. recently described how climate change may be affecting truffle production, either directly, or by affecting the biology of the truffle’s host trees. Such measurements are challenging in numerous regards; inspecting climate data is difficult enough, but reports of truffle harvesting are scarce for many reasons, one of which is the fact that many successful truffle collectors are reluctant to give information about their productive grounds.
The authors correlated climate details from 12 climate models with truffle harvests from various parts of Europe (namely Aragón in Spain, Périgord in southern France, and Piedmont and Umbria in Northern Italy). They observed that tree ring growth in Oak trees and truffle production were correlated and showed that increased measurements of summer evapotranspiration could explain both the reduction in plant growth and truffle production.
The authors hypothesize that tree and fungus competition for summer soil moisture may be reducing the production on truffle sporocarps. Unless the present course of climate change is reversed, it is expected that truffle harvests in Europe will continue to decline. This is bad news not just for the truffles and trees, but the people who enjoy both.
UPDATE: The New York Times have posted an article (December 20th) entitled “$1,200 a Pound, Truffles Suffer in the Heat“