Buried Treasure:

Truffles in the soil of Taiwan

Prior to this, beginning in 2016 some five new or previously unrecorded truffle species had been found in Taiwan, including the red fold truffle (Hydnotrya tulasnei), which had not previously been recorded in Taiwan, in 2016; Tuber elevatireticulatum, a newly described species, in 2018, and Tuber lithocarpii, also a new species, in 2021. All of these discoveries were the result of the efforts of a research team from the Forest Protection Division of the TFRI, led by researcher Fu Chuen-hsu and assistant researcher Lin Chieh-lung.

Fu reveals that the team combined basic data from truffle growing areas worldwide with forest soil survey data from the MOA’s Forestry and Nature Conservation Agency to identify potential “hotspots.” They then compared these with five major hotspots for underground fungi delineated 30 years ago by Hu Hung-tao, now a professor emeritus in the School of Forestry and Resource Conservation at National Taiwan University. They ultimately selected two or three final hotspots and began searching for traces of truffles in these target areas.

Fu mentions that the mature fruiting bodies of truffle species that grow at elevations of 1,200‡1,300 meters can be collected from November to February, while for those at 2,500 meters the collection season comes in June and July. “However, at the Lienhuachih Research Center, with elevations ranging from 576 to 925 meters, they mature seemingly at random, so it’s hard to be certain.” According to the team’s analysis of previous research, truffles grow best in alkaline soil in cool climates. However, at lower elevations, these results are not entirely reliable, making the patterns of truffle growth less predictable.

The Y-shaped outgrowth indicates that the inoculation of the seedling with synthetic mycorrhizae has been successful.

The TFRI research team attempts to propagate truffle spores to preserve precious fungal strains, and conducts inoculation experiments with seedlings of many tree species. Besides collecting data on truffle growth, they are making preparations for future volume production of these delicacies.

Indispensable data for new species

After finding a truffle, researchers must fulfill many conditions to positively identify a new species.

Members of the research team reveal that when publishing the discovery of a new truffle species internationally, the report must include numerous details including a comprehensive description of the number, size and shape of the truffle’s spores as well as the overall shape of the truffle. It must also be compared to images of related species to confirm which features of the newly published species are similar to those of known species from around the world. Only then can one say that its “story” has been adequately told.

Of these steps, the examination of mature spores is perhaps the most time-consuming. Lin Chieh-lung says that in May of one year they collected ten truffles around the Lienhuachih Research Center in Nantou County in Central Taiwan, only to find after getting them back to the laboratory that the spores were not mature. Their best option was to return in July and August of the same year and in February of the following year, yet each time they were unsuccessful.

Under a microscope, the spores of white truffles present a turtleshell pattern, making them markedly different from the thornlike appearance of the spores of black truffles. Nonetheless, both are important indicators of whether the spores are mature and viable.

The research team led by Fu Chuen-hsu (right) and Lin Chieh-lung (left) has been all over the world to gather information on truffle cultivation from production areas in various countries, in order to advance the field of truffle research in Taiwan. (courtesy of Lin Chieh-lung)

The truffle sporocarps (fruiting bodies) collected by the TFRI team range in size from as large as seven centimeters to less than one centimeter.

A 30-year truffle journey

When talking about the remarkable achievements made in truffle research in Taiwan in recent years, one cannot fail to mention the foundations laid 30 years ago by the research team of Hu Hung-tao.

This team issued Taiwan’s first report on a new truffle species, Tuber formosanum, in 1992, followed by the publication of Tuber furfuraceum in 2009. Moreover, in the 1990s Hu founded the first artificial truffle orchard in all of Asia in the National Taiwan University Experimental Forest.

Fortunately, during the intervening decades, Fu Chuen-hsu and Lin Chieh-lung have taken up the baton of Taiwanese truffle research from Hu and discovered five more species. They believe that Taiwan has even greater potential: “Based on conditions in Taiwan we estimate that there should be at least 15 truffle species.”

Most truffle species require very particular environmental conditions. They generally prefer alkaline soils, and in Europe they are frequently found in karst terrain predominantly composed of limestone. Therefore, Lin Chieh-lung believes that besides the two hotspots of the Sun Moon Lake‡Puli area in Nantou County and the forest area of Lijia, Taimali, and Anshuo in Taitung County in southeastern Taiwan, both of which boast large numbers of relict plant species from the ice ages, there may still be undiscovered truffle species amid the limestone topography of Eastern Taiwan, where there are also alkaline soils.

However, it is noteworthy that the characteristics of the humus layer in high-­elevation mountain forests in Taiwan are such that all of the truffle species discovered here to date have been found in acidic soil, which is a rare occurrence. “The pH value of the soils where truffles have been found is between five and six at most. None of them have been above the neutral pH level of seven.” Lin’s remark highlights the uniqueness of Taiwan’s truffle species and their marked difference from other truffles around the world, which grow in alkaline soils.

Truffle spores must be examined under a microscope to determine whether they are mature.

Spores of a white truffle.

Next stop for truffle research

Fu Chuen-hsu surmises, “These microorganisms came to Taiwan during the ice ages and survived here. After adapting to the temperatures, humidity and phenological conditions here they and other species co-evolved, competing with and stimulating each other, so that over a long period of time Taiwan’s species became more specialized.” This comment resonates with the fact that Taiwan’s subterranean fungi are diverse enough to account for 6% of the global total of such fungal species.

In fact, in the course of discovering and studying truffles, researchers have also been promoting the conservation of biodiversity in Taiwan. Besides life forms that live on and above the Earth’s surface, we also need to pay attention to underground organisms and bacteria, which account for 70% of the world’s biomass. Though often overlooked, they are critically important to comprehensive protection of ecosystems and the environment.

Besides contributing to biodiversity, truffles have rigorous environmental requirements and high economic value, giving them great potential for future development as part of the under-forest economy, which is currently being advocated to maintain forest ecosystems and forest cover. This is because they have a symbiotic relationship with plants. Fungi absorb carbo­hydrates and other nutrients from the roots of plants, while the plants in turn access needed water and nutrients through fungi. If land is cultivated using conventional agricultural methods, agro­chemicals will cause an imbalance in the microbiota of the soil, adversely affecting the growth of fungi. Therefore, land where truffles grow must be healthy and unpolluted.

Meanwhile, Fu Chuen-hsu reminds us that “in pursuit of the commercialization of truffles, the goal must be ‘the right species for the right place.’” In particular, truffles are not things that can be planted and harvested according to a particular schedule, and they can only be grown with patient waiting and continual irrigation. Only then will the day come when truffle research from Taiwan, which has been carried on arduously for decades, can shine in the inter­national community.

Spores of a black truffle.