Tricholoma fulvocastaneum belongs to a complex of similar looking species which includes the choice edible T. matsutake. It forms mycorrhiza with Castanopsis spp. and Quercus spp. on undisturbed soil with deep litter. It is known from three prefectures in Southern Japan, two Northern upland provinces of Laos, as well as from South Korea., north eastern and southwestern China and Northern Thailand. In Laos - and to less degree in Japan -  it is heavily harvested due high local and export demand. In Japan it has a downward trend and is red listed as Critically Endangered in Ehime prefecture. In Laos market data suggest a population decline of at least 14% over the past 5 years and this decline is predicted to continue due to unsustainable harvesting. In China the species is in decline due to habitat degradation and loss.  Most of the Greater Mekong Subregion forests have been reduced, severely fragmented, or degraded, with only 13% of primary forests remaining (FAO 2011 State of the World Forests). The reduction in forested area reached about 30% between 1973 and 2009 (WWF 2015 Living Forests Report, Chapter 5). The species is inferred to be under continuing population decline of 50-60% due to this loss of appropriate habitat coupled with the impact of unsustainable harvesting in parts of its range. Thus it is assessed as endangered. 

Tricholoma fulvocastaneum was originally described in Japan, in 1960. It is easily confused with T. matsutake, T. bakamatsutake, T. magnivelare, and T. anatolicum. 

Tricholoma fulvocastaneum belongs to a complex of similar looking species which includes the choice edible T. matsutake. It forms mycorrhiza with Castanopsis spp. and Quercus spp. on undisturbed soil with deep litter. It is known from three prefectures in Southern Japan, two Northern upland provinces of Laos, as well as from South Korea., north eastern and southwestern China and Northern Thailand. In Laos - and to less degree in Japan -  it is heavily harvested due high local and Chinese demand. In Japan it has a downward trend and is red listed as Critically Endangered in Ehime prefecture. 

The species is assessed as ……… under ….. due to a globally very small and restricted population. The number of mature individuals is currently estimated to …… compared to ……...

The fungus is known in the southern part of Japan from 3 of 17 prefectures, from two provinces in Northern Laos and one province in Northern Thailand, as well as from South Korea and Jiling and Yunnan province of China. No listing in iNaturalist.

In Laos, Tricholoma fulvocastaneum became famous in early 1990’es, due to its exports by air of fresh material from Xieng Khouang Province to Japan, under the trade name matsutake, the extremely valuable and more flavoured sister species. The export stopped after 3-4 years. High demand, however, continued and a value chain assessment (Pedersen & Phannorath, 2016) of this species within the province estimated a total harvest of 20.7 tons, from 49 upland villages, down from 23.9 tons in 2015. In subsequent years (2016-19) traders reported further harvest declines. The neighboring Lao provinces has much less harvests, and the species is mainly sold along primary roads between the two provinces.
In Ehime prefecture, Japan, it is characterized as Critically Endangered (Ehime reddatabook, 2014). The website associated with that report lists the fungus as rare within Japan - in 3 of 17 prefectures - with a downward trend due to habitat degradation. In Thailand it is extremely rare with only one record from 2002. In China the species is in decline due to habitat degradation and loss.  Most of the Greater Mekong Subregion forests have been reduced, severely fragmented, or degraded, with only 13% of primary forests remaining (FAO 2011 State of the World Forests). The reduction in forested area reached about 30% between 1973 and 2009 (WWF 2015 Living Forests Report, Chapter 5). The species is inferred to be under continuing population decline of 50-60% due to this loss of appropriate habitat coupled with the impact of unsustainable harvesting. 

Sporocarps form in the beginning to middle of the rainy season in tropical mountain forests dominated by Fagaceae. Found in fertile and undisturbed upland areas under Quercus and Castanopsis, mainly in remote locations. In Laos the peak formation of sporocarps occurs 2-3 times during the rainy season, from late May to late August.

In Laos it is intensively sought after and harvested by villagers due to the high price. Nearly all individuals are picked young (un-opened), often after removing litter accumulation. In this way the mycelium is significantly disturbed by harvesters and according to locals also by cattle. A recent report estimated the total harvest for the Xieng Khouang province from 49 villages amounted to 20.7 ton in 2015, down from 23.3 tons in 2010 (Pedersen & Phannorath, 2016). Subsequent visits to villages and the provincial central market in 2017-2019 revealed further harvest declines (pers. inform). The situation is different in China, where it is not intensively harvested. The other major threat is the reduction in suitable habitat.  Tricholoma fulvocastaneum is restricted to undisturbed or little disturbed Fagaceous tropical montane forests. This reduction results from various human activities, i.e. logging of high-valued timber, forest conversion or degradation for agriculture or understory plantation of tea or coffee, and intentional and unintentional fires that destroys the understory and negatively impacts the soil. 

 

So far, no conservation actions have been implemented, but the provincial Government in Laos has expressed interest in taking actions to stop the negative trend (pers.com). Policies are needed for implementing sustainable harvest and equatable trade. Reduction in logging to reduce habitat degradation is needed as well as stopping intentional and unintentional burning.

Research is needed to fully understand the ecology to explain the patchy distribution of the species within appropriate habitat.  More information is needed to understand the impact of soil/litter disturbance on the population of T.fulvocastaneum due to human and cattle activity as well as to assess the impact of harvesting of immature sporocarps.

In Laos the species is heavily collected for the local market and for export to China.  The fruit bodies are mainly sold fresh to local markets and traders without formal grading and official (specific) export licenses.  Surplus is dried and a minor part is used for tea or added to liquor.