Ectomycorrhizal fungi in dry and wet dipterocarp forests in Northern Thailand - diversity and use as food

Wild mushrooms are annually harvested for food from dry and wet dipterocarp forests of northern Thailand. Most of the species gathered fruit in association with host trees and form symbiotic associations know as ectomycorrhizas. This paper documents the diversity of ectomycorrhizal (ECM) fungi and collection as food. Forest fungi were collected from dipterocarp-dominated (mostly Dipterocarpus and Shorea spp.) primary and secondary forests in four provinces of northern Thailand, Chiang Mai, Chiang Rai, Mae Hong Son and Phayao Provinces, over three years. For comparative purposes, the diversity of larger fungi was also investigated in forests dominated by the Fagaceae or the Pinaceae. The dry dipterocarp forests had greater diversity of fruiting ECM fungi than the wet dipterocarp forests (11 families, 21 genera and 52 spp.; 8 families, 15 genera and 24 spp., respectively). The dominant genera in the dry dipterocarp forests were Russula (11 spp.), Boletus (7 spp.) and Amanita (5 spp.) whereas in the wet dipterocarp forests, Amanita (5 spp.) was the main genus followed by Lactarius = Russula (3 spp. each). Overall, ectomycorrhizal fungal diversity in dipterocarp forests (57 spp.) was intermediate between oak (161 spp.) and pine (15spp.) forests. However, 65% of the ECM fungi that were associated with dipterocarps were not observed fruiting in other forest types. In the wet season, 19 ECM fungal species in ten genera were taken from dipterocarp forests (19 spp. from dry forests, 8 spp. from wet forests) by local people for sale in village, roadside and town markets. The market value of the most valuable fungus, the earth star (hed phor) Astraeus hygrometricus, ranged from 300-400 Baht (7-10 US$)/kg. Aspects of fungal conservation and their use in reforestation are discussed.