Ectomycorrhizal fungi in dry and wet dipterocarp forests in northern Thailand – diversity and use as food

August 31, 2006 by

Abstract

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 (15 spp.) 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.



Introduction


The uplands of Northern Thailand support a diverse mosaic of forest types determined principally by elevation, moisture and disturbance (Gardner et al. 2000). More than fourteen genera of forest trees have symbiotic associations with higher fungi in the region. Deciduous dipterocarps (dry dipterocarp forests) occur at low elevation (350 – 400 m), on shallow soils (Khamyong et al. 1996), whereas the semi-evergreen dipterocarps (wet dipterocarp forests) occur on moist soils at mid-elevation (800 – 1200 m). The Fagaceae (Castanopsis, Lithocarpus and Quercus) are a dominant component of hill evergreen forests. Pinus kesiya and P. merkusii are locally prominent on dry sites at mid-elevation. A common feature of these forests is their dependence on ECM fungi for their growth and survival.


The Dipterocarpaceae are well-known as an ECM family of trees in SE Asia (e.g. Smits 1994, Lee et al. 1997). In spite of the likely importance of ECM fungi for the health of dipterocarp forests in northern Thailand, the subject has received little attention. There is no comprehensive higher fungal flora of Thailand though there are useful popular accounts of the more common species (Rachabunditayasathan 1996, Chansrikul 1998). Information on selected groups of fungi in northern Thai forests are available in Boonthavikoon (1998) and in unpublished theses including Konsab (1998), Phongmanee (1999), Phuthima (1999) and Tongglam (1999).


Unlike for southwest China where the human use of forest fungi has been well documented, there is little information available on the extent and scope of mushroom collecting in northern Thailand (Dell et al. 2000). Furthermore, ethnobotanical studies in the region (e.g. Anderson 1993) have neglected the importance of forest fungi. The purpose of this paper is to begin the process of documentation of forest fungi in northern Thailand and their cultural value.


Materials and methods


Sporocarps of wild macro-fungi were systematically sampled from forests in Chiang Mai, Chiang Rai, Mae Hong Son and Phayao Provinces in northern Thailand, during the wet seasons (June-September) of 2001-2003. The fungi were collected under ectomycorrhizal dipterocarps (Dipterocarpus alatus, D. costatus,D.obtusifolius, D. tuberculatus, D. turbinatus, Hopea odorata, Shorea obtusa, S. siamensis), oaks (Castanopsis acuminatissima, C. argyrophylla, C. armata, C. diversifolia, C. echinocarpa, C. ferox, C. indica, C. tribuloides, Lithocarpus polystachyus, L. tenuinervis, Quercus kerrii, Q. kingiana, Q. mespilifoliodes, Q. vestita), and pines (Pinus kesiya, P. merkusii). Specimens were photographed, their morphological and anatomical features described in detail (Sanmee 2004) and they were then lodged in the Fungal Herbarium of Chiang Mai University. Edible ECM fungi were observed in the Chiang Mai city market (Suthep), in road-side stalls of Weing Par Pao District in Chiang Rai Province, and in the local market (Mae Tam Market) in Phayao Province during the wet season in 1996 and 2000. Field collections were made at the following sites:….


Sources: 8th Round-Table Conference on Dipterocarps

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