Fungal colonisation of wood in a freshwater stream at Tad Ta Phu, Khao Yai National Park, Thailand

A study of the fungus colonisation of two timbers (Dipterocarpus alatus and Xylia dolabriformis) was initiated in a freshwater stream at Tad Ta Phu at Khao Yai National Park, Thailand. Wood was exposed and recovered every month for 12 months, then incubated in moist chambers and fungal colonisation recorded. Data on sequence of fungal sporulation, the frequency of occurrence of the fungi and percentage cover on the test blocks are presented. Seventy-three species were recorded: 48 on D. alatus and 47 on X. dolabriformis. Fungi were categorised into 3 groups: Group I those present on over 60% of the test blocks: with Helicomyces roseus and Halosarpheia aquadulcis on D. alatus and Helicomyces roseits on X. dolabriformis. Group 2 fungi were those present on more than 20% of the test blocks and numbered 8 each on D. alatus and X. dolabriformis. Group 3 fungi constituted those present on less than 20% of the test blocks. Fungi could also be grouped into those that appeared early on the wood: Bombardia sp., Cancellidium applanatum, Dictyochaeta sp. 1, H. roseits, Pycnidial sp. 1, Sporidesmiella hyalosperma var. novae-zelandiae, Sporoschisma saccardoi and unidentified hyphomycete sp. 05 on D. alatus; and with Chaetopsina fluva, Dictyochaeta sp. 1, H. roseus, Cosmospora chaetopsinae, Stilbella holubovae and Trematosphaeria sp. 2 on X. dolabriformis. Intermediate colonisers included: Aquasphaeria dimorphospora, Eluviespora bipolaris, Hymenoscyphus varicosporoides, Sirosphaera sp. 1, Tricladium anamorph of Hymenoscyphus varicosporoides on D. alatits, and Biflagellospora gracilis, B. japonica, B. papillata, B. siamensis, Cancellidium applanatum, Halosarpheia aquadulcis and Thozetella nivea on X. dolabriforinis. Late colonisers were Massarina sp. 3 and Vargamyces aquaticus on D. alatus and Helicosporium vegetum, Savoryella verrucosa and Tricladium anamorph of Hymenoscyphus varicosporoides on X. dolabriformis. The data shows a clear difference in the dominant species on each timber and is compared with other studies from tropical and temperate regions.