Zs. P. Komáromy szerk.: Studia Botanica Hungarica 15. 1981 (Budapest, 1981)
Babos, Margit: Mycological examination of sawdust depots in Hungary
Summary Above all Agaricales species used for food play a significant role In the quick decomposition of sawdust and other wood wastes, on the other hand, Poriales and Polyporales species which take part in the decompositional processes of trunks have no importance in the utilization of sawdust. On the basis of several years' observation made in sawdust depots of Hungary it can be stated that on the sawdust and wood waste of frondose trees ( Quercus , Fagus, Robinia, Populus , etc.) mixed in a smaller part with coniferous trees (Pinus, Picea) - independently of the ratio of mixing of these species - a special mycocoenosis, fructificating regularly and often in mass, can be found (Table 1.). Of the warm up substrate stored in a thick layer the following Agaricales species are characteristic (according to the order of their frequency): Pluteus patricius , P . varia bilicolor, Leucoagaricus bresadolae (incl. var.biornatus) , L.meleagris, Volvariella volvacea, Leucocoprlnus cepaestipes (incl. var.rorulentus) , Hohenbuehelia geogenia, Pluteus atricapillus . On thin layered sawdust - where the heat of decomposition is not high - thermophilous species ( Leucoagaricus meleagris, Volvariella volvacea) are missing. In forest environment, on flatly arranged bark-heaps, the mycocoenosis consists of other species: littercolous species and wooddecaying fungi appear in mass. On fresh bark waste (Fagus silvatica) , ephemeral fungus communities of small species number (3) could be observed (Table 4). On sawdust with dung the wood-rot fungi appeared together with littercolous and coprophllic fungi. Owing to their constantly and strongly disturbed conditions, the examined areas are not suitable for indication of sampling plots and for regular analyses of production, even thourgh these could have provided surprising Tesults on the basis of the frequently found mass productions. It can be mentioned as a peculiarity of the characteristic species community that a considerable quantity of the character species could often be found even in a small area (1-3 m 2 ), and also that on several occasions no other fungi than the character species could be found on the depots. Fungus growth is much more regular on sawdust - probably because of the favourable water-holding capacity of the substrate - than in the neighbouring areas. The main fruit producing period lasts from June till September (Table 2), but the warm up of the substrate made it possible for example for Volvariella volvacea to grow its fruit body even as early as May. The measurement data related to the heat req\ ent and to the heat endurance of the most frequent species are given in Table 3. Concerning me quick growth of the mycelia of certain species, indirect data have been obtained, too. For example, Pluteus patrícius and Volvariella volvacea on deeply-burnt through sawdust produced Its fruit bodies as early as 2-4 weeks after burning. A high degree of variability could be observed on certain fungi of the character species: Plu teus variabilicolor : (BABOS 1978); Leucoagaricus meleagris : (BABOS 1980); Pluteus patricius (to be published later) etc. Other species on the other hand always showed morphological identity (e.g. Volvariella volvacea, Volvariella bombycina ) . Gigantism is also frequent, and growth in groups with such species that on other substrates are not characterized by it. For the clarification of certain taxonomical questions, sawdust proved to be good habitat. Data on edibility of such fungi in relation of which edibility was not known or waB doubtful were alBO obtained. Workers of sawmills and the inhabitants of the neighbouring villages regularly consume, in addition to the Pluteus and Volvariella species, Leucoagaricus meleagris, L.bresa dolae and var.biornatus. In certain places, fungi are collected also for animal feeding. In certain experimental areas, the quick humification of sawdust could be experienced. If the depositing of the fresh sawdust was stopped, after 2-5 years the sawdust depots became covered with mostly weedy, nitrophilous plantage.
