Abstract: Polypores are the most important group of wood-inhabiting fungi. Most of these fungi can decompose cellulose, hemicellulose, and lignin in the plant cell walls, and therefore play a key role in nutrient recycling in forest ecosystems. Based on 16 years of field investigation and laboratory analyses, 304 polypore species were found and they belong to 93 genera, 14 families, and 7 orders. The dominant family is the Polyporaceae, accounting for 33.2% of all polypore species in the studied area, and the dominant genera are Phellinus, Postia and Antrodia. The majority of the polypores are the north temperate element and cosmopolitan element, showing a distinct north temperate character in floral composition. 23 threatened polypores were found and 11 of them grow on single tree species. This suggested that they need some special substrates for their growth. So the most important method for polypore conservation is to keep natural forests without disturbance. Most of the polypores are saprophytic species, and the white rot species are dominant. The percentage of brown rot polypores is 23.8% of all polypores in Northeast China, which is higher than the mean level in the world. Among these brown rot species, 80% of them were found on gymnosperm wood, suggesting that the brown rot polypores are very important for nutrient cycling in coniferous forests in Northeast China.

Key words: vapor pressure deficit, abscised measurement, maximum net photosynthetic rate, Larix olgensis.