Primary and secondary decay fungi on exposed pine tree logs in the forest

The successional diversity of basidiomycetous fungi was studied on Korean pine (Pinus koraiensis) and pitch pine (Pinus rigida) logs that were left exposed on the forest floor based on fungal surveys conducted after 18, 42, and 54 months of exposure. A total of 131 basidiomycetous isolates were recovered from the logs and grouped by their cultural morphology. Fungal identification was achieved by a BLAST search of partial nuclear large subunit ribosomal DNA sequences in GenBank. The results of the 18 month survey revealed that the isolation frequency and fungal diversity were higher for pitch pine than Korean pine. The dominant species found on Korean and pitch pine logs during the first survey were Hypochnicium karstenii and Phlebiopsis gigantea, respectively. In the 42 and 54 month surveys, the primary species were replaced by Hypochnicium eichleri, Phanerochaete velutina, Phlebia radiata, Rhizochaete sp., and Trametes versicolor. These results showed that decay fungi have host preference for woody materials that vary according to the species of tree being colonized.