Silviculture aspect of Passur (Xylocarpus mekongensis) tree in the Sundarbans with special reference to heart rot disease
Silviculture aspect of Passur (Xylocarpus mekongensis) tree in the Sundarbans with special reference to heart rot disease
A. S. M. Helal Siddiqui1, Abul Khair2, M. Masudur Rahman3 and S.M. Mosfeka Hasnin4
ABSTRACT
The Sundarbans is the largest single tract mangrove forest of the world. The forest occupies the south-west corner of Bangladesh. It covers an area of 6017 km2, of which 4143 km2 are landmass and 1874 km2 water bodies. The biodiversity of the Sundarbans is very rich. Among the floral species Passur (Xylocarpus mekongensis) is one of the important timber species in the Sundarbans. Passur belongs to the family Meliaceae. The canopy of Passur is dense, heavy and the stem is cleared bole. The tree attains a height of 15-20 m and the exploitable age 100 years. Now Passur is affected by heart rot problem. Actually heart rot is internal damaged condition locally known as "dhor". The fruit body, gall and cankers are developed on the different portion of the standing living trees. Thus it is characterized by the gradual death of the crown starting first with small twigs and then gradually larger branches die. To know the status of heart rot and its causal organism the research works were conducted from 2007 to 2009 at different locations in the Sundarbans. The locations are Baniakhali, Chunkuri, Kalabogi, Kashiabad, Bojboja and Supati. The result shows that heart rot affected percentages are 64%, 62% and 60%, 54% and 48%, 17% respectively. Very low amount of trees are affected at Supati located in the fresh water zone of the Sundarbans. The results also show that in the six locations diameter at breast height (dbh.) Class IV (>40cm) is highly affected 34%, then followed by dbh Class III (31-40cm) 31%,Class II (21-30cm) 25% and the lowest only 10% in the Class I (<20cm). So, it is clear that Passur trees having dbh class IV (>40cm) were highly associated with heart rot. This calls for pathological rotation of Passur trees arriving at dbh class IV (>40cm) for better salvage of useable trees. The International Mycological Institute, UK, identified and confirmed two fungal pathogens for causal organism namely Phaenerochaete subglobosa and Schizophyllum commune and locally identified Ganoderma appalanatum.
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March 2013
Vol. 63, Iss. 1
