Forest growth cycle of mixed dipterocarp forests with special reference to the chages of forest stratifiction

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This study deals with a forest growth cycle of a mixed dipterocarp forest or symbol of plant and animal kingdoms with rich species in South east Asea, with special reference to the changes of forest stratification with time and habitat gradients.The field research was made over a period of three months from December 1986 to March 1987 in the mixed dipterocarp forests at Bako-, Lambir-, and Bukit Mersing District, in Sarawak, East Malaysia, by establishing five to eight belt transects (200 m long and 20 m wide) on slopes in the study forests for the enumeration of living- and dead trees with mature size (over 30 cm in diameter at breast height), canopy gaps from dead trees, and small regenerated plants in gaps, and by making profile pits for soil studies.Tree fall patterns in three study areas were estimated from the records of dead trees, gaps, regenerated trees, and suggested an important role of soil fertility in the forest growth cycle, since fertile soil resulted in rapid tree growth, huge mature trees, large gaps, and shorter turn over time in forest growth cycle, ultimately. Forest stratification was analyzed by using the symmetric type difference diagram. Introducing a parameter(i) for identifying forest stories, mean tree height(Hi) and tree density(Pi) in a story were calculated. Hi and Pi satisfied the relation logHi=logK-hlogPi, where h & k are coefficients specific to a stand. If we fixed i, Hi increased linearly with an increase of the maximum tree height(Hmax) in the forest stand. This Hmax vs. Hi relation also suggested an important effect of soil fertility on forest stratification because Hmax represented a site quality index. From these results, the dynamic feature of forest growth cycle was estimated and integrated into the duality principle of the quasi-1/2 power law of tree height or Pi-Hi relation.