Spatial patterns of Cephalostachyum pergracile Munro in a mixed deciduous forest in Myanmar

Abstract

Bamboo species are common in Myanmar forests. They are monocarpic and some (but not all) conspecific bamboo clumps in a forest flower concurrently. The timing of flowering usually differs among bamboo species. Therefore, when flowering occurs in a forest, some spaces within a forest are expected to be occupied by conspecific and/or heterospecific nonflowering clumps of bamboo species. This may lead to the competition for space between seedlings and nonflowering clumps. Two species of bamboo, Cephalostachyum pergracile Munro and Bambusa polymorpha Munro were distributed in a commercial mixed-deciduous plantation forest in Myanmar. In 1997, some clumps of C. pergracile flowered but B. polymorpha did not. We analyzed the spatial relationships between C. pergracile seedlings generated in 1997 flowering and large conspecific and heterospecific bamboo clumps that must not have flowered in that flowering event. The present spatial analysis showed that bamboo seedlings were exclusively distributed in relation to conspecific large clumps and large clumps of counterpart species. Given that bamboo species are early successional and shade intolerant, these pre-empted spaces occupied by nonflowering clumps are assumed to be unsuitable for regeneration of the cohort that will be generated by the flowering event. In this manner, the occupation of spaces by nonflowering clumps during a flowering event will limit the space available for regeneration. Therefore, it was concluded that pre-emption by nonflowering clumps likely plays an important role in shaping the distribution of the two bamboo species in the forest.