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Annual wood formation of tropical pioneer species related to stem diameters
- Wang, Kang Han, Hamzah, Mohd Zaki
- Journal of wood science 2019 v.65 no.1 pp. 22
- Endospermum, Macaranga, cambium, climatic factors, monitoring, phloem, photoperiod, pioneer species, rain, relative humidity, sapwood, temperature, trees, tropical rain forests, vapor pressure deficit, wood
- Annual wood increment and cambial activity in Macaranga gigantea and Endospermum diadenum growing in tropical rainforest were monitored to examine their relationship with stem sizes and climatic factors. The monitoring period was done from March 2013 to February 2014. Wood blocks containing phloem, cambium and outer sapwood were collected monthly from the main trunk of selected trees. Results showed that M. gigantea with smaller stem diameter showed higher annual diameter increment (16.63 ± 7.2 mm) than those with larger stem diameters (3.30 ± 0.1 mm) The total amount of wood formed in E. diadenum with larger stem diameter (9.17 ± 0.3 mm) was higher than the trees with smaller stem size (3.33 ± 0.3 mm). The rhythm of cambial activity were found different among tree species and stem diameters within the same species. M. gigantea with smaller stem diameter had longer active cambial growth period and produced higher number of cell layers than trees with larger stem diameter. In contrast, E. diadenum with larger stem diameter showed longer active growth period and higher number of cell layers than trees with smaller stem diameter. This study showed no significant correlation between mean number of cambial and enlarging cell layers with monthly total rainfall, monthly mean relative humidity, vapor pressure deficit and day length. Significant negative correlations were detected between maximum temperature and number of cambial and enlarging cell layers in M. gigantea with smaller stem size. For E. diadenum with smaller stem size, monthly mean temperature had significant negative correlation with the number of cambial cell layer. This study concluded that the intra-annual wood formation patterns of this two pioneer species are species specific and stem sizes specific.