Biomass and Carbon Stocks Estimation of Lowland Dipterocarp, Riparian and Hill Dipterocarp Forests in Pahang National Park, Malaysia

Forest biomass estimation at local or global scale is very crucial and served as an important indicator for monitoring and estimating the forest carbon ecosystem especially in the context of climate change. Pahang National Park (PNP) is considered as a primary forest, and therefore, it is expected that more carbon can be absorbed and stored by forest biomass. Despite the multifunctional roles of forest biomass, lack of research had been done with regard to the extent of above-ground biomass (AGB) and below-ground biomass (BGB) in lowland dipterocarp (LDF), riparian (RF) and hill dipterocarp forests (HDF). Therefore, this study was conducted to provide an estimation of the AGB, BGB and carbon stocks with respect to different localities in PNP. A total of 60 plots were randomly set up and each forest type contains 20 plots measuring 20 × 20 m. The diameter at breast height (DBH) and height (H) were used to calculate the AGB and BGB, and the carbon conversion coefficient of 0.50 was used to calculate the carbon stocks. Based on the results, the estimation of biomass within LDF, RF and HDF not greatly varies between different species with the mean total tree biomass (TTB) values of 415.11, 323.33 and 579.05 t/ha, respectively. The estimation of carbon storage demonstrated that HDF attained the highest carbon stocks in TTB with the value of 289.52 t/ha. The information from this study is expected to provide baseline information and an understanding on the role of trees in the natural forest in sequestrating carbon

Effects of organic substrates on growth and yield of ginger cultivated using soilless culture

The effects of organic soilless substrates on growth and yield of ginger were studied. In soilless production system, many types of growing media or substrates such as rockwool, perlite, vermiculite and peat have been used to grow many kinds of crops. Alternative substrates that are cheaper and locally available such as coconut fibres and burnt paddy husks should be used as alternative media. The main objective of the study was to determine the most suitable organic growth substrate for cultivation of ginger using fertigation technique. The study was conducted under the side-netted rain shelter equipped with an irrigation system to supply fertiliser solution at a regulated time schedule. Five combinations of growth substrates were evaluated: 100% coir dust; 100% burnt paddy husks; 70% coir dust + 30% burnt paddy husks; 30% coir dust + 70% burnt paddy husks; and 50% coir dust + 50% burnt paddy husks. The ginger plants were selected randomly and the rhizomes were harvested 3 – 9 months after sowing. Plants grown in 100% coir dust gave the best growth performance and yield compared to the other treatments. They produced the highest shoot height (123 ± 23 cm), shoot fresh weight (1,340 ± 235 g) and rhizome yield (5,480 ± 325 g per plant). The lowest rhizome yield (2,570 ± 135 g) was obtained from plants planted in 30% coir dust + 70% burnt paddy husks. Hence, it can be concluded that the ginger plants cultivated in 100% coir dust substrate using fertigation technique gave the best plant growth and yields

Soil resources and topography shape local tree community structure in tropical forests

Both habitat filtering and dispersal limitation influence the compositional structure of forest communities, but previous studies examining the relative contributions of these processes with variation partitioning have primarily used topography to represent the influence of the environment. Here, we bring together data on both topography and soil resource variation within eight large (24-50 ha) tropical forest plots, and use variation partitioning to decompose community compositional variation into fractions explained by spatial, soil resource and topographic variables. Both soil resources and topography account for significant and approximately equal variation in tree community composition (9-34% and 5-29%, respectively), and all environmental variables together explain 13-39% of compositional variation within a plot. A large fraction of variation (19-37%) was spatially structured, yet unexplained by the environment, suggesting an important role for dispersal processes and unmeasured environmental variables. For the majority of sites, adding soil resource variables to topography nearly doubled the inferred role of habitat filtering, accounting for variation in compositional structure that would previously have been attributable to dispersal. Our results, illustrated using a new graphical depiction of community structure within these plots, demonstrate the importance of small-scale environmental variation in shaping local community structure in diverse tropical forests around the globe. © 2012 The Author(s) Published by the Royal Society. All rights reserved

Soil resources and topography shape local tree community structure in tropical forests

Both habitat filtering and dispersal limitation influence the compositional structure of forest communities, but previous studies examining the relative contributions of these processes with variation partitioning have primarily used topography to represent the influence of the environment. Here, we bring together data on both topography and soil resource variation within eight large (24–50 ha) tropical forest plots, and use variation partitioning to decompose community compositional variation into fractions explained by spatial, soil resource and topographic variables. Both soil resources and topography account for significant and approximately equal variation in tree community composition (9–34% and 5–29%, respectively), and all environmental variables together explain 13–39% of compositional variation within a plot. A large fraction of variation (19–37%) was spatially structured, yet unexplained by the environment, suggesting an important role for dispersal processes and unmeasured environmental variables. For the majority of sites, adding soil resource variables to topography nearly doubled the inferred role of habitat filtering, accounting for variation in compositional structure that would previously have been attributable to dispersal. Our results, illustrated using a new graphical depiction of community structure within these plots, demonstrate the importance of small-scale environmental variation in shaping local community structure in diverse tropical forests around the globe