Can mangroves help combat sea level rise through sediment accretion and accumulation?

Mangroves have substantial roles to induce sedimentation in the vulnerable coastal regions, which subsequently helps to combat climate change induced impacts like sea level rise. Although Sarawak has numerous pristine estuarine mangroves, studies on the roles of these mangroves in regards to sediment deposition are scanty. Therefore, this study was carried out to determine the sediment accretion and accumulation pattern of pristine Sibuti mangrove using tiles and sediment traps from January to December 2013. Monthly average accretion and accumulation rate of sediments of this mangrove were 0.55 mm and 0.08 g cm-2, respectively. A total of 6.56 mm and 0.93 g cm-2 sediments were accreted and accumulated annually. Significantly positive correlation (r=0.794) was found for the monthly accretion of sediments with accumulation. Accretion and accumulation of sediments were also positively correlated with rainfall. Comparatively higher rate of accretion and accumulation of sediments were estimated in the months of wet season when the rainfall and tidal inundation duration were high. Erosion was found higher in the months of dry season when the rainfall was low. Seasonal variations were not found for sediment accretion as well as accumulation in the study area. The findings of the study suggest that the roles of this forest in regards to sediment accretion through retention is compatible with the predicted annual rate of sea level rise of 1.8 to 5.9 mm within 21st century by IPCC

Rootability of Dalbergia sissoo Roxb. cuttings from different clones at two different levels and their primary field growth performance

Rootability of Dalbergia sissoo Roxb. cuttings of mature tree originated clonal hedge bed were tested and compared to the same from seedling originated hedge bed. Mature tree originated cuttings were found potential for rooting in low-cost non-mist propagator without any rooting hormone. Steckling growth in nursery and in the field was found promising which is a complete indication for its successful application by tree planters. It will be a new research avenue to get disease free germplasm for the frustrated plantation managers and scientists due to die back of this tree through out the South Asian region

Pressure distribution phenomena over a wedge and sphere surface in uniform flow

In this paper, experimentally the pressure distribution over wedge and sphere surface in uniform flow has been investigated. Fluid flow over a smooth wedge surface was investigated experimentally to determine the pressure distribution at different values of Reynolds numbers and wedge angles as well as pressure distributions around the sphere of different size are reported for different Reynolds numbers. The variation of static pressures is larger near the wedge vertex and gradually decreases along the length of the wedge surface. At the forward stagnation point the pressure distribution depends on the size of spheres. Separation of flow takes place at an angle of 78° from forward stagnation point for all sizes of spheres. At the rear stagnation point of the sphere the pressure distribution predicts negative pressures. Experimental results provide useful information of interest to potential industrial application. It helps in determining the shape of various wedge and sphere surfaces used in industries for cooling or heating of different wedge surfaces. In the present experiment, it has been found that the pressure near vertex lower as the included angle of the wedge decreases and at lower values of Reynolds number

A model of seasonal foliage dynamics of the subtropical mangrove species Rhizophora stylosa Griff. growing at the northern limit of its distribution

Background Progress of forest production in response to the environment requires a quantitative understanding of leaf area development. Therefore, it is necessary to investigate the dynamics of seasonal crown foliage in order to understand the productivity of mangroves, which play an important role in the subtropical and tropical coastlines of the world. Method Crown foliage dynamics of the mangrove Rhizophora stylosa were studies to reveal patterns of leaf recruitment, survival and seasonal leaf area growth. Results Flushing of leaves occurred throughout the year, but both flushing and leaf area growth pattern of leaves varied with season. Maximum flushing occurred in summer, but leaf areas did not differ significantly with season. The half-expansion period is longer, and the intrinsic rate of increase was lower in winter. Summer flushed leaves grew faster at their initial stage and reached their maximum area over a shorter period of time. The difference in temperature and air vapor pressure deficit (VPD) between summer and winter contributed to the present dynamics of foliage patterns. The mean leaf longevity was estimated to be 13.1 month. The crown foliage area was almost stable throughout the year. Conclusions Homeostatic control of the crown foliage area may be accompanied by the existence of ecophysiological mechanisms in R. stylosa. Integrating crown foliage dynamics into forest models represents an important step towards incorporating physiological mechanisms into the models for predicting growth responses to environmental changes and for understanding the complex responses of tree growth and litter production

Shifting regime shifted policy—interplay of interests in sustainability discourses of forest land use

Colonial interest, Commercial interest, Bangladesh forestry, Forest policy, Peoples participation, Policy interest, Regime change, Sustainability and tradition,