Papers by Normah Awang Besar
Journal of sustainability science and management, Apr 29, 2023
The tropical rainforest has various lists of crucial functions in forest productivity. However, u... more The tropical rainforest has various lists of crucial functions in forest productivity. However, unsustainable logging method has led to the decline of soil fertility in the forest. This study aimed to investigate the impacts of different logging methods on the soil's physical and chemical properties at Gunung Rara Forest Reserve, Sabah, Malaysia. The logging treatments were supervised logging with climber cutting (SLCC) and conventional logging (CL), and a virgin forest (VF) was used as the control plot. The size for each plot was one hectare and each was replicated into four plots making the total plots 12. Soil sampling was done at four depths (0-10 cm, 10-20 cm, 20-50 cm, and 50-100 cm) for soil analysis and bulk density. The finding shows that the soil properties in the treatment plots were not significantly different from the untreated plot. The soil organic matter, total nitrogen, and total carbon decreased with soil depths. The soil in all study areas was found acidic, ranging from 4.12 to 4.46. The soil textures were clay, sandy clay loam, and sandy loam. The SLCC plot recorded a higher mean of soil organic matter (5.93-7.40%), total phosphorus (0.08-0.09 meq/100 g), and cation exchange capacity (5.69-7.05 meq/100 g) compared to other plots. This study highlights the importance of analysing the impact of different logging methods on the soil's physicochemical properties.
Forests
Tropical forests play an important role in carbon storage, accumulating large amounts of carbon i... more Tropical forests play an important role in carbon storage, accumulating large amounts of carbon in their aboveground and belowground components. However, anthropogenic land-use activities have increasingly threatened tropical forests, resulting in accelerated global greenhouse gas emissions. This research aimed to estimate the carbon stocks in soil, organic layer, and litterfall in tropical montane forests under three different land uses (intact forest, logged-over forest, and plantation forest) at Long Mio, Sabah, Malaysia. Field data were collected in a total of 25 plots from which soil was randomly sampled at three depths. Litterfalls were collected monthly from November 2018 to October 2019. The results showed that the soil in the study area is Gleyic Acrisol, having pH values ranging between 4.21 and 5.71, and high soil organic matter contents. The results also showed that the total soil carbon stock, organic layer, and litterfall is higher in the intact forest (101.62 Mg C ha−...
Biodiversitas Journal of Biological Diversity
Mangroves play a significant role in reducing tropical carbon emissions and preventing climate ch... more Mangroves play a significant role in reducing tropical carbon emissions and preventing climate change. This study was carried out in Kudat's Tun Mustapha Park mangrove forest. This research aims to quantify the aboveground, belowground, and soil carbon pools. Nine 125-meter-long transect lines were set up, and every 25 meters, a 7-meter-diameter circle was placed. A forest inventory was conducted to determine the diameter at the breast height of standing trees. For soil analysis and bulk density, soil samples were collected at four different depths (0-15 cm, 15-30 cm, 30-50 cm, and 50-100 cm). An ICP-OES analyzer was used to determine the value of soil nutrients, and a CHNS analyzer was used to determine the soil carbon concentration. The aboveground and belowground biomass was calculated using the allometric equation, and the carbon stock was estimated at 50% of the total biomass. The outcome showed a 455.87 MgCha-1 total carbon pool. The soil carbon has the highest value with 273.76 MgCha-1 , followed by aboveground carbon (living trees) with 136.58 MgCha-1 and belowground carbon (roots) with 45.53 MgCha-1. This study found that soil carbon stock made up almost 60% of the total carbon stock in the mangrove forest.
Forests
The soil carbon pool holds an enormous amount of carbon, making it the largest reservoir in the t... more The soil carbon pool holds an enormous amount of carbon, making it the largest reservoir in the terrestrial ecosystem. However, there is growing concern that unsustainable logging methods damage the soil ecosystem, thus triggering the release of soil carbon into the atmosphere hence contributing to ongoing climate change. This study uses a replicated (n = 4) logging experiment to examine the impact of supervised logging with climber cutting (SLCC) and conventional logging (CL) on basic soil characteristics, litter input to soils, soil carbon pools, and soil respiration in a mixed dipterocarp forest 26 years after logging. This study found that there was no significant difference observed in the soil physicochemical properties and total carbon pools between the logging treatments and the virgin forest. Soil carbon pools dominated the total carbon pools, and the highest mean value was recorded in SLCC (87.95 ± 13.67 Mg C ha−1). Conventional logging had a lower mean value (71.17 ± 12.0...
Sustainability
In Malaysia, the main constraints of rice yield and productivity are infertile soils and poor man... more In Malaysia, the main constraints of rice yield and productivity are infertile soils and poor management practices because these soils are characterized by low pH, low nutrient availability, low organic matter, and high exchangeable Al and Fe ions, due to high rainfall and hot temperatures. Thus, an incubation study was conducted to determine the optimum amount of calcium silicate (HmbG brand) to improve the soil pH, electrical conductivity (EC), exchangeable Al, available P, and cation exchange capacity (CEC) of a paddy soil in Sabah, Malaysia. The Kelawat series (Typic Dystrudept) soil was incubated with calcium silicate at the application rates of 0 (T1), 1 (T2), 2 (T3), and 3 t ha−1 (T4) using a Completely Randomized Design (CRD) in triplicates for 30, 60, 90, and 120 days. The calcium silicate used significantly improved soil pH because of the release of SiO44− and Ca2+ ions, which neutralized and immobilized H+ ions. Furthermore, the neutralizing effects of the amendment imped...
Hydrology
There have been conflicting findings on hydrological dynamics in tropical montane cloud forests (... more There have been conflicting findings on hydrological dynamics in tropical montane cloud forests (TMCFs)—attributed to differences in climate, altitude, topography, and vegetation. We contribute another observation-based comparison between a TMCF (8.53 ha; 1906 m.a.s.l.) and a tropical lowland rainforest (TLRF) (5.33 ha; 484 m.a.s.l.) catchment in equatorial Sabah, Malaysian Borneo. In each catchment, a 90° v-notch weir was established at the stream’s outlet and instrumented with a water-level datalogger that records data at 10-min intervals (converted to discharge). A nearby meteorological station records rainfall at the same 10-min intervals via a tipping bucket rain gauge connected to a datalogger. Over five years, 91 and 73 storm hydrographs from a TMCF and a TLRF, respectively, were extracted and compared. Various hydrograph metrices relating to discharge and flashiness were compared between the TMCF and TLRF while controlling for event rainfall, rainfall intensity, and antecede...
JOURNAL OF SUSTAINABILITY SCIENCE AND MANAGEMENT
Non-Invasive Blood Pressure and Heart Rate Sensing Using Photoplethysmogram Sensor
2021 IEEE 17th International Colloquium on Signal Processing & Its Applications (CSPA)
The non-invasive and cuffless blood pressure (BP) and heart rate (HR) monitoring device is design... more The non-invasive and cuffless blood pressure (BP) and heart rate (HR) monitoring device is designed to help people to monitor their BP and HR regularly. A Photoplethysmogram (PPG) sensor was used to obtain the PPG signal needed for the BP and HR calculations. The performance of the BP and HR monitoring device was tested based on the accuracy of the readings obtained by comparing readings from the proposed device with the readings obtained by clinical instruments. The factors that are affecting the accuracy of the sensor are also discussed in this paper.
Estimation of Total Soil Carbon Stock in Different Land Use Systems at Long Mio, Sipitang, Sabah
This study aimed to estimate above and belowground carbon stock in Acacia mangium stands of diffe... more This study aimed to estimate above and belowground carbon stock in Acacia mangium stands of different silvicultural systems (planted and regeneration) at the Bengkoka Forest Plantation, Pitas, Sabah, Malaysia. Aboveground biomass (AGB) and belowground biomass (BGB), and soil organic carbon content (SOC) at depth of 30 cm were quantified. A comparison was done between the two different silvicultural systems of Acacia mangium. A random systematic sampling method was used for conducting the forest inventory. Three circular plots of 0.25 ha were established in each of the Acacia mangium systems. Diameter at breast high (DBH) of every tree was measured using a diameter tape. Shrub layer and organic layer were measured at five randomly selected positions in each plot. Five litter fall traps (1m x 1m) were set up in the same position as the shrub and organic layer. Three holes (25 cm x 25 cm x 30 cm) were dug to get the roots for quantifying the roots biomass and soil for carbon content. T...
Orthosiphon stamineus (Benth) is a herb that can be intercropped under shade trees. There is a la... more Orthosiphon stamineus (Benth) is a herb that can be intercropped under shade trees. There is a lack of information the soil properties for O. stamineus intercropped with durian. In this study, the soil was tested to determine nutrient levels with respect to the organic fertilizer treatments such as chicken dung, cow dung and oil palm empty fruit bunch (EFB). The study was carried out in the fields of smallholder’s rubber at Papar, Sabah. The soil series of this area belongs to Inanam family (Gleyic Acrisol) as it is characterized with a gleyic horizon. The objective of this study was to determine the physico-chemical soil properties growing O.stamineus for the various fertilizer application regimes. The field planting distance used was 1.5 m x 0.45 m. Higher rate of fertilizer application gave higher yields of O. stamineus. Chicken dung was the best fertilizer followed by oil palm EFB and cow dung. The productivity using oil palm EFB and cow dung was smaller compared to chicken dung...
Shadow allometry for mapping biomass of tropical forest in northern Borneo
Transactions on Science and Technology, 2016
Assessment of aboveground carbon stock in different teak plantation systems was conducted in Balu... more Assessment of aboveground carbon stock in different teak plantation systems was conducted in Balung River Plantation, Tawau, Sabah. The objective of this study is to determine the potential of teak as the main tree components to increase the above ground carbon stock in different land use system. The above ground carbon stock of agroforestry and mixed plantation system of teak (Tectona grandis) were compared with natural forest and monoculture plantation of the species. The agroforestry combinations investigated are agroforestry system 1, teak (18 years) with snake fruit (8 years) and agarwood (8 years); agroforestry system 2, teak (17 years) with coffee (14 years); and also mixed timber plantation system, teak (18 years) with agarwood (8 years); while 20 years teak monoculture plantation and natural forest reserve was set up as a control. A random systematic sampling method was used in conducting field inventory. The methodologies used include the measurement of height and diameter...
Estimating tree height and above ground biomass of tropical rainforest across different degradation levels in malaysian borneo using airborne lidar data
Estimation of Carbon Stock in Acacia Mangium Stand in Sabah, Malaysia
Transactions on Science and Technology, 2016
Studies on total aboveground carbon (TAC) and belowground carbon (TBC) stock has been conducted i... more Studies on total aboveground carbon (TAC) and belowground carbon (TBC) stock has been conducted in Balung Plantation, Tawau, Sabah. The main objective of the study was to determine the above and below ground carbon stock in agroforestry system. The combination of agroforestry systems with different ages were investigated, which is oil palm (25 years) and agarwood (7 years), oil palm (20 years) and agarwood (7 years), and oil palm (17 years) and agarwood (5 years). Monoculture of oil palm (16 years) and Tawau Hill Park forest reserve was set as control. A random systematic sampling method was used in conducting field inventory and soil sampling. The size of the sampled area in agroforestry and monoculture is 3 × 50m × 50m, while for forest reserve, the sampled area is 3 x 30m x 30m. Allometric equations were used to calculate the stand biomass. Sampling for organic and shrub layers were collected in a square frame (1m × 1m). Soil samples and bulk density was collected from three diff...
Economic analysis on Orthoslphon stamineus Benth. under rubber and durian farm was conducted at K... more Economic analysis on Orthoslphon stamineus Benth. under rubber and durian farm was conducted at Kg. Kogopon, Papar, Sabah. The main objective of this study was to study the economic viability of planting Orthosiphon stamineus (Misai Kucing) in Rubber and Durian farm involving fertilizer application of various types. A Randomized Complete Block Design (RCBD) was used. O. stamineus was planted with spacing 1.5 m between rows and 0.45 m within rows of plants. The site was divided into three (3) blocks or replicates. Each block contained four (4) treatments and 20 plants of O. stamineus for each treatment. Three (3) organic fertilizer treatments were applied to each block excluded control block. Two (2) rates of fertilizer were used and standardized for each fertilizer. In order to conduct the economic analysis, data on yield monthly harvested and recorded to make it per hectare basis. Thus, the approaches for isolating the benefits and costs of Intercropping O. stamineus with Rubber or...
Forests, 2020
Mangrove forests are highly productive ecosystems and play an important role in the global carbon... more Mangrove forests are highly productive ecosystems and play an important role in the global carbon cycle. We used Shuttle Radar Topography Mission (SRTM) elevation data to estimate mangrove above-ground biomass (AGB) in Sabah, Malaysian northern Borneo. We developed a tree-level approach to deal with the substantial temporal discrepancy between the SRTM data and the mangrove’s field measurements. We predicted the annual growth of diameter at breast height and adjusted the field measurements to the SRTM data acquisition year to estimate the field AGB. A canopy height model (CHM) was derived by correcting the SRTM data with ground elevation. Regression analyses between the estimated AGB and SRTM CHM produced an estimation model (R2: 0.61) with a root mean square error (RMSE) of 8.24 Mg ha−1 (RMSE%: 5.47). We then quantified the mangrove forest loss based on supervised classification of multitemporal Landsat images. More than 25,000 ha of mangrove forest had disappeared between 2000 and...
Estimating Aboveground Biomass of a Tropical Forest in Northern Borneo Based on Individual Tree Crowns from Ikonos 2 Data
Estimation of AGB and carbon of tropical forests has been a crucial factor to 'Reduction of c... more Estimation of AGB and carbon of tropical forests has been a crucial factor to 'Reduction of carbon emissions from deforestation and forest degradation-plus', a monetary mechanism for combating global warming. We examined the use of IKONOS 2 data for estimating aboveground biomass of a tropical forest in Long Mio, Sabah, Malaysia. The IKONOS 2 data was corrected for path radiance and topographic effect before segmentation using the watershed method in ArcGIS. Correlation analyses between the segment variables and forest variables revealed that crown area extracted from the IKONOS 2 data (CA s) had the strongest correlation with the field-measured diameter at breast height (DBH f). Linear regression analysis produced a model to estimate DBH f using CA s with R 2 of 0.71. Cross-validation using the remaining half of the data set also showed very consistent result. The CA s only represented upper canopy trees but estimated about 80% of the aboveground biomass.
Estimating Mangrove Above-Ground Biomass (Agb) in Sabah, Malaysia Using Field Measurements, Shuttle Radar Topography Mission and Landsat Data
Mangroves are one of the most productive forest ecosystems and play an important role in carbon s... more Mangroves are one of the most productive forest ecosystems and play an important role in carbon storage. We examined the use of Shuttle Radar Topography Mission (SRTM) data to estimate mangrove Above-ground Biomass (AGB) in Sabah, Malaysia. SRTM-DEM can be considered as Canopy Height Model (CHM) because of the flat coastal topography. Nevertheless, we also introduced ground elevation correction using a Digital Terrain Model (DTM) generated with GIS and coastal profile data. We mapped the mangrove forest cover using Landsat imagery acquired in 2015 with the supervised classification method (Kappa coefficient of 0.81). Regression analyses of field AGB and the CHMs resulted in an estimation model with the corrected CHM as the best predictor (R2: 0.73) and cross-validated Root Mean Square Error (RMSE) was 19.70 Mg ha-1 (RMSE%: 11.60). Our study showed Sabah has a mangrove cover of 268,631.91 ha with a total AGB of 44,163,207.07 Mg in 2015. This substantial amount of carbon storage shoul...
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Papers by Normah Awang Besar