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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.

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. The soil bulk density was determined by using undisturbed soil samples collected by using 51 mm diameter ring (100 cc.). The results showed that the total amount of carbon stock was 73.56 t ha-1 and 82.40 t ha-1 for planted and regeneration stands, respectively. The study revealed that the major contributor to total carbon stock for both planted and regeneration Acacia mangium stands was the aboveground biomass with mean values of 46.99 t ha-1 and 53.83 t ha-1 followed by belowground biomass with mean values of 26.57 t ha-1 and 28.57 t ha-1 , respectively.

Suhaili NS, Fei JLJ, Sha’ari FW, Idris MI, Hatta SH, Kodoh J, Besar NA. 2020. Carbon stock estimation of Sulaman Lake Forest Reserve in Sabah, Malaysia. Biodiversitas 21:5657-5664.Mangrove Forest has a significant role in sequestering carbon gases from the atmosphere but there are lesser literature has been made on it. This research was conducted to quantify the aboveground, belowground and soil carbon stock in Sulaman Lake Forest Reserve, Sabah, Malaysia. Nine transect lines with 125m length were established and a circle with 7m radius was set in every 25m. Forest inventory was done to get the diameter breast height of standing trees and soil sampling with four different depths (0-15 cm, 15-30 cm, 30-50 cm and 50-100 cm) were taken for soil analysis and bulk density. Allometric equation was used to calculate aboveground and belowground biomass then its carbon stock was estimated as 50% from its total biomass. The result shows the total carbon stock in the study area was 441.72Mg C ha-1, and soil has the highest value of carbon stock (351.98± 11.73Mg C ha-1) followed by aboveground carbon (67.30± 20.55 Mg C ha-1) and belowground carbon (22.44± 0.17Mg C ha-1). This study found that soil carbon stock made up almost 80% of the total carbon stock in the mangrove forest. This ecosystem also shows a higher value of carbon stock compared to other locations hence emphasized the importance of prioritizing a mangrove forest in any climate mitigation efforts.

Every species has different rooting distribution, either deep rooted or shallow rooted plants. Thus, root is one of the vital components in tree growth. This study was conducted to determine the preliminary assessment of Batai (Falcataria moluccana Miq.) under small scale experiment. Small scale experiment was carried out at near greenhouse, Forestry Complex of Faculty of Science and Natural Resources, FSSA, Universiti Malaysia Sabah. Batai seedlings were transplanted in transparent rhizotron tubes (1 m high transparent polycarbonate solid sheet) using topsoil and river sand to mimic the natural condition. There were 36 experimental units (4 treatments and 3 replicates) and arranged in a Completely Randomized Design (CRD), which were placed on the wood pallet. Root Intensity (RI), Root Length Density (RLD), Specific Root Length (SRL) and dried aboveground biomass (g) were recorded. The effect of sole fertilizer and mixed treatment shows more root growth at early stage especially at topsoil layer. However, as for root biomass, control was higher the preliminary growth interaction, in second depth (25-50cm). As for SRL, sole tillage treatment shows better performance, however in RLD, the roots in sole tillage and mixed treatment are more concentrated at the upper layer. The knowledge obtained here will be useful for plantation sector in optimize the soil resources in the plantation ecosystems.

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 2015. This has resulted in a significant decrease of about 3.96 million Mg of mangrove AGB in Sabah during the study period. As SRTM elevation data has a near-global coverage, this approach can be used to map the historical AGB of mangroves, especially in Southeast Asia, to promote mangrove carbon stock conservation.

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 breast height (DBH) of trees within a 50 m x 50 m plot dimension (for plantation) and 30 m x 30 m (forest). Allometric equations were used to derive the field measured attributes into stand biomass while carbon stock was estimated as 50 percent from the total biomass. The result shows the accumulation of carbon stock goes in the following order: forest reserve (213.84 t C/ha) > mixed timber plantation (69.94 t C ha-1 ) > agroforestry system 2 (37.75 t C/ha) > agroforestry system 1 (37.34 t C/ha) > teak monoculture (34.53 t C/ha) witnessing the teak trees to increase the total aboveground carbon stock in agroforestry and mixed timber plantation system by more than 60 percent. This study suggested that teak has great potential in transforming a low biomass land use into a carbon-rich tree based systems.

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 different layers which are 0 – 5 cm, 5 – 10 cm and 10 – 30 cm in randomly located sites within the plots. Soil samples, organic and shrub layer were analyzed using CHN628 series for carbon content. Result shows that the amount of total carbon stock in agroforestry was 79.12 tan C ha-1, 85.39 tan C ha-1 and 78.27 tan C ha-1, respectively. Monoculture of oil palm (16 years) has 76.44 tan C ha-1 while Tawau Hill Park forest reserve has total carbon stock at 287.38 tan C ha-1. Forest reserve stand has the highest total carbon stock compared to agroforestry and monoculture systems. But, in terms of soil carbon, forest reserve has the lowest TBC compared to agroforestry and monoculture systems. ANOVA was conducted to explore the impact of planting systems on total carbon stock. There was a statistically significant difference at the p < .05 level for soil carbon, living tree and organic layer between agroforestry, monoculture and forest reserve. Good crop and fertilizer management in agroforestry a

The impact of land use on carbon pools were investigated in three different land use type (forestland, arable land and grassland) in Katinger Watt area in Northern Germany. The area was once a sea floor (tidal flat) that was dyked in 1973. Relevant condition for carbon turnover in the studied area were similar, thus the different in carbon pools during soil genesis were attributed to different land use systems.

Estimating above-ground biomass is important in establishing an applicable methodology of Measurement, Reporting and Verification (MRV) System for Reducing Emissions from Deforestation and Forest Degradation-Plus (REDD+). We developed an estimation model of diameter at breast height (DBH) from IKONOS-2 image that led to above-ground biomass estimation (AGB). The IKONOS image was preprocessed with dark object subtraction and topographic effect correction prior to watershed segmentation for tree crown delineation. Compared to the field observation, the overall segmentation accuracy was 64%. Crown detection percent had a strong negative correlation to tree density. In addition, satellite-based crown area had the highest correlation with the field measured DBH. We then developed the DBH allometric model that explained 74% of the data variance. In average, the estimated DBH was very similar to the measured DBH as well as for AGB. Overall, this method can potentially be applied to estimate AGB over a relatively large and remote tropical forest in Northern Borneo.

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 (CAs ) had the strongest correlation with the field-measured diameter at breast height (DBHf). Linear regression analysis produced a model to estimate DBHf using CAs with R2 of 0.71. Cross-validation using the remaining half of the data set also showed very consistent result. The CAs only represented upper canopy trees but estimated about 80% of the above ground biomass.

Studies on carbon stock in agroforestry systems has been conducted in Balung River Plantation, Tawau, Sabah. The objective of the study are to determine carbon content of above ground vegetation including crops, shrubs and trees in agroforestry system, to determine carbon content of soil in agroforestry system, to estimate aboveground carbon stock using UDAR data and to estimate carbon sequestration potential in agroforestry system. Three combination of oil palm (Elaeis guineensis) and agarwood (Aquilaria malaccensis) in agroforestry system with different age were investigated. The combinations are oil palm (27 years) and agarwood (7 years), palm oil (20 years) and agarwood (7 years) and oil palm (17 years) and agarwood (5 years). Oil palm plantation (16 years) and forest reserve was investigated as a control. Agroforestry system of teak (Tectona grandis), agarwood (Aquilaria malaccensis) and snake fruit (Salacca zalacca) were also assessed for carbon storage ability in comparison with LiDAR data. A random systematic sampling method was used for conducting the forest inventory. Three square plots of 0.25 ha were established in each of the agroforestry system site. Soil were taken at the depth 0-5 cm, 5-10 cm and 10-30 cm. Shrub layer and organic layer were taken at five randomly selected positions in each plot. Field measured attributes such as height and DBH were measured and then converted into above ground biomass by using site specific allometric equation. carbon stocks were considered to be 50 percent of the total biomass. The results shows that forest have the highest carbon stock (287.38 tan C ha·1) in comparison with three oil palm agroforestry systems (79.12 tan C ha·1, 85.39 tan C ha·1 and 78.27 tan c ha·1) and monoculture oil palm plantation (76.44 tan C ha·1). In teak, agarwood and snake fruit agroforestry combination, the total carbon stock is 44.04 tan C ha·1 in which 70 percent of it were contributed by the teak stand. Significance correlation were al

The pattern of soil organic carbon storage is influenced by land use and landscape topo-sequence. The variations in soil carbon and land use also impact soil properties, such as bulk density, pH and soil water. The aim of this study was to determine the effects of selected land uses (forest, grassland and cropland) located in Universiti Malaysia Sabah Campus and soil depth on the soil organic matter, soil carbon and related soil properties. Soil samples from 0 to 15, 15 to 30 and 30 to 45 cm soil depths were collected for organic matter, carbon and pH analysis, and from 0 to 5 and 5 to 10 cm soil depths for soil water and bulk density determination for the cropland, forest and grassland land use types. There were significant differences in organic matter and carbon in forest, grassland and cropland for the three soil depths studied. Organic matter content at the 0 to 15 cm depth of forest, cropland and grassland were estimated at 2.27, 2.07 and 0.83%, respectively. The organic matter content in all land use types decreased land used decreased significantly with soil depth. The top 5 cm of the grassland at sampling time contained 33.2 and 48.53% more soil water than the forest and cropland, respectively. Soil bulk density in cropland soils was higher than for forest and the latter was higher than in grassland. The different land uses and soil depth accounted for the variations of soil carbon stocks. Soil pH was significantly lower in the forest soil.

Carbon sequestration was studied in the coastal soils of the “Katinger Watt”, a former tidal flat of the North Sea coast in Schleswig-Holstein, Northern Germany. Carbon sequestration was determined by the ecological approach and calculated as the difference between total annual net primary production and total annual heterotrophic respiration. The measurement was conducted every month from June 2006 to May 2007. All sites were underlain by very young soils that developed after the former marine tidal flat was diked in 1973. After diking, the soils were drained and terrestrial soil formation continued for 35 year. The initial conditions after diking were similar in all sites. All soils were classified as Normkalkmarsch according to the German soil classification, as Calcic Fluvisol (WRB, 2007) and as Typic Fluvaquent (USDA, 2010). The annual carbon sequestration in the arable land was estimated as -0.82 t C ha-1 yr-1 which indicates that the arable land acted as a net CO2 source during the investigation period. In the grassland, about 0.18 t C ha-1 yr-1 was sequestered in the soil. In other words the grassland acted as a carbon sink during the investigation period.

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 Durian are based on 'With project' and 'Without project'. Economic criteria such as Net Present Value (NPV), Internal Rate of Return (IRR), Benefit-Cost Ratio (BCR), Payback Period (PBP) and Sensitivity Analysis (SA) were analyzed for 20 years period project. From the computation of 20 years period projection, it is found that the NPV, IRR, BCR and PBP under durian at discounted factor rate 10% were RM91,751.00, 36.57%, 1.05 and 7 years for per hectare basis. Similar result also found under rubber were RM47,413.00, 55.45%, 1.04, 4 years. As a conclusion, the project intercropping of O. stamineus either under rubber and durian indicated economically feasible.