Problem statement: There was no information about the relationship between growth parameters, such as diameter and height and tree component biomass of Khaya ivorensis plantations with different soil types. The objectives of this study were, first, to determine and compare the growth of K. ivorensis in three different (Padang Besar, Durian and Rengam) soil series of Ultisols and, second, to develop an allometric equation that estimates the biomass accumulation of the K. ivorensis plantation in three different soil series five years after planting. Approach: This study was conducted at a K. ivorensis plantation in the Forest Research Institute Malaysia (FRIM) Research Station in Segamat, Johor, Malaysia. The tree height (H) and Diameter at Breast Height (DBH) were measured to evaluate the growth performance of the K. ivorensis plantation. Five sampled or trees stand of K. ivorensis in each soil series were destructively analyzed. Results: The highest growth rates in terms of MAI diameter and height, and basal area were found for the Padang Besar soil series, which was followed by the Durian and Rengam soil series. The best fit regression of site-specific equations developed from the independent variable D are recommended for estimating tree component biomass and stem volume in each site. A single allometric equation using D was applicable for the estimation of biomass and stem volume however, in Padang Besar, stem biomass and stem volume were estimated with an equation using D 2 H. The highest stem volume and biomass accumulation value were recorded at Padang Besar (77.99 m 3 h −1 and 63.16 t ha −1 , respectively), which was followed by the Durian (53.10 m 3 h −1 and 46.33t ha −1 , respectively) and Rengam soil series (43.13 m 3 h −1 and 40.96 t ha −1 , respectively). Conclusion: Differences in the growth and biomass accumulation data indicate that forest productivity of K. ivorensis was affected by different site conditions. The higher growth performance and productivity of K. ivorensis in terms of the stem volume and biomass accumulation in Padang Besar compared those in the Durian and Rengam soil series shows that the species was able to adapt to the soil characteristics of the Padang Besar soil series.

The Coronavirus disease-2019 (COVID-19) pandemic has affected over 200 countries, forcing governments to impose lockdowns to contain the spread of the disease. Although effective in reducing infection rates, the lockdowns have also resulted in a severe negative impact on mental health throughout the world; Setting the foundation for mental illnesses to become the next “silent” pandemic. This study attempts to determine a self-care method of ensuring mental health during the COVID-19 pandemic, especially for those living under lockdown. We evaluated the potential of physical exercise (in a nature setting) and nature therapy in improving mental wellbeing, among young adults with either stress, anxiety or depression symptoms. The study involved thirty subjects, who were equally divided into a nature-exercise group and a nature therapy group. The participants were briefed on the activities that they were to perform on a daily basis, and both groups performed their assigned activities concurrently for one week (27th April 2020 to 3rd May 2020) at urban greeneries accessible to them (rooftop parks, neighbourhood parks, home gardens). We used the depression, anxiety and stress scale – 21 items (DASS-21) to evaluate the mental health status of participants, once before beginning the study (baseline readings) and once at the end of the study (after a week of nature-exercise/nature therapy). There was a statistically significant reduction in stress, anxiety and depression symptoms for both the nature-exercise and nature therapy groups. However, when evaluating the effectiveness of exercise and nature therapy in treating stress, anxiety and depression symptoms on a case-by-case basis, it was discovered that nature therapy was more effective in treating mental health issues. Hence, nature therapy has the potential to be a form of preventive medicine, namely in preserving mental health during the COVID-19 crisis.

Problem statement: It is widely accepted that conversion of natural forest to other land use types leads to deterioration of soil fertility and increased soil compaction which consequently become degraded secondary forests. Degraded secondary forest is indicated by low soil fertility and organic matter due to imbalance input and output from original vegetation. Forest plantation through planting fast growing exotic species is usually implemented to curtail degradation of secondary forest or forestland and to improve the soil fertility through organic matter accumulation. However, fundamental information on degraded forestland being converted to forest plantation using exotic species such as Khaya ivorensis is not available. The objectives of this study were: (1) to characterize the properties of three degraded soils under rehabilitation using K. ivorensis; and (2) to evaluate their fertility status by Soil Fertility Index (SFI) and Soil Evaluation Factor (SEF). Approach: This study was concentrated on three soil series (Rengam, Durian and Padang Besar) found under K. ivorensis plantation and at the adjacent secondary forest in Segamat, Johor, Malaysia. To characterize and evaluate the soil fertility status for each soil series, three plots (30 x 40 m) were randomly established on each soil series. Soils for each series were sampled at the depth of 0-10 cm (surface soil) and 20-30 cm (subsurface soil). They were randomly collected at six different points for each replicate. Soil analyses were carried out physical and chemical properties. Results: The soils both in planted and secondary forests were moderately acidic to slightly acidic with low content of exchangeable bases and available P but high in Al saturation. The Rengam series under K. ivorensis plantation contained higher total carbon and clay compared with those of Padang Besar and Durian series. Clay and total carbon contents were highly correlated with the Cation Exchange Capacity (CEC), indicating the potential of negative charge produced by the clay and organic playing an important role in supplying and holding plant nutrients. The SFI result revealed that soil fertility status of Rengam soil was significantly higher than the other two soil series. There was no significant difference observed for SEF. Based on SFI and SEF values, there were no significant differences of fertility status between the planted and secondary forests for both soil depths. Conclusion: This study revealed that Rengam soil is more fertile than the other two soils. Based on the using SFI and SEF it can be concluded that fast growing exotic species of K. ivorensis has the potential to improve site productivity and soil fertility

Problem statement: The tropical rain forests in Southeast Asia have been characterized by several researchers. However empirical data on soil characteristics under degraded forest land in tropical rain forest and rehabilitated program are limited. A study was conducted to evaluate the soil morphology, mineralogical and sesquioxide properties of a rehabilitated degraded forest land (19 years after it was planted with various indigenous species) in comparison with an adjacent secondary forest. Approach: Soil samples were air-dried and pass through a 2 mm sieve. Soil morphology was determined based on field observation. The non-crystalline (amorphous) of Al, Fe and Si oxides and hydroxides (Alo, Feo and Sio) were extracted with ammonium oxalate while the dithionate-citrate-bicarbonate (DCB) method was used for extracting (crystalline) the Al, Fe and Si oxides and hydroxides (Ald, Fed and Sid). The concentrations of extracted Al, Fe and Si were determined by atomic absorption spectroscopy. Mineralogical compositions were identified by X-ray diffraction method. Results: The A-horizon of secondary forest was darker and thicker than that of the rehabilitated forest. Root mat at the secondary forest was well-developed compared to the rehabilitated forest. The clay minerals were dominated with kaolinite and illite to a lesser extent of goethite and hematite accompanied with low values of activity ratio of Al and Fe oxides and hydroxides, indicating that the soils were highly weathered. Conclusion/Recommendations: The difference between rehabilitated and secondary forests was root abundance where secondary forest had most. Good root penetration in the secondary forest indicates that the soil texture there was not heavy. Soils in the rehabilitated and secondary forests were strongly weathered (high presence of kaolin minerals), but the low presence of sesquioxides suggests that they are yet to reached the ultimately weathered phase. The soil properties in terms of morphology, sesquioxides and clay minerals should be taken into account for better management of forest rehabilitation program in tropical regions

Kenaf is an industrial crop with high potential for cultivation in a tropical climate. It is a source of raw material for fiber-based industries and paper production. Considerable research has been conducted to explore its adaptability and utilization in Malaysia since 2000, under the supervision of governmental and private organizations. A number of technologies and expertise among researchers have been developed to enhance kenaf production in Malaysia. However, international documentation of the research is limited, which is important for rectification to provide a comprehensive knowledge base for all tropical and subtropical countries. The main objective of this review is to provide an overview of the results of Malaysian research on kenaf. In addition, the past, present and likely future trends in kenaf research in Malaysia as a representative tropical region are summarized.

Problem statement:There is general agreement that human activities such as deforestation and land use change to other land use types have contributed to degraded secondary forests or forestland and increases the emission of greenhouse gases which ultimately led to global climate change. An establishment of forest plantation in particular is regarded as an important approach for sequestering carbon. However, limited information exists on productivity and potential of fast growth exotic and indigenous tree plantations for sequestering CO 2 from the atmosphere through photosynthesis. This study aimed at assessing the productivity and biomass accumulation along with the potential for sequestering CO 2 of planted exotic and indigenous species on degraded forestland. Approach: This study was conducted at Khaya ivorensis and Hopea odorata plantations, which was planted at the Forest Research Institute Malaysia (FRIM) Research Station in Sega mat Johor, Malaysia five years ago. In order, to evaluate the forest productivity and biomass accumulation of both species, we established plots with a size of 40x30 m in three replications in each stand, followed by measuring all trees in the plots in terms of height and Diameter at Breast Height (DBH). To develop allometric equation, five representative trees at each stand were chosen for destructive sampling. Results: The growth performance in terms of mean height, DBH, annual increment of height and diameter and basal area of exotic species (K. ivorensis) was significantly higher than that of the indigenous species (H. odorata). We used the diameter alone as independent variable to estimate stem volume and biomass production of both species. The stem volume of K. ivorensis stand was 43.13 m 3 ha −1 and was significantly higher than H. odorata stands (33.66 m 3 ha −1 ).The results also showed that the K. ivorensis and H. odorata stands have the potential to absorb CO 2 from the atmosphere which was stored in aboveground biomass with value 15.90 Mg C ha −1 and 13.62 Mg C ha -1 , respectively. In addition, the carbon content in root biomass of H. odorata stand was higher than that in K. ivorensis stand with value 7.67 Mg C haand 4.58 Mg C ha −1 , respectively. Conclusion/Recommendation:The exotic (K. ivorensis) and indigenous (H. odorata) species which was planted on degraded forestland exhibited different growth rate, biomass production and ability to absorb CO 2 from the atmosphere in each part of the tree. In general, forest productivity and ability to absorb CO 2 from the atmosphere of exotics species (K. ivorensis) was higher than that indigenous species (H. odorata). These findings suggest that forest plantation productivity has been affected by species characteristics and suitability of species to site condition. Thus, to sustain high productivity with suitable species selection for carbon sequestration, these factors should be considered for future forest establishment.

The demand for kenaf in the world increases rapidly by the years. Cultivation of the crop in Malaysia is a challenging task, especially when kenaf is grown on sandy soils with low fertility, such as the BRIS Soils (Beach Ridges Interspersed with Swales). A pot study was conducted in a glasshouse at Universiti Putra Malaysia to evaluate the potential of inorganic and organic fertilizers or their combination for growing kenaf on very sandy BRIS Soils, using variety V36. There were altogether sixteen treatments: (T Results showed that application of inorganic material or organic fertilizer in combination with chemical fertilizer (T 2 and T 16 ) improved soil fertility, which are reflected by the increase inexchangeable K, Ca and Mg, CEC, total N, total C and available P. The highest kenaf growth was observed in T 15 treatment.Application of biochar, zeolite or chicken manure alone on the soils did not result in better kenaf growth compared to the control. Zeolite and biochar should be applied with other fertilizers or organic substrate to obtain a positive yield of crop and increase the soil properties. In addition, more studies on the application of chicken manure at different ratios should be conducted to obtain the best yield. Combination treatment, T 15 (NPK + biochar + zeolite) can be suggested to the farmers especially cultivation of kenaf on sandy BRIS soil in order to obtain the best kenaf growth performance and indirectly reduce excessive use of chemical fertilizers.

Accelerated soil erosion is anthropogenic phenomenon and a major worldwide environmental problem. It mainly leads to removal of the clay minerals and soil nutrients and thereby reduces soil fertility because of mineralogical influence on the soil. The objectives of this study were to identify the dominant soil and rock minerals and the influences of mineralogical properties on soil erosion features. This study was conducted at the Merek watershed, located in Kermanshah, Iran. There are different geological formations comprising limestone, sandstone, radiolarite, flysch, shale and marl. The border of each formation was mapped based on geology map and was checked in the field, using GPS and digitized by GIS software (ILWIS 3.5). The erosion feature map was prepared through remotely sensed data (Landsat ETM+ 2002, Path/Row and acquired date). About 300 soil and 28 rock samples were collected from the study area for soil and mineralogy analysis. Result shows that inter-rill, rill and snow erosion were occurred mainly at soil from Sarvak, Ilam and Gurpi Formation which are mainly containing calcite, dolomite, quartz and caolinite minerals giving moderate soil erosion intensity (5 - 10 t·ha^–1·yr^–1). Whereas mica/smectite was dominant clay mineral of soil from Older Terraces resulting in gully erosion and considerable 12.90 t·ha^–1·yr^–1 soil loss. Furthermore, smectite was found as the dominant clay mineral from both soil and parent material of Kashkan Formation (marls material) contributing to landslide occurrence and severe annual soil erosion (16.6 t·ha^–1·yr^–1). This study revealed that both soil erosion feature and intensity potentially are affected by mineralogical properties.