Regeneration status and species diversity of major tree species under scientific forest management in Kapilbastu district, Nepal

In Nepal, scientific forest managementhas been practiced as an effective forest management technique to utilize forest resources sustainably. However, the program has faced many controversies such as intentional logging of only high-valued timber species like Shorearobusta. In addition, few believe this program is severely affecting the regeneration productivity and species diversity in the natural forests. In order to address these issues, we examinedthe regeneration condition and plant species diversity in the stands where scientific forest management operations were carried out. The data related to regeneration status and species diversity were collected using a systematic random sampling of the selected stands. Our results showed good regeneration conditions (Seedling >5000, Sapling>2000) in all the studied stands. The tree species community was dominated by S.robusta(Sal) followed by Schleicheraoleosa (Kusum) and Casia fistula (Rajbriksha). The value of diversity indices of different species varied significantly between felling series. The highest diversity was found in the second year felling series with the Simpsons Index of dominance value 0.6934 and the lowest species diversity was in the first year felling series with a value of 0.8448. It can be recommended that the regeneration felling practice has helped in promoting the regeneration condition and growth.

PENDUGAAN POTENSI PEREKRUTAN PERMUDAAN ALAM OLEH POHON INDUK DI HUTAN MANGROVE IUPHHK-HA PT. BUMWI, TELUK BINTUNI, PAPUA BARAT Potential Estimation of Seedling Recruitment by Seed Trees in Mangrove Forest IUPHHKHA PT. BUMWI Bintuni Bay, West Papua

Since 1978 one of the legal silviculture systems in Indonesian regard to managing mangrove forest is seed tree method. The ability of this silviculture system to recruit the seeds to fulfill the regeneration is one of the importantaspects. The research is conducted to get the information about regeneration condition and the ability of seed tree method to recruit the regeneration in any various plot with different agecutting. Vegetation analysis for naturalregeneration (seedlings and saplings) were conducted at four different age logged-over area with the total 640 plots. The plot size is 78.5 m2. The result showed that existence of seed tree can affect the type of regeneration for seedlings recruitment with percentage between 59.52% to 83.37%.Key words: mangrove, natural regeneration, seed tree, seedling recruitment

Population and vegetation structure of ramin (Gonystylus bancanus) in secondary forests of Ketapang District, West Kalimantan, Indonesia

Muin A, Astiani D. 2018. Population and vegetation structure of ramin (Gonystylus bancanus) in secondary forests of Ketapang District, West Kalimantan, Indonesia. Biodiversitas 19: 478-484. In the tropical peatland, ramin (Gonystylus bancanus Miq. Kurz) was one of many prominent species that present in peatland forest. The species distribution is mostly in Southeast Asia peatland. The beautiful wood color, pale yellow sometimes grayish with no differentiated sapwood and heartwood with straight interlocked grain, made it become the most wanted tree species from tropical peatland.The exploitation of Ramin wood since the 1970s caused the decrease of its population in the peatland forest, led to this species being listed as an endangered species. This study aimed to search information on the Ramin population and vegetation structure left in its habitat in secondary peatland forest of Pematang Gadung and Sungai Sirih villages area of Ketapang District. The study employed a survey method, and data collection was carried out using line plots system. Data assessed were natural regeneration condition-seedling, sapling and pole growth levels-, and tree growth levels. A 20 m x 20 m size plots were continually established to form a line with the length of 550-680 m. Results showed that relatively a few Ramin was found in the forests in Sungai Sirih with a mean seedling density of only 9.9 tree ha-1, height ranges of 131 cm to 150 cm, and counted sapling level of 183 trees ha-1 with diameter ranges from 0.38 to 6.37 cm. At Pematang Gadung village, more Ramin was found, especially with a bigger diameter. Tree level (diameter >20cm) was recorded at 74.1 tree ha-1 with a contradictory far less seedling (2.8 tree ha-1), sapling level (only 1 tree ha-1) and pole level (7.4 tree ha-1) established. Based on the tree population condition and the variation of their growth level, the vegetation structure of Ramin did not describe a normal curve form in the natural forest both in the villages of Pematang Gadung and Sungai Sirih.

The Effect of Regeneration Conditions on the Properties of CeO2 Desulfurization Sorbent in SO2 Atmosphere

CeO2 desulfurization sorbent was prepared by calcination of Ce(NO3)3 ● 6H2O and the effect of regeneration conditions on its properties in SO2 atmosphere was investigated in a fixed bed reactor. The regeneration conversion and the yield of elemental sulfur for CeO2 desulfurization sorbent were tested and calculated. And the composition and the morphology of CeO2 desulfurization sorbent before and after regeneration were obtained by X-ray diffraction and scanning electron microscope. It was found that the main components of the regeneration products of Ce2O desulfurization sorbent were solid CeO2 and gaseous elemental S in SO2 atmosphere. The optimum regeneration condition of CeO2 desulfurization sorbent is that the regeneration temperature of 750 °C and the SO2 concentration of 4.25 %, under which the CeO2 desulfurization sorbent shows the higher regeneration conversion of 96 % and the yield of elemental sulfur of 68.95 wt. %.

Study on Optimization of Cationic Resin Regeneration Conditions

In order to optimize the regeneration conditions of cation exchange resin, the paper based on the actual data of production, the cation exchange resin regeneration condition was optimized by the process of mathematical modeling, which achieved good results. Research showed that reducing regeneration acid feeding time could effectively reduce the consumption. It could reduce the production cost and make enterprises obtain more economic benefits. Calculated and measured were agreed showed that the study and calculation on regeneration of cation bed were accord with actual production, and had practical value for ion regeneration process. Through least square fitting showed that the 80min was the best acid feeding time, acid consumption of unit volume of water was the lowest.

Influence of Regeneration Condition on Physical and Chemical Properties of High Temperature Coal Gas Desulfurization Sorbent

Physical and chemical properties are closely related to desulfurization, regeneration performance and cycle stability for high temperature coal gas desulfurizer. This review focuses on influence rules of changes in regeneration atmosphere, temperature and space velocity on physical and chemical properties. A large number of experimental researches have shown that regeneration atmosphere, regeneration temperature, space velocity have an important influence on mechanical strength, active component and texture change for high temperature coal gas desulfurizer. The different regeneration atmosphere obviously results in different active ingredients for desulfurization sorbent after regeneration, and regeneration at a higher regeneration temperature will easily cause desulfurizer sintering, as well as small regeneration space velocity can lead to the formation of sulfates. In order to make the circulatory system of sulfidation-regeneration-sulfidation need to the requirements in industrial application, the further research of influence rules of regeneration condition on physical and chemical properties will be crucial.

Preparation of Rubber Filler by Spent Activated Carbon

In this paper, the spent Activated Carbon (AC) which came from caramel plant was regenerated by the method of microorganism and chemistry. The optimal regeneration method was the combination of microorganism regeneration and NaOH regeneration. The optimal regeneration condition was treated by microorganism in 60 min at temperature of 35 °C and in NaOH (dosage was 6%). The optimal ultrafine grinding time was 5 h at 1200 rpm by adding 5 Triethanolamine, the effect of ultrafine grinding was better and the minimal size distribution was D90 3.82µm, D50 1.62 µm. the study ofAC surface modification was explored while combining the similar characteristics of AC and Carbon Black in its structure and composition. The possibility of reusing the spent AC was studied and the mechanical performance of rubber with modified AC was 43~44% higher than that of unmodified AC. The modified AC was characterized by Scanning electron microscope (SEM).

Regeneration of Iron Oxide Sorbent Used for Hot Gas Desulfurization

Iron oxide sorbent was prepared from red mud and the regeneration behaviors were investigated in a fixed bed reactor. Regeneration parameters including temperature and concentration of oxygen have been considered in order to obtain a suitable regeneration condition. XRD and SEM techniques were used to characterize the fresh and regenerated sorbents. The experimental results show that the sulfided sorbent could be regenerated efficiently using a gas composition of 2% O2-15% H2O- balance N2, at the temperature of 700 °C.