Joeni Rahajoe - Academia.edu (original) (raw)

Papers by Joeni Rahajoe

Forests

Most of the Indonesian agarwood in the international market is harvested from the wild, which rai... more Most of the Indonesian agarwood in the international market is harvested from the wild, which raises concerns regarding its sustainability. The Government of Indonesia encourages agarwood cultivation produced from the cultivated Agarwood-Producing Tree (APT) to overcome this concern and replace natural agarwood. APT cultivation in Indonesia is not a new development, but it has faced various obstacles, ranging from production quantity and quality to funding and marketing. Therefore, an appropriate policy is needed to support the success of APT cultivation. This study aims to develop a dynamic system model in order to identify the gaps and determine appropriate policy strategies to improve APT cultivation in Indonesia. The model was established by compiling three conceptual stages: planting to harvest, cost–benefit analysis, and feasibility analysis. Agarwood from Aquilaria malaccensis Lam. cultivated by the community and private sector, which produces kemedangan (an agarwood grade in...

REINWARDTIA

YULIZAH, RAHAJOE, J. S., FEFIRENTA, A. D. & NUGROHO, A. D. 2022. The population and distribution ... more YULIZAH, RAHAJOE, J. S., FEFIRENTA, A. D. & NUGROHO, A. D. 2022. The population and distribution of agarwood producing tree (Aquilaria malaccensis) in Riau Province. Reinwardtia 21(1): 1–11. — Riau Province is one of the largest agarwood producers and supplier of Aquilaria malaccensis species in Indonesia, based on the data of trade quota that was issued by the Ministry of Environment and Forestry in 2018. The quota data will be used for monitoring the sustainability of the population agarwood producing trees in the wild. The aimed of the study were to determine the natural population distribution and habitat preference of wild agarwood-producing trees in Riau Province. The agarwood population census carried out by making random plots in the study sites, soil moisture, soil pH, temperature and the humidity recorded, and the macronutrients data also used to support the habitat preferences for the agarwood producing taxa tree. Seven locations of agarwood producing trees were selected ...

Produksi biomasa gugur serasah dan variasi musimannya dimonitor selama 5 tahun untuk mengamati po... more Produksi biomasa gugur serasah dan variasi musimannya dimonitor selama 5 tahun untuk mengamati pola musiman dari gugur serasah dan kontribusi gugur serasah terhadap ekosistem hutan. Gugur serasah dikumpulkan setiap bulan dengan menggunakan 20 perangkap serasah (luas masing-masing perangkap serasah adalah 1 x 1 m2) yang berada pada petak permanen. Seluruh sampel di oven pada suhu 70 ÂoC. Total gugur serasah adalah 8,36 Â± 0,39 t ha-1 tahun-1, dengan konstribusi terbesar pada daun (6.55 Â± 0.44 t ha-1tahun-1), diikuti oleh komponen yang tidak teridentifikasi (0.69 Â±0.2), batang kecil (0.76 Â± 0.1), bagian reproduksi (0.16 Â± 0.06), and batang besar (0.21 Â± 0.04 t ha-1 tahun-1). Pola musiman menunjukkan bahwa gugur serasah meningkat selama musim hujan. Gugur serasah daun tertinggi berada pada bulan Juli. Jenis-jenis dominan menggugurkan daun utamanya pada pertengahan musim kering. Total gugur serasah daun dari yang tertinggi ke yang terendah diamati Nauclea lanceolata (0.36 Â± 0.16),...

Tropics, 2014

There are physiognomically distinctive forest types in lowland tropics reflecting variation in ed... more There are physiognomically distinctive forest types in lowland tropics reflecting variation in edaphic conditions. Tree saplings that contribute to forest regeneration are expected to show morphological properties in response to forest environment. However, it remains unknown how sapling properties are similar or different across forest types. We examined architectural and functional traits of forest floor saplings across heath, peat swamp, and mixed dipterocarp forests that characterize lowland forests in Kalimantan, Indonesia. Saplings (150-310 cm tall) of 41 species, which represent each forest type, were selected under the canopy of developed forest stands. Among these, we chose one species found in all forest types and two species in heath and peat swamp forests. Significant differences in crown allometries were found across forest types and across species. Saplings in mixed dipterocarp forest had thicker trunk and wider crown at the same sapling height compared to other forests and they had higher specific leaf area, higher mass-based leaf nitrogen content and lower wood density. Heath forest saplings showed lowest leaf nitrogen content and highest wood density. Species with across forest-type distribution showed intra-specific variation in sapling traits, and which was similar to the difference among forest types. We conclude that saplings show morphological response to nutritional and water conditions that characterize forest types.

Environmental Earth Sciences, 2019

Boreal Forest Research, 2012

Introduction In the world, 11 % (44.1 million hectares (Mha)) of global peatland area is located ... more Introduction In the world, 11 % (44.1 million hectares (Mha)) of global peatland area is located in tropical regions. Most of the tropical peatlands (24.8 Mha, 56 %) are found in the Southeast Asia region (47 % in Indonesia, 6 % in Malaysia, 3 % in Papua New Guinea, with small pockets and remnants in Brunei, Myanmar, the Philippines, Thailand and Vietnam) (3). However, all regional peatlands are threatened by either logging, drainage, agricultural conversion (mostly to oil palm, as well as rice, rubber, coconut and pineapple), fire or other human activities. Tropical peat swamp forests are unique ecosystems, because of their extreme acidic, anaerobic and nutrient poor conditions. They support diverse forms of flora, fauna and microbes with many endemic and endangered species. Anderson (1) recorded 927 species of flowering plants and ferns in the peat swamp forests of Borneo. Most of the tree families that are present in lowland dipterocarp forests are also presented in peat swamp forests, but many of the species in peat swamp forests are specific to this habitat (8). They are also an important refuge for many endangered species including orangutan. At the same time, tropical peatlands are one of the largest sink of organic carbon. The carbon is stored not only in the living biomass, but also in the peat soil. In Southeast Asia, their high carbon density results in a large regional peat carbon store of 68.5 Gt, equivalent to 77 % of the tropical and 11 – 13 % of the global peat carbon pools (3). Indonesia has the largest stock of tropical peat carbon (57.4 Gt, 65%). This data is used to provide revised estimates for Indonesian forest soil carbon pools of 77 Gt, and total forest carbon pools (biomass plus soil) of 97 Gt. Peat carbon contributes 74 % to the total forest soil carbon pools in Indonesia. However, Indonesia is also the third largest emitter of greenhouse gases. Page et al. (5) estimated that, under the 1997 El Nino event, 32 % (0.79 Mha) had burnt in the 2.5 Mha study area in Central Kalimantan and which of 91.5 % (0.73 Mha) was peatland. According to their estimation, 0.19 – 0.23 Gt of carbon was released to the atmosphere through peat combustion and 0.05 Gt of carbon was released from burning of the overlying vegetation. They emphasized that, as a result of burning peat and vegetation, between 0.81 and 2.57 Gt of carbon was released to the atmosphere in 1997 in Indonesia. It is almost 13 – 40% of the mean annual global carbon emissions from fossil fuels. In Central Kalimantan, peat fire has been a serious problem since the last decade. Peat fire is a major cause of peatland degradation that leads to loss of biodiversity and carbon stock in peat swamp forests. When peat is ignited, fire will develop underground slowly and may spread vertically and horizontally dominated by smoldering process. Finally, peat fire will destroy ecosystem completely and change the environment drastically. Because, peat swamp forests are sustained in the sensitive balance among deep water table, canopy cover and leaf litter inputs (8), forest recovery would be difficult after a fire. In this study, we evaluated the impact of fire disturbance to forest structure and reforestation after peat fire from the comparison among peat swamp forests with differences on disturbance severity.

The study of carbon stock and biomasa of agricultural commodities was conducted in the Bodogol vi... more The study of carbon stock and biomasa of agricultural commodities was conducted in the Bodogol village, Gunung Gede Pangrango National Park - West Java. The purpose of this research to determine the biomasa, carbon stock and the rate of decomposition of agricultural commodities by using destructive sample and litterbag method. Six of agricultural commodities: green beans/buncis (Phaseolus vulgaris), chilli (Capsicum annum), corn (Zea mays), bean (Vigna cylindrica), peanuts (Arachis hypogaea) and cassava (Manihot esculenta), were calculated their biomasa and carbon stocks. The result showed that the biomasa of agriculture commodities in the range of 0.152 to 4.216 t ha-1, with a carbon stock ranging from 0.01 to 1.83 t ha-1. The decomposition rate (k) of those commodities were k = 5.6 y-1; 5.48 y-1, 5.18 y-1, 5.04 y-1, 4.42 y-1, and k = 1.21 y-1, for Manihot esculenta, Vigna cylindrica, Arachis hypogea, Zea mays, Capsicum annum and Phaseolus vulgaris, respectively.

In Sumatra, peat fire is a serious problem for the last two decades. It is a major cause of degra... more In Sumatra, peat fire is a serious problem for the last two decades. It is a major cause of degradation that leads to loss of biodiversity and carbon stocks in peat swamp forests. After peat fire, grasslands will develop in the early successional stage there. To understand the relationship between grassland vegetation and environmental factors, field observations were conducted in Riau province, Sumatra, Indonesia. Fifty-one 2 × 2 m plots in the various grassland communities were set-up which spent several years after peat fire disturbance. Species compositions and coverage rates of all species in each plot were checked. The ground water levels were measured on October/December (wet season), 2014 and February (dry season), 2015. Groundwater sample was collected at the same time. In situ pH and electrical conductivity (EC) were measured by a compact pH and EC meter, respectively. In the laboratory, dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) concentrations were ...

Penelitian model pengelolaan lahan gambut secara berkelanjutan berbasis pengelolaan ekosistem, di... more Penelitian model pengelolaan lahan gambut secara berkelanjutan berbasis pengelolaan ekosistem, dilakukan pada tahun 2016, melalui pembentukan plot lahan penelitian seluas 3,5 hektar, yang ditanami berbagai jenis tanaman, yaitu tanaman budidaya monokultur, agro-forestri dan tanaman konservasi. Berbagai penelitian dilakukan, yaitu: (1) Pengenalan karakteristik gambut dan permasalahannya; (2) Studi vegetasi, eko-fisiologis dan agronomis berbagai jenis; (3) Studi eko-hidrologis lahan gambut. Penelitian meliputi pemetaan pada skala plot dan skala Desa Kalampangan; Pengamatan fisika dan kimia, ketebalan gambut, tinggi permukaan air gambut, monitoring curah hujan dan neraca air melalui lisimeter, pendugaan cadangan karbon gambut bawah permukaan tanah; Pengamatan pertumbuhan, produksi dan prospek usahatani berbagai jenis tanaman. Hasil penelitian menunjukkan, bahwa lahan penelitian dan kawasan Desa Kalampangan rawan pengenangan/banjir, kekeringan dan kebakaran. Penguranga...

Research on land use change in Temiang Village is important as it is a part of Giam Siak Kecil-Bu... more Research on land use change in Temiang Village is important as it is a part of Giam Siak Kecil-Bukit Batu Biosphere reserve conservation area which protects and conserves the ecosystem and the biological resources and genetic resources in it. This research was conducted to determine land use changes and their effects in Temiang village, Bukit Batu. Effects of changes in land use in Temiang village can be seen in provisioning services. Provisioning services are the benefits obtained from the supply of food and other resources from ecosystems. To collect primary data, a field trip was conducted, in addition to in depth interview and Focus Group Discussion method. The land uses in Temiang village are driven mainly by local societal preferences and practices which are rubber and oil palm plantations. The other factors that drive land use change are conversion for housing and village facilities which is also the result of population growth and the arrival of migrants.

Tropical Peatland Eco-management, 2021

SN Applied Sciences, 2020

This study was conducted to understand the environmental behavior of mercury released by artisana... more This study was conducted to understand the environmental behavior of mercury released by artisanal and small-scale gold mining (ASGM) activities. For this purpose, we attempted to assess the effect of diffused mercury on mercury concentrations in soil, demonstrate the presence of methylmercury in soil affected by the deposited mercury and determine the reactions associated with methylmercury production. The vertical profiles of mercury were obtained from two sites in the forest of the ASGM village in Pongkor (West Java, Indonesia) and from two sites in Mount Halimun-Salak National Park, which is approximately 12 km from the ASGM village. The highest total mercury concentration, 8.9 mg kg −1 , was observed for soil samples collected at the ASGM village. The mercury was concentrated at the surface or in the subsurface layers, and the concentrations were several times to more than ten times higher than the lowest values observed in the deeper layers at each site. Even in the national park, the highest concentration of 1.9 mg kg −1 was observed in the upper soil layer. These results suggest that the primary source of mercury in the forest soil is atmospheric deposition; fallen plant leaves also deliver accumulated mercury to the soil surface. The organic mercury percentages of the total mercury were 0.2 ± 0.1% for the national park and 0.3 ± 0.2% for ASGM sites. The vertical variation in organic mercury concentration did not always match that in total mercury concentration, which suggested that the formation of methylmercury in soil was closely related to the decomposition of organic matter near the surface. The soil surface is an important reaction field for methylmercury production in forested areas.

IOP Conference Series: Earth and Environmental Science, 2020

Research on biodiversity study of several peatland types in Papua had been carried out in Merauke... more Research on biodiversity study of several peatland types in Papua had been carried out in Merauke and Mappi. The plot method was used for ecological research and interviews method for ethnobotany research. The results showed that the most important species which have the highest Importance Value Index (IVI) were Beilschmiedia sp., Carallia brachiate (Lour.) Merr., and Kibara coriacea (Blume) Hook. f. & A. Thomps. in Kaliki Village, whereas it was Melaleuca leucadendra (L.) L only in Marga Mulia Village, Merauke. The most important species which have the highest IVI were Semecarpus forstenii Blume, Archidendron clypearia (Jack) I.C. Nielsen, and Campnosperma auriculatum (Blume) Hook.f. in Khanami Village, while they were Calophyllum euryphyllum Lauterb, Diospyros toposiodes King & Gamble, and Syzygium effusum (A.Gray) Müll. Stuttg in Yame Village, Mappi. The plants are used for building materials and ships, medicinal materials, food ingredients, animal feed, energy-producing material...

Toxicology and Environmental Health Sciences, 2020

Objective To estimate the impact of mercury released from an artisanal small-scale gold mining (A... more Objective To estimate the impact of mercury released from an artisanal small-scale gold mining (ASGM) activities on the ecosystem. Methods Total and organic mercury concentrations in paddy field soil and freshwater snails around an artisanal small-scale gold mining area were investigated. Paddy field soil samples and freshwater snails were collected from ten sites along the Cikaniki River. A site located in a national park, which was approximately 12 km upstream from the ASGM site, was considered the reference site for this study. Results The organic mercury concentration in soil samples collected at the ASGM site was n.d.–0.018 mg kg −1 and that at the reference site was 0.005–0.008 mg kg −1 . The organic mercury concentrations in the freshwater snails collected at the ASGM and reference sites were 0.38 ± 0.21 mg kg −1 (31.0 ± 26.6% of total mercury, n = 38) and 0.056 ± 0.032 mg kg −1 (40.5 ± 11.5% of total mercury, n = 16), respectively. Conclusion Although the original form of mercury in the mining waste was elemental mercury and/or Hg 2+ , the mercury form changed to organic mercury in environment and the organic mercury was concentrated two orders of magnitude, even in low-order organisms.