Growing bioenergy crops on degraded and underutilized land is a promising solution to meet the requirement for energy security, food security, and land restoration. This paper assesses the socioeconomic and environmental benefits of agroforestry systems based on nyamplung (tamanu) (Calophyllum inophyllum L.) in the Wonogiri district of Central Java, Indonesia. Data were collected through field observations and focus group discussions involving 20 farmers who intercrop nyamplung with maize, rice, and peanuts and utilize the species in honey production. Calculating each crop's net present value (NPV) demonstrates that when grown as monocultures, staple crops rice and peanuts lead to negative profitability, while maize generates only a marginal profit; yet honey production utilizing nyamplung produces a NPV nearly 300 times greater than maize. However, when utilizing nyamplung, honey is also the commodity most sensitive to decreases in production, followed by nyamplung–peanut and nyamplung–rice combinations. While decreases in production have little effect on the NPVs of rice, peanuts, and maize, these annual crops can only be cultivated for a maximum of 6 years within the nyamplung's 35‐year cycle, due to canopy closure after this time. Nyamplung‐based agroforestry systems can provide economic, social, and environmental gains on different scales. However, when considering the high profit potential of nyamplung combined with honey production, further research is needed to improve and develop bee husbandry practices so this becomes a viable option for local farmers.

Large areas of deforested and degraded land, particularly degraded peatlands, need a viable long-term solution for restoration, ideally one that ensures energy security without compromising food security or biodiversity conversation. To address a knowledge gap on the most adaptive bioenergy crop(s) for degraded lands, this research project assessed the survival and growth performance of potential bioenergy crops to restore burned and degraded peatlands. Our methodology compared the bioenergy species with the potential to survive in extreme environments, i.e., gamal [Gliricidia sepium (Jacq.) Walp.], kaliandra (Calliandra calothyrsus Meissner), kemiri sunan [Reutealis trisperma (Blanco) Airy Shaw], and nyamplung (Calophyllum inophyllum L.). Observed parameters are plant survival rates, tree height, and circular stem growth. The experiment was conducted between March 2016 to February 2017 in a two-hectare demonstration plot on burned and degraded peatland in Buntoi village, Pulang Pisau, Central Kalimantan province. Using a split plot design, two treatments were given to each species, i.e., monoculture plantation and agroforestry (intercropped with Ananas comosus (L.) Merr.); with each treatment, the species were replicated on two separate plots. Results indicate that nyamplung is the most adoptable species followed by kemiri sunan, however both species performed very well under agroforestry treatment when compared with monoculture. Further study is needed to assess the productivity and associate biofuel yield.

Bioenergy production from degraded land provides an opportunity to secure a new renewable energy source to meet the rapid growth of energy demand in Indonesia while turning degraded land into productive landscape. However, bioenergy production would not be feasible without landowner participation. This study investigates factors affecting landowners' preferences for bioenergy production by analyzing 150 landowners with fire experience in Buntoi village in Central Kalimantan using Firth's logistic regression model. Results indicated that 76% of landowners preferred well-known species that have a readily available market such as sengon (Albizia chinensis (Osb.) Merr.) and rubber tree (Hevea brasiliensis Müll.Arg.) for restoration on degraded land. Only 8% of preferred nyamplung (Calophyllum inophyllum L.) for bioenergy production; these particular landowners revealed a capacity to handle the uncertainty of the bioenergy market because they had additional jobs and income, had migrated from Java where nyamplung is prevalent, and preferred agricultural extension to improve their technical capacity. These results contribute to identifying key conditions for a bottom-up approach to bioenergy production from degraded land in Indonesia: a stable bioenergy market for landowners, application of familiar bioenergy species, and agricultural extension support for capacity building.is expected to be 1.8 times higher than the energy demand in 2015 [8] due to population growth, urbanization, and economic development [9][10][11].Lately, there has been increased interest in bioenergy production by growing non-food seed oil, such as nyamplung (Calophyllum inophyllum L.), in degraded lands since its multiple benefits [12] It could minimize a trade-off between food and fuel production as some of these non-food crops could grow in degraded lands that cannot support food production [13][14][15][16]. It could reduce environmental impacts if these crops are harvested from degraded and underutilized lands that have limited value to store carbon and preserve native vegetation and biodiversity (e.g., [9,15,17]). In addition, it could support restoration of degraded lands with these bioenergy species and provide a variety of ecosystem services, such as carbon storage, reduction of soil erosion, and improvement of biodiversity [18,19]. It also creates employment opportunities in rural areas, particularly in developing countries where large populations live and rely on marginal lands for farming [16,[20][21][22].Capturing these benefits from bioenergy production on degraded land, however, would not be feasible without landowner participation. In other words, bioenergy production should meet landowner preferences. Otherwise, owners of degraded lands would use these lands for alternative activities that meet their preferences and expectations. Since 2007, for instance, the Government of Indonesia has implemented and tested an "Energy Sufficient Village" program (or Desa Mandiri Energi) in Java, Indonesia [23][24][25][26][27][28]. The program aime...

Reliable data on CO2 quantification is increasingly important to quantify the climate benefits of forest landscape restoration and international commitments, such as the Warsaw REDD+ Framework and Nationally Determined Contributions under the Paris Agreement. Calophyllum inophyllum L. (nyamplung as a local name or tamanu tree for the commercial name) is an increasingly popular tree species in forest landscape restoration and bioenergy production for a variety of reasons. In this paper, we present allometric equations for aboveground biomass (AGB), belowground biomass (BGB), and total above- and belowground biomass (TABGB) predictions of C. inophyllum L. Data collection was carried out twice (2017 and 2021) from 40 trees in Java, Indonesia. Allometric equations using the natural logarithm of diameter at breast height (lnDBH) and ln height (lnH) for biomass prediction qualified the model’s fit with statistical significance at 95% of the confidence interval for AGB, BGB, and TABGB predictions. The results showed that the linear models using both lnDBH and lnH were well fit and accurate. However, the model with lnDBH is more precise than the model using lnH. Using lnDBH as a predictor, the R2 values were 0.923, 0.945, and 0.932, and MAPE were 24.7, 37.0, and 25.8 for AGB, BGB, and TABGB, respectively. Using lnH as a predictor, the R2 values were 0.887, 0.918, and 0.898 and MAPE were 37.4, 49.0, and 39.8 for AGB, BGB, and TABGB, respectively. Consequently, the driven allometric equations can help accurate biomass quantification for carbon-trading schemes of C. inophyllum L.

The quality of timber could be affected by timber hauling, primarily when it remained in the forest and became vulnerable to pests and fungi attacks. Additionally, road conditions could also influence the slickness of hauling. Therefore, this study aimed to identify the effect of road conditions on hauling performance, cost, and soil deterioration. This research analyzed four types of road conditions in Acacia mangium plantations in West Java and Banten, including dry, wet, uphill, and downhill roads. The results indicated that the average hauling performance of 6.604 m3km/hour on the uphill road was the least among all road types. The uphill soil road had the highest average hauling cost of 30,685 IDR/m3km and the deepest average rut of 17.503 cm compared to others. These results would provide better information on low-cost and environmentally friendly timber hauling productivity.

Line intersect method (LIM)

South Sumatra has succeeded in meeting local rice needs. Nonetheless, rice production in South Sumatra has not been able to significantly contribute to meeting the ever-growing needs of Indonesia's population. Therefore, the government is always trying to increase rice production by increasing productivity and expanding the rice planting area. Rice is not only an economic good, but has become a political item. Therefore, government intervention is quite intense in stabilizing the availability of rice. One of the interventions carried out by the government of South Sumatra is targeting the planting area as a response to the availability of rice in the previous year. The purpose of this study was to analyze the response of planting area at the farmer level to changes in rice availability and supply elasticity in South Sumatra by using the previous year's planted area and the availability of rice from South Sumatra as determining indicators. The method used in this study is multiple linear regression using secondary data over a period of 20 years. The results show that the availability of rice in South Sumatra significantly affects the area planted with an elastic supply elasticity. Therefore, government programs such as printing new land or adding planting area (LTT), land optimization through increasing the planting index, and using abandoned land are urgently needed to support sustainable rice self-sufficiency in South Sumatra.

Papua Province has a natural production forest reaching 13.541 million ha, with log production achieving an average of 8.78% of the total national log production of 5.835 million m 3 /year. The logs were obtained from selective logging activities using reduced-impact logging techniques. This paper aimed to determine the potency, type, and quality of wood harvesting waste in the two forest concessions lowland natural forests in the province of Papua. The average potential of wood harvesting waste is 4.012 m 3 /ha or 16.25%. This figure comprises felling waste, which amounts to 2.529 m 3 /ha or 10.24%, and waste due to skidding and grading scaling, which amounts to 1.483 m 3 /ha or 6.01%. The types of logging waste consist of stump, end, and base waste with an average volume of 1.014 m 3 /ha (40.88%), 0.825 m 3 /ha (30.72%), and 0.690 m 3 /ha (28.40%), respectively. The quality of logging waste is dominated by defects, with an average of 2.733 m 3 /ha (69.10%). The waste broken due to the harvesting process averages 0.756 m 3 /ha (18.84%), while that of good quality averages 0.484 m 3 /ha (12.07%). The following measures should be taken to mitigate logging waste; (a) company management needs to train on reduced impact logging techniques for both chainsaw and tractor operators, (b) the piece rate system has to be reviewed, and (c) the monitoring function of logging activities in the field has to be improved.