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DEVELOPING SITE-SPECIFIC ALLOMETRIC EQUATIONS FOR ABOVE-GROUND BIOMASS ESTIMATION IN PEAT SWAMP FORESTS OF ROKAN HILIR DISTRICT, RIAU PROVINCE, INDONESIA Nugroho, Nunung Puji
Indonesian Journal of Forestry Research Vol 1, No 1 (2014): Indonesian Journal of Forestry Research
Publisher : Secretariat of Forestry Research and Development Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar

In forest biomass assessment studies, the selection or development of reliable allometric biomass equations is an essential step which determines largely the accuracy of the resulted biomass estimates. Unfortunately, only few studies on allometric biomass equations have been conducted for peat swamp forests and the results are usually not publicly accessible or well documented. Thus, the objective of this study was to develop site-specific allometric equations for above-ground biomass (AGB) estimations in tropical peat swamp forests in Indonesia. These equations were developed based on 51 destructively sampled trees. The results indicated that the developed site-specific allometric equations have coefficient of determination (R2) greater than 95%. The R2 values ranged from 97.0% to 98.7%, where the lowest R2 value resulted from the simplest model which used only DBH as a predictor. Model 5, which used DBH, H and Ï as predictive variables, provided best performance when estimating the AGB of the study area. Hence, as long as reliable data are available as input, Model 5 is recommended. The accuracy and applicability of the allometric equations for peat swamp forests could be improved further by adding more sampled trees from different tree species and/or with a wider DBH range. Considering the importance of wood density in the estimation of the AGB and the lack of this information for peat swamp forest tree species, research should be dedicated to analysing the wood density of the dominant tree species comprising the majority of the AGB density in the study area.

RELATIONSHIP BETWEEN TOTAL TREE HEIGHT AND DIAMETER AT BREAST HEIGHT FOR TROPICAL PEAT SWAMP FOREST TREE SPECIES IN ROKAN HILIR DISTRICT, RIAU PROVINCE Nugroho, Nunung Puji
Indonesian Journal of Forestry Research Vol 1, No 2 (2014): Indonesian Journal of Forestry Research
Publisher : Secretariat of Forestry Research and Development Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/ijfr.2014.1.2.89-107

Reliable information on total tree height (H) is fundamental of forest resource management and forest ecological studies, including assessment of forest biomass. Adding an H variable can improve the performance of the allometric equations of the biomass by reducing the average deviation significantly. However, measuring H is relatively complex, less accurate, time consuming, and expensive. Thus, H is only measured for sampled trees within the plots, whilst diameter at breast height (DBH) is commonly measured for each tree during the forest inventory. The missing H information is usually estimated based on a stand-specific allometric relationship between H and DBH (H-D model) constructed from sampled trees. Despite extensive studies on H-D model for boreal forests and for single-species/plantation forests, few studies have focused on tropical forests. Furthermore, relationship for peat swamp forest tree species, and especially those in Indonesia, have not been widely published. Thus, the objective of this study was to develop site-specific H-D models for tropical peat swamp forests using linearized and non-linear regression functions. The results indicated that the non-linear models outperformed the linearized models based on the statistical parameters and the biological criteria. The modified logistic function (Model 7) is recommended for estimating H in the study area as it has comparable model performances to the exponential function (Model 6) and passed the diameter-height point of (0, 1.3). However, all five non-linear models performed equally well and the differences between them were trivial. Further improvements are needed to improve the accuracy, the predictive ability and the geographical applicability of the models by grouping the species, adding stand variables and (or) using advanced techniques of mixed-effect modelling. In addition, model validation should be carried out prior to their application by collecting new datasets from the forest being studied.

DEVELOPING SITE-SPECIFIC ALLOMETRIC EQUATIONS FOR ABOVE-GROUND BIOMASS ESTIMATION IN PEAT SWAMP FORESTS OF ROKAN HILIR DISTRICT, RIAU PROVINCE, INDONESIA Nugroho, Nunung Puji
Indonesian Journal of Forestry Research Vol 1, No 1 (2014): Indonesian Journal of Forestry Research
Publisher : Secretariat of Forestry Research and Development Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/ijfr.2014.1.1.47-65

In forest biomass assessment studies, the selection or development of reliable allometric biomass equations is an essential step which determines largely the accuracy of the resulted biomass estimates. Unfortunately, only few studies on allometric biomass equations have been conducted for peat swamp forests and the results are usually not publicly accessible or well documented. Thus, the objective of this study was to develop site-specific allometric equations for above-ground biomass (AGB) estimations in tropical peat swamp forests in Indonesia. These equations were developed based on 51 destructively sampled trees. The results indicated that the developed site-specific allometric equations have coefficient of determination (R2) greater than 95%. The R2 values ranged from 97.0% to 98.7%, where the lowest R2 value resulted from the simplest model which used only DBH as a predictor. Model 5, which used DBH, H and Ï as predictive variables, provided best performance when estimating the AGB of the study area. Hence, as long as reliable data are available as input, Model 5 is recommended. The accuracy and applicability of the allometric equations for peat swamp forests could be improved further by adding more sampled trees from different tree species and/or with a wider DBH range. Considering the importance of wood density in the estimation of the AGB and the lack of this information for peat swamp forest tree species, research should be dedicated to analysing the wood density of the dominant tree species comprising the majority of the AGB density in the study area.

KANDUNGAN BIOMASSA ATAS PERMUKAAN PADA HUTAN RAWA GAMBUT DI KABUPATEN ROKAN HILIR, PROVINSI RIAU Nugroho, Nunung Puji
Jurnal Penelitian Hutan dan Konservasi Alam Vol 11, No 1 (2014): Jurnal Penelitian Hutan dan Konservasi Alam
Publisher : Pusat Penelitian dan Pengembangan Hutan

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Hutan rawa gambut mempunyai peranan yang penting dalam konteks pemanasan dan perubahan iklim global karena kemampuannya dalam menyerap dan menyimpan karbon serta dalam mengemisi karbon ke atmosfer.Dalam hal ini, ekosistem hutan rawa gambut mempunyai kapasitas yang lebih besar bila dibandingkandengan ekosistem hutan tropis lainnya. Peranan hutan rawa gambut tersebut ditentukan oleh kandunganbiomassa yang tersimpan, baik pada atas maupun bawah permukaan, termasuk pada lapisan tanahgambutnya. Kajian ini bertujuan untuk mendapatkan informasi tentang kandungan biomassa atas permukaan (BAP) pada hutan rawa gambut di kawasan hutan konsesi PT. Diamond Raya Timber (PT. DRT) denganmenggunakan persamaan alometrik spesifik tapak. Hasil perhitungan menunjukkan bahwa rerata BAP padahutan rawa gambut di PT. DRT adalah 210,81 ton ha-1 (rentang: 66,37-529,11 ton ha). Kandungan BAPpada lokasi kajian cenderung lebih rendah dibandingkan dengan kandungan BAP pada hutan rawa gambutlain maupun pada hutan hujan tropis. Pendugaan BAP sebaiknya dilakukan dengan menggunakan persamaan alometrik spesifik tapak dengan rentang DBH yang lebar.

Biogas Technology for Strengthening Soil and Water Conservation: A Case Study in Leksana Village, Merawu Subwatershed Suryatmojo, Hatma; Ngadisih, Ngadisih; Nugroho, Joko; Nugroho, Nunung Puji; Cahyono, Sigit Andy
Jurnal Pengabdian kepada Masyarakat (Indonesian Journal of Community Engagement) Vol 10, No 2 (2024): June
Publisher : Direktorat Pengabdian kepada Masyarakat Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jpkm.90737

Soil and water conservation is one of the keys to preserving natural resources. Livestock development can optimize the use of grass for soil and water conservation. However, livestock manure waste is a problem for the environment and health. This study aimed to explore the role of biogas technology in supporting the strengthening of soil and water conservation in the Merawu Subwatershed. Through a community empowerment approach, this research included educational programs, implementation of biogas technology, and evaluation of impacts on the environment and economic welfare of the community. After implementing the education program, the results showed a significant increase in public awareness related to environmental conservation. Biogas technology has been successfully installed in households as a pilot project and can operate the biogas system independently. It found positive environmental impacts, including improved soil quality and decreased organic waste load in local water sources. Increased economic welfare is also recorded through a decrease in costs for cooking fuel by 75%; moreover, there is a potential decrease in farming costs with organic fertilizers. The successful implementation of this biogas can be an inspiring model for households and other regions, demonstrating the potential of biogas technology as a holistic solution to soil and water conservation challenges. Although successful, the study identified several challenges, including the resilience of biogas systems to weather fluctuations and the program's expansion to a broader region. Recommendations were given to expand community education, improve technical sustainability, and strengthen stakeholder cooperation. In conclusion, this research makes significant contributions to the literature and practices of community empowerment and natural resource conservation, affirming that biogas technology can be a motor of sustainable positive change at the local level.

RELATIONSHIPS BETWEEN TOTAL TREE HEIGHT AND DIAMETER AT BREAST HEIGHT FOR TROPICAL PEAT SWAMP FOREST TREE SPECIES IN ROKAN HILIR DISTRICT, RIAU PROVINCE Nugroho, Nunung Puji
Indonesian Journal of Forestry Research Vol. 1 No. 2 (2014): Indonesian Journal of Forestry Research
Publisher : Association of Indonesian Forestry and Environment Researchers and Technicians

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59465/ijfr.2014.1.2.89-107

Reliable information on total tree height (H) is fundamental in forest resource management and forest ecological studies, including in forest biomass assessment. Adding an H variable can improve the performance of the biomass allometric equations by reducing the average deviation significantly. However, measuring H is relatively complex, less accurate, time consuming, and expensive. Thus, H is only measured for sampled trees within the plots, whilst diameter at breast height (DBH) is commonly measured for each tree during the forest inventory. The missing H information is usually estimated based on a stand-specific allometric relationship between H and DBH (H-D model) constructed from sampled trees. Despite extensive studies on H-D model for boreal forests and for single-species/plantation forests, few studies have focused on tropical forests. Furthermore, relationships for peat swamp forest tree species, and especially those in Indonesia, have not been widely published. Thus, the objective of this study was to develop site-specific H-D models for tropical peat swamp forests using linearized and non-linear regression functions. The results indicated that the non-linear models outperformed the linearized models based on the statistical parameters and the biological criteria. The modified logistic function (Model 7) is recommended for estimating H in the study area as it has comparable model performances to the exponential function (Model 6) and passed the point diameter-height of (0, 1.3). However, all five non-linear models performed equally well and the differences between them were trivial.

DEVELOPING SITE-SPECIFIC ALLOMETRIC EQUATIONS FOR ABOVE-GROUND BIOMASS ESTIMATION IN PEAT SWAMP FORESTS OF ROKAN HILIR DISTRICT, RIAU PROVINCE, INDONESIA Nugroho, Nunung Puji
Indonesian Journal of Forestry Research Vol. 1 No. 1 (2014): Indonesian Journal of Forestry Research
Publisher : Association of Indonesian Forestry and Environment Researchers and Technicians

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59465/ijfr.2014.1.1.47-65

In forest biomass assessment studies, the selection or development of reliable allometric biomass equations is an essential step which determines largely the accuracy of the resulted biomass estimates. Unfortunately, only few studies on allometric biomass equations have been conducted for peat swamp forests and the results are usually not publicly accessible or well documented. Thus, the objective of this study was to develop site-specific allometric equations for above-ground biomass (AGB) estimations in tropical peat swamp forests in Indonesia. These equations were developed based on 51 destructively sampled trees. The results indicated that the developed site-specific allometric equations have coefficient of determination (R2) greater than 95%. The R2 values ranged from 97.0% to 98.7%, where the lowest R2 value resulted from the simplest model which used only DBH as a predictor. Model 5, which used DBH, H and ρ as predictive variables, provided best performance when estimating the AGB of the study area. Hence, as long as reliable data are available as input, Model 5 is recommended. The accuracy and applicability of the allometric equations for peat swamp forests could be improved further by adding more sampled trees from different tree species and/or with a wider DBH range. Considering the importance of wood density in the estimation of the AGB and the lack of this information for peat swamp forest tree species, research should be dedicated to analysing the wood density of the dominant tree species comprising the majority of the AGB density in the study area.

Lake and Stream Buffer Zone Widths' Effects on Nutrient Export to Lake Rawapening, Central Java, Indonesia: A Simple Simulation Study Nada, F. Maftukhakh Hilmya; Nugroho, Nunung Puji; Sofwa, Nurzawani Binti Md
Forum Geografi Vol 37, No 1 (2023): July 2023
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v37i1.21537

Lake ecosystems in Indonesia face serious environmental problems. One of those problems is eutrophication caused by excessive plant nutrients, particularly nitrogen (N) and phosphorus (P). Water quality degradation and biodiversity loss are the effects of eutrophication. The government of Indonesia (GoI) has issued a regulation on determining lake and stream buffer zones, but it has not been fully implemented in the field. Additionally, the data related to the effects of each buffer zone width is not available. This study aims to begin to fill this gap. It simulates the effect of lake and stream buffer zone widths on nutrient export to Rawapening Lake. The Nutrient Retention sub-model, which is part of InVEST (Integrated Valuation of Environmental Services and Tradeoffs) software, has been used for this research to analyse information from several data sources, including a Digital Elevation Model (DEM) and measurements of soil depth, annual rainfall, land cover/use, watershed/sub-watershed boundaries, and biophysical conditions. Several studies of eutrophication in Rawapening Lake have measured the magnitude of eutrophication but have not discussed the effects of buffer zone widths. Therefore, this study accommodates the updated data on how much effect of buffer zone widths on the reduction of nutrient export. Five scenarios of buffer zone width are considered: 30 m., 90 m., and 150 m, where the lake buffer zone widths and the stream buffer zone width are 30 m. The results indicated that the maximum nutrient export reduction of lake buffer zones was only 2.63% (for N) and 3.56% (for P). On the other hand, the 30 m stream buffer zone width reduced the nutrient export to Rawapening Lake by up to 43.05% for N and by 44.90% for P. A 30 m combined lake and stream buffer zone width slightly increases the nutrient export reduction effectiveness, i.e., 0.41% and 0.56% for N and P, respectively.

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