Haruni Krisnawati
Forest Research and Development Centre, Forestry and Environment Research Development and Innovation Agency

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A Compatible Estimation Model of Stem Volume and Taper for Acacia mangium Willd. Plantations Krisnawati, Haruni
Indonesian Journal of Forestry Research Vol 3, No 1 (2016): 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.2016.3.1.49-64

Abstract

A compatible volume estimation model for Acacia mangium Willd. was developed from data corresponding to 279 felled sample trees collected from the A. Mangium plantations in South Sumatra, Indonesia. The model comprises a total volume model and a stem taper model, which is compatible in the sense of the total volume obtained by integration of the taper model being equal to that computed by the total volume model. Several well-known total volume functions were evaluated. A logarithmic model was determined to be best and was then used as the basis for deriving the taper model. Appropriate statistical procedures were used in model fitting to account for the problems of heteroscedasticity and autocorrelation that are associated with the construction of volume and taper functions. The developed model can be used to estimate total stem volume, merchantable volume to any merchantability limit, diameter of any height, and (possibly) height of any diameter based on only easily measurable parameters such as diameter at breast height and total tree height for the species analysed. The models provide a major improvement over the previous models for A. mangium plantations in Indonesia which were only applicable for estimating stem volume to a fixed top diameter limit.
The Dynamics of Species Composition Stand Structure and Above Ground Biomass of Undisturbed Forest in East Kalimantan Krisnawati, Haruni; Wahjono, Djoko; Imanuddin, Rinaldi
JURNAL BIOLOGI INDONESIA Vol 8, No 1 (2012): JURNAL BIOLOGI INDONESIA
Publisher : Perhimpunan Biologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (255.378 KB) | DOI: 10.14203/jbi.v8i1.3062

Abstract

Dinamika Komposisi Spesies Struktur Pohon dan Biomasa di Hutan Terganggu di Kalimantan Timur. Kajian dinamika komposisi spesies dan biomasanya dilakukan selama 4,3 tahun (Desember 2004 - April 2009) di hutan terganggu Kalimantan Timur. Untuk melakukan kajian di gunakan 6 plot permanen (100x100 m2), yang berada di hutan penelitian Samboja. Semua pohon berdiameter > 10 cm dbh (diukur pada posisi 1,3 m diatas tanah). Pada Desember 2004,tercatat 2143 pohon tersebar di plot tersebut terdiri dari 39 famili, 82 genus dan 111 spesies. Pada pengamatan April 2009 tercatat 2466 pohon terdiri dari 40 famili, 86 genus dan 123 jenis.Sebagian besar spesies yang mendominasi adalah Garcinia nervosa dan Trigonostemon laevigatus tetapi setelah pengamatan pada tahun 2009, keduanya tidak lagi mendominasi. Selama kurun 4,3 tahun terjadi penambahan kepadatan 15,1%, basal area 12,9% dan biomasa 11,6%. Penambahan kepadatan tercatat meningkat dari 357 menjadi 411 pohon/ha. Basal area meningkat mulai dari 20,09 menjadi 22,67 m2 ha-1, sedangkan biomasa meningkat dari 286,3 menjadi 319,4 ton ha-1.Kata kunci: Komposisi, spesies, biomas, hutan terganggu
THE DYNAMICS OF SPECIES COMPOSITION STAND STRUCTURE AND ABOVE GROUND BIOMASS OF UNDISTURBED FOREST IN EAST KALIMANTAN Krisnawati, Haruni; Wahjono, Djoko; Imanuddin, Rinaldi
JURNAL BIOLOGI INDONESIA Vol 8, No 1 (2012): JURNAL BIOLOGI INDONESIA
Publisher : Perhimpunan Biologi Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jbi.v8i1.3062

Abstract

Dinamika Komposisi Spesies Struktur Pohon dan Biomasa di Hutan Terganggu di Kalimantan Timur. Kajian dinamika komposisi spesies dan biomasanya dilakukan selama 4,3 tahun (Desember 2004 - April 2009) di hutan terganggu Kalimantan Timur. Untuk melakukan kajian di gunakan 6 plot permanen (100x100 m2), yang berada di hutan penelitian Samboja. Semua pohon berdiameter > 10 cm dbh (diukur pada posisi 1,3 m diatas tanah). Pada Desember 2004,tercatat 2143 pohon tersebar di plot tersebut terdiri dari 39 famili, 82 genus dan 111 spesies. Pada pengamatan April 2009 tercatat 2466 pohon terdiri dari 40 famili, 86 genus dan 123 jenis.Sebagian besar spesies yang mendominasi adalah Garcinia nervosa dan Trigonostemon laevigatus tetapi setelah pengamatan pada tahun 2009, keduanya tidak lagi mendominasi. Selama kurun 4,3 tahun terjadi penambahan kepadatan 15,1%, basal area 12,9% dan biomasa 11,6%. Penambahan kepadatan tercatat meningkat dari 357 menjadi 411 pohon/ha. Basal area meningkat mulai dari 20,09 menjadi 22,67 m2 ha-1, sedangkan biomasa meningkat dari 286,3 menjadi 319,4 ton ha-1.Kata kunci: Komposisi, spesies, biomas, hutan terganggu
A COMPATIBLE ESTIMATION MODEL OF STEM VOLUME AND TAPER FOR Acacia mangium Willd. PLANTATIONS Krisnawati, Haruni
Indonesian Journal of Forestry Research Vol. 3 No. 1 (2016): 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.2016.3.1.49-64

Abstract

This study describes the establishment of a compatible volume estimation model for Acacia mangium Willd on the basis of 279 felled sample trees collected from the A. mangium plantation stands in South Sumatra, Indonesia. The model comprises of a total volume model and a stem taper model, which is compatible in the sense of the total volume obtained by integration of the taper model being equal to that computed by the total volume model. Several well-known total volume functions were evaluated including constant form factor, combined variable, generalized combine variable, logarithmic, generalized logarithmic and Honer transformed variables. A logarithmic model was determined to be the best and was then used as the basis for deriving the taper model. Appropriate statistical procedures were used in model fitting to account for the problems of heteroscedasticity and autocorrelation that are associated with the construction of volume and taper functions. The simultaneous fitting method of the Seemingly Unrelated Regression (SUR) improved the parameter estimates and goodness-of-fit statistics while ensuring numeric consistency among the component models and reducing the total squared error obtained by an independent fitting method. The developed model can be used to estimate total stem volume, merchantable volume to any merchantability diameter limit at any height, and (possibly) height of any diameter based on only easily measurable parameters such as diameter at breast height and total tree height for the species analysed.
Modelling Natural Mortality of Tropical Plantation Species Acacia mangium Willd Krisnawati, Haruni
BIOTROPIA Vol. 25 No. 3 (2018): BIOTROPIA Vol. 25 No. 3 December 2018
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (289.558 KB) | DOI: 10.11598/btb.2018.25.3.835

Abstract

Natural mortality of trees is extremely variable due to the uncertainty and complexity of the functioning of forest ecosystems. The objective of this study was to develop a stand-level mortality model for Acacia mangium species by relating mortality to stand variables that affect the natural mortality process. The model was developed using data from l97 permanent sample plots measured periodically at 1-yr time intervals from 2-4 years until 8-11 years after planting in South Sumatra, Indonesia. The model consists of two complementary equations. The first equation is a logistic function predicting the probability of mortality incidence depending on stand density, site index and stand age. The second equation estimates the reduction in the number of surviving stems observed in a stand where natural mortality occurs. Nine equations were fitted using data from permanent sample plots where trees died over the time period and the best model was selected. Estimates from this second model were then adjusted by a factor equal to the probability of mortality applying three different approaches: probabilistic two-step, deterministic threshold and stochastic. All methods revealed no significant difference between the observed and the predicted number of surviving stems per ha. The probabilistic two-step approach, however, produced more consistent and the most accurate estimates. This method should provide reliable prediction when it is to be used in forest productivity prediction and management system for the species.