Allometric model to estimate biomass of leave-twigs cajuput (Melaleuca cajuput) at KPH Yogyakarta, Indonesia

Abstract

Estimation of carbon storage in plantations is an alternative strategy to mitigate climate change. The carbon storage estimation model was developed by building a biomass allometric model with specific predictors. Utilization of cajuput plantations is harvesting the leave-twigs, which is different from the utilization of commons plantation forests that emphasize on timber forest products. Therefore, the objective of the research was to develop an allometric model of cajuput leave-twigs biomass. The study was conducted in KPH Yogyakarta on cajuput plants aged 23, 27, 31, 33, 40, 41, and 43 years. 210 samples were used to develop allometric models, and 60 samples were used as model validation materials. Leave-twigs biomass of cajuput (Y) was estimated with the predictors of the canopy height of cajuput (X1), mean quadratic of canopy diameter (X2), and mean quadratic of stem diameter (X3). The results showed that the allometric model of leave-twigs biomass of cajuput was Y = 3,597X1 0.961X2 0.145X3 0.247. The results of the model validation test resulted in R2 adj value of 0.428; the aggregate deviation was 9.76%; the mean deviation was 0.50%; the bias was - 2.16%, and RMSE was 0.47%. The allometric model was less accurate in predicting leave-twigs biomass of cajuput with the predictors of canopy height, canopy diameter, and stem diameter. Furthermore, it is important to build an allometric model of leave-twigs biomass by adding other predictors.

Allometric model to estimate biomass and carbon of seedling in Pangarengan mangrove forest, Cirebon, West Java

“…Model alometrik yang dikembangkan dalam pendugaan biomassa dan karbon untuk jenis-jenis tumbuhan di Indonesia telah dilakukan pada pohon dengan batang tunggal (single stem) (Kuswandi, 2016;Qirom, 2018;Qirom & Supriyadi, 2012Samsoedin, Sukiman, Wardani, & Heriyanto, 2016;Siswanto & Imanuddin, 2008), dan jenis tumbuhan batang majemuk (multi stem) (Mulyana, Budi, Soeprijadi, dan Purwanto, 2020). Selain itu, pendugaan biomassa dan batang pohon dengan menggunakan model alometrik juga diterapkan pada pendugaan biomassa dan karbon bambu (Sujarwo, 2016), dan rantingdaun kayu putih (Mulyana et al, 2021). Namun, pendugaan biomassa dan karbon pada tingkat pertumbuhan semai masih jarang dilakukan.…”

“…di Kanada (Jego et al, 2017) dilakukan pengukuran pada ketinggian 30 cm diatas permukaan tanah. Selain itu, penelitian Mulyana et al, (2021) dalam pendugaan biomassa ranting-daun kayu putih menggunakan prediktor diameter batang pada bagian pangkal dan ujung.…”

“…Pemilihan model alometrik yang baik berdasarkan pada nilai koefisien determinasi (R 2 adj) yang paling besar dan nilai error (SEE) yang paling kecil (Badan Standarisasi Nasional, 2011b). Kriteria pemilihan model alometrik berdasarkan pada nilai koefisien determinasi yang paling tinggi dan nilai error yang paling kecil juga digunakan dalam penyusunan model alometrik penduga biomassa berat basah pohon Gliricidia (Mulyana et al, 2020) dan model alometrik penduga biomassa berat basah ranting daun kayu putih (Mulyana et al, 2021).…”