Volume 34, Issue 4, November 2021, Pages 734–744
Samuel Severin Kenfack Feukeng1, Olivier Clovis Kengne2, Junior Baudoin Wouokoue Taffo3, Vivien Rossi4, Roland Nnomo Douanla5, Victor François Nguetsop6, and Louis Zapfack7
1 Department of Plant Biology, University of Dschang, P.O. Box: 67 Dschang, Cameroon
2 Department of Life and Earth Sciences, University of Maroua, P.O. Box 55 Maroua, Cameroon
3 Département des Sciences Biologiques, Faculté des Sciences, Université de Maroua, BP 814 Maroua, Cameroon
4 RU Forests and Societies, CIRAD, P.O. Box: 2572 Yaounde, Cameroon
5 Department of Plant Biology, University of Dschang, P.O. Box: 67 Dschang, Cameroon
6 Department of Plant Biology, University of Dschang, P.O. Box: 67 Dschang, Cameroon
7 Department of Plant Biology, University of Yaounde I, P.O. Box: 812 Yaoundé, Cameroon
Original language: English
Copyright © 2021 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The search for accuracy on biomass estimation is growing significantly, however density measurements are still essential to reduce bias in biomass estimations. The objective of this research was to: (1) test longitudinal and radial variations in wood density of Distemonanthus benthamianus, Musanga cecropioides and Trema orientalis. (2) Fitting mixed models of secondary forests pioneer species. Data for density determinations and fitting allometric equations were obtained by destructive method, on a sample of 115 trees. Archimedes' principle applied to the biomass data yielded the average densities of the three respective species (0.726; 0.214 and 0.35 in g.cm-3). This variable associated with tree height, crown diameter and diameter at breast height were used to explain tree biomass through ten fitted mixed models. The model, Aboveground biomass = Exp (-0.85 + 2.19 x ln (DBH) + 1.1 x ln (φ)), with a low Akaike Information Criterion (AIC = 78.76), the high correlation coefficient (Adjusted.R2 = 96.4%), the low rate of residual standard error (RSE = 0.33) and the Relative Root Mean Square Error (RRMSE = 0.39), was selected as the best mixed model. The full model (Aboveground biomass = Exp (-0.84 + 0.63 x ln (DBH2 x H) + 0.85 x ln (φ) + 0.54 x ln (C)) under the validation criteria was found to be efficient (adjusted R2 = 0.96; RRMSE = 0.41; average error = 15,95). However, density variations must be considered to reduce bias in the estimation. In addition, increased collection of large amounts of secondary forest data remains essential for fitting more robust mixed models.
Author Keywords: allometric equations, pioneer species, secondary forests, biomass, wood density.
Samuel Severin Kenfack Feukeng1, Olivier Clovis Kengne2, Junior Baudoin Wouokoue Taffo3, Vivien Rossi4, Roland Nnomo Douanla5, Victor François Nguetsop6, and Louis Zapfack7
1 Department of Plant Biology, University of Dschang, P.O. Box: 67 Dschang, Cameroon
2 Department of Life and Earth Sciences, University of Maroua, P.O. Box 55 Maroua, Cameroon
3 Département des Sciences Biologiques, Faculté des Sciences, Université de Maroua, BP 814 Maroua, Cameroon
4 RU Forests and Societies, CIRAD, P.O. Box: 2572 Yaounde, Cameroon
5 Department of Plant Biology, University of Dschang, P.O. Box: 67 Dschang, Cameroon
6 Department of Plant Biology, University of Dschang, P.O. Box: 67 Dschang, Cameroon
7 Department of Plant Biology, University of Yaounde I, P.O. Box: 812 Yaoundé, Cameroon
Original language: English
Copyright © 2021 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The search for accuracy on biomass estimation is growing significantly, however density measurements are still essential to reduce bias in biomass estimations. The objective of this research was to: (1) test longitudinal and radial variations in wood density of Distemonanthus benthamianus, Musanga cecropioides and Trema orientalis. (2) Fitting mixed models of secondary forests pioneer species. Data for density determinations and fitting allometric equations were obtained by destructive method, on a sample of 115 trees. Archimedes' principle applied to the biomass data yielded the average densities of the three respective species (0.726; 0.214 and 0.35 in g.cm-3). This variable associated with tree height, crown diameter and diameter at breast height were used to explain tree biomass through ten fitted mixed models. The model, Aboveground biomass = Exp (-0.85 + 2.19 x ln (DBH) + 1.1 x ln (φ)), with a low Akaike Information Criterion (AIC = 78.76), the high correlation coefficient (Adjusted.R2 = 96.4%), the low rate of residual standard error (RSE = 0.33) and the Relative Root Mean Square Error (RRMSE = 0.39), was selected as the best mixed model. The full model (Aboveground biomass = Exp (-0.84 + 0.63 x ln (DBH2 x H) + 0.85 x ln (φ) + 0.54 x ln (C)) under the validation criteria was found to be efficient (adjusted R2 = 0.96; RRMSE = 0.41; average error = 15,95). However, density variations must be considered to reduce bias in the estimation. In addition, increased collection of large amounts of secondary forest data remains essential for fitting more robust mixed models.
Author Keywords: allometric equations, pioneer species, secondary forests, biomass, wood density.
How to Cite this Article
Samuel Severin Kenfack Feukeng, Olivier Clovis Kengne, Junior Baudoin Wouokoue Taffo, Vivien Rossi, Roland Nnomo Douanla, Victor François Nguetsop, and Louis Zapfack, “Radial and longitudinal variation of wood density and mixed equations for estimating biomass of pioneer species in secondary forests,” International Journal of Innovation and Applied Studies, vol. 34, no. 4, pp. 734–744, November 2021.
