Critical analyses when modeling tree biomass to ensure additivity of its components

Abstract

It is presented the theme additivity of biomass of tree components. To evaluate and discuss this context, experimental information collected in forests of Acacia mearnsii De Wild. was used. Equations for components (stem and crown) and total biomass were fitted by means of two procedures: 1) generalized nonlinear least squares and 2) weighted-nonlinear seemingly unrelated regressions. Analyzing the performance of the estimators, it can be concluded that the two tested procedures are equivalent. On the other hand, this conclusion differs when evaluated the consistency and efficiency of the estimators. Fitting equations for the components and for the total biomass by an independent way is not realistic, because from a biological point of view the estimates of biomass are inconsistent, i.e., are not additive. The biomass estimates of the components and of the total, resulting from equations adjusted by means of systems of equations, provided narrower confidence intervals in relation to the equations adjusted independently, and is therefore more efficient. The second procedure presents better biological properties and statistics to estimate allometric equations for biomass of the components and for the total when compared with the independent estimation, thus it should be the method to be used.

Modelagem Volumétrica De Árvores De Acácia-Negra Em Povoamentos De Regiões Do Rio Grande Do Sul

“…Normalmente, as estimativas do número de árvores, área basal e volume de árvores são obtidas por unidade de área, a partir da idade (WOLFF II et al, 2019). Como forma de obter uma função genérica que estime volume para diferentes condições, têm-se empregado modelos que consideram outras variáveis dendrométricas, como a idade (LEITE et al, 2006;BEHLING et al, 2018;MARTINS et al, 2019). Os autores também descrevem diferenças significativas entre tratamentos com idades diferenciadas.…”

“…Os dados de volume foram agrupados de acordo com fases de crescimento apresentados por Behling et al (2018) Média Avançada 9,83 Madura O volume alocado na árvore varia de acordo com a idade do povoamento, ou seja, tendências de indivíduos com dimensões e volumes maiores em idades superiores são comumente observadas (COLPINI et al, 2009;SANQUETTA et al, 2014;SANQUETTA et al, 2015a). Segundo Behling et al (2018), a amplitude dos estratos não deve incluir tamanhos de amplitude maior que dois anos, visto que, dessa maneira, não seria evidenciados os efeitos das taxas de crescimento.…”

“…Os modelos propostos por Hohenadl-Krenn, Kopesky-Gehrardt, Spurr, Schumacher-Hall (não linearizado), Spurr (não-linearizado); State (Austrália) e Meyer são bastante comuns na área florestal utilizados em diversos trabalhos como os de: Behling et al (2018), Gonzáles et al (2018), Lanzarin et al (2018) e Martins et al, (2019). Segundo Andrade et al (2019) dentre os 40 trabalhos, sobre modelos volumétricos, analisados em sua pesquisa, observou-se que os dez mais usuais são: Spurr (65%), Schumacher-Hall logarítmico (55%), Spurr logarítmico (45%), Stoate e Kopezky-Gehrhardt (35%), Naslung e Husch (30%), Hohenadl-Krenn (27%), Brenac (22,5%) e Schumacher-Hall (20%).…”

Additivity of tree biomass components using ratio estimate

“…For the group one, the equations were adjusted through seemingly unrelated regressions and for the other groups using weighted-nonlinear seemingly unrelated regressions (WNSUR). The equations and procedures used for the fitting are detailed in Behling et al (2018). SYLVIO PÉLLICO NETTO AND ALEXANDRE BEHLING BIOMASS MODELLING AND RATIO ESTIMATE…”

INDEPENDENT AND SIMULTANEOUS MODELING OF BIOMASS AND CARBON OF Guinean Elaeis

“…This presupposes that the equations for the components of biomass and total biomass must be estimated together, in other words, a simultaneous estimation, considering the principle of additivity of Kozak (1970). Moreover, Behling et al (2018), in studies with black wattle biomass, found the advantage of not having distortions between the sum of the equations for each compartment and the equation for the total when applied to the simultaneous adjustment technique because it guarantees the overall quality of the prediction of the biomass for the compartments and also for the total.…”