TWO METHODS FOR TREE VOLUME ESTIMATION OF Acacia melanoxylon IN PORTUGAL

Rucha, Andreia; Santos, A.; Campos, José; Anjos, O.; Tavares, Mário

doi:10.5380/rf.v41i1.21200

Cited by 4 publications

(4 citation statements)

References 4 publications

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“…If RK is ≤ 1, the fibre is good for pulp and paper production, if RK < 1, the fibre is highly appropriate for pulp and paper production, from 1 to 2 is regular, and above 2 it may not be used for paper. Almost all RK values of earlywood that corresponds to the highest proportion of acacia wood, (Rucha et al, 2011) were lower than 1 (Figure 4) suggesting a good potential for pulp and paper. This was shown in previously work of this research group (Santos el al., 2006(Santos el al., , 2012Anjos et al, 2011).The latewood presented higher RK values, but almost all were lower than 2 (regular use for pulp and paper).…”

Section: A B Cmentioning

confidence: 97%

Characterization and within-tree variation of wood anatomy of Acacia melanoxylon

Santos¹,

Pereira²,

Anjos³

2018

mill

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Section: A B Cmentioning

confidence: 97%

Characterization and within-tree variation of wood anatomy of Acacia melanoxylon

Santos¹,

Pereira²,

Anjos³

2018

mill

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“…Therefore, this type of sampling strategy is not recommended, mainly in class widths larger than 4.0 cm. Evidently, these statements are done for young trees and the researches are needed to assess older stands, since age affects strongly tree volume relationship (RUCHA et al, 2010).…”

Section: Main Highlights Of the Tree Sampling Strategiesmentioning

confidence: 99%

Strategies for Stem Measurement Sampling: A Statistical Approach of Modelling Individual Tree Volume

David

Miranda

Welker³

et al. 2016

CERNE

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ABSTRACT:The aim of this paper was to evaluate different criteria for stem measurement sampling and to identify the criterion with best performance for developing individual tree volume equations. Data were collected in eucalyptus stands 58 to 65 months old. Schumacher-Hall model was applied using five sampling criteria with nine variations (45 in total): 1) number of trees per diameter class, being (a) fixed number, (b) proportional to the diameter class of the sample, or (c) proportional to the standard deviation of the sample; and 2) the width of the diameter class, which ranged from 1.0 up to 5.0 cm. We used the equations generated from each of the five sampling criteria to estimate stem volume of trees reserved for validation. This allowed us to obtain standard errors of estimates from this data-set. In addition, residuals of volume estimates were examined by means of statistical tests of bias, autocorrelation and heteroscedasticity. Better performances of volume equations occurred when smaller diameter class widths were used, i.e., when the sample size increased. There was no clear trend in increasing/decreasing residual autocorrelation and/or heteroscedasticity. Both methods of sampling proportional to the frequency of diameter class had the best performances, inclusive using only 36 trees. The ones where choice of trees was proportional to the standard deviation had the worst. In conclusion, the selection proportional to the frequency of the diameter class, under the condition that at least two trees per class are sampled, provides models statistically better than all the other criteria. ESTRATÉGIAS DE AMOSTRAGEM DE FUSTES PARA MEDIÇÃO:UMA ABORDAGEM ESTATÍSTICA DA MODELAGEM DO VOLUME DE ÁRVORE INDIVIDUAL RESUMO: O objetivo deste trabalho foi avaliar diferentes critérios para amostragem de fustes para medição e identificar o critério mais adequado para a modelagem do volume de árvore individual. Os dados foram coletados em povoamentos de eucalipto com idade entre 58 e 65 meses. O modelo de Schumacher-Hall foi aplicado em cinco critérios de amostragem, com nove variações (45 no total): 1) número de árvores por classe diamétrica, sendo (a) número fixo, (b) proporcional à distribuição do diâmetro amostral, ou (c) proporcional ao desvio padrão da amostra; 2) tamanho da amplitude da classe diamétrica, que variou de 1,0 a 5,0 cm. As equações geradas em cada critério foram usadas para estimar o volume de fuste de árvores reservadas para validação. Isso permitiu calcular erros padrões da estimativa para esse conjunto de dados. Além disso, os resíduos das estimativas de volume foram examinados por meio de testes estatísticos para viés, autocorrelação e heteroscedasticidade. Os resultados mostraram melhores performances de equações de volume usando menores amplitudes. Não houve uma clara tendência em aumentar/reduzir a autocorrelação e/ou heteroscedasticidade dos resíduos. Aquelas amostragens com proporção à frequência da classe diamétrica apresentaram as melhores performances, inclusive usando apenas 36 árvores. A...

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“…Conical sections for 0%-5%, 5%-15%, 15%-35%, 35%-65% and 65%-top were considered. The sapwood volume was calculated by the difference of heartwood with respect to total wood, according Rucha et al [24].…”

Section: Datasetmentioning

confidence: 99%

Influence of Heartwood on Wood Density and Pulp Properties Explained by Machine Learning Techniques

Iglesias

Santos

Martínez

et al. 2017

Forests

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Abstract:The aim of this work is to develop a tool to predict some pulp properties e.g., pulp yield, Kappa number, ISO brightness (ISO 2470(ISO :2008, fiber length and fiber width, using the sapwood and heartwood proportion in the raw-material. For this purpose, Acacia melanoxylon trees were collected from four sites in Portugal. Percentage of sapwood and heartwood, area and the stem eccentricity (in N-S and E-W directions) were measured on transversal stem sections of A. melanoxylon R. Br. The relative position of the samples with respect to the total tree height was also considered as an input variable. Different configurations were tested until the maximum correlation coefficient was achieved. A classical mathematical technique (multiple linear regression) and machine learning methods (classification and regression trees, multi-layer perceptron and support vector machines) were tested. Classification and regression trees (CART) was the most accurate model for the prediction of pulp ISO brightness (R = 0.85). The other parameters could be predicted with fair results (R = 0.64-0.75) by CART. Hence, the proportion of heartwood and sapwood is a relevant parameter for pulping and pulp properties, and should be taken as a quality trait when assessing a pulpwood resource.

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TWO METHODS FOR TREE VOLUME ESTIMATION OF Acacia melanoxylon IN PORTUGAL

Cited by 4 publications

References 4 publications

Characterization and within-tree variation of wood anatomy of Acacia melanoxylon

Characterization and within-tree variation of wood anatomy of Acacia melanoxylon

Strategies for Stem Measurement Sampling: A Statistical Approach of Modelling Individual Tree Volume

Influence of Heartwood on Wood Density and Pulp Properties Explained by Machine Learning Techniques

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