Volumetry and alpha bisabolol percentage for the candeia Eremanthus erithropappus / Volumetria e teor de alfa bisabolol para a candeia Eremanthus erythropappus

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

This study aimed at fitting and select mathematical models for estimation of the total volume, with and without bark, number of fence posts, dry weight and oil yield for candeia trees (Eremanthus erithropappus) in three counties of Minas Gerais state as well as to define the stack factor per diameter class, the wood and bark basic density behavior, and the oil quality of each studied region. Data base were obtained from a scaling of 174 trees grouped in six diameter classes within the three study regions. The scaling was carried out using the xylometer method (water displacement technique). In order to determine the wood basic density and percentage of bark discs from 0%, 25%, 50%, 75% and 100% of the commercial height were collected. In addition, the quantity and the quality of the oil extracted by means of the steam distillation method were evaluated. Twelve models were fitted for estimation of the total volume, with and without bark, number of fence posts, dry weight and oil yield. The accuracy of the models was evaluated using the following statistics: coefficient of determination, mean standard deviation, and graphical residual analysis. The method developed by Graybill (1976) was used to test whether the same model could be used in the three studied regions. The Spurr logarithm model was selected as the best one for all tested variables, the stack factors were 1.44 for Delfim Moreira county, 1.50 for Aiuroca county and 1.93 for Ouro Preto county. The wood basic density and bark density were respectively 0.63 and 0.44 g/cm3 for Delfim Moreira, 0.64 and 0.41 g/cm3 for Aiuroca, and 0.68 and 0.49 for Ouro Preto. Considering the variables total volume, with and without bark, number of fence posts, and dry weight the Graybill test showed the possibility of using the same model for all regions whereas for the oil yield variable the Graybill test showed that there is no possibility of grouping. The average values for oil yield and oil quality (percentage of α-bisabolol) were respectively 1.62% and 88.73% for Delfim Moreira, 1.12% and 88.92% for Aiuroca, and 1.80% and 87.80% for Ouro Preto.

ASSUNTO(S)

candeia candeia Ãleo essencial recursos florestais e engenharia florestal stack factor fator de empilhamento graybill test essential oils model fitting alfa bisabolol identidade de modelos alpha bisabolol ajuste de modelos

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