Buscar

 

RI UFLA (Universidade Federal de Lavras) >
Revistas UFLA >
CERNE >

Por favor, utilize esse identificador para citar este item ou usar como link: http://repositorio.ufla.br/jspui/handle/1/14711

Título: STRATEGIES FOR STEM MEASUREMENT SAMPLING: A STATISTICAL APPROACH OF MODELLING INDIVIDUAL TREE VOLUME
Autor(es): David, Hassan Camil
Miranda, Rodrigo Otávio Veiga
Welker, John
Fiorentin, Luan Demarco
Ebling, Ângelo Augusto
Silva, Pedro Henrique Belavenutti Martins da
Assunto: Proportional sampling, Even-frequency sampling, Diameter distribution, Accuracy of volume equations, Examination of residuals
Publicador: CERNE
CERNE
Publicação: 7-Out-2016
Outras Identificações: http://www.cerne.ufla.br/site/index.php/CERNE/article/view/1313
Informações adicionais: 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.
Idioma: eng
Aparece nas coleções: CERNE

Arquivos neste Item:

Não há arquivos associados para este Item.

Itens protegidos por copyright, com todos os direitos reservados, Salvo indicação em contrário.


Mostrar estatísticas

 


DSpace Software Copyright © 2002-2007 MIT and Hewlett-Packard - Feedback