Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/9050
Título: Field sampling of cork value before extraction in Portuguese "montados"
Autor: Almeida, Alice M.
Tomé, Margarida
Palavras-chave: cork oak
cork value
cork quality
cork thickness
single-stage cluster sampling
intracluster correlation coefficient
Data: 2010
Editora: Springer
Citação: "Agroforestry Systems". ISSN0167-4366. 79 (2010) 419-430
Resumo: The assessment of cork quality and the estimation of cork value are very important to forest landowners, for management purposes and for cork commercialisation. The Forest Producers Associations have been using a sampling scheme with the objective of estimating cork value (price per unit of weight, usually kg) before extraction, based on the sampling of individual trees along a zigzag transect that covers the entire stand. The sampling error is usually too high, but, from a practical standpoint, it is difficult to increase the sampling intensity if it would imply an increase in sampling costs. The aim of this work was to propose, from data collected in six stands representative of the cork oak stands in Portugal, an alternative sampling methodology with a more efficient precision/ cost ratio. Precision and costs of alternative sampling designs based on clusters of different sizes, complemented with analysis of the intracluster correlation coefficient, were studied in order to propose the most adequate sampling strategy. Single-stage cluster sampling with clusters of 5–7 trees guarantees a reasonable sampling error (10–15%) and can be conducted without a large increase in cost
Peer review: yes
URI: http://hdl.handle.net/10400.5/9050
DOI: 10.1007/s10457-009-9260-8
Aparece nas colecções:CEF - Artigos de Revistas

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