Measurement error causes bias in site index equations

Goelz, J.C.G.; Burk, Tammie

doi:10.1139/x26-178

Cited by 53 publications

(36 citation statements)

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“…All the parameters were found to be significant at a 5% level when the expansion factor proposed by [29] was applied.…”

Section: Resultsmentioning

confidence: 99%

“…In this case, autocorrelation was modelled by expanding the error term in the following way [28,29,45]:…”

Section: Data Structure and Model Fittingmentioning

confidence: 99%

“…Thus, the standard errors were expanded by , where n(apd) is the number of observations using all possible differences and n(fd) is the number of observations if using only first differences [29].…”

Section: Data Structure and Model Fittingmentioning

confidence: 99%

“…This method of proceeding simultaneously optimizes the regression of H on A and A on H, and avoids parameter bias due to independent estimation of (1) site index at base age given height at some other age, and (2) height at some desired age given height (site index) at base age [28,29,45].…”

Section: Data Structure and Model Fittingmentioning

confidence: 99%

“…For timber production purposes, and especially for even-aged forest stands, site quality is commonly expressed as a species-specific site index [14,21]. Site index may be defined as height, at a predetermined age, of dominant or codominant trees that have always been dominant or codominant and healthy [29]. Empirical evidence from thinning experiments indicates that for many commercially important species, height growth is not greatly affected by the manipulation of stand density.…”

Section: Introductionmentioning

confidence: 99%

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Site quality equations for Pinus sylvestris L. plantations in Galicia (northwestern Spain)

et al. 2005

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-Difference equations derived on the basis of the Sloboda and McDill-Amateis differential functions, and from the integral form of the Bertalanffy-Richards, Korf and Hossfeld growth functions were used to model the dominant height growth of Scots pine (Pinus sylvestris L.) in Galicia (north-western Spain). Data from stem analysis and permanent sample plots were combined and used for fitting. Both numerical and graphical analyses were used to compare alternative models. The cross-validation approach was used to analyse the predictive ability of the models. The algebraic difference form of the differential function proposed by McDill and Amateis resulted in the best compromise between biological and statistical aspects, producing the most adequate site curves. It is therefore recommended for height growth prediction and site classification of Scots pine plantations in Galicia. This equation is base-age invariant, so any number of points (A 1 , H 1 ) on a specific site curve can be used to make predictions for a given age A 2 and the predicted height H 2 will always be the same.height growth / site classification / algebraic difference equation / even-aged forest stand Résumé -Équations prédictives de la fertilité des stations pour des plantations de Pinus sylvestris L. en Galice (nord-ouest de l'Espagne). À partir des équations différentielles de Sloboda et McDill-Amateis, ainsi que de la forme intégrale de Bertalanffy-Richards, Korf et Hossfeld, un modèle a été établi pour caractériser la croissance en hauteur dominante du pin sylvestre (Pinus sylvestris L.) en Galice (nordest de l'Espagne). Des données, issues à la fois de l'analyse de tiges et de l'accroissement de placettes semi-permanentes, ont été combinées pour établir ce modèle. Des analyses numériques et graphiques ont été utilisées pour comparer les différents modèles existants. Les résidus de la validation croisée ont été utilisés pour évaluer le comportement des équations. L'équation en différences algébriques obtenue à partir de la fonction différentielle de McDill et Amateis donna le meilleur compromis entre les aspects biologique et statistique, fournissant les courbes de qualité les plus adéquates. C'est donc l'équation recommandée pour prédire la croissance en hauteur et pour réaliser les classifications de qualité des sites de plantation des pins sylvestres en Galice. Cette équation est invariante quant à l'âge de référence, de sorte que la hauteur à un âge donné peut être estimée à partir de la hauteur à un autre âge, sans compromettre la validité des prédictions. croissance en hauteur / classement des sites / équation en différence algébrique / peuplement équienne

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“…All the parameters were found to be significant at a 5% level when the expansion factor proposed by [29] was applied.…”

Section: Resultsmentioning

confidence: 99%

“…In this case, autocorrelation was modelled by expanding the error term in the following way [28,29,45]:…”

Section: Data Structure and Model Fittingmentioning

confidence: 99%

Section: Data Structure and Model Fittingmentioning

confidence: 99%

Section: Data Structure and Model Fittingmentioning

confidence: 99%

Section: Introductionmentioning