Construction of site index equations for Pinus sylvestris L. using permanent plot data in Sweden

-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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“…For model M7, the parameter Asi was ranged from 5 to 50 years in order to reduce the mean square error [23,54].…”

Section: Data Structure and Model Fittingmentioning

confidence: 99%

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

et al. 2005

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“…Researchers often test several models and choose the best one based on fit statistics such as the R 2 and mean squared error. Usually, though, the models have such similar fit statistics that in practical terms any of the tested models would suffice [3,4,8,33]. Therefore, I chose the log-logistic model because it was used successfully in the past for other species [3,19,33], and because of its properties [20].…”

Section: Methodsmentioning

confidence: 99%

A comparison of fitting techniques for ponderosa pine height-age models in British Columbia

Nigh

2004

Ann. For. Sci.

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-The ponderosa pine height models currently in use in British Columbia, Canada, were calibrated for southwest Oregon, USA. Height growth patterns in British Columbia may be different from those in Oregon. Furthermore, they may be different between biogeoclimatic zones within British Columbia. To check this, 80 stem analysis plots were established to develop a new ponderosa pine height model. One tree in each 0.01 ha plot was intensively sampled to obtain annual heights from the pith nodes. A conditioned log-logistic function was used as the base height model. Various model fitting procedures were employed to meet assumptions about the data and the regressions. These procedures included using an autoregressive model to account for serial correlation, and using nonlinear mixed modelling so that site index could be treated as having a random component. The final version of the model tested for differences in height growth patterns across the four biogeoclimatic zones where ponderosa pine most often grows. Although growth differences between the zones were detected, the results may be uncertain due to small differences in height growth trajectories and small sample sizes for some zones. A new height model for ponderosa pine is now available for British Columbia. This model gives only slightly different height estimates from the current models, so the use of the previous model in the past has not led to poor forest management decisions.height model / mixed effects model / nonlinear regression / site index / yellow pine Résumé -Modèle de croissance en hauteur pour le pin ponderosa en Colombie-Britannique. Les modèles de croissance en hauteur pour le pin ponderosa actuellement en vigueur en Colombie-Britannique ont été mis au point pour le sud-ouest de l'Orégon. Les modèles de croissance en hauteur en Colombie-Britannique peuvent différer toutefois de ceux que l'on retrouve en Orégon. De plus, ils peuvent différer d'une zone biogéoclimatique à une autre à l'intérieur de la Colombie-Britannique. Afin de vérifier ceci, 80 placettes d'analyse de tige ont été réalisées afin de mettre au point un nouveau modèle de croissance en hauteur pour le pin ponderosa. Un arbre par placette de 0,01 ha a été échantillonné de façon détaillée dans le but d'obtenir les valeurs annuelles de hauteur à partir des verticilles. Une fonction logistique logarithmique a été adaptée et utilisée comme base du modèle de hauteur. Plusieurs procédures d'ajustement ont été utilisées afin de satisfaire les hypothèses concernant les données et les régressions. Ces procédures concernent l'utilisation d'un modèle d'autorégression afin de tenir compte de la corrélation en série ainsi que l'utilisation d'un modèle nonlinéaire mixte de façon à ce que l'indice de fertilité de station soit examiné en supposant la présence d'une composante aléatoire. La version finale du modèle a été testée pour des différences entre les modèles de croissance selon les quatre zones biogéoclimatiques où l'on retrouve plus fréquemment le pin ponderosa. Bien que des différ...

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“…In developing site index prediction systems, some desirable characteristics of site index models are polymorphism, multiple horizontal asymptote, one inflection point, and base-age invariance (ELFVING; KIVISTE, 1997;CIESZEWSKI;BAILEY, 2000). indicated for site classifi cation, but the polymorphic equation derived by the GADA approach from LundqvistKorf function (LG) resulted in a more adequate model for prediction of dominant height.…”

Section: Figurementioning

confidence: 99%

Site Quality Curves for African Mahogany Plantations in Brazil

Ribeiro

Filho

Tomé

et al. 2016

CERNE

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Site quality estimation is an important tool in forest management since it is useful for modeling growth and yield for even-aged stands. Data from African mahogany (Khaya ivorensis A. Chev.) Brazilian plantations were used to develop a model to predict dominant height growth, comparing dynamic base-age invariant site index models with the guide curve method (static models). For the evaluation of the candidate models qualitative and quantitative criteria were used. We also verified the stability of the candidate models, preferring a model providing fewer site class changes when predicting site index from different ages. The Lundqvist-Korf function fitted with the guide curve method proved to be effective and accurate for site classification and dominant height predictions of African mahogany stands. The range of observed site index, at a reference age of 15, was between 17 and 33 meters. CURVAS DE CLASSIFICAÇÃO DE SÍTIO PARA PLANTIOS DE MOGNO AFRICANO NO BRASIL RESUMO:A estimativa da qualidade de sítio é uma importante ferramenta para o manejo florestal, uma vez que auxilia na modelagem do crescimento e produção de florestas equiâneas. Dados de plantios brasileiros de mogno africano (Khaya ivorensis A. Chev.) foram utilizados para avaliar modelos de crescimento em altura dominante comparando modelos dinâmicos invariantes com a idade padrão e modelos estáticos (método da curva guia). Para a avaliação dos modelos foram utilizados critérios quantitativos e qualitativos. Também foi verificada a estabilidade dos modelos candidatos, sendo preferido o modelo que resultou em menos mudanças de classes na predição da mesma parcela em diferentes idades. O modelo de Lundqvist-Korf com o método da curva guia se mostrou eficiente, sendo recomendado para a classificação de sítios e para a predição de altura dominante em povoamentos de mogno africano. A amplitude dos índices de sítio, na idade de referência de 15 anos, foi de 17 a 33 metros.

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Construction of site index equations for Pinus sylvestris L. using permanent plot data in Sweden

Cited by 122 publications

References 7 publications

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

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

A comparison of fitting techniques for ponderosa pine height-age models in British Columbia

Site Quality Curves for African Mahogany Plantations in Brazil

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