Site quality curves for birch stands in north-western Spain

Diéguez-Aranda, Ulises; Grandas-Arias, José Antonio; Álvarez‐González, Juan Gabriél; Gadow, Klaus von

doi:10.14214/sf.319

Cited by 52 publications

(37 citation statements)

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“…); for this they need tools for evaluating different management practices and their effects on stand structure. Development of a growth models for the species (Rojo et al, 2005;Diéguez-Aranda et al, 2006) enables promotion of the productive and protective aspects of birch stands in northwest Spain. Diameter class models allow prediction of stand growth and planning of various uses and provide data about stand structure.…”

Section: Introductionmentioning

confidence: 99%

Modelling diameter distributions of Betula alba L. stands in northwest Spain with the two-parameter Weibull function

et al. 2007

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The diameter distributions of 125 permanent plots installed in birch dominated (Betula alba L.) stands in Galicia were modelled with the two-parameter Weibull distribution. Four different fitting methods were used: that based on percentiles of the distribution, non linear regression, maximum likelihood and the method of moments. The most accurate fit was obtained with the non linear regression (NLR) approach, considering the following statistics in the comparison: bias, mean absolute error (MAE), mean square error (MSE) and number of plots rejected by the Kolmogoroff-Smirnoff (KS) test.The scale parameter (b) and the shape parameter (c) obtained with the most accurate method (non linear regression), were first modelled with simple linear models and then related to commonly measured prediction variables (quadratic mean diameter, dominant height and stand density) with the parameter prediction model (PPM). The parameters fitted with the method of moments were recovered with the parameter recovery model (PRM) from the first and the second moments of the distribution (mean diameter and variance, respectively). Results indicated that both methods were successful in predicting the diameter frequency distributions. The PRM was more accurate than the PPM method.Key words: diameter class model, two-parameter Weibull distribution, fitting methods, parameter modelling. ResumenModelización de las distribuciones diamétricas en masas de Betula alba L. en el noroeste de España con la función Weibull biparamétrica Las distribuciones diamétricas de 125 parcelas permanentes instaladas en masas puras de abedul (Betula alba L.) en Galicia fueron modelizadas con la distribución Weibull de dos parámetros. Se emplearon cuatro métodos de ajuste: basados en percentiles de la distribución, regresión no lineal, máxima verosimilitud y el método de los momentos. Los ajustes más precisos fueron obtenidos con regresión no lineal, considerando los siguientes estadísticos en la comparación de los resultados: sesgo, error medio absoluto, error medio cuadrático y número de parcelas rechazadas por el test de Kolmogoroff-Smirnoff.El parámetro de escala (b) y el parámetro de forma (c) obtenidos con el método más preciso (regresión no lineal), fueron relacionados con variables de masa de frecuente medición (diámetro medio cuadrático, altura dominante y densidad) mediante modelos lineales sencillos aplicando la metodología de predicción de parámetros. Los parámetros ajustados con el método de los momentos fueron recuperados con modelos de recuperación de parámetros a partir del primer y del segundo momento de la distribución (diámetro medio y varianza, respectivamente). Los resultados indicaron que ambos métodos fueron satisfactorios para predecir las distribuciones de frecuencias de diámetros. El mé-todo de recuperación de parámetros fue más preciso que el método de predicción de parámetros.Palabras clave: modelo de clases diamétricas, distribución Weibull biparamétrica, métodos de ajuste, modelización de parámetros.

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Section: Introductionmentioning

confidence: 99%

Modelling diameter distributions of Betula alba L. stands in northwest Spain with the two-parameter Weibull function

et al. 2007

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“…For the qualitative criteria an evaluation of the different candidate models involved visual examination of the residuals against the estimated values and the fitted curves for different site index classes overlaid on the profile plots of the stands. Visual inspection is an essential point in selecting the most accurate model because curve profiles may differ considerably, even though goodness-of-fit statistics are similar (DIÉGUEZ-ARANDA et al, 2006). The models were chosen according to the goodness-of-fit, predictive ability, biological sense and compliance with the assumptions of nonlinear least square method (homoscedasticity, lack of autocorrelation and normality of residuals).…”

Section: Resultsmentioning

confidence: 99%

“…Many are the models based on the dominant heightage relationship applied to site index curves construction (SCOLFORO; MACHADO, 1988;DIÉGUEZ-ARANDA et al, 2006, DAVID et al, 2015, and those are the basis of most traditional stand-level forest management regimes (RENNOLLS, 1995). Among the techniques available to fit site index curves, most are based on three general methods (CLUTTER et al, 1983): guide curve; parameter prediction, and difference equation methods.…”

Section: Introductionmentioning

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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“…This requires field tree measurements and the development of models and tools such as height growth models and biomass or volume equations, to represent in a simplified way the complexity of forest ecosystem dynamics (Burkhart & Tomé, 2012). Numerous static (Barrio-Anta et al, 2006;Diéguez-Aranda et al, 2006;Menéndez-Miguélez et al, 2014) and dynamic models (Castedo-Dorado et al, 2007;Crecente-Campo, 2008) are now available for different forest species. These models allow managers to simulate forest dynamics and growth, with the prediction of how forests will be at particular times in the future, helping them to make sound decisions regarding sustainable management.…”

Section: Introductionmentioning

confidence: 99%

Resource communication: ApkFor©, an Android Open-Source Project for research and technology transfer in forest management

2018

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Aim of the study: To introduce and describe ApkFor © , an Android Open-Source Project to generate basic mobile applications to transfer forest growth and yield models for even-aged stands.Material and methods: ApkFor © was developed in Android Studio using Java and XML languages integrating transition functions for dominant height and basal area, equations of tree and stand volume and structural models. The project was applied and validated for Pinus pinaster Ait. stands in Northeastern Portugal.Main results: ApkFor © is an Open-Source project freely available from the Source Force repository: https://sourceforge.net/projects/ apkfor/, licensed under the GNU General Public License version 3.0 (GPLv3).Research highlights: This project has been designed and created to provide the code and promote its re-use and modification to develop simple growth and yield mobile applications in Android, and with it to transfer research results of forest modelling to forest managers. Moreover, an example of application of the compiled code is provided using the models of Pinus pinaster Ait. previously validated for the Northeastern Region of Portugal.Additional keywords: Java; growth and yield; dynamic models; Pinus pinaster Ait.; Northeastern Portugal.

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Site quality curves for birch stands in north-western Spain

Abstract: Peninsula, these two taxa are freely hybridized, and their taxonomy is somewhat confused, with each possessing a number of different nomenclatural identities (Castroviejo et al. 1990). Of the two taxa, Betula pubescens is the more oceanic, westerly distributed taxon while Betula pendula

Cited by 52 publications

References 37 publications

Modelling diameter distributions of Betula alba L. stands in northwest Spain with the two-parameter Weibull function

Modelling diameter distributions of Betula alba L. stands in northwest Spain with the two-parameter Weibull function

Site Quality Curves for African Mahogany Plantations in Brazil

Resource communication: ApkFor©, an Android Open-Source Project for research and technology transfer in forest management

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