Individual tree diameter increment model for managed even-aged stands of ponderosa pine throughout the western United States using a multilevel linear mixed effects model

Uzoh, Fabian C.C.; Oliver, William W.

doi:10.1016/j.foreco.2008.04.046

Cited by 90 publications

(92 citation statements)

References 38 publications

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“…The nature of repeated measures experiments is often ignored and independence between observations is assumed (Zhang et al, 2004;Uzoh and Oliver, 2008). However, two measurements taken at adjacent units of time and/or space are more highly correlated than two measurements taken several time points or space apart.…”

Section: Modeling Diameter Increment In Pinus Occidentalis 171mentioning

confidence: 99%

“…High autocorrelations can make two mutually exclusive variables appear to be related. While ignoring the least-squares regression assumptions of independence still results in unbiased estimates of the model parameters, estimates of model errors are biased (Uzoh and Oliver, 2008). If error estimates are biased, inferences of model coefficients are in question.…”

Section: Modeling Diameter Increment In Pinus Occidentalis 171mentioning

confidence: 99%

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Modeling Stem Diameter Increment in Individual Pinus occidentalis Sw. trees in La Sierra, Dominican Republic

Bueno

Bevilacqua

2010

For. syst.

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One of the most common and important tree characteristics used in forest management decision-making is tree diameter-at-breast height (DBH). This paper presents results on an evaluation of two growth functions developed to model stem diameter increases in individual Pinus occidentalis Sw. trees in La Sierra, Dominican Republic. The first model was developed in order to predict future DBH (FDM) at different intervals of time and the other for predicting growth, that is, periodic annual diameter increment (PADIM). Each model employed two statistical techniques for fitting model parameters: stepwise ordinary least squares (OLS) regression, and mixed models. The two statistical approaches varied in how they accounted for the repeated measurements on individual trees over time, affecting standard error estimates and statistical inference of model parameters. Each approach was evaluated based on six goodnessof-fit statistics, using both calibration and validation data sets. The objectives were 1) to determine the best model for predicting future tree DBH; 2) to determine the best model for predicting periodic annual diameter increment, both models using tree size, age, site index and different indices of competitive status; and 3) compare which of these two modeling approaches predicts better the future DBH.OLS provided a better fit for both of the growth functions, especially in regards to bias. Both models showed advantages and disadvantages when they were used to predict growth and future diameter. For the prediction of future diameter with FDM, accuracy of predictions were within one centimeter for a five-year projection interval. The PADIM presented negligible bias in estimating future diameter, although there was a small increase in bias as time of prediction increased. As expected, each model was the best in estimating the response variable it was developed for.. However, a closer examination of the distribution of errors showed a slight advantage of the FDM against the PADIM. Based on this, it is proposed that the FDM model is used to estimate future diameter and periodic diameter increment (growth) of P. occidentalis.Additional key words: diameter growth, repeated measures, mixed models, OLS, site index, indices of competitive status. Resumen Modelando el incremento en diámetro del fuste en árboles individuales de Pinus occidentalis Sw. en La Sierra, República DominicanaUna de las características más empleadas e importantes utilizada en la toma de decisiones en el manejo forestal es el diámetro normal -DBH-de los árboles. En este artículo se presentan los resultados de la evaluación de dos funciones de crecimiento utilizadas para predecir el incremento futuro en diámetro normal (FDM) en intervalos de tiempo diferentes, y el crecimiento o incremento periódico anual en diámetro normal (PADIM) en árboles individuales de Pinus occidentalis, en La Sierra, República Dominicana. Se emplearon dos técnicas estadísticas para el ajuste de los parámetros: cuadrados mínimos ordinarios (OLS) por etapas de regresión...

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Section: Modeling Diameter Increment In Pinus Occidentalis 171mentioning

confidence: 99%

Section: Modeling Diameter Increment In Pinus Occidentalis 171mentioning

confidence: 99%

Modeling Stem Diameter Increment in Individual Pinus occidentalis Sw. trees in La Sierra, Dominican Republic

Bueno

Bevilacqua

2010

For. syst.

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“…The individual tree radial growth models are commonly used as submodels in a growth simulator (Sterba, Monserud 1997;Pretzsch 2002;Hasenauer et al 2006;Lacerte et al 2006;Gobakken et al 2008). The individual tree radial growth models offer a good possibility of exploring detailed management alternatives, because these models can adequately describe the forest growth dynamics (Martin, Ek 1984;Uzoh, Oliver 2008;Subedi, Sharma 2011;Wagle, Sharma 2012). Since basal area growth is highly correlated with volume growth, basal area growth models are preferred to diameter growth models (Wykoff 1990;Monserud, Sterba 1996;Schröder et al 2002;Andreassen, Tomter 2003;Anta et al 2006).…”

mentioning

confidence: 99%

“…Distance dependent or distance independent individual tree growth models can be developed using either of the two methods: indirect control over the growth with potential modification (Biging, Dobbertin 1992;Pretzsch 2002;Pommerening et al 2011;Sharma 2013) or direct estimation of growth by regression techniques (Wykoff 1990;Huang, Titus 1995;Rivas et al 2005;Uzoh, Oliver 2008;Subedi, Sharma 2011). With the indirect method, potential growth is expressed as a function of current size or age of the trees and site index, while competition index and measures of tree vigour are used as modifiers that reduce potential growth (Biging, Dobbertin 1992;Pretzsch 2002;Reed et al 2003;Pretzsch 2009).…”

mentioning

confidence: 99%

“…With the indirect method, potential growth is expressed as a function of current size or age of the trees and site index, while competition index and measures of tree vigour are used as modifiers that reduce potential growth (Biging, Dobbertin 1992;Pretzsch 2002;Reed et al 2003;Pretzsch 2009). However, with the direct method, periodic tree growth is modelled as a function of tree size, site index, competition index, and mean stand characteristics by applying regression techniques (Wykoff 1990;Huang, Titus 1995;Mailly et al 2003;Rivas et al 2005;Uzoh, Oliver 2008). In this study, the direct method was applied by using tree size or tree age as independent variable, because potential growth data (i.e.…”

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confidence: 99%

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Individual tree basal area growth models for Chir pine (Pinus roxberghii Sarg.) in western Nepal

Gyawali¹,

Sharma²,

Bhandari³

2015

J. For. Sci.

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ABSTRACT:The individual tree growth models are important decision-making tools in forestry. Age dependent and age independent individual tree basal area growth models were developed for Chir pine (Pinus roxberghii Sarg.) in one of the western districts, Rukum district, in Nepal. Data from thirty-five destructively sampled trees, which were representative of all possible stand densities, site productivities, age classes, and size classes of Chir pine forests in the district, were used. Sample trees were felled and diameters and ages were measured on the cut surface of the stump (at 30 cm above the ground). Since measurements from the same stump of a tree were strongly correlated, the autoregressive error structure modelling approach was applied while specifying the model in order to reduce bias. All parameter estimates of the models were significant (P < 0. 01) and the models described most of the variations of basal area growth (R 2 adj > 0.86). Residual graphs showed no serious systematic bias for all observed age classes and diameter classes. The age independent growth model showed relatively better fit statistics (R 2 adj = 0.8751, RMSE = 4.8494) than its age dependent counterpart (R 2 adj = 0.8668, RMSE = 5.0158). Because of being more precise and simpler, the age independent model is recommended to apply to both even-aged and uneven-aged stands of Chir pine in the district.

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Forest Growth and Yield Modeling

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Individual tree diameter increment model for managed even-aged stands of ponderosa pine throughout the western United States using a multilevel linear mixed effects model

Cited by 90 publications

References 38 publications

Modeling Stem Diameter Increment in Individual Pinus occidentalis Sw. trees in La Sierra, Dominican Republic

Modeling Stem Diameter Increment in Individual Pinus occidentalis Sw. trees in La Sierra, Dominican Republic

Individual tree basal area growth models for Chir pine (Pinus roxberghii Sarg.) in western Nepal

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