Modeling frequency distributions of tree height, diameter and crown area by six probability functions for open forests of Quercus persica in Iran

Mirzaei, Mehrdad; Aziz, Jalal; Mahdavi, Ali; Rad, Asma Mohammad

doi:10.1007/s11676-015-0194-x

Cited by 15 publications

(10 citation statements)

References 16 publications

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“…In the process of forest management, the spatial distribution and pattern within a forest are often adjusted to improve species composition and structural diversity [6][7][8]. Therefore, it is particularly important to study the optimization of a secondary forest's structure and function.…”

Section: Introductionmentioning

confidence: 99%

Effect of Thinning on the Spatial Structure of a Larix gmelinii Rupr. Secondary Forest in the Greater Khingan Mountains

Tian

Xiao

Guan

et al. 2018

Forests

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Thinning is an important way to adjust and optimize the spatial structure of forests. The study of its impacts support a better understanding of the succession process of secondary forests after interference. To study the changes in forest spatial structure under different thinning intensities and stand densities, we considered five thinning intensities including unthinned (0%), low (3.4%, 6.2%, 12.5%), medium (16.8%, 20.9%, 25.5%), high (34.4%, 40.0%, 47.9%), and extra-high (50.6%, 59.9%, 67.3%) intensity. In addition, three different stand densities for each degree of thinning intensity. The results showed that the most horizontal distribution patterns after thinning were uniform distribution and near-uniform random distribution. Most of the trees were not mixed while several were mixed to an above medium degree. The effect on dominance of thinning was not significant and the overall plots were in the middle level. The tree density was in the sparse status. Competitive pressure on the reference tree was reduced. Thinning intensity and stand density affected stand spatial structure to different degrees. There were no obvious pattern under different thinning intensities and it was optimal at approximately 1600 trees/ha. As thinning intensity increased, the impact tended to decrease first and then increase under certain stand density. The improvement was greatest when thinning intensity was low. By analyzing the stand’s spatial structure after thinning, the unreasonableness of the stand’s spatial structure can be found, which provides the basis for optimizing management measures. We used the AHP-entropy to weigh the importance of each spatial structure parameter and we proposed a comprehensive distance evaluation index based on the optimal value obtained in order to perform a comprehensive evaluation of a forest’s spatial structure.

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Section: Introductionmentioning

confidence: 99%

Effect of Thinning on the Spatial Structure of a Larix gmelinii Rupr. Secondary Forest in the Greater Khingan Mountains

Tian

Xiao

Guan

et al. 2018

Forests

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“…T , which satisfies the initial condition P X(t 0 ) = x 0 = 1 and represents a diffusion process with a drift vector defined by Equation (3) and diffusion matrix defined by Equation (4). Using the Itô formula [15], SDE (1) can be converted into a well-studied Ornstein-Uhlenbeck process [17] by transformation Y(t) = e β i t X i (t), i = 1, ..., 4 T in the following form:…”

Section: Stochastic Differential Equation Modelmentioning

confidence: 99%

“…The most popular static probability density functions used to model diameter distributions are those of the lognormal, gamma, beta, Johnson's SB, and Weibull functions (e.g., Reference [4] and references therein). Many forms of probability density functions for height distribution such as Weibull, gamma, normal and lognormal, and many more may be chosen [5].…”

Section: Introductionmentioning

confidence: 99%

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A Linkage among Tree Diameter, Height, Crown Base Height, and Crown Width 4-Variate Distribution and Their Growth Models: A 4-Variate Diffusion Process Approach

Rupšys

Petrauskas

2017

Forests

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Abstract:The evolution of the 4-variate probability distribution of the diameter at the breast height, total height, crown base height, and crown width against the age in a forest stand is of great interest to forest management and the evaluation of forest resources. This paper focuses on the Vasicek type 4-variate fixed effect stochastic differential equation (SDE) to quantify the dynamic of tree size components distribution against the age. The new derived 4-variate probability density function and its marginal univariate, bivariate, trivariate, and conditional univariate distributions are applied for the modeling of stand attributes such as the mean diameter, height, crown base height, crown width, volume, and slenderness. All parameters were estimated by the maximum likelihood procedure using a dataset of 1630 Scots pine trees (12 stands). The results were validated using a dataset of 699 Scots pine trees (five stands). A newly developed 4-variate simultaneous system of SDEs incorporated covariance structure driving changes in tree size components and improved predictions in one tree size component given the other tree size components in the system.

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“…Diversos estudos florestais apresentam alguns modelos e confirmam a eficácia dessas equações, dentre as pesquisas podemos citar os trabalhos realizados por Azevedo et al (2011);Binoti et al (2013b); Campos e Leite (2013); ; Miguel et al (2015); Santos, et al (2015); Vibrans, et al (2015); Mirzaei et al (2016); Mugasha et al (2016); Debastiani et al (2019) dentre outros.…”

Section: Introductionunclassified

Redes neurais artificiais e modelos alométricos aplicados para estimativa de volume e altura em Eucalyptus urophylla S.T.Blacke

Leal¹,

Leal

Silva³

2020

ADV. FOR. SCI.

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Redes neurais artificiais (RNA) destacam-se como ferramentas alternativas na modelagem florestal, com resultados muitas vezes superiores em relação aos métodos tradicionais de regressão. Este estudo objetivou avaliar se as estimativas de volume e altura, obtidas por redes neurais artificiais e modelos alométricos, são compatíveis ao método tradicional de cubagem rigorosa. Para obtenção dos dados foram cubadas, pelo método de Hohenadl, 394 árvores de Eucalyptus urophylla. Destas árvores, 70% foram utilizadas nos ajustes dos modelos hipsométricos, volumétricos e para treinamento da RNA e 30% fizeram parte da validação. Para selecionar as melhores equações e RNA observou-se as melhores estatísticas de ajuste e precisão. Estatisticamente, não houve diferença entre os dados da cubagem em campo e as estimativas, ao nível de 5% de significância. Tanto os modelos de regressão quanto as RNA apresentaram bons ajustes, no entanto, as RNA foram superiores em desempenho, pois apresentaram Syx de a 2% no treinamento e 2,5% na validação, para variável altura, e Syx de 6,5% no treinamento e 5,1% na validação, para o volume.

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Modeling frequency distributions of tree height, diameter and crown area by six probability functions for open forests of Quercus persica in Iran

Cited by 15 publications

References 16 publications

Effect of Thinning on the Spatial Structure of a Larix gmelinii Rupr. Secondary Forest in the Greater Khingan Mountains

Effect of Thinning on the Spatial Structure of a Larix gmelinii Rupr. Secondary Forest in the Greater Khingan Mountains

A Linkage among Tree Diameter, Height, Crown Base Height, and Crown Width 4-Variate Distribution and Their Growth Models: A 4-Variate Diffusion Process Approach

Redes neurais artificiais e modelos alométricos aplicados para estimativa de volume e altura em Eucalyptus urophylla S.T.Blacke

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