A light model for spatially explicit forest stand models

Brunner, Andreas

doi:10.1016/s0378-1127(97)00325-3

Cited by 157 publications

(149 citation statements)

References 139 publications

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“…Some studies reported the importance of knowing crown characteristics for predictions of growths, waste materials (residual wood), fertilizer inputs, irrigation or pesticides (Doruska and Burkhart, 1994;Brunner, 1998). Furthermore, a large crown cover increases the protection and restoration of the soil and reduces the impact of rain and other erosive agents on it (Rodriguez et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Calculation of biomass volume of citrus trees from an adapted dendrometry

Velázquez‐Martí¹,

Estornell²,

Cortés³

et al. 2012

Biosystems Engineering

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The aim of this work was to develop a suitable methodology and computational algorithms to calculate volumes and total biomass contained in citrus trees from an adapted dendrometry. This laid the foundations for the use of this methodology as a tool to manage resources from the orchards, establishing adequate predicting models for assessing other parameter such as incomes in raw materials for the cultivation, fruit production, CO2 sink, and waste materials (residual wood) used for energy or industry. The dendrometry has been traditionally applied to forest trees. However, little research has been conducted on fruit trees due to their structure is heterogeneous. To develop the process of biomass quantification it was necessary to perform systems of measurement, enabling to determine volumes of the analyzed trees. This issue was the first step of this research. Afterwards, relationships between actual volume (no hollows) and biomass of trees were established. To do this, form factors, real volume of crown (without holes), and occupation factor were calculated. Form factors relate actual volume of the branch or stem with the volume of a geometric model (solid of revolution). Occupation factors relate the crown model volume of a tree with the actual volume of solid material contained therein. These results could be correlated with production and quality of the fruit, with the amount of residual biomass coming from pruning, and with LiDAR data what may mean a simple, quick and accurate way to predict biomass.Highlights Paper: Calculation of biomass volume of citrus trees from an adapted dendrometry 1. It was developed a methodology for calculating the branch biomass of citrus from simple measurements. 2. Two approaches were followed for estimating the biomass contained in the crown, measuring its mean diameter and height. 3. The equations obtained allow calculating the volume of woody materials contained by the different structures of citrus. 4. The findings obtained could be used in production predictions (fruits and wastes) as well as their logistic. 5. This also allows estimating the CO 2 captured by the trees from atmosphere in the photosyntesis. SummaryThe aim of this work was to develop a suitable methodology and computational algorithms to calculate volumes and total biomass contained in citrus trees from an adapted dendrometry. This laid the foundations for the use of this methodology as a tool to manage resources from the orchards, establishing adequate predicting models for assessing other parameter such as incomes in raw materials for the cultivation, fruit production, CO 2 sink, and waste materials (residual wood) used for energy or industry. The dendrometry has been traditionally applied to forest trees.However, little research has been conducted on fruit trees due to their structure is heterogeneous. To develop the process of biomass quantification it was necessary to perform systems of measurement, enabling to determine volumes of the analyzed trees. This issue was the first step of this res...

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Section: Introductionmentioning

confidence: 99%

Calculation of biomass volume of citrus trees from an adapted dendrometry

Velázquez‐Martí¹,

Estornell²,

Cortés³

et al. 2012

Biosystems Engineering

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“…The light environment inside a forest canopy is a major factor influencing the surface energy balance, the canopy microclimate, as well as photosynthesis, and plant growth [1]. Studying the light distribution within a forest canopy is possible using radiation transfer models, provided that the stand architecture and leaf optical properties are adequately described [2].…”

Section: Introductionmentioning

confidence: 99%

“…For example, using in situ data of tree architecture [17][18] or virtual environment plant growth algorithms that respect the plant's genetic code and reconstitutes tree morphology [19] such as the Atelier de Modelisation et d'Architecture des Plantes (AMAP) model [20]. These geometric explicit canopy architecture models are capable of describing the radiation regime within canopies using current advances in computer power and path tracing algorithms such as tRAYci [1] and the PBRT path tracer [21]. As a result they provide a more accurate calculation of light intercepted by particular elements of the canopy [22].…”

Section: Introductionmentioning

confidence: 99%

Assessing the Impact of Canopy Structure Simplification in Common Multilayer Models on Irradiance Absorption Estimates of Measured and Virtually Created Fagus sylvatica (L.) Stands

et al. 2009

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Abstract:Multilayer canopy representations are the most common structural stand representations due to their simplicity. Implementation of recent advances in technology has allowed scientists to simulate geometrically explicit forest canopies. The effect of simplified representations of tree architecture (i.e., multilayer representations) of four Fagus sylvatica (L.) stands, each with different LAI, on the light absorption estimates was assessed in comparison with explicit 3D geometrical stands. The absorbed photosynthetic radiation at stand level was calculated. Subsequently, each geometrically explicit 3D stand was compared with three multilayer models representing horizontal, uniform, and planophile leaf angle distributions. The 3D stands were created either by in situ measured trees or by modelled trees generated with the AMAP plant growth software. The Physically Based Ray Tracer (PBRT) algorithm was used to simulate the irradiance absorbance of the detailed 3D architecture stands, while for the three multilayer representations, the probability of light interception was simulated by applying the Beer-Lambert's law. The irradiance inside the canopies was characterized as direct, diffuse and scattered irradiance. The irradiance absorbance of the stands was computed during OPEN ACCESSRemote Sens. 2009, 1 1010 eight angular sun configurations ranging from 10° (near nadir) up to 80° sun zenith angles. Furthermore, a leaf stratification (the number and angular distribution of leaves per LAI layer inside a canopy) analysis between the 3D stands and the multilayer representations was performed, indicating the amount of irradiance each leaf is absorbing along with the percentage of sunny and shadow leaves inside the canopy. The results reveal that a multilayer representation of a stand, using a multilayer modelling approach, greatly overestimated the absorbed irradiance in an open canopy, while it provided a better approximation in the case of a closed canopy. Moreover, the actual stratification of leaves differed significantly between a multilayer representation and a 3D architecture canopy of the same LAI. The deviations in irradiance absorbance were caused by canopy structure, clumping and positioning of leaves. Although it was found that the use of canopy simplifications for modelling purposes in closed canopies is demonstrated as a valid option, special care should be taken when considering forest stands irradiance simulation for sparse canopies and particularly on higher sun zenith angles where the surrounding trees strongly affect the absorbed irradiance and results can highly deviate from the multilayer assumptions.

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“…A média dos valores encontrados entre os três sensores, para cada intervalo de tempo, foi utilizada na comparação com os valores observados em cada dia de medição. Na avaliação do ajuste entre valores observados e estimados para a estimativa do número de folhas, pelas equações alométricas e métodos de estimativa da densidade de área foliar, foram utilizados os seguintes indicadores: precisão, coeficiente de correlação "r"; exatidão, índice de Willmott "d" e de confiança ou desempenho "c" (Campelo Júnior, 2000). A exatidão (d) está relacionada ao afastamento dos valores estimados em relação aos observados.…”

Section: Methodsunclassified

“…Outra variável importante é a densidade de área foliar (F), que consiste na área de folhas encontradas em um volume, utilizada principalmente em estudos de interceptação da luz em árvores. Essas duas variáveis são parâmetros fundamentais de entrada para os modelos de simulação de interceptação da luz, de produção de biomassa, de consumo de água, de fi xação de gás carbônico e, consequentemente, para a comparação entre espécies e cultivares (Brunner, 1998;Sinoquet et al, 2007;Takeda et al, 2008).…”

Section: Introductionunclassified

Métodos não destrutivos para estimativa de densidade de área foliar em mangueira

Antunes

Ferronato

et al. 2009

Pesq. agropec. bras.

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Resumo -O objetivo deste trabalho foi estimar o número de folhas de ramos do dossel de cultivares de mangueira e estimar a densidade de área foliar utilizando, respectivamente, uma relação alométrica e um modelo de interceptação de luz. O trabalho foi conduzido com as cultivares Alfa, Roxa e Malind, na fazenda experimental da Universidade Federal de Mato Grosso, no Município de Santo Antônio do Leverger, MT. As equações testadas para a determinação do número de folhas apresentaram desempenho ótimo, com índices de confi ança que variaram entre 0,85 e 0,94, e podem ser utilizadas como alternativa para a estimativa da área foliar das três cultivares. O modelo de interceptação da luz também apresentou desempenho ótimo e bom na estimativa da densidade foliar, com índices de confi ança que variaram entre 0,97 e 0,99 e 0,68 e 0,95 para as cultivares de mangueira Roxa e Malind, respectivamente.Termos para indexação: Mangifera indica, lei de Beer-Lambert, PAR. Non-destructive methods for estimating leaf area density in mangoAbstract -The objective of this work was to estimate the number of leaves in the branches of mango cultivars canopies and to estimate the leaf area density using, respectively, an allometric relation and a light interception model. The work was carried out with the Alfa, Roxa and Malind cultivars, grown at the experimental farm of the Universidade Federal de Mato Grosso, in the municipality of Santo Antônio do Leverger, MT, Brazil. The equations tested for determining the number of leaves had excellent performance, with confi dence indexes ranging from 0,85 to 0,94, and can be used as an alternative for estimating the leaf area of the three cultivars. The light interception model also had good performance in estimating leaf density, with confi dence indexes ranging from 0,97 to 0,99 and from 0,68 to 0,95 for the Roxa and Malind mango cultivars respectively.

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A light model for spatially explicit forest stand models

Cited by 157 publications

References 139 publications

Calculation of biomass volume of citrus trees from an adapted dendrometry

Calculation of biomass volume of citrus trees from an adapted dendrometry

Assessing the Impact of Canopy Structure Simplification in Common Multilayer Models on Irradiance Absorption Estimates of Measured and Virtually Created Fagus sylvatica (L.) Stands

Métodos não destrutivos para estimativa de densidade de área foliar em mangueira

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