Predicting understory light microclimate from stand parameters in young paper birch (Betula papyrifera Marsh.) stands

Comeau, Philip G.; Heineman, Jean L.

doi:10.1016/s0378-1127(02)00581-9

Cited by 57 publications

(55 citation statements)

References 31 publications

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“…On May [18][19]2004, CBE sensors were calibrated against a quantum PAR sensor (LI-191SB from Li-Cor Inc., Lincoln, NE, USA). A fourth order polynomial without intercept term was adjusted in order to predict PPFD from output voltage of the sensors.…”

Section: Light Sensorsmentioning

confidence: 99%

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Reconstructing crown shape from stem diameter and tree position to supply light models. I. Algorithms and comparison of light simulations

et al. 2005

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-Light models provide an interesting way to analyse the influence of the forest canopy on understory biological processes but need a detailed description of tree crowns, requiring many field measurements. This study proposes supplying light models with only stem diameter and tree position and reconstructing crowns using diameter-related allometric relations. First, the diameter-related relations for total height, crown base height and mean crown radius were established for each species. Second, two reconstruction methods were compared: a simple isotropic method and a more sophisticated method, the Crown Reconstruction by Overlap Minimisation method. The latter method gave better results than the simpler one, even if some small bias was not completely resolved in the darkest areas. However, using crown centre position instead of stem position resolved this bias. crown reconstruction / crown competition / light model / heterogeneous forest / broadleavesRésumé -Reconstruction de la forme des houppiers à partir du diamètre des arbres et de leur position pour alimenter un modèle de lumière. I. Algorithmes et comparaison des simulations de l'éclairement. Les modèles de lumière constituent un bon moyen pour analyser l'influence du couvert forestier sur les processus biologiques sous-couvert. Malheureusement ils nécessitent une description détaillée des houppiers des arbres, ce qui implique des mesures de terrain assez lourdes. Cet article propose d'alimenter les modèles de lumière uniquement avec le diamètre et la position des arbres, et de reconstituer les houppiers en utilisant des relations allométriques en fonction du diamètre à 1,30 m. Les relations allométriques sont tout d'abord établies pour la hauteur totale, la hauteur de base de houppier et le rayon moyen du houppier, pour chaque espèce. Ensuite deux méthodes de reconstruction des houppiers sont comparées : une méthode simple dite isotrope et une plus sophistiquée, la méthode de reconstruction des houppiers par minimisation des chevauchements. Cette dernière donne de meilleurs résultats, même si un léger biais subsiste dans les zones les plus sombres. Cependant le fait d'utiliser la position des centres de houppiers au lieu de celle des troncs permet de complètement supprimer ce biais. reconstruction des houppiers / compétition des houppiers / modèles de lumière / forêt hétérogène / feuillus

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Section: Light Sensorsmentioning

confidence: 99%

“…However, since PACL is directly determined by canopy structure, it would be possible to link PACL values under the canopy to stand-scale evaluated characteristics [17,18,33,51,53,58]. This approach is relatively effective but the relationships are generally obtained for a specific stand structure and silvicultural and ecological context.…”

Section: Introductionmentioning

confidence: 99%

Reconstructing crown shape from stem diameter and tree position to supply light models. I. Algorithms and comparison of light simulations

et al. 2005

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“…Unfortunately, site effects could not be tested using our data set. Although fairly large differences in soil type and geographic location did not significantly affect stand structure-light relationships in other forest types (Messier et al 1998, Comeau and Heineman 2003, Sonohat et al 2004, the models presented here should be tested prior to use in eastern and western regions of the range of white pine-red pine forests. Finally, GLI values reported here are estimates of canopy transmittance, and represent the maximum average understory light levels associated with, for example, a given stand basal area or density.…”

Section: Conclusion and Management Recommendationsmentioning

confidence: 97%

The relationship of stand structure with canopy transmittance: Simple models and practical methods for managing understory light conditions in eastern white pine (Pinus strobus L.)-dominated forests

Parker

2014

The Forestry Chronicle

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The relationship of stand structural features with understory light levels, estimated by gap light index (GLI), was investigated in 22 second-growth eastern white (Pinus strobus L.) and red pine (Pinus resinosa Ait.)-dominated stands in central Ontario that encompassed a broad range in density and basal area. Simple, empirical light models were developed to quantify the influence of several stand structural variables on canopy transmittance as estimated by GLI. Models were also derived to facilitate the operational identification of residual basal area, density, and percent canopy closure associated with target understory light levels that optimize the growth of white pine regeneration and its protection from weevil and blister rust when using the uniform shelterwood silvicultural system. Regression models indicated significant negative, nonlinear relationships of GLI with density, basal area, a stand density index, total crown area, and foliar biomass, while GLI was linearly related to percent canopy closure. Application of these models to identify density, basal area, and canopy closure values associated with target light levels for the regeneration and removal cuts of uniform shelterwoods demonstrates the use of this information to help guide management of white pine-red pine forests.Keywords: canopy closure, empirical light models, hemispherical photography, red pine, Pinus resinosa, regeneration, uniform shelterwood, weevil and blister rust protection Résumé La relation entre les caractéristiques structurelles d'un peuplement et les niveaux de luminosité du sous-étage, estimée par l'indice d' écart de luminosité (IEL), a été étudiée dans 22 pinèdes de seconde venue à dominance de pin blanc de l' est (Pinus strobus L.) et de pin rouge (Pinus resinosa Ait.) du centre de l'Ontario qui recoupaient un vaste éventail de densités et de surfaces terrières. Des simples modèles empiriques de luminosité ont été élaborés pour quantifier l'influence de certaines variables de la structure du peuplement sur la transmission du couvert végétal tel qu' estimé par l'IEL. Les modèles ont été dérivés afin de faciliter l'identification opérationnelle de la surface terrière résiduelle, de la densité et du pourcentage de fermeture du couvert associé aux niveaux de luminosité ciblés du sous-étage qui optimise la croissance de la régénération du pin blanc et sa protection contre le charançon et la rouille vésiculeuse lorsqu' est appliqué le mode de régénération par coupe progressive uniforme. Les modèles de régression ont affiché des relations non linéaires significatives et négatives de l'IEL avec la densité, la surface terrière, l'indice de densité du peuplement, la superficie totale des cimes et la biomasse foliaire, tandis que l'IEL était en relation étroite avec le pourcentage de fermeture du couvert. L'application de ces modèles pour identifier les valeurs de la densité, de la surface terrière et de la fermeture du couvert associées aux niveaux cibles de luminosité pour la régénération et les coupes progressives de rég...

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“…En varios estudios, las mediciones del área basal, densidad y altura de los árboles, dimensiones de las copas y el índice de área foliar (en forma individual o en combinación) se han correlacionado bastante bien con la radiación solar bajo el dosel de copas (Comeau & Heineman, 2003;Promis, Schindler, Reif, & Cruz, 2009). Sin embargo, y aunque las correlaciones son razonables, tales relaciones deberían ser solamente utilizadas dentro del rango de condiciones de rodal que fueron consideradas en el muestreo (Comeau, 2000).…”

Section: Indirect Estimates Of the Light Environment In Forestsunclassified

“…In several studies, the measurements of basal area, tree density and height, crown dimensions and leaf area index (individually or in combination) have been fairly well correlated with below-canopy solar radiation (Comeau & Heineman, 2003;Promis, Schindler, Reif, & Cruz, 2009). However, although the correlations are reasonable, such relationships should be only utilized within the range of stand conditions considered in the sampling (Comeau, 2000).…”

Section: Indirect Estimates Of the Light Environment In Forestsmentioning

confidence: 99%

Medición Y Estimación Del Ambiente Lumínico en El Interior Del Bosque. Una Revisión

Promis

2013

Rev Cha Se Cie For y del Amb

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RESUMENE l ambiente lumínico en el interior de un bosque influye en la supervivencia y crecimiento de las plántulas de especies arbóreas y en el desarrollo de las plantas del sotobosque. Por este motivo, existe mucho interés en medir el ambiente lumínico bajo el dosel de copas. Varios métodos, técnicas e instrumentos se han desarrollado para medir directamente o estimar indirectamente el ambiente lumínico en el interior del bosque. También se han realizado varios estudios que comparan la eficiencia de ambos métodos (directos e indirectos). En esta revisión se describen varios instrumentos, técnicas y metodologías para estimar el ambiente lumínico, indicando la naturaleza y propiedades de cada uno de ellos, como apoyo para la elección del equipamiento necesario y así responder a las necesidades del investigador en este tema. ABSTRACTT he below-canopy light environment influences the survival, the tree regeneration growth and the development of the understory plant species. Therefore, there has been much interest in measuring the below-canopy light environment. Several instruments, techniques and methods have been developed to measure directly or to estimate indirectly the below-canopy light environment. To date, many comparisons of direct and indirect methods for the measuring and estimation of below-canopy light environment have been conducted in order to determine the best way to measure the light in the understory. In this review a scientific description of the currently instruments, techniques and methods used to measure or to estimate the below-canopy solar radiation is shown. The nature and properties of the different methods, techniques and instruments are commented. Finally, the choice of equipment to meet the needs of the researcher in this topic is supported. 140 INTRODUCCIÓNLa radiación solar se considera el elemento meteorológico de mayor importancia (Geiger, Aron, & Todhunter, 2003). Las variaciones temporales en la intensidad de la radiación solar tienen consecuencias ecológicas sobre las plantas afectando su fotosíntesis, morfología, tolerancia a la sombra, crecimiento y supervivencia (Kimmins, 1987). Para entender la dinámica de los bosques es importante comprender el comportamiento de la radiación solar en el interior de éstos, debido a que la calidad y la intensidad de dicha radiación afectan los patrones de regeneración de las plantas, tales como la germinación, el establecimiento, el crecimiento y la supervivencia (Grant, 1997). Es por esto, que ha existido mucho interés por mejorar la forma de medir y estimar la radiación solar bajo el dosel de un bosque (Comeau, 2000;Jennings, Brown, & Sheil, 1999). La cantidad total de radiación solar que llega sobre el dosel de un bosque es afectada por la latitud, hora del día, claridad de la atmósfera y altitud (Kimmins, 1987). El dosel es una estructura tridimensional que cambia a través del tiempo (Grant, 1997). La superficie heterogénea del dosel modifica la reflexión, la transmisión y la absorción de la radiación solar que llega al interior del bosq...

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Predicting understory light microclimate from stand parameters in young paper birch (Betula papyrifera Marsh.) stands

Cited by 57 publications

References 31 publications

Reconstructing crown shape from stem diameter and tree position to supply light models. I. Algorithms and comparison of light simulations

Reconstructing crown shape from stem diameter and tree position to supply light models. I. Algorithms and comparison of light simulations

The relationship of stand structure with canopy transmittance: Simple models and practical methods for managing understory light conditions in eastern white pine (Pinus strobus L.)-dominated forests

Medición Y Estimación Del Ambiente Lumínico en El Interior Del Bosque. Una Revisión

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