Spatial and temporal distribution of solar radiation beneath forest canopies

Reifsnyder, William E.; Furnival, George M.; Horowitz, Josepha

doi:10.1016/0002-1571(71)90004-5

Cited by 176 publications

(78 citation statements)

References 5 publications

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“…Este rango es consistente con observaciones hechas en otros estudios, en que la RSG oscilaría entre 1-2 % y 62 % dependiendo de la cubierta forestal, la estructura del bosque, el índice de área foliar, y la estación del año (Reifsnyder et al 1971/1972, Ghuman y Lal 1987, Chen et al 1993, Aussenac 1997, 2000, Carlson y Groot 1997, Davies-Colley et al 2000, Holst y Mayer 2005.…”

Section: Discussionunclassified

Microclima en el interior de un bosque de Nothofagus pumilio y el efecto de una corta de regeneración

2010

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Section: Discussionunclassified

Microclima en el interior de un bosque de Nothofagus pumilio y el efecto de una corta de regeneración

2010

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“…The number of randomly positioned sensors required for canopy-level estimation depends on the precision required. Reifsnyder et al (1971) found coefficients of variation (CV) of 121% for pine and 225% for hardwood values for each sensor averaged over a 5-min period. If averaged over the entire day, however, the CV dropped to 43 and 13.5%, respectively, indicating that fewer sensors are needed to characterize light over days or seasons.…”

Section: Continuous Seasonal Measurementsmentioning

confidence: 99%

“…Reifsnyder et al (1971) also noted that on overcast days, fewer sensors are needed to characterize light with the same level of precision as on sunny days. In theory, at high latitudes with their lower solar angles, the probability of penetration of the canopy by direct-beam light may be lower than the average penetration of diffuse light.…”

Section: Measurements On Overcast Daysmentioning

confidence: 99%

Predicting and managing light in the understory of boreal forests

Lieffers¹,

Messier²,

Stadt³

et al. 1999

Revue canadienne de recherche forestière

102

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This paper reviews current information relating to the dynamics of light in northern and boreal forests and discusses factors affecting overstory light transmission, seasonality of light, sunflecks, canopy gaps, and understory development, particularly with regard to tree regeneration. Techniques for measurement of light in forests such as radiometers, photosensitive paper or chemicals, hemispherical canopy photographs, the plant canopy analyzer, or visual estimators of canopy density are each discussed in terms of their accuracy, costs, ease of use, and conditions required during measurement. Predictive models of light transmission based on canopy architecture are also described in terms of their assumptions, accuracy, and input data costs. Lastly the paper discusses the relationship among overstory and understory densities, ground-level light, and "windows of opportunity" for regeneration of trees in the understory following management interventions.Résumé : Cet article passe en revue les connaissances courantes sur la dynamique de la lumière dans les forêts nordiques et boréales. Les auteurs y discutent des facteurs qui affectent la transmission de la lumière dans le couvert, les variations saisonnières de la lumière, les trouées de lumière, les trouées du couvert et le développement du sousétage, particulièrement en relation avec la régénération des arbres. Les diverses techniques de mesure de la lumière, telles que l'utilisation de radiomètres, de produits chimiques ou de papiers photosensibles, de photographies panoramiques du couvert, d'analyseurs de la composition du couvert ou d'estimateurs visuels de la densité du couvert, sont analysées sur la base de leur précision, de leur coût, de leur facilité d'utilisation et des conditions requises pour effectuer les mesures. Les modèles de prédiction de la transmission de la lumière qui reposent sur l'architecture du couvert sont aussi décrits en fonction des hypothèses sur lesquelles ils reposent, de leur précision et du coût d'acquisition des données. Finalement, les auteurs discutent des relations entre la densité de l'étage dominant et celle du sous-étage, de la lumière au niveau du sol et des circonstances opportunes pour la régénération des arbres en sousétage suite à des interventions d'aménagement.[Traduit par la Rédaction] Review / Synthèse 811

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“…Light penetration depends on the intensity of incident light and upon the number, size, as well as the spatial distribution of canopy openings (Anderson 1964, Reifsnyder et al 1971, Hutchinson & Matt 1977, Brokaw 1985, Brokaw & Busing 2000. Crown traits such as leaf area determine the carbon gain of the whole plant, in interaction with light levels received by leaves and the ability to convert light to plant assimilates.…”

Section: Gaps and Regenerationmentioning

confidence: 99%

“…The technique involves taking photographs looking upward from beneath a canopy through a 1800 lens, which permits direct measurement of canopy openings and estimation of light transmittance. Light penetration through the canopy depends on the intensity of incident light and upon the number, size, and spatial distribution of canopy openings (Anderson 1964, Reifsnyder et al 1971, Hutchinson & Matt 1977, Brokaw 1985, Brokaw & Busing 2000. Consequently, hemispherical canopy photographs can be used to quantify both the status of the canopy and light levels for a particular understory location.…”

Section: Measurement Of Canopy Dynamicsmentioning

confidence: 99%

Dynamics of canopy cover in a wet forest in Costa Rica

Brinez

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In addition, I found highly significant inter-annual variation in all analyses that was concordant on all plot types. This is the first long-term study to document substantial inter-annual variation in canopy cover for a tropical wet forest. These patterns are a combination of seasonal changes in leaf area, forest dynamics resulting from gap formation and closure, and inter-annual variation in leaf area coverage caused by climate variation.

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Spatial and temporal distribution of solar radiation beneath forest canopies

Cited by 176 publications

References 5 publications

Microclima en el interior de un bosque de Nothofagus pumilio y el efecto de una corta de regeneración

Microclima en el interior de un bosque de Nothofagus pumilio y el efecto de una corta de regeneración

Predicting and managing light in the understory of boreal forests

Dynamics of canopy cover in a wet forest in Costa Rica

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