Predicting solar radiation transmittance in the understory 
of even-aged coniferous stands in temperate forests

Sonohat, Gabriéla; Balandier, Philippe; Ruchaud, F.

doi:10.1051/forest:2004061

Cited by 81 publications

(65 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As expected, given the well-known negative relationship between stand BA and light transmission (e.g., Palik et al, 1997;Comeau, 2001;Sonohat et al, 2004;Comeau et al, 2009;Hale et al, 2009), mean light levels increased with increasing rate of tree removal (Fig. 5A).…”

Section: Effect On Light Conditionsmentioning

confidence: 61%

Managing understory light conditions in boreal mixedwoods through variation in the intensity and spatial pattern of harvest: A modelling approach

Beaudet

Harvey

Messier

et al. 2011

Forest Ecology and Management

View full text Add to dashboard Cite

a b s t r a c tIn the context of partial harvesting, adequately managing post-harvest light conditions are essential to obtain a desired composition of tree species regeneration. The objective of this study was to determine how varying the intensity and spatial pattern of harvest would affect understory light conditions in boreal mixedwood stands of northwestern Quebec using the spatially explicit SORTIE-ND light model. The model was evaluated based on comparisons of observed and predicted light levels in both mapped and un-mapped plots. In mapped plots, reasonably accurate predictions of the overall variation in light levels were obtained, but predictions tended to lack spatial precision. In un-mapped plots, SORTIE-ND accurately predicted stand-level mean GLI (Gap Light Index) under a range of harvest intensities. The model was then used to simulate nine silvicultural treatments based on combinations of three intensities of overstory removal (30%, 45% and 60% of basal area) and three harvest patterns (uniform, narrow strips, large gaps). Simulations showed that increasing overstory removal had less impact on light conditions with uniform harvests, and a more marked effect with more aggregated harvest patterns. Whatever the harvest intensity, uniform cuts almost never created high light conditions (GLI > 50%). Gap cuts, on the other hand, resulted in up to 40% of microsites receiving GLI > 50%. Our results suggest that either a 30% strip or gap cut or a 45-60% uniform partial harvest could be used to accelerate the transition from an aspen dominated composition to a mixedwood stand because both types of cut generate the greatest proportion of moderately low light levels (e.g., 15-40% GLI). These light levels tend to favour an accelerated growth response among shade-tolerant conifers, while preventing excessive recruitment of shade-intolerant species. A better understanding of how spatial patterns of harvest interact with tree removal intensity to affect understory light conditions can provide opportunities for designing silvicultural prescriptions that are tailored to species' traits and better suited to meet a variety of management objectives.

show abstract

Section: Effect On Light Conditionsmentioning

confidence: 61%

Managing understory light conditions in boreal mixedwoods through variation in the intensity and spatial pattern of harvest: A modelling approach

Beaudet

Harvey

Messier

et al. 2011

Forest Ecology and Management

View full text Add to dashboard Cite

show abstract

“…These critical parameters may also need to be adjusted for different climates or regions since studies in Ireland suggested 5-10% lower transmittance for a given basal area [57] (figure 6), than was found in equivalent British studies [61]. Time since thinning will also be important because the canopy gaps and more heterogeneous canopy resulting from a recent thinning will lead to a higher RLI: this decreases with time as the canopy closes [62].…”

Section: Stand Microclimatementioning

confidence: 99%

Implementing Continuous Cover Forestry in Planted Forests: Experience with Sitka Spruce (Picea Sitchensis) in the British Isles

Mason

2015

Forests

View full text Add to dashboard Cite

Planted forests of Sitka spruce, a non-native species from north-west America, are the major forest type in Great Britain and Ireland. Standard management involves even-aged stands, rotations of 40-50 years and a patch clear-felling system with artificial regeneration. However, forest policies support managing these forests for multifunctional objectives with increased diversity of species composition and stand structure. Continuous cover forestry (CCF) is an alternative silvicultural approach used to provide such diversity, but the amount of CCF forest is under 10% of the forest area, and less in Sitka spruce forests; This paper reviews research carried out in the last two decades to support the implementation of CCF in Sitka spruce planted forests; Stand structures and microclimate favouring natural regeneration are understood. Harvesting systems have been adapted for use in CCF stands, a single-tree growth model has been calibrated, comparative costs and revenues have been determined, and operational trials established. The interaction between thinning and wind stability in irregular stands is problematic, together with the lack of suitable species for growing in mixture with Sitka spruce; Introduction of an alternative silvicultural approach may take decades and must overcome technical challenges and cultural resistance.

show abstract

“…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

View full text Add to dashboard Cite

-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

show abstract

Predicting solar radiation transmittance in the understory of even-aged coniferous stands in temperate forests

Cited by 81 publications

References 50 publications

Managing understory light conditions in boreal mixedwoods through variation in the intensity and spatial pattern of harvest: A modelling approach

Managing understory light conditions in boreal mixedwoods through variation in the intensity and spatial pattern of harvest: A modelling approach

Implementing Continuous Cover Forestry in Planted Forests: Experience with Sitka Spruce (Picea Sitchensis) in the British Isles

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

Contact Info

Product

Resources

About