The single tree-based stand simulator SILVA: construction, application and evaluation

Pretzsch, Hans; Biber, Peter; Ďurský, J.

doi:10.1016/s0378-1127(02)00047-6

Cited by 448 publications

(315 citation statements)

References 21 publications

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“…[2,37]), tree growth (e.g. [7,41]), and tree physiology (e.g. [50]) depend on information about crown dimensions of individual trees.…”

Section: Introductionmentioning

confidence: 99%

Estimation of crown radii and crown projection area from stem size and tree position

Grote

2003

Ann. For. Sci.

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-This paper describes a method for crown radii estimation in different cardinal directions using tree diameter, height, crown length, and stem position within the stand as independent variables. The approach can serve for the initialisation of crown dimensions if measured crown radii are not available in order to address various research questions. Test calculations are carried out with 4 pure spruce (Picea abies L. Karst), 5 beech (Fagus sylvatica L.), and 6 mixed stands with both species. Simulated tree radii, crown projection area and canopy cover are compared with measurements and simple estimation procedures based on logarithmic and linear equations. In beech stands and dense spruce stands the estimates with the new approach are similar or superior to those obtained with the other methods. However, in sparse plots or in stands, which have experienced a recent thinning crown size of trees is overestimated.crown projection area / crown radii / Fagus sylvatica / mixed forests / Picea abies Résumé -Estimation des rayons et de la zone de projection de la couronne en utilisant les dimensions de la tige et la position de l'arbre. Cet article introduit une méthode mathématique qui permet une estimation du rayon, en utilisant seulement les dimensions de la tige de la couronne et la position de l'arbre. Cette méthode permet d'initialiser les dimensions de la couronne dans le cas où on ne connaît pas les rayons pour ainsi traiter de différentes questions scientifiques. La méthode est testée sur de nombreux peuplements d' épicéas (Picea abies) et de hêtres (Fagus sylvatica), non seulement constitués d'une seule essence mais aussi de forêts mixtes, dans le sud de l'Allemagne. Les simulations du rayon des couronnes, de la surface de projection d'une couronne et du degré de couverture sont comparées avec des mesures et d'autres estimations basées sur des équations linéaires ou logarithmiques. Les résultats montrent que la nouvelle méthode est appropriée pour la représentation des rayons des couronnes de hêtres et pour des peuplements denses d'épicéa. En revanche le rayon et la surface de la couronne d'arbres ayant poussé dans des lieux clairsemés ou ayant subi une éclaircie sont surestimés.projection des couronnes / rayons des couronnes / Fagus sylvatica / forêts mixtes / Picea abies

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“…[2,37]), tree growth (e.g. [7,41]), and tree physiology (e.g. [50]) depend on information about crown dimensions of individual trees.…”

Section: Introductionmentioning

confidence: 99%

Estimation of crown radii and crown projection area from stem size and tree position

Grote

2003

Ann. For. Sci.

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“…Sibyla is empirical single-tree oriented climate sensitive forest model with a one-year simulation step, and the core components of the model are based on the Silva model (Pretzsch et al 2002). A detailed description of the model can be found in the studies we referred to earlier.…”

Section: Used Model and Simulation Designmentioning

confidence: 99%

Effect of different tree mortality patterns on stand development in the forest model SIBYLA

Trombik¹,

Barka²,

Hlásny³

2016

Forestry Journal

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Forest mortality critically affects stand structure and the quality of ecosystem services provided by forests. Spruce bark beetle (Ips typographus) generates rather complex infestation and mortality patterns, and implementation of such patterns in forest models is challenging. We present here the procedure, which allows to simulate the bark beetle-related tree mortality in the forest dynamics model Sibyla. We explored how sensitive various production and stand structure indicators are to tree mortality patterns, which can be generated by bark beetles. We compared the simulation outputs for three unmanaged forest stands with 40, 70 and 100% proportion of spruce as affected by the disturbance-related mortality that occurred in a random pattern and in a patchy pattern. The used tree species and age class-specific mortality rates were derived from the disturbance-related mortality records from Slovakia. The proposed algorithm was developed in the SQLite using the Python language, and the algorithm allowed us to define the degree of spatial clustering of dead trees ranging from a random distribution to a completely clustered distribution; a number of trees that died in either mode is set to remain equal. We found significant differences between the long-term developments of the three investigated forest stands, but we found very little effect of the tested mortality modes on stand increment, tree species composition and diversity, and tree size diversity. Hence, our hypothesis that the different pattern of dead trees emergence should affect the competitive interactions between trees and regeneration, and thus affect selected productivity and stand structure indicators was not confirmed.

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“…They reflect growth as dependent on stand-scale soil and climate conditions. The competition factor equations for height and diameter growth use parameters which are exclusively dependent on species (for more details see Pretzsch et al 2002). SILVA uses a time step of five years, because its growth curves do not represent the interannual variability of weather, and a higher temporal resolution would not add quality to the simulation result: the curves of potential growth are sigmoid (height) or unimodal (diameter).…”

Section: Model Descriptionmentioning

confidence: 99%

“…Furthermore to get the actual value of potential growth, the basal area growth that results from Eq. 3 is modified by a climate and nutrient-dependent factor that is named ESto in Pretzsch et al (2002). MoBiLE was modified in such way that the vegetation structure module delegates the cohort's representative tree dimension growth to the individual tree module (Fig.…”

Section: Model Descriptionmentioning

confidence: 99%

Extending a physiological forest growth model by an observation-based tree competition module improves spatial representation of diameter growth

2013

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One of the pivotal objectives in forestry research is to estimate the response of silvicultural target variables to climate change scenarios at high temporal resolution in order to consider within-year feedbacks between growth and environmental conditions. To meet this challenge, models are needed which support and complement the widely used observation-based decision systems in forest management and consulting. Physiological models in particular provide the fundamental prerequisites to reflect the impact of various simultaneously changing environmental conditions. However, a physiological representation at the individual tree level is computationally very expensive and sensitive to uncertain initializations. We thus propose an approach that combines a modern representative of the physiological cohort model type, MoBiLE-PSIM, with the individual tree competition concept of a distance-dependent empirical growth simulator (SILVA). The resulting hybrid provides a key feature for the consideration of forest management in long-term simulations at high computational efficiency. The extended model was evaluated with growth-diameter distributions obtained from core-boring at two beech (Fagus sylvatica L.) forest sites in south-west Germany that differ in exposure and soil conditions. The mean bias of annual standscale growth from 2001 to 2007 decreased from -0.59 to -0.41 mm at one evaluation plot and from -0.55 to -0.24 mm at the other when the competition module was coupled in. Inclusion of the SILVA-based individual tree module into MoBiLE-PSIM improved the size-dependent representation of competition and growth on five-year and even annual timescale. This was particularly the case where the spatial distribution of dominant trees was clustered.

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The single tree-based stand simulator SILVA: construction, application and evaluation

Cited by 448 publications

References 21 publications

Estimation of crown radii and crown projection area from stem size and tree position

Estimation of crown radii and crown projection area from stem size and tree position

Effect of different tree mortality patterns on stand development in the forest model SIBYLA

Extending a physiological forest growth model by an observation-based tree competition module improves spatial representation of diameter growth

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