Séverine Le Dizès, Philippe Balandier, Pierre Cruiziat, Patrick Jacquet, André Lacointe, Xavier Le Roux, Hervé Sinoquet. (1997). A model for simulating structure-function relationships in walnut tree growth processes. Silva Fennica vol. 31 no. 3 article id 5628. https://doi.org/10.14214/sf.a8530

Keywords: carbon; simulation; pruning; growth; Juglans regia; structure-function relationships; frame-based representation; rule-based representation; walnut

Abstract | View details | Full text in PDF | Author Info

An ecophysiological growth process model, called INCA, for simulating the growth and development of a young walnut tree (Juglans regia L.) during three or four years, is presented. This tool, currently under development, aims at integrating architectural and physiological knowledge of the processes involved, in order to give a more rational understanding of the pruning operation. The model describes a simple three-dimensional representation of tree crown, solar radiation interception, photosynthesis, respiration, growth and partitioning of assimilates to leaves, stems, branches and roots. It supports the hypothesis that the tree grows as a collection of semiautonomous, interacting organs that compete for resources, based on daily sink strengths and proximity to sources. The actual growth rate of organs is not predetermined by empirical data, but reflects the pattern of available resources. The major driving variables are solar radiation, temperature, topological, geometrical and physiological factors. Outputs are hourly and daily photosynthate production and respiration, daily dimensional growth, starch storage, biomass production and total number of different types of organ. The user can interact or override any or all of the input variables to examine the effects of such changes on photosynthate production and growth. Within INCA, the tree entities and the surrounding environment are structured in a frame-based representation whereas the processes are coded in a rule-based language. The simulation mechanism is primarily based on the rule chaining capabilities of an inference engine.

Le Dizès, E-mail: sl@mm.unknown
Balandier, E-mail: pb@mm.unknown
Cruiziat, E-mail: pc@mm.unknown
Jacquet, E-mail: pj@mm.unknown
Lacointe, E-mail: al@mm.unknown
Le Roux, E-mail: xl@mm.unknown
Sinoquet, E-mail: hs@mm.unknown

Category : Research article

article id 628, category Research article

Stefan Daume, Dave Robertson. (2000). A heuristic approach to modelling thinnings. Silva Fennica vol. 34 no. 3 article id 628. https://doi.org/10.14214/sf.628

Keywords: thinning; heuristic model; rule-based; knowledge-based

Abstract | View details | Full text in PDF | Author Info

Thinnings play an important role in guiding forest development and are considered by many to be the most important influence on forests in Central Europe. Due to their importance, thinning models are a major part of any forest growth model for managed forests. Existing thinning model approaches have a number of problems associated with structure and model development that weaken their reliability and accuracy. To overcome some of these problems this paper proposes a heuristic approach to modelling thinnings, where the focus is on distance-dependent, single-tree models. This alternative approach tries to capture the information, strategies and deductive processes likely to be employed by a forester deciding on the removal of individual trees in a stand. Use of heuristics to represent thinning knowledge simplifies the construction and refinement of a thinning model and increases its plausibility. The representation of thinning heuristics in Prolog – a programming language based on formal logic – is a straightforward process without losing expressiveness of the original heuristics. Limited tests of the model implemented in Prolog indicate that the proposed model outperforms its competitors.

Daume, The University of Edinburgh, Institute for Representation and Reasoning, Division of Informatics, 80 South Bridge, Edinburgh EH1 1HN, United Kingdom E-mail: stefand@dai.ed.ac.uk
Robertson, The University of Edinburgh, Institute for Representation and Reasoning, Division of Informatics, 80 South Bridge, Edinburgh EH1 1HN, United Kingdom E-mail: dr@nn.uk

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