Simulating the development of Fraxinus pennsylvanica shoots using L-systems

Introduction

This paper presents a methodology for creating computer models that capture the development of plants using the formalism of L-systems and incorporating biological data. The modelling process is divided into the following steps:

• A qualitative model is constructed according to observations of plant growth and form.
• Measurements of key characteristics are gathered from actual plants.
• Statistical analysis is performed to convert the raw data into functions which describe growth.
• The quantitative model is formed from the qualitative model and growth functions, as well as approximated functions describing the growth of model elements for which data has not been obtained.
• A visualisation of the model is produced.
• An evaluation of the model is performed. The visualisation aids in exposing any flaws in the qualitative or quantitative models, and helps identify any incorrectly estimated functions.
• If a further iteration of this modelling process is required, this process is repeated. The choices and assumptions made in the construction of this model are then reconsidered and modifications are applied to improve the model's reflection of reality.

This paper makes use of a model of shoots of Fraxinus pennsylvanica, also called green ash, to illustrate the presented modelling methodology. It compliments research performed in 1994 as a collaboration between biologists and computer scientists, which resulted in a publication in the Canadian Journal of Botany. In the following sections, a brief introduction to L-systems is given and then the methodology is described in greater detail.

Reference

Mark Hammel, Przemyslaw Prusinkiewicz, William Remphrey, and Campbell Davidson. Simulating the development of Fraxinus pennsylvanica shoots using L-systems. In Proceedings of the Sixth Western Computer Graphics Symposium (Banff, Alberta, 20-22 March, 1995), pages 49-58, March 1995.