Henry S. Horn
Department of Ecology and Evolutionary Biology
This is a photograph of the screen of an IBM PC-AT, taken in the penultimate decade of the last Century of the previous Millennium. The trees realize a 6-times fractally iterated ‘turkey-track,’ with variations in the angle between the toes and in the shrinkage at each iteration. Code in BASICA was less than two pages, ... and most of that was housekeeping. As ‘educational’ software, this won a local IBM contest and got me a trip to Disneyland. Parameters like the branching angle, shrinkage, and number of iterations can be measured on real twigs and real trees. Constructing fake trees with real parameters led me to novel insights into the role that developmental ‘architecture’ plays in adapting trees to gradients of light to shade, dry to wet, canopy to understory, and field to forest. Horn, H. S. (2000) Twigs, trees, and the dynamics of carbon in the landscape, pp. 199-220 in J. H. Brown & G. B. West, eds., Scaling in Biology, Santa Fe Institute Studies in the Sciences of Complexity, Oxford University Press.