Figure 1: Growth of two genetically similar trees using our system. The top images are of a tree grown during good conditions while the tree in the bottom row of images suffered a water shortage. AbstractThis paper describes a method using L-systems that models tree growth based on the interaction of the tree's internal attributes with themselves and with environmental conditions. Modeled components include chemical flow and water distribution within the tree, phototropism, space tropism, energy generation and usage, weight support, and self-pruning.Our system is described and many results are presented which show how the individual factors affect tree growth, and also how they interact with each other.