Convective heat transfer between vegetal sets and the surrounding air in the context of forest fires has not yet been fully investigated and understood in existing studies. This process may have a great influence on many environmental problems such as forest fires. This study is devoted to the computational heat transfer characterization of tree structures. These structures were generated by Iterated Function Systems (IFS) and the fluid flow was computed using balance equations (mass, momentum, heat, etc.). The heat transfer was then characterized using the macroscopic Stanton number on several tree structures. The main objective of this study was to demonstrate that the macroscopic Stanton number only depends on the macroscopic Reynolds number using a power law. In addition, the power law exponent was found to be quasi-constant for all the configurations tested in this work and it tends to be universal. (C) 2011 Elsevier Ltd. All rights reserved.