I think the typically referenced softwares in this space are X Frog and SpeedTree.<p>The developers of XFrog have a few references listed:<p><a href="http:&#x2F;&#x2F;xfrog.com&#x2F;company&#x2F;about&#x2F;" rel="nofollow">http:&#x2F;&#x2F;xfrog.com&#x2F;company&#x2F;about&#x2F;</a><p><a href="http:&#x2F;&#x2F;graphics.uni-konstanz.de&#x2F;publikationen&#x2F;1998&#x2F;creating_plants_cgforum&#x2F;Lintermann%20et%20al.%20--%20A%20Modeling%20Method%20and%20User%20Interface%20for%20Creating%20Plants.pdf" rel="nofollow">http:&#x2F;&#x2F;graphics.uni-konstanz.de&#x2F;publikationen&#x2F;1998&#x2F;creating_...</a>
(A Modelling method and user interface for creating plants, Lintermann et. all.)<p><a href="http:&#x2F;&#x2F;graphics.uni-konstanz.de&#x2F;publikationen&#x2F;1998&#x2F;plant_ecosystems&#x2F;Deussen%20et%20al.%20--%20Realistic%20Modeling%20and%20Rendering%20of%20Plant%20Ecosystems.pdf" rel="nofollow">http:&#x2F;&#x2F;graphics.uni-konstanz.de&#x2F;publikationen&#x2F;1998&#x2F;plant_eco...</a>
(Realistic modeling and rendering of plant ecosystems, Deussen et. all.)