If you need trees, you should consider to either upgrade or use Vue. It should be mentioned here that there are tree models downloadable from the internet as well as tree models that you can buy on CDs. Besides the plant system, I don't think that an upgrade of Bryce 4 to 5 is really worth the money (for me it was Bryce 3D to 5, that makes more sense). For making tree (and other) models, you might also consider to buy the "Lite" version of XFrog (www.greenworks.de). Just my two cents... Gabi