Tree Types Not Generating

Hello, I have just figured out how to generate my first type of tree, and it works really well. However, I am having a problem where two other tree types that are specified are not generating. 
For testing purposes, they're very similar trees (the generation code is identical for testing, besides the leaf block), but I've tested by changing leaf blocks and they are not showing up. Only the first type appears. Could this have something to do with generation order?