Hi Raistlin,
Please try to increase the Face size value for all MetaMesh builders of all paths. It's much reduce generation time. When you are finished setting your tree, set the previous values.
Also, use the following options:
1. Turn on Stop stitching for branches;
2. Turn on Stop stitching for the trunk, and set Stop after pos is equal to 70% (for example).
Of course, we'll soon make a new tutorials, and there will be shown how to create plants with metamesh.
Cheers