It's Aqua and Terra for Victus.Sounds like you don't know one of the aspects in wood.
If I remember correctly, you'll need to combine a couple aspects (Two primals, I forget which ones... probably not Ignis, Aer, or Perditio) in the research table to learn Victus, then you can scan seeds for Granum, if I'm not mistaken, then you should be able to do wood just fine.
There's a Thaumcraft cheat sheet somewhere on these forums that'll tell you exactly what you need to do.
And in my testing I still need to scan for Herba before I can get Arbor(not that this is hard or anything)