Board Thread:Theories and Speculation/@comment-27075290-20151102051236/@comment-734582-20151105102127

SJ 88 wrote: Also spsm doesnt come from the bijuu it comes from the sage. Just a small correction here:

SPSM is different from his chakra cloak. SPSM indeed comes from the Sage, whereas the cloak (and apparently, truth-seeking balls) come from the Biju. The ability to use Biju powers comes from the biju (obviously). It seems Naruto doesn't have enough chakra in him to perform the Biju abilities (though that's probably easily recharged by a quick visit), but can perform the SPSM abilities.

It actually does give him understanding of chakra, but the practical part of that seems to be simply full control over Shape and Nature transformations (as naruto combined numerous elemental releases with shape transformations to create extremely complex and powerful jutsu on-the-fly.). So in this case, Understanding = Mastery.

I do believe there's no real restriction for Naruto to use Wood Release, but i simply think that the amount he has is too low. The cases where Wood Release was used had immense amounts in their body. I don't recall the details of Yamato but i believed he got a gene therapy. Obito was half hashirama goo, Madara had it infused into him and it merged slowly into Six Paths chakra (it transformed his body, similar to Yamato). The case where it failed, Danzo, had only an arm and Naruto has even less than that.