Vine To Tree Root Grafting
I don't think this will work. Grafting will usually work between the same species and sometimes between the same genus. You're talking about grafting Philodendron cordatum to Quercus robur. The former is a tree from Europe, the latter a flowering plant from Brazil. They aren't compatible in the slightest. The graft will never take.

One possible route you might want to consider that may be more successful, but a lot more difficult, is using agrobacterium tumefaciens to infect a mix of cells from the two species. If you have a homogeneous mix of individual cells in culture, infect it with A. tumefaciens, the resulting gall will contain cells from both (incompatible) species. How they grow from there is unknown.