3D vs Planar tracking ? A little confuse

As I said earlier,I’m new on Motion Graphics.
I’m a little bit confused about Planar vs 3D tracking . I’m trying to track
a clip what the camera is moving + - 25ft in Z axis - dolly in (real camera,obvious)
the camera is going to pass through a tree ( tree is the object what I want to track)
because I want to put a stop sign next to this tree.
Is this 3D tracking? I think so. So my question is,every time the camera is moving
to front (dolly in) is 3D Tracking?
I upload a very similar example what I found on the net.
again,sorry about my english,I wish you can understand my doubt

Thank you for theinformativeposts.

HI There,
Mocha is a planar tracker, and coming in mocha 3’s release next month, mocha will have a 3d camera solver that will solve most shots you’ll need solved for 3D. You do not need a 3D solve to stick a sign in this shot. You can just track the rocks with mocha’s planar tracker and corner-pin a sign right into the shot.
Not every moving shot needs a 3D camera solve to put flat objects into. 3D objects you’ll want to place in the scene will need a 3D track 80-90% of the time. But even then sometimes all you need is a null, and you can get that out of mocha.