The prophecy of the vine tree in Ezek 15:1-8 foretells the destruction of Jerusalem by fire.  

The Vine Tree Typifies Israel

The prophecy begins in v.2 with a comparison of the value of wood from the vine tree to the other trees in the forest.  Israel is like the vine tree in this prophecy.  

In Jud 9:8-15, Jotham compares Israel to three different trees: 

In v.3 the Lord asked if wood from the vine is good for work.  It’s not.  He asked if it is good to use as a pin on which to hang a vessel.  It’s not.  You can use a vine for fuel, v.4, but it burns up quickly and just turns to ashes.  Therefore, it isn’t meet for any work.  And it’s particularly useless after you burn it, v.5.

The Burning of the Vine Pictures the Burning of Jerusalem

Having established the metaphor, the Lord said in v.6, “As the vine tree among the trees of the forest, which I have given to the fire for fuel, so will I give the inhabitants of Jerusalem”.  The burned up vine tree pictures the burning of the inhabitants of Jerusalem.

In v.7 the Lord set his face against them.  Then he said, “they shall go out from one fire, and another fire shall devour them”.   

Once again we read that they will know that God is the Lord, v.7.  And in v.8 he made the land desolate, because they committed trespass.

Conclusion: the vine tree is only good for bringing forth its fruit.  When it’s not fruitful, then its branches are burned, just like the fruitless branches of the vine in Jn 15.