I remember watching Dragon Ball Z: Tree of Might when it first premiered on Toonami back in the late 90's. It was the third Dragon Ball Z film, and one of the most memorable for me. Mainly because they kept showing a lot of re-runs of it.
The story is about a group of alien warriors coming to Earth. When they land they plant The Tree of Might which can easily absorb Earth's energy and resources. The use it mainly to grow the fruit the tree produces which will grant greater strength to the person who eats it.
The leader of the group is an evil Saiyan named Turles who looks just like Goku but with a tan. I didn't like the fact he was basically Goku's (non-related) evil twin. His team-members were also very forgettable.
This was also the first film that made no attempt to make sense with the main story-line. As Goku has powers that he learned from King Kai, but feature members of the Z Warriors that died in the battle against Nappa and Vegeta. Despite all that, I did find it to be a decent movie.