How do you achieve this effect?

[andrewgray123]

It looks like the pen tool has been used for a path. Then the path has been stroked then decreasing the brush spread or size as its got closer to the bends of the tree. But I can't figure out how? Any clues or tips to what tool was used?

 

[fredfish]

Have a look here as a starting point (though you will want to add to it)

Sparkle trails

Cheers

John