The simplest way of doing what you want is to use a Multi Channel Mixer shader. In Source 1 load your leaf texture map (or just choose a green color) in the color channel. Make sure the Transparency slider is at 0. In Source 2 choose Complex Shaders, Single Channel, set the channel to Transparency then the shader to Value 100%. Then in the blender channel load your black & white trans map for what you want leaf and what you want transparent. You may need to invert the color which will switch things if you've got it the wrong way round. You can use movies as texture maps, just load in the same way. Two keyframes will appear in your timeline, drag the right hand one across until the end of your animation. If you want the texture movie to repeat double-click between the two keyframes then select Oscillation tweening in the Properties tray, choose Sawtooth, set Up Phase to 100% and adjust Oscillations for the number of loops you want. HTH Mark