Phototropism or Hydrotropism is a more important factor for trees beside the lakes growing bending to the water?

Question

I see a lot trees beside the lakes are growing bending to the water and I wonder why. After reading this I think it might be a combined effects by:

• Phototropism: the lake works as a mirror and sunlight are reflected
• Hydrotropism: of course, Hydrotropism...

But which one is a more important factor? Phototropism or Hydrotropism?