Why do trees on the surface of a slump tip back into the slope?

Question

Why do trees on the surface of a slump tip back into the slope?

ON a slope of 15 degrees, where is the colluvium the thickest on the slope?

Answer 1

isnt it just because they're growing up towards the sun?

Answer 2

Because on a slump, the movement takes place along a spoon-shaped glide plane.

So the bottom of the slump moves outward and the top moves downward to fill in the space vacated by the bottom movement as a result it rotates.