Engineers make trees grow down all the time, and have been for thousands of years. They call it kengai.I'm an engineer---not a biologist. But I was looking at a forest of tall pine trees and got to wondering why, exactly, do trees grow upwards?
Is it because they are the attracted to the sun?
Or repulsed by gravity?
How do they even know which way "up" is?
Would a tree growing on a spaceship (absent gravity) under artificial light grow towards the light?
And what, internally, makes them grow towards the sun, if that is the driving factor?