[barnbilder]

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?

Engineers make trees grow down all the time, and have been for thousands of years. They call it kengai.

 

[barnbilder]

Yes! Kengai is an excellent example of engineering trees to grow downwards. But the leaves still all point towards the light so they can use their solar collectors.

Pictures of kengai:

kengai - Google Search

www.google.ca

.

I'm working with an olive tree. It hasn't told me yet if it wants to be Kengai, Han-kengai or Fukinagashi. I'm hoping the latter, but there is still much time.