Stanton D. answered 01/10/24
Tutor to Pique Your Sciences Interest
Fractal trees and your functions don't appear to have any theoretical overlap. Maybe someone else has a completely different idea they call a fractal tree.
Anyway, your function "rules" don't seem to make sense either. It's easy to just state what the functions are, as mathematical statements
'the first y = 3^(x+1)
the second y = 3^(-x)
Again, these have no overlap with what you have furnished as "rules".
It would be possible to incorporate your functions into the drawing of a fractal tree, for example as numbers of branches for the first function, where "x" is the index number of a stage of drawing, and as length and diameter of such sequential branches for the second function. You can't draw a 3-D object that indefinitely splits into threes with a constant arm length and diameter -- the figure closes up presently -- a property which has been used to imprison small molecules within a polymerizing "star polymer".
-- Cheers, --Mr. d.