Yes there is a config you can change!
In a long term of testing, I figgured out which.
You can Edit the MaturityAgeDays of each Plant in the EcoSim config.
Eg Birch trees need 4 days to grow, you will find in the Data:
edit the number behind the last one and you will have a much faster growing plant.
notice that the Number behind is always counted in full days! I recommend 0.02 for any trees and 0.003 for plants.
I hope it helped