Sorry if its done before :D
As we know hashi creates living trees that are full of life. And hashi is full of sheer life force.
Mby he uses his own life force to create wood release and that may be the one reason he died young beacause he used up all of his life force. Had no choise beacause of the wars.
And if we take this to count then edo madaras wood release should be weaker (the scale may be the same) beacause he is dead (edo) and cant use life force to make stronger mokuton... just a tought. Or he uses hashis cells to fuel mokuton with hashis life force.
But then yamato is alive and has not shown any living wood release only timber like wood. (i may be mistaken or forgoting something) Mby he cant control hashis cells so well and cant get the life force of hashi.
Any toughts ? :D