I made a new HugeRedwood tree in the biomes config and when i placed 2x2 saplings, only 1 of the 4 saplings were turned in the tree (the one i bone-mealed) PROBABLY because the tree has only 1 origin and it doesn't know in which direction the 3 other vertical lines "expands".

as explained above, it CAN happen that all 4 sapling get replaced with the tree, if i bone-meal the right sapling.

Thanks, will look into it later. Which version are you running?

Sorry for the late answer, but i'm using version 2.6.4. Apperrantly i wasn't thinking when i posted this issue but i don't see a real solution for the problem other then have the opportunity to set 4 diffrent "origins"...

It seems the rotation of the object is causing the issue. From my testing, the sapling with the lowest x and z is found correctly, but then the object is rotated and doesn't spawn correctly anymore.

Should now be fixed. As long as your object expects the trunk to start at (x,z) (0,0), (0,1), (1,0) and (1,1) the object will spawn correctly.

Download