Tried to start a new game with treees enabled and got:

The mod Treeees (4.2.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Trees::on_init()
__Trees__/control.lua:70: attempt to index field 'data' (a nil value)
stack traceback:
__Trees__/control.lua:70: in function 'reset'
__Trees__/control.lua:383: in function 'get_all_positions'
__Trees__/control.lua:448: in function <__Trees__/control.lua:445>

Thank you very much!

fixed in version 4.2.1 and 3.3.1

Thank you!