manufactured boards aren't bad for the environment.
They made from old wood chipping/ saw dust, so they are almost "recycled" boards.
They are bonded together, but this is totally biodegradable unlike the first answer.
if your asking this for an environmental issues page (a school project say)
mention:
made from recycled old boards.
totally biodegradable.
no deforestation caused directly from them.
can be recycled themselves.