Yes. I realize the properties of cedar but did not consider the Organic approach.
Have you tried contacting an Organic yard to ask what they are using?
Cedar is just not a common stock for this size of lumber/poles.
However, CCA or Chromated Copper Arsenate was outlawed (in the US) for the production of pre-treated lumber in 2004 favoring the less toxic Alkaline Copper Quat and/or Copper Azole so, it begs the question if lumber treated with those compounds meet the certification criteria. They are definitely easier attainable.