Dear Analyst, I have seen, on many occasions, pink stains/blotches on newly produced Yellow Cedar (Chamaecyparis nootkatensis) shingles. These shingles can be produced by different manufacturers from the Mainland or from Vancouver Island. These stains are not the result of iron contaminant or oil/grease. I have been told that these stains are the result of exposure to a mold/mildew which react with the extractive in Yellow Cedar and the result are the pink stains. I have always noticed that when these pink stains are exposed to the weather they do disappear in a short period, generally in about 7-10 days. I would just like to obtain clarification on the cause(s) of these stains on this species. Thanks! Tony B.