We have an eastern red cedar, about 35 feet high, and maybe 60 years old. It drops about a bushel of leaves and stems every year. I rake these up, and use them for mulch around our blueberry shrubs. The mulch is about 8 inches deep. Some of our blueberry shrubs get mulched with chopped maple leaves, from a norway maple that we have in the front yard. All of our blueberry shrubs are healthy and productive, but I have to work at getting the pH right, we have hard water, and calciferous soil. I have not seen any adverse effect due to the cedar duff, after three years of using it as mulch. Also, I have about 10 prairie smoke (Geum triflorum) growing near the base of the cedar, & these have been in this location for over 10 years, but I cheated, I saw prairie smoke growing near a red cedar while on a hike up ferry bluff, on the Wisconsin River near Sauk City, so I knew that these two species were compatible.

Thanks very much for the response! Of course, blueberries need acid soil, so that answers that. As to your maple foliage, ericwi glad that you are a composter! Blueberries also may not be affected by the alleliopathic properties of redcedar, so that remains a question. I have a situation where, as a horticulturist, I have been asked to opine on the re-use of redcedar duff in compost that will be used for a number of things. My "nose" tells me that it SHOULD NOT. Herein lies my question.
Thanks! hortster

Wooden chests made of cedar wood are supposed to suppress moth infestation, and they smell nice. If you like the smell of cedar...Cedar can be used for fence posts, and while they don't last forever, they do outlast posts made from pine. So I am guessing that there are essential oils in cedar wood that repel insects and also help protect the wood from soil microbes. Cedar shakes are used for roofing. In our yard, the lawn grows right up to the base of the cedar tree. We are successfully growing tomatoes within four feet of the base of the same tree. I have noticed that the cedar duff that I spread around our blueberry shrubs does not seem to break down very fast. But I have never tried to compost cedar duff, so I have no direct experience with compost made from this material.

Non of the needles or wood from any conifer (evergreen) will significantly affect soil pH. Some Cedars have properties that can repel insects that are harmful, but not all those plants in that family will do that to with thje same affect. Eastern White Cedar is not much more rot resistant that is Aspen, but Western Red Cedar is fairly rot resistant and that is what you need to look for for fence posts or other uses where rot resistance id desired. Most every Cedar Chest I have seen is also made of Western Red Cedar and you can smell that property something I've not noticed with Eastern White Cedar. I've not seen enough about the Eastern Red Cedar (a different species from the Western Red Cedar) that indicates the wood is rot resistant to believe it might be.