Perhaps the Cedar harvested to make your trim has been infected with the Japanese Cedar Longhorned Beetle. These beetles have been well established in North Carolina for close to 10 years now. While they are known to infest living trees, quite possibly they were already in the wood when it was harvested.

"The adults, which live about 20 days, are active between late March and early June. The adult beetles are about 1/2-inch in length.
Adults mate on their host plants, and then females lay eggs under bark, apparently without feeding. After hatching, the larvae bore under the bark to feed on the cambium and phloem. Once the larvae have stopped their feeding, they bore into the sapwood and carve an elongate pupal cell. Here they pupate, and then emerge as adults in about 2 weeks. The adults, however, are destined to stay in their pupal cell until the following spring. This species has just one generation per year."
(credit to Dr. Chris Maier - Department of Entomology,The Connecticut Agricultural Experiment Station)

Have you seen any bugs that look like this?

{{!gwi}}
Adult beetles are 6 to 14 mm long, 3 to 4 mm wide and have a slightly flattened body. The head and thorax are brown with reddish-brown hairs

{{!gwi}}
Elliptical exit hole in infected tree (6-10 mm wide).

gourmet81, have you found an answer to your insect problem?
Can you post a picture of the damage? I'm sure that with a little bit of feedback from YOU someone would be able to help you find the source of your cedar problem.

I think i know what you're talking about, they're called carpenter bees. They look like bumble bees but eat perfectly round holes through wood just like if you used a drill. My uncle just replaced a section of facia trim on his house they had bored into, these things actually went in and bored left and right down the length of the board.

Here is a link that might be useful: http://www.ca.uky.edu/entomology/entfacts/ef611.asp

Yeah, sounds like the carpenter bees we've had in the DC area. You should be able to get them treated by a termite company.