Anywhere with lower animal or microbial activity.

The Rocky Mountains are a good example. Cold, dry, and a high elevation (reduced oxygen). You are told in those places explicitly to pack out everything because it won't decomposes.

Desert environments can also have the same issues just due to the dryness.

Here's an article

https://www.reconnectwithnature.org/news-events/the-buzz/even-if-it-is-a-banana-peel-it-is-still-littering

according to the Facebook post from Glacier National Park. "Some fruit products can take years to decompose depending on the environment they are in!"