I'm not from New Orleans so excuse the silly question, but what is the buzzing noise coming from the trees? Some sort of animal or insect?

My guess would be cicadas

Locust has are in the trees they sound like Cricket's a little bit

Yes. I agree with Shane. Cicadas, though I wouldn't really describe the sound as a buzzing... Hard to come up with a better descriptor, though

They are called cicadas https://www.google.com/amp/s/relay.nationalgeographic.com/proxy/distribution/public/amp/animals/invertebrates/group/cicadas