(There was a delightfully snarky website ((of course I can't find it now)) which once wrote, "It is often called the Citizen Kane of horror films, but no one calls Citizen Kane the Wicker Man of mainstream films...." And there are some great filming details, like this:)
"Autumn" was turned into "summer" by employing fake plastic apple trees and by decorating the real bare trees with imitation blossom. Locals were recruited to fill out the crowd scenes, and pupils from a ballet school helped with some of the dance routines – everybody being kept warm with industrial fan heaters.
Robin Hardy, director: The final scene, the sacrifice, took place in Dumfriesshire. The wicker man was enormous. The stunned look on Howie's face when he first sees it wasn't acting – up until then, Edward had only seen drawings. He clambered in and we set it on fire, filming from the inside. There was a goat inside there, above us. Understandably concerned about the fire, it pissed on us.
....any extra inanity just adds to the film's overall phantasmagorical weirdness. I mean, this is a film where Christopher Lee spouts odd Pagan poetry over lovingly photographed snails intertwined in the act of mating. And yes, those snails, like the talk of apples, are there for well-calculated reasons.