Forest fires are a type of wildfire, which to spread effectively need at least two things:
Sufficient dry starting fuel.
Wind in the direction of spread.
If constructed correctly, it is conceivable that the non costal side of the forest would not experience a sustained wind coastwards, but would experience a sea breeze, pushing the fire front away from more trees and fuel. This doesn't stop anyone from methodically burning the forest down, but it will force them to put a fair amount of effort into it.
Forest fires are more complicated than this, read Wikipedia on wildfire models: https://en.m.wikipedia.org/wiki/Wildfire_modelingWikipedia on wildfire models.