Hi,
we do have several different tags for checkpoints, e.g. by police. We also have tags for fire lookouts.
But I think there's nothing for this special case. 

How about some generic tagging and a description:

amenity = checkpoint (used 200 times in various contexts)
access:conditional = yes @ Jun 15 - Nov 30; no @ Dec 01 - Jun 14
description = ... fire prevention ... guard ... no access
operator = XY

Maybe access=private or permit is better depending on the actual situation

Make sure the node is part of the highway so that a router sees the barrier.