- The lower images looks like being a barrier=lift_gate made from a log, i.e. IMHO it's a lift_gate, just like a wooden house is a house not wood/log. In the upper image I cannot recognize any mechanic to move the log, hence I'd map as a log. --Schoschi (talk) 12:35, 26 July 2018 (UTC)
I feel this is a duplicate with barrier=block since in practice it means the same: a large block of something meant to obstruct the passage of users. That something being different is not important as long as they influence all kinds of users in the same way when using the map. Let's compare a block of concrete with a fallen trunk, pedestrians and cyclist are still able to pass quite easily but not 4 wheeled vehicles on both situations.
Also, a cut log, fallen trunk or complete tree with its dense branches blocking passage are different kinds of situations of a same kind of material, therefore i think it is necessary to keep some tag modularity to represent all the possible situations.
Finally, i noticed users using "barrier=block" + "description=fallen trunk" to map such elements. If the element really restricts a kind of user, let's just use the specific tag of access per kind of user. For example a fallen tree whith branches dense enough to block passage of cyclists even by carrying the bicycle but not for pedestrians, it would be a node tagged as: "barrier=block" + "natural=tree" + "description=fallen tree" + "foot=yes" + "bicycle=no".