i love the Fallout trapps, bear trapps, rigged shootgun, grenade bouqet etc
other way to defend to etc improved barricade - stronger or maby add sharpned poles to it so you get damage when running in to it or trying to climb/jump over it.
maby option to get guard dog or something thats in a hidden cage that be relesed when coming to close or stepping on tripp wire.
May I suggest barbed wire or shards of glass to be a lot less clunkier in terms of materials and space?:) Incognito is the way to go, if you want people to wonder why they're bleeding or stuck at a certain place. Although sharpened poles would be a good defense against enemy AI, it probably would be too obvious for people to run into. You could make a way to make a maze with it and lead people / monsters to a place you can easily kill them and safely loot their body at.
landmines, alarm system (noise and light)
Edited:
...that is what I'd LIKE to do, but as it stands, the amount of wood you find doesn't even compare to how much wood you need to build anything remotely large. If you manage to find multiple wood piles then you're set, but the odds of that are extremely low and you can always die.
I'd love to build large mazes and death pits but Wood is earned far too slowly when you're just wacking at trees. Spikes would be a cool addition to add for some time in the future when wood is less scarce.
If I was trying to survive in a forest filled with people out to kill me, I would grind away at some wood until it could possibly impale an intruder. After all, everyone else has guns. We need more methods to best enemies with superior weaponry with cunning and wit, and traps would fit that purpose.
I see your point of the whole "Rambo" perspective and utilizing terrain mixed with easily accessible materials. Definitely a great starting point to increasing your chance of survival against mobs and players alike