Protecting trees from pigs?

I'm making paddocks for my pigs so I can rotationally graze them. I bought tree seedlings that I want to plant along one edge and some shade trees for inside the paddocks. Now I'm stumped about how to make something strong enough to keep the pigs out of the trees until they get bigger. Any ideas?? The paddocks will be around 3000 square feet so they'll have plenty of space. My current boar goes around all the fencing pushing it outward whenever he's bored, so it has to be strong or I need to hurry up and get rid of him.

1. electric fence - pigs respect electric fence.
or
2. https://permies.com/t/1805//Sepp-Holzer-recipe-animals-trees

No offense, reading through the link in #2 is the silliest argument ever. Hasn't anyone tried it?? Where do you get two cast iron pots?

I was reading about bone crafts and according to that, old bones smell really nasty and if you want to make stuff out of them there's a lot you have to do to get rid of the really offensive odor they can give off when you disturb them (like by sawing). I bet he meant to use old bones, not fresh ones. So it probably works similar to "Liquid Fence" which repels by it's nasty odor. Not sure I'd want to do that in any rare hard to find iron pots. LOL.

Renate Haeckler wrote:No offense, reading through the link in #2 is the silliest argument ever. Hasn't anyone tried it?? Where do you get two cast iron pots?

I was reading about bone crafts and according to that, old bones smell really nasty and if you want to make stuff out of them there's a lot you have to do to get rid of the really offensive odor they can give off when you disturb them (like by sawing). I bet he meant to use old bones, not fresh ones. So it probably works similar to "Liquid Fence" which repels by it's nasty odor. Not sure I'd want to do that in any rare hard to find iron pots. LOL.

Quite a few people have tried it and claim good results. I wouldn't be worried about messing up the pots. Cast Iron is not likely to uptake any odor. I'm pretty sure that the idea is to make a basic pressure cooker to steep the nasty out of the bones and into the goop in the bottom of the pots. I'll bet a crappy pressure cooker with a strainer basket inside would work just as well. You might find one at a thrift shop cheap. It's certainly a cheaper solution that replacing trees and/or a boar. there is a thread here too. https://permies.com/t/14922/projects/Burra-Bone-Sauce-Experiment#175580

Renate Haeckler wrote:No offense, reading through the link in #2 is the silliest argument ever. Hasn't anyone tried it?? Where do you get two cast iron pots?

No offence taken, but I dont think the type of pot actually matters all that much, sounds like just about any small metal containers would do fine.