Tips for establishing trees alongside animals

Hi all, I am looking for effective and economical solutions for establishing trees (ideally in large numbers) on a large farm that also has sheep and cows.

The most obvious and possibly most effective but also most expensive way would be serious fencing but I am curious if anyone has clever planting techniques, tree species that animals generally don't eat or biological solutions for protecting trees.

I have seen trees protected by creating large 'doughnuts' of slashed brush (preferably thorny).

I wonder about purposefully seeding desired planting areas with fast growing thorny shrubs (gorse is ideal as it is N fixer) then, once it is sufficiently tall plant into it and hope nurse species is shaded out over time.

Your thoughts / contributions are most appreciated

An effective, inexpensive, long-term solution is a challenge, no doubt.

Portable electric fencing, solar or grid, and paddock rotation.

Protecting individual trees from the animals will be costly, better to control the animals directly. It would only have to be a few years. Once the trees have an out of reach canopy they'll be able to survive.