My Wisconsin uncle backs up the idea of using two short fences, or an enclosure about 5 or 6 feet across, as an effective deer barrier. They had some kind of study a while back, using temporary little fenced-off areas for deer exclusion, and he said with these tighter fenced circles (about 6 feet across) they reported that only one brave, young buck tried to jump into a circle and eat. He jumped back out again and didn't try it again - that tight of a take-off and landing is just not fun for a critter that likes a quick escape route. You may be able to do similar things with some flagged string or wire, like you do for hawks over a
chicken run. Break up the "runways" so they can't get a clean jump in or out, and it can be a more effective physical and psychological barrier for less total material and cost. A 5-foot "chicken moat" around big garden areas doubles as a deer fence.
My in-laws' orchard has done pretty well with an 8-foot vertical fence, here in inland WA. But in bad years for deer, or good years for apples and gardens, the neighbors report that some of their deer will Fosbury-flop their way over an 8 foot fence. If they are determined
enough, eventually they can bend over the tops of high fences.
Voles, rabbits, etc. have been observed in the gardens, but have not done much damage to the fruit trees that we've seen. We tend to keep two boisterous dogs on the property, and they get excited about critters even if they can't get to them. (Doesn't have to be a trained LGD, any mutt can bark at deer.)
The fenced orchard area doubles as a dog turnout when we all have to leave home the same day, but our leggy mutt can jump the fence as good as any deer, so it's not quite perfect.
(280 yards of 8-foot fence with one 10-yard run of 6-foot fence is as good as a 6-foot fence.)
We have more problems with frost and drought (and privately, my begrudging opinion, with shallow watering and anti-mulch
gardening practices by my well-meaning mother in law, who would rather have a co-dependent garden than learn to develop self-tending plantings). So all my tree planting experiments for low-attention
gardening are dependent on really hardy stock to survive really crappy first-year tending. We are often gone for weeks or months at critical times in the garden. If you're a good farmer, and given that you're in a much friendlier climate for summer humidity, you will probably have far better success than we do. And we would not likely have any relevant
experience of what blights to avoid - very different, arid-summer climate.
In the open meadow area, I've tried using brush piles to protect new trees, with some success. There are currant bushes that are browsed to the ground across the meadow, but survive as puffball-trimmed shrubs in the center of a "driftwood" pile (old logging slash) that the deer and horse can't quite reach past.
I got distracted with wildfires and publishing, and killed off some of the starts from lack of water - but the sticks are still there, so deer didn't get 'em. I also used some cayenne pepper spray on some of the starts and not others - seemed to help OK but I don't have live trees to show for it, just intact sticks. Might be voles in those piles, come to think of it, it would be a perfect place for them. I know there are ant-hills in some of them (not that I suspect them of killing trees, but they like the undisturbed, uncompacted earth there).
In the boggy
pond area, I've had some success planting larger quantities of new trees - rooted willow cuttings - so that the deer and moose can browse the outer ones without killing all the inner trunks. I get free willow trimmings from a local farm, so it's not much work to keep shoving sticks in the mud and
feed the moose.
If you can get cuttings to root (using willow-water for rooting "hormone," or the hard-core stuff), or have another way to get a lot of surplus planting material, or if you can use scrubby trees or thorny scrub of other varieties to protect experimental plantings-from-seed, this might be of interest for half-wild, half-food-forest areas. I could see using a thorny plum thicket as the outer guard for a mixed-fruit stand, and then putting up a "stile" where you can get in to tend, pick, and aggressively prune the interior. (Maybe a gate made of thorny branches, or something like that). Haven't done that yet, but all in good time.
Thorny fences are used a lot for livestock control in areas where metal fencing is expensive; in combination with guardian dogs, watchful humans, or other active deterrents, they're a useful option for defining the protected/"dangerous" zone and concentrating the deterrent effects of your guardians.
Good luck! Have fun with it.
-Erica