I have a home in zone 5/6 farmland I put a few trees in on 5 and a 600 acre lease on zone 3/4. Once you hit zone 3, offering for apples go way down. Camp is in the Adirondacks and get polar vortexes every few years. February 2023 was recorded as -37, and thats a few degrees warmer where the weather station is. Maybe 400ft lower in elevation too.
At camp 30-06 has survived and grown fairly well. I fhave few apples varieties up there, but have several kerr crabaples that are very edible. Some folks on here prefer it to other commercial apple varieties they have. I have a MN 1734 up there from last year.
I have a few on farmland, but not many. A few 30-06's doing, well as well as a big dog growing ok. THe farmalnd gets sprayed, none have been harmed yet. My brother in law takes excellent care of his john deere spray rigs. I put a Galarina up there 2 years ago and thats doing good. Got 3 galarinas at home too. That is an apple tree I have alot of promise for. Disease resistant version of Gala. Apples are on the small side so they hang on the tree going into winter. Skin is supposed to be on the thick side, which can help with bugs too
At home I have over 40 trees on 6 acres. I keep scion photocopies of everything at camp incase I want make more, or loggers destroyed a few trees. About a dozen crabapple trees and maybe 5 or 6 other crabapple varieties growing on a branch or two on apple trees. I also spray for bugs and a bit for diseases too. Crossbow has been growing like a weed with excellent branch angles are bugs seem to have been dodging it like whitetail crabs touts. Japanese beetles somehow really dislike this tree. MY wife loves macoun and empire and have those. Sundance on M7 is doing great. Might more be the m7 part. The roots are touching my foodplot, so it might be getting better soil too.
I have no permissons. I believe the edge of USDA zone is 4 and thats pushing them too. Heard way too many bad stories about chestnuts getting beat up to play with those too. I do plant a few oaks at camp, for someones kid to hunt under someday. I hide them well in mounds in the swamp area. Be real tough to get a logging truck there. I do have a few northrup mulberries. Deer love those and birds and squirrels go nuts for them. Tons of grouse at camp, but only sightings of grouse at my home has been on my mulberries. They're a july / august fruit. Some good rain years september. Great for summer trail camera pics, every animal in the woods is at those trees.