if you plant a tree with the intention of lifting it, knock the bottom out of an old large plastic pot, and plant the sapling in the pot in the hole in the ground. this will help shape the roots some what and facilitate the replanting of it.
note ..pear tree roots grow downwards, which is why traditionally they were planted next to stone dykes and walls, consider putting a few old slates in the planting hole before planting the sapling. you may wish to do the same for apple tree saplings if leaving in the ground for more than 3 years
there are reports that really old pear trees, over 300 years old, with rootstocks even older, 1550-1700, and when they blow down and the roots are ripped up side ways, old reused grave stones are revealed. this is also a good planting technique for trees planted in rocky ground where the soil is thin as it eventually causes the roots to grow sideways.
of course, old gravestones are at a premium, (although, oddly enough, i have a spare in a shed dating from 1605??) slabs make an acceptable substitute