I think everyone who does yamadori or dug up a tree in a garden has broken at least one folding shovel or even spade in the process. Almost all of the commercially available products are cheap, weak and just not reliable.
Thankfully, last year I discovered the "special forces shovel" made by Cold Steel and aquired one after a bit of research. As many reviews confirm, this shovel IS extremely tough and versatile at the same time. This 50 cm long, 750 g light tool can be thrown, used to hack (e.g. through roots), to defend and to dig. The spade blade comes super sharp and can easily be resharpened if needed. A sheat is also available and considered useful. The hardwood handle makes this digging spade very robust. It is hardly likely to break even when massive force is applied when lifting a tree. It fits nicely into larger backpacks and accompanied with a good pair of garden pruners, a folding saw and possibly a mason's hammer and crowbar in rocky terrain, these are all the tools you need to dig most trees up to medium size.