How To Kill A Tree

Alrighty folks here is my rather strange question. In my WIP I need to kill off an orange tree. (Toldja it was weird) The MC digs up the orange tree and takes it to another location, planning on re-planting it. I need the tree to be dead/dying before it gets re-planted. So if the MC, when digging it up, accidentally cut off a large chunk of the roots, could that kill the plant? How fast? And if it wouldn't then what are some other accidental ways to kill a plant when moving it?

Thanks in advance for any help!

Hmm...the tree in my book is actually kind of like a dryad, so it's a person that shape-shifted into an orange tree, which makes the circumstances harder.

Would it be believable to have the dryad get severely dehydrated because of root damage combined with really hot weather and that's how it dies?

lol no it's really helpful to disect this kind of stuff. Basically the book is full of were-people (you know people who can turn into whatever specific animal they want whenever they want although they can't always control it in scary situations, etc.).

Dryads are about the same except that they change into a plant instead of an animal, so it's a literal person that can shift into a tree. Although any long-term connection while in plant-form with a place will give the person an emotional attachment to the area, so theoretically "moving" would be just as taxing to the dryad as it would be to its normal plant equivalent. So I'm trying to find a way where the dryad could die accidentally through damage to the tree that would transfer over to when she shifts back into human form, which is why I'm leaning more towards dehydration as the ultimate cause of death.

lol thanks for answering guys! I actually really like the hypothermia idea Theo. Ringing the tree would be really effective too but I can't figure out a way someone could ring it accidentally without the dryad realizing, where as she may not realize the roots of the tree having frost on them until it's too late.

Thanks for all the help! I'll start handing out the reps

The place is near the coast so that could also work...but I think I'm leaning more towards the frost simply because there's no cause really because a main point is that the MC blames himself. But there is this whole war going on so that is an extremely useful piece of information on how to kill trees. Along with the copper...instead of machine gun they could just have nail guns. Thanks everyone, I'm making notes of all the suggestions here just in case they come in handy later!