How to kill a Treeman without a beaver (how to beat Wood Elves with High Elves)

In a week's time my noble High Elf army will be facing their sundered Wood Elf kindred. How it has come to this is another story but I suspect it's all over some precious elven heirloom or, more likely, a beautiful Elf maiden.

Anyway, what I am pretty certain of is there will be a very large, talking moving tree that I will need to fell.

You know, I'm not too worried about it either. Infact, I wouldn't be worried at all if the wretched things weren't stubborn.

I do expect to take some damage but I think as long as I engage the big fella (I assume they're all male ?) with the right unit(s).

The best thing about Treemen (as far as their enemies are concerned) is that they are S L O W......

Also their Ws is nowhere what it used to be in early army lists. I know I'll hit him and I know I'll damage him.

My plan however will not be to rush into combat with him. I need to knock off some wounds first. He could well beat me in combat and I don't feel like having a whole unit wiped out by a single treeman.

Magic and missile fire (ie repeating bolt thrower) will be the order of the day for this fellow until I feel confident of taking him out in one round in close combat.

I could use some wood for the victory celebration barbeque :)

Errata:

the above game has long since been played and my forces coped admirably with the endm Treeman, indeed a unit of Swordmasters reduced him to 1 wound (from 6). It give me a lot of faith in Swordmasters (although they did have to sacrifice themselves to the cause)