I’m now working with board from shifting trees (6,4)

I believe the answer is:

birnam wood

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'shifting trees' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'i'm now working with board' is the wordplay.
'working with' indicates an anagram (working with the letters).
'im'+'now'='imnow'
'imnow' mixed up with 'board' gives 'BIRNAM WOOD'.

'from' is the link.

Can you help me to learn more?

I've seen this clue in The Independent.

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