Tree-axe (7)

I believe the answer is:

gumboot

I'm a little stuck... Click here to teach me more about this clue!

'tree-axe' is the definition.
I know nothing about this answer so I can't judge whether this works.

'tree-axe' is the wordplay.
'tree' becomes 'gum' (gum is a kind of tree).
'axe' becomes 'boot' (I've seen this in another clue).
'gum'+'boot'='GUMBOOT'

Can you help me to learn more?

(Other definitions for gumboot that I've seen before include "Wellington" , "Waterproof footwear" , "Wader" .)

I've seen this clue in the Sydney Morning Herald.

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