Tree waste around capital of Latvia (8)

I believe the answer is:

brigalow

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'tree' is the definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?

'waste around capital of latvia' is the wordplay.
'waste' becomes 'blow' (synonyms).
'around' indicates putting letters inside.
'capital of latvia' becomes 'Riga' (synonyms).
'blow' placed around 'riga' is 'BRIGALOW'.

Can you help me to learn more?

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

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