Crossword Genius

Theresa arranged source of timber (3,4)

Ross

I believe the answer is:

ash tree

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

'source of timber' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.

'theresa arranged' is the wordplay.
'arranged' is an anagram indicator (letters rearranged).
'theresa' with letters rearranged gives 'ASH TREE'.

Can you help me to learn more?

(Another definition for ash tree that I've seen is " A big plant".)

Want a hint initially instead of a full solution? Install my app