YMCA upset/angry about growth of branches (8)
I believe the answer is:
sycamore
'growth of branches' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'ymca upsetangry about' is the wordplay.
I cannot really see how this works, but
an anagram of 'ymca' is 'ycam' which is within the answer.
'about' could be 're' ('re' means regarding or about) and 're' is found within the answer.
The remaining letters 'so' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sycamore that I've seen before include "Tree with winged seeds" , "Timber producer" , "Type of maple tree" , "Tree - may score (anag)" , "Tree producing propeller-shaped seeds" .)