What does the cryptic crossword clue "Calls after elder, perhaps as they reveal age (4,5)" mean?

The wordplay uses a charade (building blocks). TREE (synonym="elder, perhaps") + RINGS (synonym="calls") = TREERINGS The answer is TREERINGS.

Calls after elder, perhaps as they reveal age (4,5)

Guardian Cryptic #29161 | 16 Down | 2023-08-29 flower