I more or less just answered to this on another thread. Yes, some word derivations are kinda weak at differentiating the words and the difference gets often lost. That's a bit crazy. But it's kinda good to make at least some difference. New meanings can be also achived by a "zero derivation", where the words are not altered at all - they just get new meanings.
I think it's likely that etymologically
halahi is just a plural of
halah, which has broken into a separate meaning for "flowering tree" and while doing that been also simplified into an inanimate declension pattern (which, remember, does not explicitly mark plural, so
halahi means both "tree" and "trees").
- | flower | flowers | tree(s) |
nominative | halah | halahi | halahi |
accusative | halahes | halahis | halah |
genitive | halahi | halahi | halahi |
allative | halahaan | halahea | halahaan |
ablative | halahoon | halahoa | halahoon |
| | | |
It's a coin toss, if the difference is apparent.