In Latin, some vowels are marked by a macron, they are long vowels. However, I found that in French and Spanish there's no macron in their writing.
Is the long vowel feature completely lost in the derived languages?
Not just the long vowel future—all Latin future-tense marking was lost in the Romance languages!
A few different factors conspired to make the future tense no longer useful in Vulgar Latin:
b in between vowels and
v everywhere both turned into something kind of like English
And most importantly:
And this was really the death knell of the original future tense. Forms like amābit became amāvit, identical to the perfect, and came too close to amābat > amāvat for comfort (differing only in a single, short, unstressed vowel). Later, forms like audiet became audjet through sound changes, too close to the present audit > audet. With all this confusion, at least one tense would have to go, and the unpopular future was the obvious choice.
Then, with the synthetic future gone, the periphrastic in habeō got bleached to a plain future meaning during the first few centuries CE. This is mostly where the Western Romance future tense comes from: Spanish amará comes from amāre hábet > amar' ávɛ > amará, while amarás comes from amāre hábēs > amar' áves > amarás.
(Eastern Romance future forms come from a few different sources, such as debeō "to owe", but they're not as consistent as in Western Romance. None are from the original Latin future.)
P.S. If it seems like the third/fourth "long vowel" future was less confusing and disposable than the first/second "-bi-" future, that's absolutely true. But it was still one additional point of confusion, and it was easier to use habeō with all conjugations rather than two completely different sets of morphology.
Since the question's changed, here's an answer to the updated one…
Yes, long vowels were lost very early in Vulgar Latin, in the first few centuries CE.
Originally, Latin's long and short vowels (excluding
æ, which don't fit into the 5+5 system) were identical in quality: the long and short version of each vowel were pronounced exactly the same, one was just, quite literally, longer than the other.
But over time, this system changed, with the vowels being distinct in quality as well as length. Then length disappeared entirely and only quality was left. Roughly:
/iː i eː e aː a o oː u uː/ →
/iː ɪ eː ɛ aː a ɔ oː ʊ uː/ →
/i e e ɛ a a ɔ o o u /
This seven-vowel system is what was inherited into the earliest forms of Romance, with length being entirely gone. The mid vowels
/ɛ ɔ/ tended to disappear too, but they left different traces in each language: in Spanish, for instance, they "broke" into diphthongs when stressed (
/ɛ ɔ/ →
Some languages later re-established vowel length, but I don't believe it's phonemic in any modern Romance language—that is, given a word without any vowel length marking, you can figure out precisely which vowels are long and which are short. That's not the case in Latin, where ālium "garlic" and alium "another" are distinguished only by length.
P.S. One and only one Romance language didn't go through this vowel development: Sardinian, which is a very strange outlier. Sardinia was abandoned by the Romans very early, before these sound changes happened in Vulgar Latin, so it evolved on its own and ended up just dropping length with no other changes to give a five-vowel system
/i e a o u/.
ȳ y merged into
ī i early on, except in very refined/educated speech.
æ survived somewhat longer before merging with