The Nature of Middle-earth essay "Lives of the Numenoreans" seems to 'resolve' something I always found a stretch in LOTR: Elrond's implication that the War of the Last Alliance (and Disaster of the Gladden Fields) had a long-lasting demographic effect on Arnor, beginning its decline.
This isn't what we would see in our world; Arnor itself was not ruined in the war, and was ultimately on the winning side, and societies that lose a large number of soldiers but aren't conquered or sacked don't remain demographically diminished for generations to come.
But the "Lives of the Numenoreans" essay makes it clear that Numenoreans are very much not our-world humans demographically. Despite lengthened life and great health, they have fewer children in their longer lives than preindustrial humans tended to have in their shorter ones: they "seldom had more than four children in each marriage".
Furthermore, while the Numenoreans grew up physically as fast as we do, they tended to marry later (usually at 40 to 45 for women, even later for men) and with long intervals between children - never less than five years between successive children, more often ten, sometimes 15-20. Thus generation time would be far longer than any real world human population has (or *can* have).
The combination of relatively small families and very long generation times would mean slow population growth even in ideal conditions.
But the other wrinkle, and why the War of the Last Alliance was such a key factor, was that tie Numenoreans were very strictly monogamous. Thus all the men lost in the War of the Last Alliance directly reduced the population of the next generation drastically.
The combination of small family size and very long generation time gives another perspective on the "waning of the Dunedain": arguably the Dunedain were never really able to survive demographically outside the protected land of Numenor, without disease or war and where accidents were rare. In the dangerous lands of Middle-earth normal humans were far better able to survive over many generations.
(Hobbits marry later, than normal humans - but not so late as Numenoreans; generally in their 30s. And unlike Numenoreans they frequently have large families. So while their population growth in the Shire may be slower than that of preindustrial humans would be in similarly ideal conditions - ample food and apparently rare disease - since their generations are longer, they appear to grow in population in most generations and thus recover well from disasters such as the Great Plague or the Long Winter / Days of Dearth when "many thousands" perished. So while the longer generation time than 'default human' is a risk, the tendency to large families balances it out.)
This isn't what we would see in our world; Arnor itself was not ruined in the war, and was ultimately on the winning side, and societies that lose a large number of soldiers but aren't conquered or sacked don't remain demographically diminished for generations to come.
But the "Lives of the Numenoreans" essay makes it clear that Numenoreans are very much not our-world humans demographically. Despite lengthened life and great health, they have fewer children in their longer lives than preindustrial humans tended to have in their shorter ones: they "seldom had more than four children in each marriage".
Furthermore, while the Numenoreans grew up physically as fast as we do, they tended to marry later (usually at 40 to 45 for women, even later for men) and with long intervals between children - never less than five years between successive children, more often ten, sometimes 15-20. Thus generation time would be far longer than any real world human population has (or *can* have).
The combination of relatively small families and very long generation times would mean slow population growth even in ideal conditions.
But the other wrinkle, and why the War of the Last Alliance was such a key factor, was that tie Numenoreans were very strictly monogamous. Thus all the men lost in the War of the Last Alliance directly reduced the population of the next generation drastically.
The combination of small family size and very long generation time gives another perspective on the "waning of the Dunedain": arguably the Dunedain were never really able to survive demographically outside the protected land of Numenor, without disease or war and where accidents were rare. In the dangerous lands of Middle-earth normal humans were far better able to survive over many generations.
(Hobbits marry later, than normal humans - but not so late as Numenoreans; generally in their 30s. And unlike Numenoreans they frequently have large families. So while their population growth in the Shire may be slower than that of preindustrial humans would be in similarly ideal conditions - ample food and apparently rare disease - since their generations are longer, they appear to grow in population in most generations and thus recover well from disasters such as the Great Plague or the Long Winter / Days of Dearth when "many thousands" perished. So while the longer generation time than 'default human' is a risk, the tendency to large families balances it out.)