[Findegil]

As I found no place to put this in Valinor and the Two Trees, I think we should use it in this chapter:

§39 EPE-EX-12.3 {Upon}Thus upon the crown of Túna, the green hill, the city of the Elves was built, the white walls and terraces of Tirion; and the highest of the towers of that city was the Tower of Ingwë, the Mindon, Mindon Eldaliéva, whose silver lamp shone far out into the mists of the sea. Few are the ships of mortal Men that have seen its slender beam. In Tirion[footnote to the text: That is the Watchful City. Eldamar (that is Elvenhome) it was also called; but the regions where the Elves dwelt, and whence the stars could be seen, were called Elendë, or Eldanor (that is Elvenland){: quoth Ælfwine}.] the {Lindar [> }Vanyar{]} and the Ñoldor dwelt long time in fellowship. And since of all things in Valinor they loved most the White Tree, Yavanna made for them a tree in all things like a lesser image of Telperion, save that it did not give light of its own being; and this tree was planted in the courts beneath the Tower and there flourished, and its seedlings were many in Eldanor. Of which one was after planted in Eressëa, and prospered. Thence came in the fullness of time, as is later told, the White Tree of Númenor. EPE-EX-12.4 <MT, Text XI
Aman
In Aman things were far otherwise than in Middle-earth. But they resembled the mode of Elvish life, just as the Elves more nearly resemble the Valar and Maiar than do Men.
In Aman the length of the unit of 'year' was the same as it was for the Quendi. But for a different reason. In Aman this length was assigned by the Valar for their own purposes, and was related to that process which may be called the 'Ageing of Arda'. For Aman was within Arda and therefore within the Time of Arda (which was not eternal, whether Unmarred or Marred). Therefore Arda and all things in it must age, however slowly, as it proceeds from beginning to end. This ageing could be perceived by the Valar in about that length of time (proportionate to the whole of Arda's appointed span) which they called a Year; but not in a less period.
But as for the Valar themselves, and the Maiar also in their degree: they could live at any speed of thought or motion which they chose or desired.[Footnote to the text: They could move backward or forward in thought, and return again so swiftly that to those who were in their presence they did not appear to have moved. All that was past they could fully perceive; but being now in Time the future they could only perceive or explore in so far as its design was made clear to them in the Music, or as each one of them was specially concerned with this or that part of Eru's design, being His agent or Subcreator. In this way of perception they could foresee none of the acts of the Children, Elves and Men, in whose conceiving and introduction into Eä none of the Valar had played any part at all; concerning the Children they could only deduce likelihood, in the same way as can the Children themselves, though from a far greater knowledge of facts and the contributory events of the past, and with far greater intelligence and wisdom. Yet there always remained an uncertainty with regard to the words and deeds of Elves and Men in Time not yet unfolded.]
The unit, or Valian Year, was thus not in Aman related to the natural rates of 'growth' of any person or thing that dwelt there. Time in Aman was actual time, not merely a mode of perception. As, say, 100 years went by in Middle-earth as part of Arda, so 100 years passed in Aman, which was also a part of Arda. It was, however, the fact that the Elvish speed of 'growth' accorded with the unit of Valian time[Footnote to the text: Not by the design of the Valar, though doubtless not by chance. That is, it may be that Eru in designing the natures of Elves and Men and their relations one to another and to the Valar ordained that the 'growth' of the Elves should accord with the Valian perception of the progress or ageing of Arda, so that the Elves should be able to cohabit with the Valar and Maiar. Since the Children appeared in the Music, and also in the Vision, the Valar knew something or indeed much of the ordained natures of Elves and Men before they came into existence. They knew certainly that Elves should be 'immortal' or of very long life, and Men of brief life. But it was probably only during the sojourn of Oromë among the fathers of the Quendi that the Valar discovered precisely what was the mode of their lives with regard to the lapse of Time.] that made it possible for the Valar to bring the Eldar to dwell in Aman. In one Valian year the Eldar dwelling there grew and developed in much the same way as mortals did in one year upon Middle-earth. In recording the events in Aman, therefore, we may as did the Eldar themselves use the Valian unit, though we must not forget that within any such 'year' the Eldar enjoyed an immense series of delights and achievements EPE-EX-12.5{which even the most gifted of Men could not accomplish in twelve times twelve mortal years}. Nonetheless the Eldar 'aged' at the same speed in Aman as they had done in their beginning upon Middle-earth.
But the Eldar were not native to Aman, which had not been, by the Valar, designed for them. In Aman, before their coming, there had dwelt only the Valar and their lesser kindred the Maiar. But for their delight and use there were in Aman also a great multitude of creatures, without fear, of many kinds: animals or moving creatures, and plants that are steadfast. There, it is believed, were the counterparts of all the creatures that are or have been on Earth, and others also that were made for Aman only. And each kind had, as on Earth, its own nature and natural speed of growth.
But since Aman was made for the Valar, that they might have peace and delight therein, all those creatures that were thither transplanted or were trained or bred or brought into being for the purpose of inhabitation in Aman were given a speed of growth such that one year of the life natural to their kinds on Earth should in Aman be one Valian Year.
For the Eldar this was a source of joy. For in Aman the world appeared to them as it does to Men on Earth, but without the shadow of death soon to come. Whereas on Earth to them all things in comparison with themselves were fleeting, swift to change and die or pass away, in Aman they endured and did not so soon cheat love with their mortality. On Earth while an elf-child did but grow to be a man or a woman, EPE-EX-12.6{ in some 3000 years, forests would rise and fall, and all the face of the land would change, while} birds and flowers innumerable would be born and die in löar upon löar under the wheeling Sun.
But beside all this Aman is called also the Blessed Realm, and in this was found its blessedness: in health and joy. For in Aman no creatures suffered any sickness or disorder of their natures; nor was there any decay or ageing more swift than the slow ageing of Arda itself. So that all things coming at last to fullness of form and virtue remained in that state, blissfully, ageing and wearying of their life and being no swifter than the Valar themselves. And this blessing also was granted to the Eldar.
On earth the Quendi suffered no sickness, and the health of their bodies was supported by the might of the longeval fear. But their bodies, being of the stuff of Arda, were nonetheless not so enduring as their spirits; for the longevity of the Quendi was derived primarily from their fear, whose nature or 'doom' was to abide in Arda until its end. Therefore, after the vitality of the hroa was expended in achieving full growth, it began to weaken or grow weary. Very slowly indeed, but to all the Quendi perceptibly. For a while it would be fortified and maintained by its indwelling fëa, and then its vitality would begin to ebb, and its desire for physical life and joy in it would pass ever more swiftly away. Then an Elf would begin (as they say now, for these things did not fully appear in the Elder Days) to 'fade', until the fëa as it were consumed the hröa until it remained only in the love and memory of the spirit that had inhabited it.
But in Aman, since its blessing descended upon the hröar of the Eldar, as upon all other bodies, the hröar aged only apace with the fear, and the Eldar that remained in the Blessed Realm endured in full maturity and in undimmed power of body and spirit conjoined for ages beyond our mortal comprehension.>
§40 Manwë and Varda loved most the {Lindar [> }Vanyar{]}, the {High}[Fair] Elves, and holy and immortal were all their deeds and songs. ...

The second part of the essay might then be included in the scond age stuff.

Respectfully
Findegil