What we we know about the source of the light in the Two Trees of Valinor?

Question

The sun and the moon were created from the light of the trees of light, Laurelin and Telperion, after they had been destroyed; some parts of them survived the destruction and could thus be used for that purpose. This makes sense.

It would also make sense if the light that the Valar gave to the trees came from the wreckage of the lamps of light, Ormal and Illuin, which were destroyed by Morgoth early in history, or if it came from light of the lamps caught by the Valar in some way, before the lamps had been destroyed.

Do we have any reason to believe that the light of the trees came from the lamps? Or do we have any information about some other source?

One reason to speculate that the light might have come from the lamps in some indirect way is their hues: Laurelin's golden hue matches that of Ormal and the sun, as Telperion's bluish light matches that of Illuin and the moon. Some sort of continuity is suggested to the naïve reader: the moon's light matches that of Telperion because it came from Telperion's light; so why does Telperion's light match that of Illuin?

Answer 1

It is not specifically stated that the Trees used the light of the Lamps.

The Valar Yavanna sung them into existence, their light source was their own, with no mention of usage of the lamps existing light.

And when Valinor was full-wrought and the mansions of the Valar were established, in the midst of the plain beyond the mountains they built their city, Valmar of many bells.

Before its western gate there was a green mound, Ezellohar, that is named also Corollairë; and Yavanna hallowed it, and she sat there long upon the green grass and sang a song of power, in which was set all her thought of things that grow in the earth.

But Nienna thought in silence, and watered the mould with tears. In that time the Valar were gathered together to hear the song of Yavanna, and they sat silent upon their thrones of council in the Máhanaxar, the Ring of Doom near to the golden gates of Valmar, and Yavanna Kementári sang before them and they watched.

And as they watched, upon the mound there came forth two slender shoots; and silence was over all the world in that hour, nor was there any other sound save the chanting of Yavanna.

Under her song the saplings grew and became fair and tail, and came to flower; and thus there awoke in the world the Two Trees of Valinor.

_{The Silmarillion - Of The Beginning of Days}

The Moon and the Sun were the last flower and the last fruit of Telperion and Laurelin respectively which were created when Yavanna and Nienna sang and wept following their destruction by Ungoliant

Furthermore, once the Silmarils are created there is the following description of them.

And the inner fire of the Silmarils Fëanor made of the blended light of the Trees of Valinor, which lives in them yet, though the Trees have long withered and shine no more.

_{Of the Silmarils and the Unrest of the Noldor}

If the trees were made from the light of the Lamps you might have expected a mention of this link back to the Lamps.

However

There is the following passage that describes the leaving of Almaren (emphasis my own)

Behind the walls of the Pelóri the Valar established their domain in that region which is called Valinor, and there were their houses, their gardens, and their towers.

In that guarded land the Valar gathered great store of light and the fairest things that were saved from the ruin; and many others yet fairer they made anew, and Valinor became more beautiful even than Middle-earth in the Spring of Arda;

_{The Silmarillion - Of The Beginning of Days}

Which suggests that the light from the Lamps may have been saved. Though the rest of the world would have been left in darkness.

But all Middle-earth lay in a twilight under the stars. While the Lamps had shone, growth began there which now was checked, because all was again dark.

_{Of the Coming of the Elves and the Captivity of Melkor}

Again no mention is made of the light being used in Yavanna's song

According to The Annals of Aman found in Morgoth's Ring there was 50 Valian years (or 492.6 solar years) between the destruction of the Lamps and the creation of the two Trees, raising the question could the light have been kept for that long, and if it was able to be kept and sustained for that long why did Aúle not make another set of lamps, or just use the existing light in whatever storage medium it is in?

As to why would Yavanna use the same colour light that the lamps gave out if she didn't have any of the existing light?

Perhaps the Valar wanted a reminder of Almaren before Melkor destroyed all they had created. A piece of their old world that they will never be able to recover.

Answer 2

While there is no direct indication in the published Silmarillion as to where the light of the Two Trees originated from, we have a description in The Book of Lost Tales, Tolkien's first "version" of The Silmarillion.

It describes aetherial light that flowed through the air and even fell down like rain and flowed like rivers:

Those were the days of Gloaming (Lomendanar), for light there was, silver and golden, but it was not gathered together but flowed and quivered in uneven streams about the airs, or at times fell gently to the earth in glittering rain and ran like water on the ground; and at that time Varda in her playing had set but a few stars within the sky.

The Valar gathered some of that light to fill the Lamps with. After the lamps were destroyed, that liquid light was spilled, creating blazing lakes. That light was then gathered into two artificial pools in Valinor:

But Manwe suffered not more radiance to be gleaned from heaven, for that the dark was already that of night, but at his asking Ulmo rose from his deeps and fared to the blazing lakes and the pools of brilliance. Therefrom he drew rivers of light into vast vessels, pouring back waters in their place, and with these he got him back to Valinor. There was all the light poured into two great cauldrons that Aule fashioned in the gloom against his return, and those are called Kulullin and Silindrin.

Then, in creation of the Two Trees, the light from those lakes was poured over the earth:

Now in the midmost vale they digged two great pits, and those are leagues asunder yet nigh together beside the vastness of that plain. In the one did Ulmo set seven rocks of gold brought from the most silent deeps of the sea, and a fragment was cast thereafter of the lamp that had burned awhile upon Helkar in the South. Then was the pit covered with rich earths that Palurien devised, and Vana came who loveth life and sunlight and at whose song the flowers arise and open, and the murmur of her maidens round her was like to the merry noise of folk that stir abroad for the first time on a bright morning. There sang she the song of spring upon the mound, and danced about it, and watered it with great streams of that golden light that Ulmo had brought from the spilled lakes — yet was Kulullin almost o'erflowing at the end.

But in the other pit they cast three huge pearls that Osse found in the Great Sea, and a small star Varda cast after them, and they covered it with foams and white mists and thereafter sprinkled lightly earth upon it, but Lorien who loveth twilights and flittering shadows, and sweet scents borne upon evening winds, who is the lord of dreams and imaginings, sat nigh and whispered swift noiseless words, while his sprites played half-heard tunes beside him like music stealing out into the dark from distant dwellings; and the Gods poured upon that place rivers of the white radiance and silver light which Silindrin held even to the brim — and after their pouring was Silindrin yet well nigh full.

That, I'm sure we can conclude, is the origin of the light of the Two Trees and eventually of the Sun and the Moon.

The only counter-argument could be that The Book of Lost Tales is not canon and Tolkien might have eventually abandoned the idea of aetherial light floating through the airs of Arda. But as Christopher Tolkien said, many things that don't appear again in Tolkien's later writings and the published Silmarillion haven't necessarily been rejected; rather, they were omitted for the purposes of keeping the narrative brief and condensed.

(All quotes are from The Book of Lost Tales, chapter The Coming of the Valar and the Building of Valinor)