The basis for Elvish “tree” words, this root first appeared in The Etymologies of the 1930s as an extension of ᴹ√GALA “thrive” (Ety/GALAD). This replaced the earliest derivation of “tree” from the Qenya Lexicon of the 1910s, where the Qenya word for “tree” ᴱQ. alda was derived from ᴱ√ALA “spread” (QL/29). In The Etymologies, the Quenya form of this word remained the same, but the 1910s Gnomish words G. âl “wood” and †alwen “tree” (GL/19) became the 1930s Noldorin word N. galadh “tree” (Ety/GALA). Quenya and Sindarin retained these words for “tree” thereafter, and while Tolkien did not mention the root √GALAD again, his continued use of primitive ✶galadā “tree” (Let/426; PE17/153; PE21/74; UT/266) made it clear this root remained valid.
Middle Primitive Elvish
day
root. shadow
ar
root. day
ari
noun. day
atyēnar
noun. anniversary day
anār
noun. Sun
edenā
adjective. first
galad
root. tree
galadā
noun. tree
gālæ
noun. light
il
root. all
kalat
noun. light
k’lā
noun. light
lūme
noun. time
met
root. end
metta
noun. end
settā
adjective. first
tul-
verb. come, am coming, have come, am arrived, am here, are approaching
A root in The Etymologies of the 1930s glossed “day” with various derivatives like ᴹQ. are, N. aur “day” and ᴹQ. arin “morning” (Ety/AR¹). In Tolkien’s later writings, the Quenya word for “day” became aurë (RC/727; S/190), and in 1957 Quenya Notes he devised a new etymology for these day-words from the root √UR “heat” as in ✶auri “heat, period of sun” (PE17/148). That opens the question whether the various 1930s Quenya “morning” words from ᴹ√AR remain valid, but many Neo-Quenya writers (including me) retain them since there aren’t really any good alternatives. They might be salvageable as derivatives of the later root √AS “warmth” (so that “day” = “hot” and “morning” = “warm”).