On the whole "Sealed Tree" thing:

Fact:  Belldandy made a promise to Keiichi to meet him the next day.
Fact:  Belldandy was punished for being discovered on the Earth plane,
let alone having made a promise (which had all the binding power of a
Goddess, even though she was not yet fully qualified).
Fact:  Belldandy's sentance was to erase Keiichi's memory of the whole
event.
Fact:  Keiichi willingly submitted to the punishment.

Supposition:  Belldandy sealed the memories inside the tree.
Supposition:  Belldandy broke her promise to meet him the next day.  (We
assume that she never returned to Earth, since that was a "sin" or
"crime" in the first place, so they couldn't let her fulfill her promise
- since her promise was made while committing a divine crime.)
Supposition:  As Belldandy and Keiichi spent more time together in the
"present", it was the precense of this unfulfilled promise which started
to break the seal.
Supposition:  If the seal over the broken promise was itself broken,
then it could prove a problem to the Earth itself.  (Who knows what
might happen on a broken Divine being's promise?  According to "Dogma",
all reality might vanish (interesting movie - not great, but not bad).)

Fact:  Urd and Skuld, sticking their noses in where they didn't belong
(but they can be forgiven for a) trying to help their sister and b)
being such cuties), attempted to break the seal, thinking that releasing
all the energy would help.

Supposition:  The Seal was broken (or severaly weakened)- but when
Belldandy went into Keiichi's mind and relived those moments, he gave
permission to reseal the memories (though that particular moment wasn't
shown), and perhaps a more mature Belldandy (and a once again willing
Keiichi) were able to make a better Seal.

Supposition:  Sooner or later Belldandy and Keiichi will get married.
  Skuld will build special earphones to block out the sound of while
Goddess/mortal monkey lovin', and Urd will keep trying to sneak in a
video camera and claim credit.  Keiichi may/may not remain clueless as
to his erased memories, but he probably won't care.

Fact:  Sora is way overlooked.  All hail cute mousy girls in glasses!

-- 
John Hummel
Owner, Editor-in-Chief, Main Monkey Man
The Gamers Press
http://www.gamerspress.com
dpaladin@gamerspress.com