It is true that there are many other healing allies that are cheaper and can heal more than just heroes, Daughter of the Nimrodel is actually really good when combined with Ent heroes. As of this writing there are only two so far (Treebeard and Quickbeam), and both have abilities that are triggered by damaging them, and both abilities are really powerful. You might think sticking self preservation on those Ents would be better since it's harder for the Encounter deck to get rid of attachments than allies (usually), and for the same cost. And you would be right, except for the fact that Daughter of the Nimrodel has something in exchange for this vulnerability: the ability to heal fellow player heroes, and the ability to heal either Treebeard or Quickbeam depending on your current needs--i.e. a little more versatility than Self Preservation. Using these two in combination (Daughter and Self-pres) is really nice.

Daughter of Nimrodel totally satisfies my carebear attitude. —

For the cost, Beechbone is kind of pricey. But the ability to combine him with Ent Draught and then letting him hang around 4-5 damage, while keeping him alive by healing him with Wellinghall Preserver makes Beechbone a ridiculous attacker.

I love this card with Rossiel. I don't care about secrecy. Even in Solo play it's worth it. If you're under 20 threat, great. But I use it with Rossiel in over 20 threat decks all the time. It is very much worth 3 resources to give her the buff that adding cards to the victory display gives her. 4 Will power? 4 Defense? Heck yeah! For only 3 resources you give her a permanent stat increase against most of the subsequent enemies or locations (depending on what you remove), and Keen As Lances becomes much cheaper, especially after the errata 1.9 which adds it to the victory display as well. Not only that, obviously you get to remove a card from play--the whole point of the card, after all--which can be game changing as Warden of Arnor so brilliantly explains in his review of the card. Get rid of that annoying enemy with surge, or that enemy that has a nasty "when revealed effect", a stupid crazy shadow effect, or a location with a crazy high threat. Very versatile card, plus the artwork is Magali V...always a treat. Absolutely required in any Rossiel deck.

I have mixed feelings about this card. I love it because I love Ents, and the artwork is fantastic. But honestly, Wellinghall Preserver is a better use for 3 resources, which are precious when you play Lore. I like that he is only really worth it in mid to end game because of his ability--that's thematic--but even then, Wellinghall Preserver can heal and has a consistent 3 . So Leaflock is really only worth it if you have 4 or more damaged Ents, and even then you get 1 in exchange for the ability to heal near mid to end game, otherwise he is an inferior Wellinghall Preserver. I think they could have balanced this by giving him maybe 1 more hp, or made the max buff +5 instead of +4.

To me, he is a one-of so I can stuff more affordable ents into an ent deck. —
So you don't include him in your Ent decks? Or just put x1 in your deck? I have him in mine because I value theme over power generally, but just x1. I also have x3 Wellinghall Preservers, though. —

I'm surprised this card hasn't received any real buzz on this page (although I've seen it appear in quite a few decklists. For me, this is my favorite and in my opinion, one of the best healing options out there. It might stem from the fact that Lore is my least played sphere and I always seem to have at least one leadership hero in most of my lists. It's a free heal the turn it comes out and while it's cost efficiency does eventually lose to cards like Ioreth or Warden of Healing the payments aren't dedicated to particular player or resource which is nice.

If Elrond is out then obviously this gets even sillier. My experience has shown me that this card can really clean up archery damage. Not to reference the two allies above but another plus for this card versus the allies is that it doesn't require any exhausting to trigger, meaning you have more than just one shot at the healing.

Not much more to say about this card. I think enough people have seen its versatility and just how much it can save Heroes. I guess a downside is you can't heal allies with this, but that's a pretty minor negative depending on the decklist.