I've seen a lot of Celtic oriented "birth trees" and there is the story where humans are made from drift wood (Askr and Embla, or Ash and Elm). Yggdrasil is considered an Ash tree in the lore. Personally I associate Pine trees with the surface of Svartalfheimr, specifically with Dokkalfar. There is also some shared gnosis with that and Deciduous trees being associated with Alfheimr. Beyond that, I can't remember many associations of trees in Heathenry, though I'm sure there are more (though not associated with dates on a calendar).