The wood elves' rituals of marriage
"Don't you have something important to gift her? We elves make a gift of wood to who we love..."
In the Wood Elven culture, there is nothing more sacred than Nature. It is of such importance that they try to not harm its integrity, and one way they do that is by only cutting down trees planted especially for harvesting wood. As it takes so long for them to grow, a strong cultural bond grew between individuals and the trees they plant - and that eventually reached their marriage traditions.
When an elf wants to ask another in marriage, they are expected to show how serious they are by giving up part of their own wood as a gift. The wood is not only a representation, but it is the actual "life savings" of an elf that cannot be easily replaced, so parting with it is the greatest sign of commitment to another person. It is up to the elf to decide how to gift the wood; it was once the norm to carve a pair of rings out of it, but since then the gifts have taken many other shapes, such as musical instruments, bows, tools, etc.
If the gift is accepted, the couple may proceed to marriage; if not, the gift must be discarded, as keeping it to give to someone else shows a lack of commitment. Assuming the proposal is accepted, the proposer begins preparations for the marriage while their significant other crafts a gift of reciprocity, which will be given to the proposer during the ceremony.
Unlike in most Human and Dwarven societies, elven marriage ceremonies are simple and quick, as they are not a ritual of religious nature, nor do elves care much about traditions. It is a demonstration of seriousness and commitment, a promise between two people that they want to share experiences and support each other - nothing more.