Romantic style arborglyphs are common - these are normally represented by a heart, names and the number 4 or often partner's names
Romantic tree carvings represent relationships or hoped for relationships. They are often represented by hearts pierced with an arrow with initials or a loved one's name inside. The number "4" is often used to represent "for" inside a carved love heart. We dont know when this number was first used and this is something we would like to find out.