Mark Hoppus from Blink-182 is waging legal war with his neighbor in Beverly Hills … and it’s all because of a pine tree Mark says is growing too tall.

According to a new lawsuit, obtained by TMZ, Mark and his wife Skye are suing their neighbor over a tree they claim is blocking their view.

In the docs, Mark says the neighbor is violating rules adopted by the planning commission they hashed out years ago, which called for her to remove a bunch of trees and maintain a pine tree at a maximum height of 15 feet.

Mark says his neighbor is flouting the rules, claiming the tree is over 15 feet now, and new trees are growing in place of those that had previously been removed … obstructing his view in the process.

In his suit, Mark claims his neighbor’s been ignoring repeated requests to maintain the trees … so now he’s running to a judge for help.

Mark’s seeking an injunction to force his neighbor to follow the rules and trim the trees … he’s also going after his neighbor for damages.