In NJ what is the time limit for a legal suit against accidental cutting of trees 2" thick on neighbors property with no visible demarcation line.

About 2 1/2 yrs ago, I accidentally cut some trees on my neighbours property while cleaning up my own back yard. There was no demarcation line between the fences, and the two properties on either side of my house extended far beyond my property, giving me the impression that the mound behind my house belonged to my property. Later I found out that the last 6ft or so belonged to the neighbor behind my house. What is the time limit in New Jersey within which my neighbor can start a legal suit against me?