Hadithcore
Sunan Abi Dawud, 3078
sahih· Al-Albani

Hisham said “The unjust vein means that a man implants a tree in the land of another man so that they may be entitled to it. Malik said “The unjust vein means that a man takes (a thing) digs a pit and implants a tree without (his) right.

حَدَّثَنَا أَحْمَدُ بْنُ عَمْرِو بْنِ السَّرْحِ، أَخْبَرَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي مَالِكٌ، قَالَ هِشَامٌ الْعِرْقُ الظَّالِمُ أَنْ يَغْرِسَ الرَّجُلُ فِي أَرْضِ غَيْرِهِ فَيَسْتَحِقَّهَا بِذَلِكَ ‏.‏ قَالَ مَالِكٌ وَالْعِرْقُ الظَّالِمُ كُلُّ مَا أُخِذَ وَاحْتُفِرَ وَغُرِسَ بِغَيْرِ حَقٍّ ‏.‏

References2 variants
In-Book Reference
Book 20, Hadith 151
English Reference
Book 19, Hadith 3072