1) To cleave wood was to split it along the grain, using iron wedges and a heavy hammer: ‘cleft’ and its variants referred to pieces of cleft wood or board.
1520 pro carr. ijbus le clyftes, Ripon
1591 certain old clogges or cliftes on the Blome Banke, Clint
1681 6 clifts of esh, Burn
1704 found certain cliffs of oak and ashwood, West Riding. It probably developed as a short form of ‘cleft board or wood’ which is on record earlier: 1478 a half hundredth of clift burde, York
1515 pro c et di: clife burde, York
1518 xiij peysses of clyft wodd, York
1670 William Smyth, cooper, having severall peeces of cleft wood about his house … ready to be imployed in the uses of his trade, Brodsworth.