An 11,000-Year German Oak and Pine Dendrochronology for Radiocarbon Calibration

Sequences of dendrodated tree rings provide ideal sources for radiocarbon calibration. The wood structure of trees consists of continuous series of annual growth layers, the carbon content of which can be 14 C-dated and calibrated to calendar yr. The cellulose and lignin of trees deposited in river gravels or peat-bog sediments below the water table are often very well preserved, even after several millennia. Such tree-trunk deposits are well protected from contamination by younger or older organic materials. Further, the physical and chemical structure of wood allows a strong chemical pretreatment of samples for 14 C analysis.