TEMPERATE FOREST ECOSYSTEMS IN THE GLOBAL CARBON-CYCLE

Although recent estimates have concluded that the temperate forest is approximately in carbon balance or perhaps a small carbon source, failure to balance the global carbon budget indicates that some of the accepted ranges for sinks or sources contain large errors or that an important sink has not been properly accounted for. Two very recent attempts to account for the fluxes by identifying carbon sources and sinks have provided evidence, of a missing carbon sink and that the missing sink is located somewhere in the temperate region of the Northern Hemisphere. The estimates of the temperate forest as being roughly in carbon balance in recent decades are at variance with the well-documented rise in northern forest timber volumes that has been occurring throughout much of the temperate Northern Hemisphere for the past several decades. Newly available data for all the forests of North America, Europe, and the former USSR allow a reexamination of the overall northern forest carbon balance. The findings of that re-examination suggest northern forest ecosystems as a missing carbon sink. These forests are estimated to be sequestering carbon at a rate of about 0.7 Gigatons (Gt) annually. A sink of this size is outside the range of recent estimates that are commonly used for purposes of estimating the global carbon budget.