The Accrual of Land-Use History in Utah's Forest Carbon Cycle.

The out-of-control carbon cycle with its risks on climate has increased interest in the carbon that is stored and cycling through terrestrial ecosystems.  In Utah’s contemporary forests, carbon is accumulating in biomass, detritus, and soil in response to 150 years of domestic livestock grazing, altered fire regimes, logging, and forest regrowth.  This forest-carbon sink is attributed to timberland regrowth following historical logging and to extensive afforestation of piñon pine and juniper woodlands that are expanding into former grasslands and sage and may now cover more than 13 million acres (5 million hectares) in the state.  Utah’s forest carbon sink compensates for no more that 25% of statewide greenhouse gas emissions, and more likely ranges between 10 to 15%.  This article encourages historians to help scientists explore landscape history and the carbon cycle because historical patterns of land-use and industrialization exert strong controls over the atmosphere’s changing composition of greenhouse gases.  A critical question for carbon policy of states and nations is whether changes in land uses can appreciably increase terrestrial carbon sinks in the next few decades, especially given how deeply and variously land-use history has altered the landscape’s carbon cycle.