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Forests strongly affect climate through the exchange of large amounts of atmospheric CO2 (ref. ). The main drivers of spatial variability in net ecosystem production (NEP) on a global scale are, however, poorly known. As increasing nutrient availability increases the production of biomass per unit of photosynthesis and reduces heterotrophic respiration in forests, we expected nutrients to determine carbon sequestration in forests. Our synthesis study of 92 forests in different climate zones revealed that nutrient availability indeed plays a crucial role in determining NEP and ecosystem carbon-use efficiency (CUEe; that is, the ratio of NEP to gross primary production (GPP)). Forests with high GPP exhibited high NEP only in nutrient-rich forests (CUEe = 33 ± 4%; mean ± s.e.m.). In nutrient-poor forests, a much larger proportion of GPP was released through ecosystem respiration, resulting in lower CUEe (6 ± 4%). Our finding that nutrient availability exerts a stronger control on NEP than on carbon input (GPP) conflicts with assumptions of nearly all global coupled carbon cycle-climate models, which assume that carbon inputs through photosynthesis drive biomass production and carbon sequestration. An improved global understanding of nutrient availability would therefore greatly improve carbon cycle modelling and should become a critical focus for future research. [ABSTRACT FROM AUTHOR]

A response form the author for two articles including one related to effects of nutrient availability on carbon balance of global forest and another on data quality and role of nutrients in carbon-use efficiency of forest, which appeared in a previous issue is presented.

A correction to the article "Nutrient availability as the key regulator of global forest carbon balance," that was published in the April 6, 2014 issue is presented.

A correction to the article "Nutrient availability as the key regulator of global forest carbon balance" by S. Vicca, I. A. Janssens, J. Sardans and colleagues that was published in the previous issue is presented that inadvertently failed to include some texts of the acknowledgement section.