Du Enzai

[Du, Enzai] Beijing Normal Univ, State Key Lab Earth Surface Proc & Resource Ecol, Beijing 100875, Peoples R China.

[Du, Enzai] Beijing Normal Univ, Coll Resources Sci & Technol, Beijing 100875, Peoples R China.

[Du, Enzai] Wageningen Univ, Environm Syst Anal Grp, NL-6700 AA Wageningen, Netherlands.

To the Editor — Fernández-Martínez et al. show that nutrient availability is the chief determinant of net ecosystem production (NEP) and ecosystem carbon-use efficiency (CUEe, the ratio of NEP to gross primary production, GPP) in global forests. But their conclusions depend on an improper treatment of differences in the GPP range of nutrient-rich and nutrient-poor forests (uneven sampling effect) and outliers. A statistical re-analysis of their data sets while simultaneously excluding the uneven sampling effect and outliers indicates no significant control of nutrient availability on carbon balance.

Published in NATURE CLIMATE CHANGE.2015,5(11):958-959