Abstract: To understand soil N2O fluxes from temperate forests in a climate-sensitive transitional zone, N2O emissions from three temperate forest types (Pinus tabulaeformis, PTT; Pinus armandii, PAT; and Quercus aliena var. acuteserrata, QAT) were monitored using the static closed-chamber method from June 2013 to May 2015 in the Huoditang Forest region of the Qinling Mountains, China. The results showed that these three forest types acted as N2O sources, releasing a mean combined level of 1.35 ± 0.56 kg N2O ha-1 a-1, ranging from 0.98 ± 0.37 kg N2O ha-1 a-1 in PAT to 1.67 ± 0.41 kg N2O ha-1 a-1 in QAT. N2O emission fluctuated seasonally, with highest levels during the summer for all three forest types. N2O flux had a significantly positive correlation with soil temperature at a depth of 5 cm or in the water-filled pore space, where the correlation was stronger for temperature than for the water-filled pore space. N2O flux was positively correlated with available soil nitrogen in QAT and PAT. Our results indicate that N2O flux is mainly controlled by soil temperature in the temperate forest in the Qinling Mountains.
Keywords: Forest types; Greenhouse gases; N2O fluxes; Qinling Mountains; Soil temperature