Abstract. Wildfires typically affect multiple forest ecosystem services, with carbon sequestration being affected both directly, through the combustion of vegetation, litter and soil organic matter, and indirectly, through perturbation of the energy and matter balances. Post-fire carbon fluxes continue poorly studied at the ecosystem scale, especially during the initial window-of-disturbance when changes in environmental conditions can be very pronounced due to the deposition and subsequent mobilization of a wildfire ash layer and the recovery of the vegetation. Therefore, an eddy-covariance system was installed in a burnt area as soon as possible after a wildfire that had occurred on 13 August 2017, and has been operating from the 43^rd post-fire day onwards. The study site was specifically selected in a Mediterranean woodland area dominated by Maritime Pine stands with a low stature that had burnt at high severity. The carbon fluxes recorded during the first post-fire hydrological year tended to be very low, so that a specific procedure for the analysis and, in particular, gap filling of the eddy covariance data had to be developed. Still, the carbon fluxes varied noticeably during the first post-fire year, broadly revealing five consecutive periods. During the rainless period after the wildfire, fluxes were reduced but, somewhat surprisingly, indicated a net assimilation. With the onset of the autumn rainfall, fluxes increased and corresponded to a net emission, while they became insignificant with the start of the winter. From the mid winter onwards, net fluxes became negative, indicating a weak carbon update during spring followed by a strong uptake during summer. Over the first post-fire year as a whole, the cumulative net ecosystem exchange was −347 g C m⁻², revealing a relatively fast recovery of the carbon sink function of the ecosystem. This recovery was mainly due to understory species, both resprouter and seeder species, since pine recruitment was reduced. Specific periods during the first post-fire year were analyzed in detail for improving process understanding. Perhaps most surprisingly, dew formation and, more specifically, its subsequent evaporation was found to play a role in carbon emissions during the rainless period immediately after fire, involving a mechanism distinct from de-gassing of the ash/soil pores by infiltrating water. The use of a special wavelet technique was fundamental for this inference.

中文翻译：

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使用涡度协方差技术估算火灾后立即的碳通量

摘要。野火通常会影响多种森林生态系统服务，碳固存不仅会通过燃烧植被，垃圾和土壤有机质而受到直接影响，还会通过对能量和物质平衡的干扰而间接受到影响。火灾后的碳通量在生态系统规模上仍未得到很好的研究，尤其是在最初的扰动窗口期间，由于野火灰层的沉积和随后的动员以及植被的恢复，环境条件的变化非常明显。因此，涡度相关系统很快就安装在烧伤面积尽可能2017年8月13日所发生的野火之后，并已经从43操作^RD火灾后的一天开始。该研究地点是在地中海林地中特别选择的，该林地以海松松林为主，林木矮小，高度燃烧。火灾后的第一个水文年记录的碳通量往往很低，因此必须制定一种具体的分析程序，尤其是要填补涡度协方差数据的缺口。尽管如此，在火灾后的第一年，碳通量变化显着，大致揭示了五个连续的时期。在野火过后的无雨期，通量减少了，但有些出乎意料的是，表明净吸收。随着秋季降雨的开始，通量增加并与净排放量相对应，而随着冬季的开始它们变得微不足道。从冬季开始 净通量变为负值，表明春季碳更新较弱，而夏季则大量吸收。在整个火灾后的第一年，累积的净生态系统净交换量为−347 g C m^－2，表明生态系统的碳汇功能恢复相对较快。这种恢复主要是由于松树采伐量减少而引起的林下物种，既是繁殖物种又是播种物种。详细分析了火灾后第一年的特定时期，以提高对过程的了解。也许最出乎意料的是，发现刚形成的露水在着火后的无雨时期对碳排放起着重要作用，其机理与通过渗透水使灰/土壤孔隙脱气不同。使用特殊的小波技术是这一推断的基础。