An integrated characterization of physical, chemical, biochemical and microbiological properties of litter fractions (litter, fragmented and humified), corresponding at three decomposition phases, has been conducted in a degraded pine forest. Litter fractions were characterized in terms of C and N content, microbial communities’ structure, enzyme activities and optical properties. The objective of this approach was to give an insight of actors and mechanisms operating during decomposition process, evaluating the relationships between litter pools (organic matter and microbial communities) and activities (respiration and enzymes). The effect of different thinning treatments (traditional and selective) on litter biomass and respiration was also investigated for 2 years, to identify forest management practices aiming at increase C storage and mitigate climate change. The litter fractions showed well-distinct chemical composition, with a decrease in carbon and an increase in nitrogen as decomposition advanced. Parallelly, an increase in fungal richness and diversity, and related enzyme activities, was observed. Bacteria were similar in the three fractions but seemed to have a role in the early phase of cellulose and hemicellulose decomposition. Thinning induced a short-term increase in litter input to soil, which disappeared after the first year until determining a general decrease in litter biomass, stronger with selective thinning. Further, in the warmer months of the second year after thinning litter respiration showed an increasing trend. Overall, positive effects of thinning on C storage were evident in the short term, followed by a decrease in litter pool driven by higher litter respiration.

中文翻译：

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间伐处理后退化松林的凋落物分数和动态

在退化的松林中，对对应于三个分解阶段的凋落物部分（凋落物、碎片和腐殖质）的物理、化学、生化和微生物特性进行了综合表征。凋落物部分的特征在于 C 和 N 含量、微生物群落结构、酶活性和光学特性。这种方法的目的是深入了解分解过程中的参与者和机制，评估垃圾池（有机物质和微生物群落）与活动（呼吸和酶）之间的关系。还研究了不同的间伐处理（传统和选择性）对凋落物生物量和呼吸的影响长达 2 年，确定旨在增加碳储存和减缓气候变化的森林管理实践。凋落物部分显示出截然不同的化学成分，随着分解的进行，碳含量减少，氮含量增加。同时，观察到真菌丰富度和多样性以及相关酶活性的增加。三个部分中的细菌相似，但似乎在纤维素和半纤维素分解的早期阶段起作用。间伐导致土壤凋落物输入的短期增加，在第一年后消失，直到确定凋落物生物量普遍减少，选择性间伐更强烈。此外，在稀疏凋落物后第二年的温暖月份，呼吸量呈增加趋势。全面的，