Temperate forest soils are often considered as an important sink for atmospheric carbon (C), thereby buffering anthropogenic CO₂ emissions. However, the effect of tree species composition on the magnitude of this sink is unclear. We resampled a tree species common garden experiment (six sites) a decade after initial sampling to evaluate whether forest floor (FF) and topsoil organic carbon (C_org) and total nitrogen (N_t) stocks changed in dependence of tree species (Norway spruce—Picea abies L., European beech—Fagus sylvatica L., pedunculate oak—Quercus robur L., sycamore maple—Acer pseudoplatanus L., European ash—Fraxinus excelsior L. and small-leaved lime—Tilia cordata L.). Two groups of species were identified in terms of C_org and N_t distribution: (1) Spruce with high C_org and N_t stocks in the FF developed as a mor humus layer which tended to have smaller C_org and N_t stocks and a wider C_org:N_t ratio in the mineral topsoil, and (2) the broadleaved species, of which ash and maple distinguished most clearly from spruce by very low C_org and N_t stocks in the FF developed as mull humus layer, had greater C_org and N_t stocks, and narrow C_org:N_t ratios in the mineral topsoil. Over 11 years, FF C_org and N_t stocks increased most under spruce, while small decreases in bulk mineral soil (esp. in 0–15 cm and 0–30 cm depth) C_org and N_t stocks dominated irrespective of species. Observed decadal changes were associated with site-related and tree species-mediated soil properties in a way that hinted towards short-term accumulation and mineralisation dynamics of easily available organic substances. We found no indication for C_org stabilisation. However, results indicated increasing N_t stabilisation with increasing biomass of burrowing earthworms, which were highest under ash, lime and maple and lowest under spruce.

中文翻译：

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树种是否会影响丹麦公共花园实验中土壤有机碳和总氮储量的十年变化？

温带森林土壤通常被认为是大气碳 (C) 的重要汇，从而缓冲人为 CO ₂排放。然而，树种组成对该汇规模的影响尚不清楚。我们在初始采样十年后重新采样了一个树种普通花园实验（六个地点），以评估森林地表 (FF) 和表土有机碳 (C _org ) 以及总氮 (N _t ) 库存是否随树种（挪威云杉）而变化— Picea abies L.、欧洲山毛榉— Fagus sylvatica L.、有花梗的橡木— Quercus robur L.、梧桐槭— Acer pseudoplatanus L.、欧洲白蜡木— Fraxinus excelsiorL. 和小叶酸橙——Tilia cordata L.)。_{根据 C org}和 N _t分布确定了两组物种：(1) FF 中具有高 C _org和 N _t库的云杉发展为具有较小 C _org和 N _t库的铁质腐殖质层和矿物表土中的C _org : N _t比更宽，以及 (2) 阔叶树种，其中灰和枫树与云杉的区别最为明显，因为 FF 中的 C _org和 N _t库存非常低，发育为 mull 腐殖质层，具有更大的C _org和 N _t库存，以及矿物表土中的C _org : N _{t比率较窄。}11 年来，云杉下 FF C _org和 N _{t库增加最多，而散装矿质土壤（特别是 0-15 cm 和 0-30 cm 深度）C org}和 N _t库的小幅下降占主导地位，与物种无关。观察到的年代际变化与场地相关和树种介导的土壤特性相关，这暗示了容易获得的有机物质的短期积累和矿化动态。我们没有发现 C _org稳定的迹象。然而，结果表明增加 N _t随着穴居蚯蚓生物量的增加而稳定，在灰、石灰和枫树下最高，在云杉下最低。