Alternative afforestation options on sandy heathland result in minimal long-term changes in mineral soil layers
Alternative afforestation options on sandy heathland result in minimal long-term changes in mineral soil layers
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DOI：
10.1016/j.foreco.2020.118906
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发表时间：
2021-03
影响因子：
3.7
通讯作者：
Eleanor R. Tew;E. Vanguelova;W. Sutherland
中科院分区：
文献类型：
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作者：
Eleanor R. Tew;E. Vanguelova;W. Sutherland
目前，广泛的植树造林作为缓解气候变化的一个基于自然的关键解决方案得到了广泛推广。这一战略的基础是将碳封存到木制品或土壤中进行长期稳定储存。然而，植树对土壤碳或其他土壤特性的长期影响却很少被研究。重要的是，造林可以采取多种不同的形式，对土壤特性产生不同的影响。在这里，我们评估了历史上沙质荒地造林采用一系列管理方案（包括单一栽培和混合栽培中针叶树和阔叶树的不同组合）如何影响近一个世纪后的土壤 pH 值、总碳和氮浓度、C:N 比以及碳和氮储量。我们通过有机土层（枯落物层、F 层和草层）和上部矿物土层（0-5 厘米、5-10 厘米和 10-20 厘米深度）分析不同土壤深度的这些特性。与历史上的石南荒地相比，植树造林降低了土壤 pH 值（在针叶树下最为显着），并提高了 C:N 比率。然而，替代管理方案之间的碳和氮浓度总体上差异不大。虽然与开放地点相比，森林选择的有机层中的总碳和氮浓度要高得多，但这并没有转化为矿物层的差异。此外，尽管我们发现了一些碳和氮转移到最上层土壤矿物层的证据，但与有机层的浓度相比，这是最小的。我们研究地点的土壤质量低劣，多为沙质，因此不利于有机质的吸收，但值得注意的是，经过近一个世纪的造林，有机质的吸收量仍然很少。鉴于当前强调植树作为应对气候变化的手段，这些结果表明适当考虑造林管理方案和底层土壤类型的根本重要性。
Extensive afforestation is currently being widely promoted as a key nature-based solution for climate change mitigation. Fundamental to this strategy is the sequestration of carbon into long-term stable storage, either in wood products or the soil. However, the long-term effects of tree planting on soil carbon, or other soil properties, has rarely been examined. Importantly, afforestation can take many different forms, with differing effects on soil properties. Here, we evaluate how the historical afforestation of sandy heathland adopting a range of management options – including different combinations of conifers and broadleaves in monocultures and mixtures – have affected soil pH, total carbon and nitrogen concentrations, the C:N ratio, and carbon and nitrogen stocks almost a century later. We analyse these properties at a range of soil depths through the organic (litter, F and grass layers) and upper mineral (0–5 cm, 5–10 cm and 10–20 cm depth) soil layers. In comparison to the historical heathland sites, afforestation decreased soil pH, most dramatically under conifers, and increased the C:N ratio. However, there was overall little difference in carbon and nitrogen concentrations between alternative management options. While the total carbon and nitrogen concentrations were much higher in the organic layers of the forest options compared to the open sites, this did not translate into differences in the mineral layers. Furthermore, although we found some evidence of the transferral of carbon and nitrogen into the uppermost soil mineral layers, this was minimal in comparison to the concentrations of the organic layers. The soils at our study site are low quality and sandy, and are therefore unfavourable for incorporating organic matter, but it is still notable how little was incorporated after nearly a century of afforestation. Given the current emphasis on tree planting as a means to tackle climate change, these results demonstrate the fundamental importance of the appropriate consideration of both the afforestation management option and underlying soil type.