Aims

We conducted a suite of tracer studies using the stable isotope ¹³C to follow and quantify the flow of carbon from leaf litter and roots into soil components including aggregates and biota with and without invasive earthworms.

Methods

Ten-year-old saplings of sugar maple growing in the understory of a thinned northern hardwood forest were labeled with ¹³CO₂. The ¹³C labeled leaf litter was applied to forest plots with and without invasive earthworms (Lumbricidae) and traced for three years. We also traced the label from the trees through the roots and into soil components in the labeling chambers. Labeled fine roots and stem wood were incubated in a forest and the label was quantified over six years of decomposition.

Results

We were able to detect the litter tracer to 10 cm soil depth in plots without earthworms and to 20 cm with earthworms present, and earthworms promoted C incorporation into soil aggregates. The soil food web was much more enriched in the label from roots than from aboveground plant litter.. Rapid fine root decay was observed (k = 0.9 yr⁻¹), and although labelled wood was almost completely decayed, little ¹³C was recovered in soil (0.33%).

Conclusion

The approach was successful for quantifying transport and fate of tree carbon in forest soils and could be enhanced with careful quantification of gross assimilation.

中文翻译：

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追踪通过糖枫森林及其土壤成分的碳流：入侵性role的作用

目的

我们使用稳定的同位素¹³ C进行了一系列示踪剂研究，以追踪和量化碳从叶凋落物和根部进入土壤成分（包括有和没有侵入性aggregate）的土壤成分（包括聚集体和生物群）的流量。

方法

在变薄的北部硬木林的林下生长的十岁的枫糖树苗被标记为¹³ CO ₂。将带有¹³ C标记的叶子凋落物应用于有或没有侵入性（（Lumbricidae）的森林地块，并追踪了三年。我们还从树上穿过根部追溯到标签，并在标签室中追踪到土壤成分。将标记的细根和茎木在森林中孵育，并在分解的六年内对标记进行定量。

结果

在没有earth的地块中，我们能够检测到土壤垫层示踪剂达到10 cm的土壤深度，在有with的情况下，我们能够检测到20 cm的土壤，并且worm促进了C掺入土壤团聚体中。与地上的植物凋落物相比，土壤食物网中根部的标签丰富得多。观察到快速的细根衰变（k = 0.9 yr ^-1），尽管标记的木材几乎完全被腐烂，但在土壤中几乎没有¹³ C的回收。土壤（0.33％）。

结论

该方法成功地定量了森林土壤中树木碳的迁移和归宿，并且可以通过仔细量化总同化来增强。