Purpose

Nutrient distribution among tree tissues influence the growth, yield, and persistence of trees. One of the factors which can affect the nutrient concentrations can be stand density because competition for growth space and below-ground resources play a significant role in the productivity of plantation forests.

Methods

This study analyzed the impact of planting density and soil quality indicators on the annual growth process, nutrient uptake, nutrient use efficiency, and carbon storage in mid-aged Chinese fir (Cunninghamia lanceolata) stands established at low, intermediate, and high-density. Stem density was 1450 trees hm² (2.36 × 2.36 m spacing), 2460 trees hm² (1.83 × 1.83 m spacing), and 3950 trees hm² (1.44 × 1.44 m spacing) in low-, intermediate-, and high-density stands, respectively.

Results

Stand density (R² = 0.812) was the primal factor responsible for altering nutrients dynamics in tree components, while soil quality (R² = 0.572) indicators play a secondary role. Across the years, the diameter and volume annual growth increment were more significant in the low-density, whereas height growth increment was more prominent in the intermediate-density. The highest carbon storage (33.78 t hm⁻²) was observed in the intermediate-density stand. Plant nutrient concentrations and nutrient use efficiency varied significantly among different densities (p < 0.05). Significant associations of soil properties with biomass, height, and diameter were observed in intermediate-density.

Conclusions

These patterns were co-regulated by planting density, tree growth rate, and soil nutrient status and reflected the plant tissue’s nutrient status, which could provide valuable information for sustainable nutrient management practices in tree plantations for maximizing productivity, yield, and long-term sustainability.

中文翻译：

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单株杉木组织的年生长进程、养分转化和碳储量与受种内竞争强度影响的土壤质量指标的关系

目的

树木组织中的养分分布影响树木的生长、产量和持久性。影响养分浓度的因素之一可能是林分密度，因为对生长空间和地下资源的竞争对人工林的生产力起着重要作用。

方法

本研究分析了种植密度和土壤质量指标对低、中、高密度中龄杉木（Cunninghamia lanceolata）林分年生长过程、养分吸收、养分利用效率和碳储量的影响。低、中、高密度的茎密度分别为1450棵树hm ² (2.36 × 2.36 m间距)、2460棵树hm ² (1.83 × 1.83 m间距)和3950棵树hm ² (1.44 × 1.44 m间距)分别站立。

结果

林分密度 ( R ²  = 0.812) 是改变树木成分中养分动态的主要因素，而土壤质量 ( R ²  = 0.572) 指标起次要作用。各年间，低密度的直径和体积年增长增量更为显着，而中等密度的高度增长增量更为显着。最高的碳储存量（33.78 t hm ^-2）在中等密度的支架中观察到。不同密度下植物养分浓度和养分利用效率差异显着（p  < 0.05）。在中等密度下观察到土壤特性与生物量、高度和直径的显着关联。

结论

这些模式受种植密度、树木生长速度和土壤养分状况的共同调节，并反映植物组织的养分状况，可为人工林可持续养分管理实践提供有价值的信息，以最大限度地提高生产力、产量和长期可持续性.