Zhichun Yang, Zikun Mao, Wenwen Ji, Antonio Gazol, Shufang Liu, Chao Wang, Ji Ye, Fei Lin, Xugao Wang, Zhanqing Hao, Edith Bai, Zuoqiang Yuan
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引用次数: 0
Abstract
Examining whether nitrogen (N) enrichment promotes secondary tree growth in both young (YF) and old-growth forests (OF) is crucial. This will help determine how N addition influences plant carbon sequestration across successional phases in temperate forests. We conducted an eight-year N addition experiment (0, 25, 50, 75 kg N ha-1 yr-1) in YF and OF in northeast China to investigate the effects of enhanced in situ N deposition on tree growth. Our results indicated that N addition accelerated the accumulation of annual mean aboveground biomass (ΔAGB) of trees only in OF. Specifically, for the species co-occurring in both YF and OF plots, their ΔAGB in OF peaked under the medium N treatment (3.69 Mg ha-1 yr-1), which was 2.3 times higher than that of YF (1.58 Mg ha-1 yr-1). Regarding mycorrhizal types, only the ΔAGB of EcM-associated trees peaked under the high N treatment (2.81 Mg ha-1 yr-1), increasing by 126.6% compared to the control (1.24 Mg ha-1 yr-1). This increase in biomass primarily came from large trees with a DBH ≥15 cm, most of which are EcM -associated species, such as Pinus koraiensis. In conclusion, continuous N addition increases nutrient supply and alleviates N limitation in old growth forest, leading to faster biomass accumulation. The growth of large-diameter trees with EcM-associated may contribute significantly to aboveground biomass accmulation under N addition. Nutrient limitation is dependent on stand age, mycorrhizal type and size, so these factors must be considered when assessing forest nutrient limitations.
研究氮(N)富集是否促进幼树和老林的次生树生长是至关重要的。这将有助于确定N添加如何影响温带森林演替阶段的植物碳固存。为了研究原位氮沉降对东北地区青枯树生长的影响,在东北地区青枯树和黄枯树进行了为期8年的施氮量(0、25、50、75 kg N / h -1年-1)试验。结果表明,施氮加速了林分年平均地上生物量的积累(ΔAGB)。其中,在YF和OF样地共生的物种,其ΔAGB in OF在中氮处理下达到峰值(3.69 Mg ha-1年-1),是YF处理(1.58 Mg ha-1年-1)的2.3倍。在菌根类型方面,在高氮处理(2.81 Mg ha-1年-1)下,ecm相关树木只有ΔAGB达到峰值,比对照(1.24 Mg ha-1年-1)增加了126.6%。这种生物量的增加主要来自胸径≥15 cm的大树,其中大部分是与EcM相关的树种,如红松。综上所述,连续施氮增加了原生林的养分供应,缓解了氮素限制,使生物量积累更快。施氮条件下,与ecm相关的大径乔木的生长对地上生物量积累有显著贡献。养分限制取决于林龄、菌根类型和大小,因此在评估森林养分限制时必须考虑这些因素。
期刊介绍:
The Journal of Environmental Management is a journal for the publication of peer reviewed, original research for all aspects of management and the managed use of the environment, both natural and man-made.Critical review articles are also welcome; submission of these is strongly encouraged.