Chronic atmospheric nitrogen (N) deposition could influence the functioning of ecosystems as well as their biodiversity. However, N deposition in urban forest ecosystems, especially natural evergreen broad-leaved forests, is not well known. In this study, the concentrations and fluxes of dissolved inorganic N (DIN) and dissolved organic N (DON) in bulk deposition, throughfall, and stemflow were assessed in an urban evergreen broad-leaved forest site over three years, in order to clarify the characteristics of N deposition. At the study site, bulk DIN deposition was 3.7 kg N ha⁻¹ year⁻¹ (1.5 kg N ha⁻¹ year⁻¹ for NH₄–N and 2.2 kg N ha⁻¹ year⁻¹ for NO₃ + NO₂–N), which is the same level as that found in rural areas. In contrast, 6.5 kg N ha⁻¹ year⁻¹ for bulk DON deposition contributed to 66% of the bulk N deposition, which suggests the importance of bulk DON deposition in Japanese forest ecosystems. Passing through the tree canopy, DIN was enriched by 8.8 kg N ha⁻¹ year⁻¹ (3.7 kg N ha⁻¹ year⁻¹ for NH₄–N and 5.1 kg N ha⁻¹ year⁻¹ for NO₃ + NO₂–N) and DON was enriched by 1.5 kg N ha⁻¹ year⁻¹ as net throughfall in the evergreen broad-leaved forest. This reveals that dry deposition of DIN dominates the total DIN deposition onto the urban forest floor, compared to that found in the rural areas, due to the non-negligible N emissions from outside and possibly because of the evergreen broad-leaved forest's greater ability to capture N.

长期的大气氮沉积可能影响生态系统的功能及其生物多样性。但是，人们对城市森林生态系统，特别是天然常绿阔叶林中的氮沉降知之甚少。在这项研究中，对三年来城市常绿阔叶林地块的沉积，穿透和茎流中溶解性无机N（DIN）和溶解性有机N（DON）的浓度和通量进行了评估，以阐明N沉积的特征。在研究现场，DIN的大块沉积为3.7 kg N ha - ¹年^-1（对于NH ₄ -N为1.5 kg N ha - ¹年^-1和2.2 kg N ha - ¹年^-1的NO₃  + NO ₂ -N），与农村地区的水平相同。相比之下，散装DON沉积的6.5 kg N ha ^-1 year ^-1占散装氮沉积的66％，这表明散装DON沉积在日本森林生态系统中的重要性。通过树冠，DIN的富集量为8.8 kg N ha - ¹年^-1（NH ₄ –N为3.7 kg N ha - ¹年^-1和NO ₃  + NO ₂为5.1 kg N ha - ¹年^-1 –N）和DON富集1.5 kg N ha - ¹年^-1作为常绿阔叶林中的净穿透量。这表明，与农村地区相比，DIN的干沉降主要占城市森林地面上DIN的总沉降，这是由于来自外部的N排放量不可忽略，并且可能是由于常绿阔叶林具有更高的分解能力。夺取N