Kauri dieback, caused by Phytophthora agathidicida, is an emergent threat to the ecologically unique and carbon-rich kauri (Agathis australis) forests in New Zealand. Our main aim was to assess the effect of kauri dieback on canopy and forest floor dissolved and particulate carbon (C) and nitrogen (N) fluxes. Throughfall and stemflow collectors and free-draining lysimeters were deployed underneath the canopy of ten kauri trees differing in their soil P. agathidicida DNA concentration and visual health status and sampled weekly to monthly over 1 y. Throughfall and forest floor dissolved C and N fluxes decreased significantly with increasing soil P. agathidicida DNA concentration which may be related to changes in leaf chemistry, leachable kauri leaf surface area and uptake of N by the understory vegetation. The observed alteration in dissolved and particulate C and N fluxes under P. agathidicida infected kauri trees could lead to long-term changes in biogeochemical processes (e.g. mineralization, nutrient availability) in these ecologically unique kauri forests.

由疫霉疫霉（Phytophthora agathidicida）引起的贝壳杉枯死是对新西兰独特的生态学和碳含量丰富的贝壳杉（Agathis australis）森林的紧急威胁。我们的主要目的是评估贝壳杉枯萎对冠层和林地溶解以及颗粒碳（C）和氮（N）通量的影响。贯穿的和茎流收集器和自由排水的测渗仪被部署在十个贝壳杉树冠下，这些贝壳树的土壤P. agathidicida DNA浓度和视觉健康状况各不相同，并在1年内每周一次至每月采样。随着土壤假单胞菌（P. agathidicida）的增加，穿透力和林地中可溶性碳和氮通量显着下降DNA浓度可能与叶片化学变化，可浸贝壳杉叶表面积和地下植被对氮的吸收有关。在agathidicida感染的贝壳杉树下观察到的溶解态C和N和N和通量的通量变化可能导致这些生态独特的贝壳杉林中生物地球化学过程的长期变化（例如矿化，养分利用率）。