A subtropical mangrove along the Miyara River in Ishigaki Island, Japan was studied for evaluating the carrying capacity for biomass of the mangrove stands. The stem diameters D, tree height H, and fine roots mass were measured, while aboveground biomass (AGB) and belowground coarse root biomass (BGB_coarse) were estimated. The AGB, BGB_coarse, and fine root mass were estimated as 130, 31, and 13 Mg ha⁻¹ in the Rhizophora stylosa; 271, 94, and 11 Mg ha⁻¹ in the downstream Bruguiera gymnorrhiza; and, 228, 81, and 6.4 Mg ha⁻¹ in the upstream B. gymnorrhiza stand, respectively. The AGB and BGB_coarse in the R. stylosa stand were significantly lower than B. gymnorrhiza stands, and fine root mass was significantly higher than upstream B. gymnorrhiza stand. Significantly lower mean individual phytomass w_t specific to tree density ρ of R. stylosa stand than B. gymnorrhiza stand in the ρ − w_t relationship denoted the lower carrying capacity for AGB of R. stylosa than that of B. gymnorrhiza. The results showed that high soil pore water salinity and low pH at the downstream did not limit biomass and potential canopy height H_max of mangrove along a river gradient but AGB and BGB_coarse differed between different species at the same edaphic environment. Analysis of aboveground and belowground biomass variations between stands of two mangrove species along environmental gradients from upstream to downstream could be useful in assessing the consequences of sea level rise in relation to climate change on the evolution of blue carbon dynamics.

中文翻译：

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从森林结构特征推断日本沿河亚热带红树林树木生物量承载力

对日本石垣岛宫良河沿岸的亚热带红树林进行了研究，以评估红树林的生物量承载能力。测量茎直径D、树高H和细根质量，同时估计地上生物量（ AGB）和地下粗根生物量（BGB_粗）。Rhizophora stylosa的AGB 、BGB_粗根和细根质量估计分别为 130、31 和 13 Mg ha ^-1；下游木榄中271、94 和 11 Mg ha ^-1；上游裸露林中分别为228、81和6.4 Mg ha ^-1。红花林的AGB和BGB粗根_量显着低于裸木林，细根质量显着高于上游裸露林。在ρ  -  w _t关系中，特定于树密度ρ的红花林的平均单株质量w _{t显着低于}裸木林，这表明红花林的AGB承载能力低于裸露林。结果表明，下游高土壤孔隙水盐度和低pH值并没有限制沿河流梯度红树林的生物量和潜在冠层高度H _{max ，但在同一土壤环境下，不同物种之间的}AGB和BGB_粗度存在差异。分析两种红树林物种沿从上游到下游的环境梯度之间的地上和地下生物量变化，有助于评估与气候变化相关的海平面上升对蓝碳动态演化的影响。