The controls on large wood (LW; wood >1 m in length and >0.1 m in diameter) and coarse particulate organic matter (CPOM; organic material >1 mm in diameter) deposition on floodplains have rarely been assessed, and there are few studies that explore the bidirectional interactions between wood, standing trees, and geomorphic processes. We use field data from West Creek, Colorado, USA, to assess the influence of river corridor morphology and forest stand density on the depositional patterns of floodplain LW and CPOM accumulations (jams) resulting from an extreme flood. Relatively high LW loads per area (mean ± SE = 678.6 ± 192.3 m³ ha⁻¹) point to the importance of extreme floods for LW deposition on floodplains. We find that LW jams decreased in size with distance from and elevation above the channel, but that CPOM jams did not, demonstrating that the relatively smaller CPOM can be more easily transported within a forested floodplain. Steeper reaches contained smaller LW and CPOM loads per area, which may indicate that reaches with higher stream power during the flood were less depositional. As forest stand density increased, the number of CPOM jams per area increased, and a majority of jams were pinned by standing trees. Trees were trapping locations for LW and CPOM, highlighting the importance of preserving riparian forests. Floodplain LW and CPOM provide habitat and nutrients to floodplain ecosystems and influence geomorphic processes, creating an opportunity to use LW in restoration while reducing potential hazards caused by in-channel LW.

中文翻译：

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大洪水后泛滥平原大型木材和有机物堵塞的形成：调查泛滥平原林分特征和河流走廊形态的影响

很少评估对洪泛区大型木材（LW；木材长度 > 1 m，直径 > 0.1 m）和粗颗粒有机物（CPOM；有机材料直径 >1 mm）沉积的控制，并且很少有研究探索木材、立树和地貌过程之间的双向相互作用。我们使用来自美国科罗拉多州 West Creek 的现场数据来评估河流走廊形态和林分密度对极端洪水造成的漫滩 LW 和 CPOM 堆积（堵塞）沉积模式的影响。每个区域的 LW 负载相对较高（平均值 ± SE = 678.6 ± 192.3 m ³  ha ^-1) 指出了极端洪水对漫滩上 LW 沉积的重要性。我们发现 LW 堵塞的尺寸随着与通道的距离和海拔升高而减小，但 CPOM 堵塞没有，这表明相对较小的 CPOM 可以更容易地在森林泛滥平原内运输。较陡的河段包含较小的 LW 和 CPOM 载荷，这可能表明洪水期间具有较高水流功率的河段沉积较少。随着林分密度的增加，单位面积的 CPOM 堵塞数量增加，并且大部分堵塞被立树钉住。树木是 LW 和 CPOM 的诱捕地点，突出了保护河岸森林的重要性。洪泛区 LW 和 CPOM 为洪泛区生态系统提供栖息地和养分，并影响地貌过程，