Changes in soil organic carbon and nutrient stocks in conventional selective logging versus reduced-impact logging in rainforests on highly weathered soils in Southern Cameroon
Changes in soil organic carbon and nutrient stocks in conventional selective logging versus reduced-impact logging in rainforests on highly weathered soils in Southern Cameroon
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DOI：
10.1016/j.foreco.2019.117522
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发表时间：
2019-11-01
影响因子：
3.7
通讯作者：
Veldkamp, Edzo
中科院分区：
文献类型：
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作者：
Lontsi, Rodine Tchiofo;Cone, Marife D.;Veldkamp, Edzo
尽管与选择性采伐有关的干扰可能导致土壤特性和养分储量的显著变化，但对于非洲高度风化的土壤，这种信息非常有限。我们评价了减少冲击伐木(RIL，30年轮伐期管理计划)和常规伐木(CL，无管理计划)对喀麦隆热带雨林前寒武纪岩石上发育的费拉尔索尔土壤物理和生化特性的影响。在伐木作业完成五到七个月后，我们绘制了CL和RIL地点的地图，并量化了受干扰的区域：砍伐缺口、打滑路径、伐木甲板和道路。我们在每个地点选择了四个重复的地块，包括这四个受干扰的地层和邻近的未受干扰的区域作为参考。在每个扰动地层和每个样地的参照区，我们采集了50厘米以下的土壤样本，并量化了土壤的物理和生化特性。采伐强度很低，每公顷砍伐0.2株和0.3株，受干扰的地面面积仅占林地总面积的5.2%和4.0%。就每收获一棵树的面积干扰而言，CL比RIL多753 m(2)株(-1)受影响的地面面积。道路和伐木平台受采伐作业影响最大，与未受干扰的参考区相比，土壤有效阳离子交换量、土壤有机碳(SOC)、全氮(N)、溴可提取磷(P)和交换性铝(P)下降，而pH、N-15自然丰度和交换性锰增加(P<；0.01-0.04)。与参照区相比，干扰区土壤有机碳、氮、磷储量总体减少21%~29%(P=0.02~0.07)。随采伐木材输出的C、N、P和盐基阳离子的量仅为扰动地层中这些元素储量变化的0.4-5.9%。在这种极低强度的伐木系统中，在一次伐木事件后，CL和RIL之间的土壤和木材采伐出口中的养分减少是相似的。我们的结果表明，与RIL相反，无计划的作业加上CL固有的频繁重新采伐会增加面积损害，并加强SOC和养分的变化，这可能会影响后续植被的恢复。
Although disturbances associated with selective logging can cause pronounced changes in soil characteristics and nutrient stocks, such information is very limited for highly weathered soils in Africa. We assessed the effects of reduced impact logging (RIL, with a 30-year rotation management plan) and conventional logging (CL, without a management plan) on physical and biochemical characteristics of Ferralsol soils that developed on pre-Cambrian rocks in rainforests of Cameroon. Five to seven months after the logging operations were completed, we mapped the CL and RIL sites and quantified the disturbed areas: felling gaps, skidding trails, logging decks and roads. We selected four replicate plots at each site that encompassed these four disturbed strata and an adjacent undisturbed area as the reference. At each disturbed stratum and reference area per plot, we took soil samples down to 50 cm, and quantified soil physical and biochemical characteristics. Nutrient exports with timber harvest were also quantified.The logging intensity was very low with removals of 0.2 and 0.3 tree per hectare, and the ground area disturbed accounted only 5.2% and 4.0% of the total area in CL and RIL, respectively. In terms of area disturbance for each harvested tree, CL had 753 m(2) tree(-1) more affected ground area than RIL. Roads and logging decks were the most affected by logging operations, where effective cation exchange capacity, soil organic carbon (SOC), total nitrogen (N), Bray-extractable phosphorus (P) and exchangeable aluminum decreased whereas pH, N-15 natural abundance and exchangeable manganese increased compared to the undisturbed reference area (P < 0.01-0.04). The disturbed area showed overall reductions of 21-29% in SOC, N and P stocks relative to the reference areas (P = 0.02-0.07). The amounts of C, N, P and base cations exported with harvested timber were only 0.4-5.9% of the changes in stocks of these elements in the disturbed strata. Nutrient reductions in the soil and exports through timber harvest were comparable between CL and RIL, after one logging event in this very low intensity logging systems. Our results suggest that unplanned operations together with frequent re logging inherent to CL can increase area damage and enhance changes in SOC and nutrients as opposed to RIL, which may affect the recovery of the succeeding vegetation.