Studies of forest clear-felling operations in 1995–97 in the Afon Tanllwyth sub-catchment of the upper River Severn on Plynlimon, mid-Wales, by Stott et al. (Journal of Environmental Management (2001), 63, 3), indicated elevated suspended sediment loads (SSLs) immediately following timber harvesting. UK Forestry Commission (1993) Forests and Water Guidelines recommended that riparian buffer zones adjacent to streams were left unplanted. This study 20 years on assessed the SSLs at the same point in the Afon Tanllwyth for 21 months between January 2017 and September 2018. While SSLs reported by Stott et al. (Journal of Environmental Management (2001), 63, 3). increased during and after the clear-felling operations, by 2017–18 (20 years later) they appear to have recovered to levels similar to those measured pre-clear-felling (1995), despite this study taking place only a few months after approximately 3 ha of mature forest was clear-felled on the north side of the catchment. Although the mean monthly SSL for 2017–18 of 1628 ± 95 kg is slightly lower than the 1,800 ± 176 kg reported for 1995, the difference is not significant. When SSL is corrected for differences in total monthly flow the flow adjusted SSLs are 1,346 ± 132 kg for 1995 and 945 ± 55 kg for 2017–18, thus significantly lower in 2017–18. These new data for 2017–18 indicate that SSLs seem to have recovered to levels significantly below those measured and reported by Stott et al. (Journal of Environmental Management (2001), 63, 3–25) in 1995 pre-clear-felling period, likely as a result of the establishment of the 50 m buffer zone.

中文翻译：

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河岸缓冲区和新的森林管理实践是否会减少河流悬浮沉积物负荷？：20 年后重访 Plynlimon 的 Hafren Forest 的 Afon Tanllwyth

Stott等人对 1995-97 年在威尔士中部 Plynlimon 的上游 Severn 河的 Afon Tanllwyth 子流域的森林砍伐作业的研究。（Journal of Environmental Management (2001), 63, 3）表明木材采伐后悬浮沉积物负荷 (SSLs) 立即升高。英国林业委员会（1993 年）《森林和水指南》建议不要种植与溪流相邻的河岸缓冲区。这项研究在 2017 年 1 月至 2018 年 9 月期间对 Afon Tanllwyth 同一点的 SSL 进行了 20 年的评估，为期 21 个月。而 Stott等人报告的 SSL 。(环境管理杂志(2001), 63, 3)。在清伐作业期间和之后增加，到 2017-18 年（20 年后），它们似乎已恢复到与清伐前（1995 年）测量的水平相似的水平，尽管这项研究仅在大约流域北侧有 3 公顷的成熟森林被砍伐。尽管 2017-18 年的平均每月 SSL 为 1628 ± 95 公斤，略低于 1995 年报告的 1,800 ± 176 公斤，但差异并不显着。当 SSL 根据月总流量的差异进行校正时，1995 年的流量调整 SSL 为 1,346 ± 132 kg，2017-18 年为 945 ± 55 kg，因此在 2017-18 年显着降低。2017-18 年的这些新数据表明 SSL 似乎已恢复到明显低于 Stott等人测量和报告的水平。(Journal of Environmental Management (2001), 63, 3–25) 1995 年的砍伐前时期，可能是由于建立了 50 m 缓冲区。