Sensitivity of pH in a boreal stream network to a potential decrease in base cations caused by forest harvest
Sensitivity of pH in a boreal stream network to a potential decrease in base cations caused by forest harvest
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DOI：
10.1139/f10-052
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发表时间：
2010-07-01
影响因子：
2.4
通讯作者：
Laudon, Hjalmar
中科院分区：
文献类型：
--
作者：
Agren, Anneli;Buffam, Ishi;Laudon, Hjalmar
增加森林采伐，更多地利用整棵树，可以减少土壤和径流中的盐基阳离子（BC）。本文分析了如何减少流BC的变化能力的北方河流网络缓冲pH值的变化。我们估计在春季融雪流pH值的变化，在60个地点，整个68平方公里的北方集水区在北方瑞典与不同的情况下，从溪流中去除BC范围从10到50毫当量。.L（-1）。pH值下降，在所有的情况下，如果BC减少50毫当量。.L（-1），春季融雪期pH值大于pH 5的河流长度从82%减少到44%，而pH值大于5.5的河流长度从60%减少到10%。不同的流达到减少BC的pH值的敏感性呈正相关的集水区，森林覆盖率，森林沼泽的坡度，而它是负相关的农业领域的百分比。由于不同的林业实践对BC流的长期影响尚不清楚，因此更有理由在最终问题出现之前而不是之后评估BC敏感性。
Increased forest harvest with more whole-tree utilization can decrease base cations (BC) in soils and stream runoff. This paper analyses how reducing stream BC changes the capacity of a boreal stream network to buffer pH changes. We estimated change in stream pH during spring snowmelt in 60 locations throughout a 68 km2 boreal catchment in northern Sweden with different scenarios of BC removal from stream water ranging from 10 to 50 mequiv. .L(-1). The pH decreased in all scenarios, and if BC decreased by 50 mequiv. .L(-1), stream length with pH above the acid threshold pH 5 during spring snowmelt decreased from 82% to 44% of the stream network, whereas the stream length with pH above 5.5 decreased from 60% to 10%. The pH sensitivity of different stream reaches to reductions in BC was positively related to the slope of the catchment, forest cover, and forested mires, whereas it was negatively related to the percentage of agricultural fields. Because the long-term effect of different forestry practices on stream BC is unclear, there is all the more reason to evaluate BC sensitivity before, rather than after, eventual problems arise.