Did annual run‐off and low flow decrease with reduced forestry practices in Japan?
Did annual run‐off and low flow decrease with reduced forestry practices in Japan?
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DOI：
10.1002/hyp.7657
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发表时间：
2010-08
影响因子：
3.2
通讯作者：
H. Komatsu;T. Kume;Yoshinori Shinohara;Y. Miyazawa;K. Otsuki
中科院分区：
文献类型：
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作者：
H. Komatsu;T. Kume;Yoshinori Shinohara;Y. Miyazawa;K. Otsuki
日本在20世纪50年代至70年代开发了大面积的针叶林用于木材生产;然而，自20世纪80年代以来，大多数人工林的间伐，修剪和采伐等林业实践已经下降。研究人员推测，减少林业活动可以减少径流，从而减少可用的水资源。作为应对这一潜在风险的对策，许多地方政府已引入地方税，以刺激种植园的林业做法。然而，没有研究提供证据表明，在林业活动减少的流域，年径流量减少和/或流量低。作为评估这一风险的起点，本研究考察了寺内流域年径流和低流量的潜在变化。这个分水岭的大部分地区都被针叶林覆盖着。我们首先调查了尼木市每年的林业投资和森林所有者的数量。(Note（Amagi包括Terauchi流域。在1979-2007年期间，这两个数字都有所下降，表明林业活动减少。在流域的种植园林树龄的频率分布也表明减少林业的做法。在排除降水的影响后，我们研究了1979-2007年期间年径流和低流量的潜在变化。在此期间，我们没有观察到年径流量和低流量的显著减少。因此，水资源减少的风险可能低于预期，应重新考虑风险应对措施。版权所有© 2010约翰威利父子有限公司.
Japan developed large areas of coniferous plantations for timber production between the 1950s and 1970s; however, forestry practices such as thinning, pruning, and harvesting in most of the plantations have declined since the 1980s. Researchers speculated that reduced forestry practices could reduce run‐off and therefore available water resources. As a countermeasure to this potential risk, many local governments have introduced local taxes to stimulate forestry practices in the plantations. However, no studies have presented evidence for decreased annual run‐off and/or low flow in watersheds where forestry practices have declined. As a starting point for assessing this risk, this study examined potential changes in the annual run‐off and low flow in the Terauchi watershed. A large area of this watershed was covered with coniferous plantations. We first surveyed the annual investment in forestry operations and the number of forest owners in the city of Amagi. (Note that Amagi includes the Terauchi watershed.) Both decreased during the period 1979–2007, indicating reduced forestry practices. The frequency distribution of plantation tree ages in the watershed also suggested reduced forestry practices. After excluding the effect of precipitation, we examined potential changes in the annual run‐off and low flow during the period 1979–2007. We did not observe significant decreases in the annual run‐off and low flow during the period. Thus, the risk of decreased water resources might be less than expected, and countermeasures to the risk should be reconsidered. Copyright © 2010 John Wiley & Sons, Ltd.