The impact of bushfires on water yield from south-east Australia's ash forests
The impact of bushfires on water yield from south-east Australia's ash forests
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DOI：
10.1002/wrcr.20351
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发表时间：
2013-07-01
影响因子：
5.4
通讯作者：
Roderick, Michael L.
中科院分区：
文献类型：
--
作者：
Brookhouse, Matthew T.;Farquhar, Graham D.;Roderick, Michael L.
森林集水区内的广泛干扰通常会增加径流。然而，在1939年澳大利亚东南部发生大面积火灾后，Kuczera（1987年）报告说，由于再生灰林的蒸散量增加，径流量持续减少。Kuczera预测，在大约150年的时间里，水产量将持续减少。2003年，墨累-达令盆地（MDB）源头的大面积火灾再次刺激了白蜡林的广泛再生，提高了随后水量减少的前景。为了了解2003年森林大火的潜在影响，我们重新评估了Kuczera最初使用相同校准期研究的三个集水区的减产情况。我们还使用了一个扩大的发射前校准期（1908年至1938年）的基础上，数据最初没有提供给库切拉。我们在1939年观察到的受影响的集水区的火灾后水量的趋势是定性与Kuczera的预测一致，但定量的细节，如预期的那样，火灾前的校准期间使用的敏感。然后，我们使用了一种简化的方法来研究进一步的五个灰为主的集水区受2003年火灾。我们报告的相对减少，在所有五个集水区和统计学显着（=0.05）火灾后减少在五个集水区之一的年平均流量。火灾后产量减少在南方夏季（10月至4月）的相对幅度较大，在所有五个集水区，并在统计上显着（=0.05）的五个集水区。我们的结论是，火灾后Kuczera型的反应可能是广泛的再生灰森林。在此基础上，我们预计其他地方的火山灰森林火灾后产量减少，并得出结论，至少在未来十年内，MDB的径流量可能会进一步减少。
Widespread disturbance within forested catchments typically increases runoff. However, following widespread fire in 1939 throughout south-east Australia, Kuczera (1987) reported persistent reductions in runoff that were attributed to increased evapotranspiration from regenerating ash forests. Kuczera projected ongoing reductions of water yield for approximate to 150 years. In 2003, widespread fire in the headwaters of the Murray-Darling Basin (MDB) again stimulated extensive regeneration of ash forests, raising the prospect of subsequent water yield reductions. To understand the potential impact of the 2003 bushfires, we re-evaluated yield reductions from three of the catchments originally studied by Kuczera using the same calibration period. We also used an expanded prefire calibration period (1908-1938) based on data not originally available to Kuczera. The trend of postfire water yield that we observed in 1939-affected catchments is qualitatively consistent with Kuczera's projections, but the quantitative details were, as expected, sensitive to the prefire calibration period used. We then used a simplified method to examine a further five ash-dominated catchments affected by the 2003 fires. We report relative reductions in mean annual stream flow in all five catchments and a statistically significant (=0.05) postfire reduction in one of five catchments. Postfire yield reductions during the austral summer (October to April) were greater in relative magnitude in all five catchments and were statistically significant (=0.05) in three of five catchments. We conclude that a postbushfire Kuczera-type response may be widespread in regenerating ash forests. On that basis, we anticipate postfire yield reductions in ash forests elsewhere and conclude that further reductions in stream flow are likely in the MDB for at least another decade.