Research paperChange in yield of water following a bushfire in a forest of eucalyptus regnans
Abstract
The hydrological changes following regeneration by fire of forests of Eucalyptus regnans were analysed in detail using non-parametric statistical methods. The streamflow data showed that some three to five years after the fire the flows started declining below the levels prevailing before the fire. The average annual reduction in flow over the 163-km2 study area for a 21-year period was 35,000 Ml or 24% of the average streamflow before the fire.
Measurements of fogdrip and canopy interception showed that those processes could not be the sole cause of the reduction in flow. A difference in transpiration is the most likely cause. Since E. regnans is one of the world's tallest hardwood species the height of the mature trees, and consequent low leaf water potential could be increasing the stomatal resistance to the diffusion of water vapour; differences in transpiring biomass and energy exchange within the canopy could also cause important differences between the water consumption of mature and regrowth forests.
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Variable self-thinning explains hydrological responses to stand replacement in even-aged forests
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