Wednesday, December 10, 2008
The recent fires in California remind us of the devastation caused to property and to the local ecology. Often the fires are so hot that most of the ground vegetation is completely burnt off. Recovery is slow and in the mean time the land is exposed to rainfall and consequential erosion, high rainfall runoff, and sometimes land slippage.
Over the years we have plenty of evidence that shows that vetiver will, if green, be very difficult to burn, and when dry it may burn off, sometimes completely, and then recovers very quickly within weeks. Thus enabling the hedgerow to function effectively in order to meet its design objectives.
Green vetiver hedgerows are very dense and fire has difficulty in penetrating the grass. Under such circumstances the hedgerow actually acts as a fire break to slow creeping fires. In Fiji where vetiver was grown in conjunction with sugar cane it survived the annual fire that was set prior to cane harvesting.
Below are some images (thank you Doug Richardson) showing the revival of vetiver after November's fires in the Santa Barbara area of California. The images show vetiver at 1 week and three weeks after the fire.
On Vanuatu (South Pacific) vetiver hedgerows were used to improve moisture and soil fertility to allow the replanting of forests destroyed by fire. This process was successful and is described elsewhere on the TVNI website. The new forests were also subject to fire; those which were burnt were able to recover quite quickly because of the vetiver that started regrowing (ex-hibernation) as soon as the tree canopy was burnt off. The revived hedgerows were able to reduce erosion and runoff, thus helping the trees to recover quickly
Below: Vetiver goes in to complete or partial hibernation under heavy shade.
Quick regrowth occurs when shade is removed (Image - Don Miller).
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Useful gallery of all blog images (with captions) posted on Picassa