Dr P.D. McIntosh, Senior scientist, Earth Sciences, Forest Practices Authority, has responded to my Mercury letter (11/2) questioning the ongoing relevance of the 1950s research into native forest regeneration. /b>
J.M. Gilbert’s research is often cited as the justification for the current forestry practice of clearfelling and burning.
In the 1950s the dangers of climate change and the associated drying of Tasmania were much less widely appreciated. The research objective of the time was to determine how to encourage eucalyptus regrowth on sites that had been occupied by mixed wet native forests.
It is my contention that the 1950s research agenda may no longer be the best fit for 21st century realities.
In his publication; Water; Facts, issues, problems, and solutions, (2007) Geohydrologist Dr David Leaman makes the statement; “mature forest type is a crucial stage in the restoration of the hydrological balance since a long maturity time is needed to restore storages and catchment yields”. Dr Leaman goes on to state; “We need to tread much more lightly if we wish to retain the water we have now”.
Dr Leaman bases these assertions on his research and modelling which demonstrates, unequivocally, that rapidly growing trees (whether they be regrowth forests or eucalyptus plantations) dramatically reduce water yields in the affected catchment.
Forestry Tasmania research, published in Tasforests in 2000, indicated that, in a regeneration burn on clearfelled native forest in southern Tasmania, 700 tonnes of carbon dioxide per hectare burnt were released into the atmoshere from the forest floor.
A 2004 scientific study, published on the Timberworkers for Forests website (HERE), addressing the issue of biodiversity following clearfelling, burn, and sow treatment found that this regimen detrimentally and significantly affects biodiversity and abundance of plants and invertebrates.
Importantly the study also concluded that resulting poor soil structure and lack of soil humus adversely affected forest health.
Earlier on Tasmanian Times: Experts question aspects of prescribed burning
