Economy
The problem with monoculture E.nitens
#4 Water Wizard, is heading in the right direction in asking “what can we do about this?”
Piping from the headwaters would be fine except for two problems.
1. The E.nitens that I saw were growing over the ridge-lines so there may not be an upstream uncontaminated site.
2. This doesn’t help downstream native animals that still have to drink the water.
Then there is the old argument of “it’s natural, don’t worry”. Yes, it comes from plants but it doesn’t accumulate in natural catchments. St Mary’s was not toxic. Sydney’s water is not toxic. St Mary’s has been tested three times. Sydney has been tested for over a decade using 24 hour a day fish monitors, monitoring gill movement (are the fish stressed). Sydney has never had an incident despite the water supply being drained through 9,000 sq.km of native plants.
The problem with the Mono-culture of E.nitens is the sheer number of trees of the same species. Eucalypts have cocktails of toxins which vary between species, indeed can vary within species. So the opportunity for the accumulation of one cocktail is limited. In the mono-cultures the genetic variety is controlled to produce trees with favourable qualities.
This leads to un-naturally high numbers of one species and un-naturally low genetic diversity and therefore un-natural quantities of the trees toxic chemical defenses. In natural systems it is reported that these chemical defenses have short half life (in the order of half an hour). We have found half lives of days to weeks.
In short it appears the natural processes that would ordinarily neutralise these chemicals have been overwhelmed. This is the problem.
One solution may be buffer zones, but how big?
Does anyone have any other solutions?
Marcus Scammell