Northern Rivers koalas were first sighted eating camphor laurel foliage in 1996-97 near Mullumbimby (Morrow/Mullumbimby Rivercare 2000), an argument used in favour of keeping camphors on or near creeks at that time.
Further sightings (1998-99) of koalas in camphor trees (Rocky Creek Dam and Mullumbimby) did not link feeding with observations, as few if any people undertook night-time observations. However, one unexplained koala death, near Rocky Creek Dam, is listed as 'suspect' as the animal resorted to groundcover (lantana) for its daytime sojourns. (Ralph Woodford, Whian Whian, 9/10/00).
During the year 1999-2000 three independent sightings were made of koalas eating camphor leaves, on both roadsides (Corndale, Flynn-Rosebank) and in more dense canopy (Kooyman, near Murwillumbah, two observations). The latter set of observations represents a significant scientific find since Robert Kooyman is widely regarded in the Northern Rivers as being the area's leading Forest Ecologist.
Upon learning that koalas have become interested in varying their diet or 'turning to camphor' most people, when asked, respond that they know the animals now do not have sufficient food trees of their normal gum type. Secondly, people are concerned to learn that the reported escalating increase in koala death rates around Lismore-Goonellabah can be linked to camphor infested areas and loss of appropriate native habitat.
A close correlation exists between the areas of Lismore and Goonellabah that have experienced an escalating death rate in their koala population, and the heavy camphor regrowth densitites. Of most concern is that camphor intake by koalas could be inducing sterility in local populations -- as shown in various bird species eating camphor seed. National Toxics Network (Canberra) professionals confirm that the camphor molecule 'is an oestrogen receptor', and Lismore homeowners with koalas in both gums and camphor state that they have seen no young koalas in pouches over the past three years.
Interviews with the district leaders of Friends of the Koala (Lismore & Tweed), at the same time as close inspections of the official autopsies held at NSW Agriculture(Wollongbar) reveal inconsistencies in the stated 'cause of deaths' indicated by these three groups. Circumstantial evidence of Central Nervous System disorder or dysfunction shows-up in certain autopsy data, which is consistent with the frequently and widely reported observations of reliable vehicle drivers, and Carers over the past 5 years, especially in most highly/densely infested Camphor districts and land units.
The powerful mammalian liver carcinogen Safrole is not found in the traditional diet of any species of Eucalyptus, so regularly eaten by Koalas; it is therefore not known if they can sense what it is, and, due to analyses of the most toxic Camphor chemotypes (NSW Ag.) it is the safrole and other volatile toxins on the hottest days that may well be contributing to the frequent disorientation of koalas, on, adjacent, and near roadways.
A direct link between the reported increased death-rate of Lismore Koalas, and the rising populations of Camphor Laurel, particularly more toxic 'Hybrid ones is not yet proven.
Concerned individuals sufficiently interested and caring can donate to a Fund to have the full toxicological assessment of camphor performed at the best laboratories in the country, in Melbourne, using foliage from trees known to have been eaten by koalas. Contact Joe Friend on 6688 6150
A bushwalk in 1997 led ecologist Joe Friend to begin conducting research trials in NSWs Northern Rivers region, proving that root, leaf and berry extracts of camphor laurel trees - native to the Northern Hemisphere - can effectively kill amphibian tadpoles, including local frogs and cane toads.
Subsequent surveys of consumer and industry groups support the findings that camphor extracts emanating from the foots, bark, leaves and berries of the Cinnamomum camphora tree are not suitable chemistry for Southern Hemisphere fauna and flora.
Various genera and species of native rainforest plants and animals have taken a sustained nose-dive in population levels since the invasion of camphor trees, first noticed and recorded in 1900 in Lismore's Northern Star
Whereas the camphor toxins are largely colourless and odourless, in recent years many creeks are beginning to show signs of discoloration, toxic precipitates and 'interseasonal death' of aquatic (native) invertebrates. CSIRO testing of root oil distilled from middle aged camphors proves its extreme toxicity.
For terrestrial fauna, even brush tailed possums appear tob e disappearing in areas where more genetically advanced higher level toxin producing camphors are predominating. Various bird species are now known to be turning sterile from over consumption, or merely eating the camphor berries.
Fauna reliant on access to soil in water for breeding purposes - egg laying and hibernation - may well be the worse affected, especially since the most toxic bark and root-toxin, safrole, is known to be partly-soluble in water. One toxic root alkaloid, exuded no doubt for the purposes of tree protection from moth and beetle attack, is linolitsene, a known precursor to morphine.
Lab trials already conducted show that even the tadpoles of cane toads, and other amphibians, keel over, apparently anaesthetised by root-toxins; the synergistic biochemical action of all three camphor root-toxin types is no doubt the main reason so few species go near the trees most of the year, all bees and most butterflies are repelled, and no bird will nest in them!
The 'same-day death' of various bird species was reported as far back as 1950, whilst in the case of koalas now proven to be feeding on it (Phillips, 1996) death may be weeks coming, after early disorientation, then declining health. As with birds, sterility is also reported for koalas feeding regularly, even in daytime, on the camphor leaves.
To date, no individual has published a review on all these aspects of a toxic herb-tree gone rampant. However, it is clear to Joe Friend that the species C. camphora indeed deserves in-depth toxicological examination, and all of what is currently known about its cryptic chemistry should be scientifically published and revealed at the earliest opportunity. A grant will help to ensure that both these aims are successful.
Recent article from The Land newspaper on koala deaths