Observation methodologies in use for data collection and assessment of damage-impacts due to camphor laurel on flora, fauna, and humans ...
It is believed that only short-term testing, and further laboratory analysis within one year would be sufficient to conclusively prove that most camphor laurel is indeed a weed 'worse type'/including more toxic chemotypes than mere 'Noxiousness*.
1. A method has been developed, but requires refinement for the purposeful screening of Camphor Laurel tree root bark samples, to assess individual trees for relative toxicity.
2. Assessment of toxic alkaloid concentrations in root tissue or root bark, season by season (individual trees);
3. Inter-seasonal variation in safrole (carcinogen) and camphor (human toxin) % contents of browse foliage (leaf and twigs) due to the impact on the tree of regular browsing or bark eating e.g. by koalas and possum respectively.
4. To ascertain by laboratory testing with ethically approved species if the three groups of toxins in Camphor laurel roots or berries could be synergistically poisonous when consumed together.
Over the past three (3) years, driving with windows down in or shortly after at least 40 mm of rainfall, and knowing frogs to be about due largely to warmer weather arriving, I have stopped at known and audible frog-rich sites on either roadside (E/W) of the main road from Rous to The Channon, and return, and looked for any sign of Camphor laurel trees within the visible catchment of the roadside site; no site/s were found, or seen to have any Camphor tress within 50 ms of any abundant 'happy' (remnant) frog community.
For three years, detailed observations have been made of which bird species feed on Camphor Laurel fruit, and at what stage of fruit ripening any such birds begin to eat (eg Domestic Pigeons only eat old, fallen seeds) across an even-age planting of some Camphor Laurels in central Lismore; no Native Pigeons species have been sighted eating Camphor fruit off this range of differing chemotype trees.
Commencing with a small survey (N~100) of Terania and Tuntable Valleys, in that community it was found that no-one was/is in favour of keeping any Camphor laurel trees.local attitudes were confirmed by mailing out three 'camphor newsletters' to every residence, and on site landholder interviews.
The survey was extended to the residents of Lismore CBD, many of whom live adjacent to large/mature camphor laurel specimen-shade roadside trees, and to over 100 residents along a 21 km roadway from Lismore to The Channon (a 'representative transect); not one person has been found who wants to keep or protect Camphor-laurel, or have the 'Noxious* declaration of that species revoked in Lismore Shire (as occurred in Byron, Ballina and Tweed shires in 1999).
4. Billinudgel Survey for King Parrots, the Aboriginal totem of Nudgel township; only 3 out of 19 residents have seen them, and the species eats camphor fruits!
5.0 A cluster of 40 even aged camphor laurel trees grows by roadsides surrounding two parks in central Lismore, all believed planted from a single *mother tree' and in the same season; they appear to be approximately 50 years of age.
Variation between trees is being recorded, including:
5.1 Presence or absence of epiphytic species, including mistletoe that dies out on certain camphor laurel individuals.
5.2 Leaf chemistry definition, to assess the species heritability trait for toxic leaf products, eg camphor.
5.3 Other distinctive morphological traits, eg bark type, butt or original trunk.
6. A regular seasonal appraisal of what fruit or age of fallen camphor laurel seed the remnant small population of domesticated pigeon (Columba livia) is consuming in wet/dry and whether anv birds have learnt not to eat certain camphor chemotypes.
7. Soil and water Analyses
To assess the cause of milkiness-opaque waters due to camphor impacted soils and clay and name the orange precipitate continuing interseasonal observations are being recorded on all or for most of the above chemical and its natural origins.
At flowering and pre-flowering, in order to discern the different chemotypes of the tree, sampling individuals showing the greatest morphological differences.
After flowering, to attempt to find what larvae of which species of butterfly or moth (2/3 species) still live on the trees, or what types of the tree species still support insect attack.
All substantive surveys and methods in use to be to be fully summarised in any foreshadowed thesis.
24th September, 2001