HOW TO RECOGNISE MORE TOXIC CAMPHOR LAURELS

Different chemotypes of Camphor laurel

 

A reliable scientific/analytical test that is sufficiently cheap is not yet available, so visual differences must be relied upon presently; the differences between types are clearly greatest in late Autumn and early Winter, especially after a dry, hot summer.*

Testing of bark, leaf and roots of proven very toxic camphors has resulted in the following general profile of a more toxic chemotype individual tree:

1. Less than average tree canopy density, with leaf area index below 1 for most of the year;
2. Leaves smaller and more concave than on 'dense green' tree;
3. Leaves yellow-green and turning yellow in Autumn, although in Springtime new flush colours vary;
4. Generally harder, more 'scaly' bark and deeper furrows longitudinally;
5. Leggier look to tree, with many boughs bent or curved, not straight;
6. Commonly in aggregations, or 'multi-stemmed' clusters;
7. Usually, but not always, a shorter tree and less overall volume;
8. Cut timber mostly with brown/dark brown or streaky core/heartwood.
9. Extremely toxic 'bird killer' camphor laurels can be seen to rarely, if ever, harbour roosting birds, and in the Summer heat can have dead native birds lying underneath them! (Friend, 2002).

* Cinnamomum camphora subspecies var.chemotypes (9?)