|Closeup of topsoil root showing glands|
TAFE (Queensland) teachers at Rockhampton tell horticulture students in training that camphor laurel roots' propensity to turn subsoil and topsoil virtually sterile is the reason that the camphor trees will be removed from that city's original planting in Rockhampton Botanic Gardens. The old Rocky' trees are the oldest in central Queensland, spreading their seed as fruits (by birds), to ensure that the tree seedlings are springing up everywhere!
As depicted (see photo), large Camphor roots can effectively protect large boulders from eroding or slipping away rapidly, but they are notorious in NSW's Northern Rivers for consistently allowing 'bank slumping' of creeks and infested river edges; it would appear that most of the camphor's fine root system is both very deep down ,or at the elongated periphery (25 ms average) of camphor root penetration -for the majority of chemotypes..
Seasonal Change to Oil-Toxin Excretion Glands
Inspections of summer and winter roots dug from the same depth, off the same Camphor trees at The Channon reveal that the toxic oil excretion glands dilate, and extend in summertime, shortly after ,or with the first rains of 'the annual wet', combined with higher temperatures in sub-tropical conditions. The glands extend to be approximately three times longer in the summer period, apparently to discharge the oils and toxins further away from the roots; these are on what is considered first or second generation 'more toxic types/chemotypes of Camphor Laurel on government land at The Channon.
Loss of Biodiversity Due to Cumulative Camphor Exudation into Soil & Subsoil
Whilst not yet exactly proven at least one dissertation at SCU-Lismore university clearly proves that floral biodiversity declines under Camphor trees in test situations; down-to-earth observations by farmers and naturalists consistently indicate that total Soil Biodiversity declines markedly each and every year as Camphor trees expand their canopy, and approach maturity, dropping a thick monocultural litter layer underneath them.