ABSTRACT
Allelopathy has been the subject of much speculation in vegetation dominated by Eucalyptus in Australia. Direct allelopathy seldom has been demonstrated in native eucalypt woodlands or forests, although many species can be shown to have allelopathic potential. There are many reports of eucalypt seedling suppression associated with mature tall open-forests, especially those dominated by species of the subgenus Monocalyptus. The low open-woodland known as mallee in Australia has long been a source of interest for ecologists. As seedlings of mallee eucalypts (or mallees) are rarely seen, it is widely believed that the seeds do not readily germinate under natural conditions. Prescott and Piper suggested that eucalypt oils may prevent seed germination, as certain soils have an aromatic odor reminiscent of sandalwood. The regeneration of eucalypts is often poor, especially on undisturbed sites, and bracken, which is a common understory element in many eucalypt open-forests, has been investigated recently as a potential agent in inhibiting eucalypt seedling growth.
