Complex sentence: The research and development of domestication of the species was first under taken by Brian Powell, at a property in Quorn, South Australia, these are classed as'Significant Trees' by the state's National Trust.
Split into simpler sentences: The research and development of domestication of the species was first under taken by Brian Powell, at a property in Quorn, South Australia. The successful plants in this trial are classed as'Significant Trees' by the state's National Trust.