Quality trees for landscape use
The long-awaited publication last week of the latest tree-related Australian Standard, AS-2303:2015 Tree Stock for Landscape Use, should ensure a minimum standard of nursery grown trees for urban landscape use.
Unlike smaller plants, it is vital that there are minimum standards for trees planted in our urban landscape. Trees grow into large structures, often tens of tons in weight and needing to withstand massive wind loads. Structurally deficient trees are more likely to fail, either branches breaking or the entire tree falling out of the ground. Often these failings can be traced back to poor nursery stock.
The more likely it is that a tree fails, the higher the risk of injuring someone, especially in urban environments. Structurally sound trees will last longer, providing important urban forest benefits that are lost when trees are removed prematurely.
Until now, NATSPEC (Specifying Trees by Ross Clark, 2003) has defined the standard sought by many local councils, landscape architects and consulting arborists. Unfortunately the high standard expected by NATSPEC has not been commercially viable for many suppliers, and Tree Stock for Landscape Use is less prescriptive. Nonetheless, if the new Standard achieves broad industry compliance, it will be a welcome step forward.