Our Size Index charts aim to provide Landscape architects and designers appropriate tree size expectations for given container volumes. These sizes are based on appropriate Size Index as determined by NATSPEC and growth habits of individual species. Width is included only for the benefit of designers but has no bearing on the calcuation of size index.
When specifying sizes for trees it is better for the size index to be a little below maximum to allow trees room to grow if landscaping is held up.
Pacific Trees Qld aims to only list container products that fit within NATSPEC size index range.
Further information on NATSPEC can be obtained from
Clark, R. 2006, Specifying Trees, NATSPEC Construction Information