Wilson died when she was hit by a falling cedar branch at Royal Botanic Gardens, Kew in September 2012. The inquest was adjourned in October 2013.
Assistant coroner Elizabeth Pygott said her probe would "firmly focus" on whether proper trimming of the tree would have prevented Wilson's death. "It is a fairly broad question of what caused that branch, or tree branches, to fall," she added.
"There is the question of whether pruning the trees may have prevented the fall from happening. I need to know whether summer branch-drop was involved in this case.
"I think it is appropriate to look at the issue of pruning, whether it was or was not pruned and whether if it was pruned it would have made any difference to the outcome, and that is firmly going to be in my focus."
Wilson's barrister, John McLinden QC, told the inquest: "It was just a fluke that there was not more than one fatality or that other people did not suffer injury."