Kirk said on Wednesday it was sad that the chestnut tree was being felled by arborists, but "the damage to it from yesterday's wind storm was too extensive to save it".
"Over the years the tree has provided shade and a point of interest for many who have walked through the hospital grounds.
"Luckily no one was hurt or injured and while the arborists work it is important to abide by the cones around the site to keep people away."
Once the tree is removed from the hospital grounds and the extent of the damage to the memorial garden is known, fundraising to replace the water feature would commence, Kirk said.