Three more protected trees have been removed to make way for the of the Sarjeant Gallery extension.
Five oaks and four phoenix palms, all protected, were felled for the gallery redevelopment project in January.
"We never want to remove trees if we can possibly help it," project director Gaye Batty said.
"This was sadly our only option.
"It was originally anticipated that our contractor could manoeuvre site vehicles around the trees, with mitigation measures in place to protect tree roots."
However, in January it became clear that five more oak trees would need to be removed to allow safe access for heavy vehicles during the excavation, to enable creation of an entrance below ground level and to make space for a new access road.
Resource consent for removal of all five was granted in April.
By changing the plan, the team managed to save two other oaks. Doing so maintained the character and cultural importance of the trees and Queen's Park, Batty said. Moving the other three oaks was contemplated, but they were large trees and each move would have cost tens of thousands of dollars.
The timber from the latest three oaks will be milled and added to that from the other five. It may be used in the gallery redevelopment.
More trees will be planted when the development is finished.
"Landscaping will include sympathetic tree plantings," Batty said.
"The oak trees will be replaced with trees of the same progeny and will be located nearby."
Whanganui district has many protected trees that are listed in the Whanganui District Plan. They include 72 English oaks in Halswell St, 19 tōtara on the Somme Parade riverbank and one rimu in the Glen Logie Rose Garden.
Their protection can be removed only by a resource consent.