A university with thousands of trees said it is "deeply disappointed" plans for a world-class sports centre have been rejected to save three oaks.
But Nottingham City Council, which removed 40 trees next to the university to make way for tram lines, said the "veteran" oaks must be saved.
They are thought to be at least 150 years old.
The university has accused the council of hypocrisy after it felled dozens of mature trees around the city to make way for tramlines.
But Sally Longford, a member of the planning committee and a ward councillor, said she could not let the oaks "go without a whimper".
"None of the trees that were lost during the tram construction were veteran trees and the older the tree the more valuable it is to the eco-systems surrounding it," she said.
The council's own planning officers had recommended approval for the £40m sports complex.
Paul Greatrex, the university's registrar, said he hoped the planning committee "will speedily reconsider its decision".
"It's double standards frankly," he said.
"We are talking about a major investment in university facilities which is needed to sustain our premier position in the UK and internationally, and attract more and bigger investment into the city."
He said the university "cares deeply" about its trees.
"We've got over 6,000 trees on site, about 600 of which are a similar vintage to the three trees in question," he said.
"We want to turn our campus into a national arboretum as well, so trees do genuinely matter to us.
"But sometimes you can't do everything for trees."