"So many of us have connections to people in the South Island and so we chose as a particular focus of this forest the Otago region."
The project is the biggest undertaken by the arboretum in 50 years and will cost about US$2 million - paid for by sponsors, Seattle City Parks, the University of Washington and the foundation.
Christchurch woodcarver Caine Tauwhare has carved a bench for the forest, which will be dedicated to the Seattle-Christchurch Sister City Association when the exhibit opens.
Mr Tauwhare will give a lecture before the forest is opened explaining the symbols carved into the bench, Ms Miller said.
"This land in the arboretum was very important to our natives and part of it was sacred ground for them."
Featured plants include:
• Hebes
• Phormiums
• Southern beeches
• Grasses