It was decided they would plant native trees.
The students wrote letters and made phone calls to nurseries and plant shops explaining their project and asked for donations.
They received about 300 native trees from several companies and organisations, including Paper4trees, Kereru Gardens, Palmers, Tauranga Tree Company and Naturally Native.
There was also support from Tauranga City Council.
Most of the trees were planted yesterday under blue skies.
Mr Buller said the whole process was "really cool" and all worthwhile.
"It all links to our overarching theme of connect - connecting with the community, connecting with nature, and we're connecting with each other."
He said the children led the project from the beginning with the team slogan "Bring back the kereru".
There were about 90 children from three classes involved, along with teachers, the school's caretaker, parents, and neighbours.
"I'm just really proud of the kids because it just came from them and we've done so much learning," Mr Buller said.
One of the students, Gianni Martin, said "it was fun and hard work".
The 9-year-old said he planted five trees and enjoyed "just helping Jill Best and planting trees".
Ms Best said the students were wonderful yesterday and were focused on completing the project they had been preparing for most of the year.
"It was great to see them learning about conservation in a practical way they can be proud of for many years. Special thanks to teacher Nathan Buller who dreamed up the project and then let the students run with it," she said.
"Thanks also to other staff and parents and one set of grandparents, and to the nurseries which supplied many of the plants.
"I am delighted with all the plants which I hope will bring back native birds."