It was made possible by a $2million grant from the NSW Environmental Trust to sequester carbon and enhance the environment.

The students and teachers at Mitchell High School, Blacktown visited Liverpool Plains to plant trees as part of the Regenesis Project.

Mitchell High and Quirindi High School students made their final contribution to a 21-hectare property known as Fairfield in Liverpool Plains Shire.

More than 7000 native trees have been planted in the past two months as part of Blacktown Council's and Liverpool Plains Shire Council's project.

As with each Regenesis tree-planting, work done on the Fairfield property was designed to meet Kyoto Protocol requirements for carbon forests.

Deputy principal Tanya Baghurst, who accompanied the students and teachers, said the link between the two schools was also a cultural exchange.

``The students were all billeted and they all had a fantastic time,'' she said. ``Some students stayed in town and others on farms. All students had positive stories to tell of their home stays.''

Blacktown Mayor Charlie Lowles said the completion of Fairfield was a great achievement for the project.

``The Regenesis project is just one example of how our sister-city relationship with Liverpool Plains Shire Council is benefiting our communities and the environment,'' he said.

Details: Regenesis team, Blacktown Council, regenesis @blacktown.nsw.gov.au or 98396283.