The Boardman family owns land bordering the site of the proposed school.

The members of the family want councillors to think of the environment and of Camden's rural heritage when they vote on the school.

Family spokeswoman Kay Scarlett, who is daughter-in-law of patriarch Vic Boardman, said it was hard to imagine how the school could be approved in light of awareness about global warming and climate change.

``The council's response to this development will really demonstrate its grasp of the environmental issues that threaten our society's very existence, and its preparedness to act at a local level to address them,'' she said.

``The Boardmans passionately believe in the preservation of rural lands and food production in the greater Sydney region.

``But if this high-density development is approved, the natural watercourses will be radically altered, and that will have a major impact on our ability to continue to farm.

``The council must consider the carbon footprint of this development and its demands on local infrastructure, but must also imagine Camden without this green space, and the probable domino effect that will be triggered by the loss of this pivotal and ecologically rich greenbelt.

``It's the keystone to the entire Cawdor Valley and, indeed, to rural Camden.''

Ms Scarlett said the Boardman family had been disappointed by the development debate ``which has focused almost exclusively on the intended users of the site, and not on the far more significant environmental issues''.