She told The Times: 'I think it is unlikely we would ever promote or allow a wind farm on our land.'
She also said the charity was concerned about proposals for offshore wind farms which could be visible from its land in Hampshire and the Isle of Wight.
The Trust's director general said that the charity is studying the environmental impact that fracking has on the earth.
She told The Times: 'We all have yet to see what the surface environmental impact of fracking is and when we have seen it then we would reach a view about whether (we would object to it) adjacent to National Trust land or on National Trust land.'
This is an about-turn for the charity, which in August said on its website that is has 'a presumption against fracking on National Trust land' because natural gas is a fossil gas.
By Rebecca Morelle 7th May 2014
The World Health Organization says air pollution in many of the world's cities is breaching its guidelines.