The irony might escape some, but Bronwyn Petrie says thick clumps of eucalypts thriving on her Tenterfield farm are blocking rain and draw up so much moisture that the earth is withering away.

''There is this big myth that trees save the soil, but we know it’s time to thin trees when we start losing ground cover,'' Ms Petrie says.

However, laws protecting native bush mean not a single gum can be removed.

''It’s an absolute joke. Our moral obligation is to care for that land, and we are being prevented by perverse legislation. That is leading to adverse environmental outcomes.''

It has been almost a decade since former NSW Labor premier Bob Carr introduced laws to slow down widespread land clearing that had helped make Australia one of the world’s worst vegetation destroyers.

Now the Coalition government is shaking up the regime, which farmers complain is too complicated, and unfairly hampers how they work their land.

But conservationists say the review is politically driven – aimed at shoring up regional support for the Nationals.

They warn the overhaul may reverse positive outcomes that have saved thousands of native mammals.

''Land clearing laws are delivering environmental benefits, and these laws must be protected,'' Wilderness Society NSW campaign manager Belinda Fairbrother said.

''Most of Australia’s accessible land has already been cleared for agriculture. We can’t let these protections be watered down and let the bulldozers rip.''

By 2003, Australia had one of the highest land clearing rates in the world, behind only Bolivia, Brazil, the Democratic Republic of Congo and Indonesia.

Landholders hoping to clear land must submit detailed plans, and only routine clearing is allowed without approval.

Ms Petrie said limits on clearing her land, and the consequence for soil and ground cover, has a ripple effect on the environment.

“Sediment-heavy water flows into nearby rivers, and weeds have taken hold. Unhealthy soil affects the whole food chain, from worms’ right through to the big birds and mammals,” she said.

The ripple effect also sneaks into their financial returns.

''If your cows aren’t getting enough grass, they won’t get pregnant, therefore your calving numbers drop.''

''My son and I have been driving trucks in a mine to compensate for it,'' she said.

Ms Petrie insists farmers have a duty of care to the land, and should be trusted to execute it.