The state's farmers have lopped paddock trees at an accelerating rate in the past 18 months even before a new land-clearing law eases controls further, government data shows.

The new figures, which reveal the rate of clearing of paddock trees has more than doubled since November 2014, come as the Wentworth Group of Concerned Scientists wrote to all MPs to call for a reversal of "retrograde changes" planned in the new Biodiversity Conservation act.

Farmers have been cutting down paddock trees at an increasing rate. Credit:Scott Hartvigsen

NSW farmers used a new self-assessment code to remove 21,716 paddock trees – or more than 50 a day – over the past year and a half.

The rate, at an average of about 50 per day, was 140 per cent more than the average over the previous seven years, data from the Office of Environment and Heritage showed. Paddock trees, judged to be single or small patches of trees, make up 40 per cent of remaining woodland cover, OEH says.