A veteran conservation worker says the Department of Conservation is killing kauri in Northland with poorly-designed walking tracks.
Stephen King, of the Native Forests Restoration Trust, says trees just metres away from giants like Tane Mahuta in the Waipoua forest, are dead or dying.
He says some are showing the classic signs of phytophthera and may have a new species of the root fungus that's killing kauri in Auckland forests.
In almost every case, Mr King says the dying trees are next to road or gravel tracks that have damaged their root systems leaving them vulnerable to disease.
He says DoC walking tracks compact the soils over the roots, or drown them by channelling water.
He says the ancient trees like Tane Mahuta, are still healthy because they are protected by boardwalks, and DoC should urgently build more.
Northland Conservator Chris Jenkins says DoC has the funding for more boardwalks in Waipoua and hopes to have them built in a year.