Councils say they will not be able to stop people cutting down native bush and coastal pohutukawa in cities under planned changes to environment laws.
The Government wants to take away councils' power to stop trees over a certain size being chopped without permission.
If the change goes ahead, landowners will be free to cut down any tree on their land unless it is listed in their council's district plan.
Auckland, North Shore, Waitakere and Manukau cities have schedules of protected trees in their district plans, as well as general rules covering trees of certain types and sizes.
North Shore City environmental policy and planning manager Phill Reid said the council relied on general tree rules of the sort that are about to be banned to protect gullies of native bush in Birkdale, Northcote, Glenfield and Beach Haven and strips of pohutukawa along the coast.
Only rare or landmark trees were included in the district plan schedule.
If the change went ahead, those large areas of trees would not have legal protection.
"To include all coastal pohutukawa in North Shore City as one item on a schedule may legally present us with some difficulties," Mr Reid said.
Waitakere group manager of planning and community services Phillip Brown said his council would look at listing more trees if general tree protections were banned.
But he was concerned that large areas of bush in Titirangi and Laingholm would be unprotected if people wanted to cut them down.
The Resource Management (Simplification and Streamlining) Amendment Bill, which contains more than 100 changes aimed at reducing cost and delays, allows group of trees to be listed in district plan schedules, but does not say what constitutes a group.
A spokesman for Environment Minister Nick Smith said the changes were intended to make councils focus on which trees needed protection.
It would be up to councils to prove that larger groups needed protection.
Mr Reid said people would probably want more trees listed if general protections were removed.
But changing the district plan to include more trees was slow and costly.
Tree Council chairwoman Sigrid Shayer said that if the law changed, councils would be flooded with requests to schedule more trees.
Environmental lawyer Janette Campbell, who represented the Tree Council in court cases supporting general tree protection rules, said councils could not afford to list each individual significant tree.
This meant trees covered by general rules under the existing law would probably not be protected, even when local communities had decided they should be.
"I think it's a bit heavy-handed to make that decision at a national level, where the community can't even have a discussion about it," she said.
Auckland City Council heritage manager Nicola Short said it cost about $200 a site to assess a tree or group of trees and decide whether they were worth listing. This did not include any legal costs associated with changing the district plan.
Environmental lawyer Padraig McNamara said although scheduling more trees would be costly, councils would save money because they would not have to process so many applications to fell trees. About 4500 applications a year are now made.
John Woolley - whose tree in Remuera took more than a year and more than $60,000 to remove after the Auckland City Council took his case to the High Court - welcomed the changes and said tree protection had got "a bit out of hand".
"If they avoid the sort of thing we've had to go through, I think it's a good thing."
Public submissions on the bill are open until April 3. The change does not affect trees in reserves.
* North Shore City: 600 trees or groups of trees protected.
* Auckland City: 830 sites where trees or groups of trees protected.
* Waitakere: 116 trees or groups of trees protected.
* Cost to decide if a tree should be protected: $200 a site.