Council spray poisons pines

Mount Maunganui's ailing Norfolk pines were poisoned by spray used by Tauranga City Council to control prickleweed, it was announced today.

The discovery was made by independent arborist Paul Kenny, who credits the discovery to the council's toxic agrichemical policy.

Tauranga is the only council in the country that logs use of agri-chemicals, and a detailed database going back several years states which chemicals were used, as well as where and when.

'We were finding trees with the worst symptoms were in large grass catchment areas that were actually lying back towards trees, so the surface water run off was going back into this area,” says Paul.

'Obviously the tree was taking up more of it because it had a greater root area that was taking up this chemical.

'Trees that had a ground surface that sloped away from them onto the road and onto the beach obviously had a lesser impact. Trees with a hard surface around them, that you would normally look at and think we're having a hard time, were the healthy looking trees.

'An example of that is if you go closest to the boat ramp at Pilot Bay by the hot pools, where a tree completely surrounded by tarmac is probably your healthiest tree in the Mount now.”

Though there is no absolute proof, it fits the facts, and the active spray ingredient picloram was found in the upper leaf of a tested Norfolk pine.

Paul was able to track it down because unlike other councils, Tauranga City Council records spray usage under its toxic agri-chemical policy.

In other centres it is impossible to get information on what sprays have been applied.

'Paul's looked at all the patterns,” says TCC team manager for city parks, Steve Webb. 'Without that information we wouldn't have been able to do this.”

He thinks the brushkiller spray is absorbed by the trees in the first rain or irrigation after spraying, which washes the residue into the sandy soils where they are taken up by the trees' root systems.

If the trees have not been severely affected, however, stopping use of the spray could lead to most of them making a good recovery.

'People I have spoken to who have a lot of experience with the species believe they will,” says Paul.

Rebecca Perrett, general manager for environmental services says that until the Council has more information, broadleaf herbicides will no longer be used by Tauranga City Council in areas where the chemicals could come into contact with tree roots.

'This will probably change the way we maintain the grass reserves along Marine Parade and Pilot Bay.

'We may even need to ask the community if they are prepared to accept prickles at some sites,” says Rebecca.

Independent arborist Paul Kenny

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3 comments

Goo job!

Posted on 01-10-2014 16:15 | By morepork

It is a refreshing change to see the Council listening and acting sensibly on information. While most of us probably don't like toxic chemicals in the environment, there is sometimes little option. Kudos to the Council for keeping records, so at least the effects can be studied. Good job all round, I'd say.


unbelievable

Posted on 01-10-2014 20:45 | By usandthem

according to wikepedia picloram is used to control general woody plants and broad leaved weeds.Why anyone would use this spray to control prickle weed is unbelievable when the average gardener uses onehunga weed spray.totally over the top.


Prickle Madness!

Posted on 02-10-2014 10:10 | By Croaky

Rather than learning from this incident, it seems the council is being self-congratulatory! The council's Toxic Agrichemical Advisory Forum have been warning staff about the over-use of these chemicals for years yet the staff continue to ignore TAAF's advice and indeed they are pressing to be allowed to use MORE chemicals despite the fact that Norfolk Pine dieback is happening throughout New Zealand wherever sprays are being used, including where councils have access to an unlimited list of chemicals. These chemicals are highly toxic (which is why they work in the first place) so why be surprised at the collateral damage and how can the council staff guarantee other chemicals won't have unforeseen negative effects? What are these substances doing to our health? So instead of wearing shoes to avoid prickles we have to wear them to avoid absorbing toxic chemicals? Madness!


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