Consultant urges rethink of forestry on Tasman district's fragile soils

Thursday, 12 April 2018

Debris covers a swath of the Otuwhero River, near Marahau, after ex-Tropical Cyclone Gita hit the Tasman district on February 20.

As the call grows for tougher controls on forestry, consultant Roger May adds his voice. Cherie Sivignon reports.

Forestry consultant Roger May feels a sense of deja vu.

In the 1990s, as part of Eco-Net, he was calling for improved forestry practices on fragile Separation Point granite (SPG) soils in the Tasman district along with more stringent council rules accompanied by increased monitoring and enforcement.

Now, as many residents of the district clean up the damage wrought in February by ex-Tropical Cyclone Gita, May finds himself raising those same issues again.

A graphic showing plantation forestry on Separation Point granite soils in part of Tasman district.

* Forced to swim through ex-Cyclone Gita's floodwaters after slip threatens homes

* Tasman farmer adds to calls for tougher controls on forestry

* Gita-hit communities feel threatened by forestry

* Surrounded by natural beauty**

Forestry consultant Roger May is calling for a rethink of forestry operations on Separation Point granite soils.

From his home in the Orinoco Valley, near Motueka, May says he was not surprised by the devastation inflicted on pockets of the district when the intense rain of Gita caused multiple slips that carried silt and debris on to many properties in their paths.

Some of those slips were on grasslands, some in native forest and some on plantation forestry land.

'The thing about erosion on grass is all you get is the silt,' he says. 'When you've got regenerating native [bush], you get some logs but usually they're smaller. But when you've got pine plantation in a storm, you've got silt and logs of all sorts of sizes.'

May visited badly affected areas near Marahau and at the Shaggery, off Motueka River West Bank Rd. He says the most damage was inflicted by slips from recently harvested plantation forestry land, which may have been cut up to five years earlier.

Farmer and historian Edward Stevens sits among some of the logs deposited on farmland at Ngatimoti when ex-Tropical Cyclone Gita hit.

'It's not surprising because you've got [forestry] roads, you've got lots of run off.'

Lyn Rombouts among some of the post-Gita debris left on her property beside Shaggery Creek.

May says he believes the Ligar Bay-Tata area is a 'sitting duck' for similar damage if a storm of Gita's force strikes that part of Golden Bay after a large block of forestry was harvested about 18 months ago.

He estimates there is about 15,000ha of plantation forest on SPG. This strip of granitic bedrock is about 10km wide and extends for more than 100km from Separation Point in Abel Tasman National Park to Mt Murchison. It is deeply weathered at the land surface, can be several metres deep, is extremely erodible and readily breaks.

May created a map of the northern area of SPG with an overlay of plantation forestry that is, or was until recently, on that granite. It has been turned into a graphic and shows the extent to which forestry, mostly radiata pine, covers these fragile soils.

Adding to the risk of erosion is the clearcutting method of harvesting that tree species.

Some of the post-Gita debris at Otuwhero.

'Clearcutting and radiata pine have to go together to be economic,' May says. 'Because radiata pine is a low-value crop, it doesn't make financial sense to do it any other way.'

But clearcutting has downsides including soil loss, scarred landscapes, silt and debris in streams, adverse effects on water quality, loss of riparian and aquatic habitat, inundation of paddocks and property downstream, and the associated effects on people and communities, he says.

'The evidence is plain to see. Clearly, this has to stop.'

May has several suggestions to tackle what he sees as two problems – fixing up the mess after Gita and making sure it does not happen again:

* There needs to be some accountability by the forest owners/managers to 'properly clean up the damage they have created'.

* Tasman District Council should consider a moratorium on new consents for forestry earthworks and harvesting on SPG until its rules are aligned with the new National Environmental Standards for Plantation Forestry, due to take effect on May 1, and its rules are reviewed.

* The council should 'significantly increase' the monitoring and enforcement of existing consents for earthworks and harvesting.

* A conversation about the new rules should be held among stakeholders including corporate and small forest owners along with iwi, which now own much of the plantation land under Treaty settlements.

* May calls for an analysis to determine which areas of SPG should be 'excluded from economic production … simply because it is too fragile' with any excluded land managed back into tall native forest. He adds that he believes the Crown has an obligation to stump up some funds because in many cases, it was the Crown that put in the radiata via the State Forest Service. Iwi have 'been given a pup basically', he says.

* A rethink of which species should be planted on areas that could still be economically productive. The chosen species need to be more valuable than radiata pine so more sensitive – and expensive – harvesting methods can be used, have a longer rotation, retain live root systems and be suited to low-impact shelterwood harvesting systems. May suggests redwood as a possibility.

* Council rules need to 'better reflect the risks of environmental and social impact'.

May says it is vital for the public, people from previously affected communities in particular, to have a say on any review of council rules.

'They've got to be around the table, too, eyeballing the owners and the forest companies – that's where you're going to get change, when ordinary people are face to face with the people who are creating problems.'

However, TDC environment and planning manager Dennis Bush-King says the planned alignment of the Tasman Resource Management Plan (TRMP) with the National Environmental Standards for Plantation Forestry will be completed without a formal plan change.

'As there are no changes to the TRMP, there is no need for a public consultation.'

But Bush-King points out that 'significant changes' to the land disturbance rules are to be considered later in the year, which may be of greater relevance and they will be subject to public consultation.