The Marlborough District Council is considering widening the buffer between forestry and the coastline in the Sounds, as a way of improving the health of the seafloor.
Wairangi Bay Photo: RNZ / Tracy Neal
A series of reports in recent years show run-off from the land is linked to environmental damage to the seabed.
The chair of the council's environment committee, David Oddie, said the council has spent about six years analysing reports on changes to its coastal environment.
The most recent report showed dramatic changes to the Pelorus Sound over the last millennium happened in the last century and a half. The report's author and Niwa marine ecologist Sean Handley said the effects of farming and forestry have smothered parts of the seafloor in sediment, faster than natural deposits caused by rain and floods in the centuries before.
Mr Oddie said planting trees further up the hills around the ribbon of coastline is just one option being considered.
"We've been looking at the Sounds and changes over the last 30 or 40 years, but the driver for this is that the council is in the middle of re-writing its district plan."
Mr Oddie said forestry and aquaculture have been pulled out and handled as separate subjects, because of the complexity of their economic input versus their environmental impacts.
He said the council was now fine-tuning options before drafting proposals for public feedback, followed by the hearings process.
A 2015 report showed coastal setbacks of 30 metres, 100m and 200m would reduce the harvestable area and log volume, increase the cost of harvesting, decrease revenue and employment opportunities.
The forestry industry told Fairfax media that replant setback areas in riparian zones and around the coast could cost them millions of dollars in lost production.
Mr Oddie said the council recognised the forestry industry's value to the region in economic terms, as an exporter and employer.
He said the council hopes it will be able to tailor its own rules around forestry and land use in the Sounds, once new national standards are created.
The Ministry for Primary Industries under the previous government proposed a National Environmental Standard for Plantation Forestry, which would change how plantation forestry activities are managed under the Resource Management Act.
Forestry is one of four separately branded branches to be set up in the Ministry for Primary Industries in 2018. Fisheries, biosecurity and food safety are the others.
"We as a council need to know whether or not we can put in bespoke rules or conditions for certain parts of the Sounds regarding forestry, and possibly other land uses," Mr Oddie said.
He said there might also be other land uses that cause sedimentation.
Mr Oddie said the council needed to weigh up all interests and find a balance, which the revised district plan would seek to do.
