A Taupō forest damaged in Cyclone Gabrielle. Photo: Supplied
Forestry owners hit by devastating cyclones this year have been given extra time to replant so they won't have to repay millions of dollars in carbon credits.
The land can stay bare for an extra three years if needed, but the damage has raised questions about how the areas could fare next time there is an extreme event.
According to a briefing from the Environment and Primary Industries ministries, about 35,000 hectares of forestry land had been harvested and was awaiting replanting when Cyclone Hale and then the disastrous Gabrielle hit.
That does not include land that used to be in pine trees, but was cleared and waiting to be converted to native forest when the disasters happened.
Officials have told ministers that replanting of forests is being delayed by slips, road damage and flooded nurseries.
Without an extension, officials estimated landowners could be liable for $37,000 a hectare to repay carbon credits they had claimed for the trees.
Under the Emissions Trading Scheme, people can keep carbon credits for forestry land after they harvest the trees, so long as the land is replanted with trees within a certain period.
Missing the deadlines would have cost over $1 million in penalties for a 30-hectare area, the briefing said.
But the government stepped in to give forest owners an extra three years to replant their trees, as part of the cyclone recovery effort.
Gisborne District Council principal scientist Murry Cave said some plantation owners faced a difficult future.
Some forests with mature trees, 10 years or older, had lost up to half of their standing trees, making it tough for the owners to replant without ending up with patches of forest of different ages. That could make harvesting uneconomic, he said.
Aerial surveys of one cyclone-hit catchment showed diverse native forests fared better than pine, he said, although the native forests were still damaged. Both types of forest fared better than pasture.
The government will need to decide how to treat the cyclone's impact on New Zealand forests in its country-level reporting of greenhouse gas emissions.
The briefing warned ministers that damage to trees is going to increase with climate change, and they need to think about how to address this in their climate policy.
New Zealand relies on forests to absorb about a third of its greenhouse gases.
The Ministry for the Environment says it is too early to determine the overall impact of the severe weather events on New Zealand's emissions or the country's 2030 international emissions target.
But the ministry told RNZ based on an initial assessment it did not expect the delay in replanting to have a big impact.
It is a topic that will come up more often as climate change increases.
Scientists concluded February's Cyclone Gabrielle was probably made wetter and more intense by climate change, though their models for that particular event and region aren't yet good enough to produce a percentage impact.
Projections for regions such as Tai Rāwhiti are for drier conditions, but heavier extreme rain when it comes.
"Extreme rainfall, drought, and wildfire risk are expected to increase in many places," the briefing to ministers said.
"We also expect there to be an increasing frequency of climate-related extreme weather events occurring at the same time, or closely together in time while recovery is still occurring."
"Because of this, we can expect to see an increase in the damage to, and emissions from, forests in New Zealand."
