Monday, 09 October 2023 16:25

Climate Positive: Grape Days Marlborough

Written by  Sophie Preece
Mt Impey Conservation Estate Mt Impey Conservation Estate

When Dr Robert Holdaway was a kid, he wanted a bach and a boat in the Marlborough Sounds, not a block of marginal land up the Wairau Valley.

But three decades after his father planted 350 hectares of pines at Birch Hill, the Holdaway family's commitment to climate positive winegrowing is rooted in the trees they grow as a carbon sink, and the pests they eradicate to protect them. "Yes, do emissions reductions," Robert told audiences at the Marlborough Grape Days event. "But what we really need, if we are talking about tackling the climate crisis, is to invest in carbon sinks."

Robert, who has a PhD in forest ecology from Cambridge University and spent eight years as an ecosystem ecologist at Manaaki Whenua Landcare Research, returned to the family vineyards in 2017 "as a slightly overqualified tractor driver", joining his brother Richard at Lowlands Wines. The family wants to leave a positive legacy for future generations, he said at Grape Days. "And we are always looking for practical things that we can do to improve our business."

In 2020, Robert did a "ballpark" emissions profile for Lowlands, using standard lifecycle assessment methods. He found annual vineyard emissions of 991.34kg CO2e (carbon dioxide equivalent) per hectare, and lifecycle emissions of Lowlands Wines per year of 0.828kg CO2e/bottle. The relatively low emissions are partly down to the Lower Wairau location, with high yields from 3 metre rows, as well as the likes of lightweight bottles and efficient logistics.

But any big carbon reductions in the future will require technological advances, including electric tractors, Robert said. That will be "especially promising" if they can be lightweight to reduce soil compaction, and automated, to help tackle labour shortages. "There's a chance to merge those problems together and come up with a really good future solution." Before that happens, New Zealand requires a massive increase in its renewable energy suppl, he explained. "That is a big investment that needs to happen."

Until the technology and infrastructure arrive, diesel use is inevitable for Lowlands, so they use trees to provide "breathing space". Trees are "the ultimate carbon storing technology", Robert told the audience at Grape Days. "This is something designed to be self-replicating and solar powered. The most amazing tech out there." They've committed heavily to that 'tech', by replanting the original pine block after harvest. In 2020 they bought a 2,381ha hill country farm in the upper Wairau Valley and planted another 340ha of pine and 6ha of hardwood eucalyptus. The remaining 2,000ha became the Mt Impey Conservation Estate, with naturally regenerating native bush and mature remnant forest, all of which is vigilantly protected against grazing and predator pests.

The unregimented native block is much less effective as a sink than plantation but as plenty of other positive benefits, Robert told attendees, noting that carbon cannot be the only lens with which to view environment and ecology. "We would be doing this conservation work regardless of whether we were rewarded for carbon credits or not." His family has been busy tackling wilding pines and cutting back pest numbers, including the feral cats that pose a major threat to birds that would otherwise help in the regeneration, by moving seed. About 400 traps have dealt to thousands of destructive possums, while 500 pigs and 800 goats have been killed during the past three years, said Robert, noting that 100 head of goats are responsible for 21 tonnes of CO2 emissions a year.

When it comes to offsetting emissions, Lowlands Wines is now "quite a bit climate positive", Robert said, in the understatement of the event. The combined sinks of their natural and plantation trees accounted for 122,000 tonnes of CO2 by 2023, set to grow to 280,000 tonnes by 2040. That means Lowlands, while creating 0.7% of Marlborough wine, will produce enough credits to offset 13% of the region's wine industry emissions every year foe the next 17 years.

Robert urged others to "implement easy-wins now" and invest in carbon sinks, either on their own land or in partnership with farmers who supply sheep for winter grazing. The region has "vast" areas of land "itching to go back into natives" and able to provide offsets until there's technology to better reduce emissions. "Don't sit around waiting for legislation to come in and force you to take action, or to reward you do the right thing - do it because it is the right thing to do, and it will make Marlborough a better place for future generations."

Red Herring For Sequestration

While trees are perfectly designed for carbon sequestration, growing soil carbon is a bit of a “red herring” when it comes to offsetting emissions, says Dr Robert Holdaway. “It is a very, very, very good thing. But for us it’s not a solution to carbon sequestration.” Much of Lowlands Wines’ management is aimed at putting carbon back into the soil, with Robert calling the operation “conventional-plus”, maximising photosynthesis and using cover crops, roller crimping, compost, rotational sheep grazing, biological controls and soil bio-stimulants to grow soil health. But most of this added carbon gets used as food by the soil biology and released as CO2, he says. “So, in fully functioning soil the vast majority of the carbon put in on an annual basis gets respired back out again by soil life.”

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