When I saw the news that Mangaohane Station was on the market and under threat of being bought up by investors who would turn the station into a carbon sink I felt my spirits sink. In my youth I spent several enjoyable years shepherding and farming through several regions in the North Island. These areas included Wairoa (up the Ohuka Valley near Waikaremoana), on several properties on the East Coast.
In this region I worked on Ruangarehu Station in the Ihungia Valley and it went under trees post Cyclone Bola. In this case the property was under major threat from erosion and I can recall paddocks which a horse could be ridden over one year, the next would have been a death trap.
Then to Puketawa Station, a Gisborne Harbour Board property and at the time nearly 9,000 ha (later cut up into more manageable properties). Now called Tauwhareparae Properties (11,500 ha) of which around a third is under trees. This block sits next to Huiarua and Matanui stations sold into trees and also next to Waipaoa Station which has also has had a large section go under trees.
Next came Mangaohane Station in the Pukeokahu District between Napier and Taihape. I was there in the latter part of the 1970’s at which stage the station (not long bought by Jim Bull from the Chambers family) was under going massive development largely motivated by the subsidies and incentives available to farming at that time.
This was/is a different property to the East Coast properties with minimal erosion and the biggest limitation being winter, but extensive cropping mitigated that. So, seeing it on the market and now being threatened by the threat of non-productive forestry was a bit of a shock, although predictable given the current environment.
As with the East Coast properties, Managaohane is situated with many other well known large properties in it vicinity; Otupae, Erewhon and Ngamatea to name a few. If Mangaohane goes then these other iconic stations may also be on the same slippery slope.
Jumping forward a few steps I got thinking, how much farmland could be under threat?
So, agriculture makes up approximately 48% of around 8,850 kilotonnes (1 x1000 tonnes) of CO2e emitted annually (38,808 ktns) nationally. If ‘we’ consider land use mitigation should only be used to off set land use emissions (I’m not sure politicians would wear this as it may not be convenient) and ‘we’ set a high goal of zero net emissions then how much land would need to go under trees to get to that stage?
On average sheep and beef farms emit about 2.8 tonnes of GHG annually (I’m going to assume dairy are not going to go into trees. Sheep and beef land is cheaper so why would you?). Pine trees can sequester approximately 30 tonnes of CO2e per hectare annually after year 5 up to year 40 and I’m not game to predict what the political yet alone climate environment will look like after 2060. At roughly a 10x rate of sequestering versus emitting the sums would be relatively simple however the decreasing livestock numbers also need to be incorporated.
So: 80,851 ktn is the total national GHG emissions
48% = 38,808 ktns is the share emitted by agriculture
@30tns GHG per ha to mitigate annually,
then, 38,808/30 means 1.29 million hectares are required to balance books before adjusting for decreased livestock.
So, by adding the 2.8 tns of reduced GHG due to removed livestock to the 30 tonnes sequestered (32.8 tns annually) we get a grand total of 1.18 million hectares removed from farming.
According to Beef+Lamb Farm Facts we have around 13.3 mill ha in sheep and beef, so a reduction of about 9% of land area is required (somehow sounds better than 1.18 million ha).
While a 40 year rotation is assumed and then the proverbial hits the fan again; I think we can assume technologies will have developed considerably to both reduce emissions and sequester GHG’s.
The Government has come out saying that 20% of sheep and beef farms are expected to go into forestry so all I can assume is that land use change is carrying the can for the rest of society.
While perhaps pragmatic I feel more needs to be done to drag the average member of society into the conversation and shoulder more of the responsibility.
Someone will no doubt check my numbers we will soon hear if there is a major error but the numbers feel intuitively close especially with the almost 10 to 1 ratio of sequestering versus emitting.
Back to Mangaohane Station, a group has been set-up to try and gather enough interest to purchase the property and keep it as a sheep and beef property or at least not under trees. I can certainly empathise with them as also with “50 Shades of Green” group.
However, what is required is a regulation change, as while well meaning individuals may be able to ‘save’ the odd property here and there unless something happens to alter the incentives to buy and plant these properties it could be like King Canute trying to hold back the tide although his motivations were somewhat different.
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