Trees, sheep and beef make an interesting mix
Victoria Lamb, New Zealand Tree Grower May 2018.
New Zealand has an area of about 25.9 million hectares. Around 40 per cent or 10.6 million hectares of that is in sheep and beef farming.
As many will know first-hand, there is a lot of native vegetation growing on sheep and beef farms, representing a significant biodiversity resource.
A recently completed report by researchers from Canterbury University and Auckland University of Technology for Beef + Lamb New Zealand has looked at just how much native vegetation there is and how it is distributed through the country. The results are some fairly significant numbers.
Native vegetation of all types cover about 44 per cent of New Zealand, with more than half of it found on public conservation land. Just under a quarter of all native vegetation, amounting to a significant 2.8 million hectares, is found on sheep and beef farms.
About a quarter of all sheep and beef farms have native vegetation on them, ranging from a high of 41 per cent cover on Marlborough farms to a low of 12 per cent in Hawkes Bay.
The study looked at three classes of vegetation −
- Forest and potential forest as native woody vegetation
- Native grasslands
- Native wetland vegetation, the proportion that occurs on sheep and beef farms and the different distributions by region.
Native woody vegetation nationally is estimated at 30 per cent which is about eight million hectares across New Zealand. Out of the eight million hectares, about 1.36 million hectares are on sheep and beef farms, with the percentage of woody vegetation occurring on sheep and beef farms varying across regions. Where there is a lot of public conservation land, the proportion on sheep and beef land is often low, whereas in regions with less public conservation land, the percentage found on sheep and beef farms can be much higher. For example, around Gisborne, just over half of all native woody vegetation remaining is on sheep and beef farms.
Native grassland vegetation nationally is estimated at 10 per cent or 2.6 million hectares with 1.2 million hectares on sheep and beef farms. Not surprisingly, Marlborough, Canterbury, Otago and Southland feature as the regions with the biggest amount of native grassland.
When it comes to wetlands, the story is not good. Native wetland vegetation nationally is estimated at a critically low one per cent or 259,000 hectares, of which 3,600 hectares is on sheep and beef farms. Almost 80 per cent of remaining native wetland vegetation is on public conservation land. Overall, however, the report shows, sheep and beef farmers have a significant amount of native vegetation on their land.
Of course, woody native vegetation is not the only type on sheep and beef farms as the following data from the Beef and Lamb Economic Service Sheep and Beef survey shows. Their survey, based on a statistically representative sample of 550 farms, identifies 181,000 hectares of planted forestry blocks on sheep and beef farms across the country.
|Farm class||Forestry block average size in hectares||Number of farms||Total area of forestry blocks in hectares|
|9 Total of all classes||16||11,295||180,720|
The data collected did not determine which tree species was being grown but the majority is likely to be radiata pine. Further work is needed to look at what trees make up the forestry blocks on sheep and beef farms.
These figures do not include the other trees found on farms. Shelter belts, erosion prevention plantings of willows and poplars and other more widely spaced or scattered trees are common, especially on the hill and high country farms. These also have value for their primary purpose of shelter, shade, erosion prevention, but also for the looming issue of climate change.
Changing climate of climate change
Climate change policy is fast moving and changing. We have seen the Paris agreement targets, but the new government has signalled a desire of the much greater target for the entire economy to be nett carbon neutral by 2050, compared with the earlier aim of 50 per cent below 1990 emissions by 2050.
New Zealand has a unique emissions profile when compared to the rest of the world. Around half of the country’s greenhouse gas emissions are generated by the agricultural sector, predominantly from livestock and livestock farming. As a result, most of the emissions are methane and nitrous oxide as products of ruminant animal digestive processes and the by-products urine and faeces.
The sheep and beef sector is responsible for about half the emissions from livestock. At last count there were about 27,580,000 sheep and 3,470,000 beef cattle on sheep and beef farms. Sheep numbers have fallen by more than half since the early 1980s when numbers were in excess of 70 million.
Now the 27 million sheep produce almost the same amount of meat as a result of improvements in genetics, animal management, higher reproduction rates, pasture improvements and better feeding. Beef cattle numbers have also fallen, but not to the same degree as more beef animals are produced from the dairy herd.
One of the benefits of the reduced livestock numbers associated with improved performance is that there has been a significant decrease in the sector’s emissions profile Greenhouse gas emissions from the sheep and beef sector are currently 19 per cent below 1990 levels, putting the sector ahead of New Zealand’s current target of 11 per cent below 1990 levels by 2030.
Total emissions have fallen, along with the emissions per kilogram of meat. Further reductions are possible by building on the genetic gains and further improvements in reproductive performance, feed types and pasture utilisation, but these are likely to be small although they will be cumulative. Research is continuing into novel mitigation which can generate significant reductions in emissions, but potential products are still being tested and some years away from being available on the farm.
As with any product, markets fluctuate, with the sheep and beef sector being no exception. Currently, red meat prices are good and the sector is doing well. The products have appeal as the animals are pasture-fed, free range and fit well into the calls for sustainable farming.
To continue to meet the call for sustainable production, the sector is looking closely at how it can become nett carbon zero. The good news is that, based on recent research, if sheep and beef sector’s tree coverage is taken into account − native vegetation along with forestry planting − then it is realistic and achievable for the sector to become fully carbon neutral. This will require modest further planting of about 73,000 hectares of radiata pine or 368,000 hectares of native forest. This translates to about seven hectares of radiata pine per farm based on 11,295 farms, or 33 hectares of native forestry for each farm.
How many trees
To calculate these figures we have used the Parliamentary Commissioner for the Environment’s 2016 calculator for emissions and forestry offsets.
|Hectares of radiata pine||Hectares of native forest|
|One beef cow||0.057||0.28|
|3,470,000 beef cattle||197,790||971,600|
|Forest on sheep and beef land||180,720||1,360,000|
|Forest needed||73,080 or 367,700|
|Forest needed per farm||7 or 33|
Not all farms will be able to put in more trees, particularly the intensive finishing farms which may have all their land committed to production. However, many others will be able to put some of their less productive, highly erodible or less accessible areas into trees. This would make the sector nett carbon neutral for now.
Consideration will also need to be given to the tree species. Trees which are destined for harvest will, when harvested, need to be replaced with an equivalent amount of land planted or replanted. On the other hand, native forest, if left to regenerate and mature, will remain a permanent carbon sink.
All trees come with other benefits. They help keep soil in place, reduce overland flow of water which can carry sediment and pathogens into waterways. They can also help soil retain moisture, have biodiversity benefits, can provide shade and shelter for livestock, have social and cultural values, can be used for timber and they can add value to the landscape.
Victoria Lamb works for Beef and Lamb with sheep and beef farmers for a nett carbon neutral future.