Pine forestry offers a tempting alternative for land use that has economic and environmental benefits, researchers say. Photo:
Rivers and lakes could be cleaned up with profits still generated for landowners by converting sheep and beef farms to pine trees, according to a new paper from the Our Land and Water science challenge.
But the authors questioned whether New Zealanders want a sea of pine.
Four different research projects, using different models and involving different researchers, all found New Zealand was heading towards having many more pine trees.
The big push to pine was being driven by a combination of attractive prices for carbon credits generated by pine trees, the poor economics of sheep and beef and the need to improve water quality.
All three factors together were going to cause a significant change, said the lead author of a paper pulling together the findings, Dr Bill Kaye-Blake, a principal economist at economic consultants NZEI (NZ Institute of Economic Research).
"The easiest solution is to plant a lot of pine trees. Now that's probably not acceptable to a lot of people in New Zealand, to a lot of rural communities in New Zealand," said Kaye-Blake.
Even with a carbon price of zero, about a fifth of sheep and beef land would still be converted to pine forests, the research found.
About half the conversions were driven by carbon credits, 20 percent by low profits from sheep and beef and 15 percent or so was for meeting water quality targets, he said.
Poor profits from sheep and beef were "simply a result of the current economic conditions," Kaye-Blake said.
"If you look at pine trees, there is a strong market for logs and a strong market for timber products, so forestry is making a lot of money, and on the other side sheep and beef are struggling a bit.
"In particular, if we look at wool, the cost of shearing the sheep is almost more than the cost of the wool clip you get from that."
The studies showed New Zealand could have cleaner lakes, rivers and beaches, with more pine, he said.
And water quality benefits of pine forest versus sheep and beef farms included lower nitrogen pollution and lower e-coli in the water.
"One group of researchers looked at the Tukituki catchment in Hawke's Bay and found meeting the water quality bottom lines would mean changing most of the sheep and beef land into pine forests.
"It also found if the region did that it would increase profit to land owners in the area, so you have both a water quality benefit and an economic benefit."
Read more:
- Freshwater contamination a challenge for New Zealand land use
- Water quality of almost all surveyed lakes and rivers very poor
But Dr Kaye-Blake said the models could not include the downsides of pine plantations such as lower biodiversity, sediment run-off and damage to bridges and houses from debris washing away in storms, as has happened in Tai Rāwhiti.
"There are also negative impacts that aren't actually included in these models, one of the big ones for example is forestry debris."
Read more:
- Large slash must now be removed after harvesting - new forestry regulations
- Environmental group hails court decision against forest company
Our Land and Water challenge director Dr Jenny Webster-Brown said the findings of the four studies were "surprisingly consistent" that pine was the "best, easiest, most obvious option", but asked if New Zealanders would be happy with the cost of a pine-filled landscape.
"We appreciate that having more pine trees is not the solution to New Zealand's problems," she said.
The researchers concluded that if the government wanted to change the direction of land use it should look at options like encouraging more native trees and biodiversity.
Read more:
- Planting pine or native forest for carbon capture isn't the only choice - NZ can have the best of both
- The future forest industry - Our Changing World
Finding ways to make sheep and beef more profitable would also help, because it could give farmers more money to tackle water pollution problems without converting their land to pine, they said.
In all they made eight recommendations.