A Lincoln University student’s PhD work offers new insight into on-farm carbon sequestration and the ecological benefits of shelterbelts, which he says may be part of the puzzle to sustainable management of agricultural environments and improved environmental credentials.
Johannes Welsch, who recently submitted his PhD in Agro-ecology, says that, shelter belts are a farm-friendly way to improve carbon sequestration outcomes in the agricultural sector, and may be one answer to growing consumer concern around the environmental footprint of farming and the need for New Zealand farms to adapt to climate change.
“The general population, both in New Zealand and in key overseas markets, are becoming more concerned about where their food comes from and the environmental impact of its production. The agricultural sector should be motivated to get out in front of a new wave of opportunity fuelled by consumer concern, with the aim of cornering that high end of the market.” Carbon sequestration could be a key part of this approach.
As Canterbury becomes warmer, drier and windier, with more frequent droughts and storms, increased efficiency of water use and farming practices will be necessary to maintain and increase production. Wind is one of the few elements that farmers can control with the use of windbreaks and shelterbelts. Ironically, says Johannes, over the past few decades many shelterbelts have been removed to facilitate irrigation equipment and more intensive land use.
“A case study on shelterbelt loss in central Canterbury revealed a reduction of 46% between 1984 and 2004 as a result of dairy conversions. It is mind boggling how many huge areas have become green pasture deserts.” He began to question what else is lost with these removals and whether opportunities to sequester carbon dioxide are being sacrificed.
Johannes visited 34 sheep, beef, dairy and arable farms in the Canterbury region, from Banks Peninsula to the foothills of the Alps, to investigate their use of shelterbelts and the benefits of these, including increased biodiversity, soil ecology and shade and shelter for stock. Shelterbelts have also been shown to raise agricultural productivity. “Shelterbelt species selection with strategic placement and clear objectives can have numerous potential benefits to farm productivity and profitability.”
“It is only a matter of time before this happens,” says Johannes. “There is growing pressure on farmers to do their bit and government policies may change. Farmers should look at the ‘free’ benefits they will gain across the whole farm. Shelterbelts are not a short-term panacea, but a mid- to long-term proposition that requires a flexible approach and site-specific solutions. They contribute to equity for future generations, position farmers for a ‘low carbon’ future and enable adaption to a changing climate.”
Concern has been raised over the large-scale use of potentially fertile agricultural land for permanent forest carbon sinks, but Johannes emphasises that most shelterbelts are planted along, boundaries, slopes or gullies, roadsides and on marginal land. “The planting of these areas with shelterbelts benefits not only the farmer but New Zealand as a whole.”
With only one percent of native vegetation remaining on the Canterbury plains, and native species averaging similar amounts of carbon per hectare to exotic species, he recommends planting a mixture of native and exotic species to give optimal benefits of shelter, permeability, low maintenance, wildlife habitat, resistance to drought, frost and snow, is aesthetically pleasing and increases property values.
“It doesn’t have to be done overnight either. Existing exotic shelterbelts can gradually be replaced with native species.”
Johannes Welsch recently submitted his PhD in Agri-ecology at Lincoln University and is working on native vegetation and biodiversity projects on farms across the Canterbury Plains with Te Ara Kākāriki – Canterbury Greenway Trust.
You can view an ‘On the Land’ interview with Johannes Welsch here