The potential of agroforestry to answer climate concerns
The comments below are part of a brief prepared by Dr. Naresh Thevathasan for his presentation to the House of Commons’ Standing Committee on Agriculture and Agri-Food Presentation on Dec. 7, 2017 . To hear Dr. Thevathasan’s presentation, visit the House of Commons website. The notes here have been edited slightly for formatting purposes.
Dear honourable Members of the Standing Committee on Agriculture and AgriFood.
My name is Naresh Thevathasan. I am an Associate Professor and leader of the Agroforestry Research and Development and Woody Biomass Research Initiative at the University of Guelph.
For the Canadian agricultural sector, a plethora of climate change adaptation and mitigation strategies have been recommended. These strategies include selection of crop types, breeding improvements, changes to production management, precision agricultural farming techniques, region-specific recommendations based on climate change model predictions, social and economic considerations, and relevant policy measures. However, agroforestry, a globally recommended (http://www.worldagroforestry.org/cop22; FAO, 2013) land-use system where trees are deliberately integrated into agricultural ecosystems in order to derive environmental, ecological, economic and social benefits, and its impact on climate change mitigation and adaptation in the Canadian agricultural systems, has not yet been fully realized. This is irrespective of the Canadian government’s commitment to research in temperate agroforestry land-use systems through the AGGP under the auspices of the Global Research Alliance (GRA) initiatives. The AGGP is currently funding research projects across 4 major themes: cropping systems, livestock, water-use efficiency, and agroforestry.
A recently published study conducted by scientists from the U.S.-based Nature Conservancy, along with 15 other institutions worldwide (Griscom et al., 2017), concludes that the most cost-effective climate change mitigation strategy is “planting more trees in all landscapes, including trees in crop lands.” As per this study, increasing tree numbers globally will remove close to 7 billion tonnes of CO2 per year, which is equivalent to taking 1.5 billion gasoline cars off the road. This should be able to hold global warming below 20C by 2030. In this context, even though Canada has 28% of the world’s boreal forest area, additional carbon sinks are needed to execute climate change mitigation and adaptation strategies. Excluding classes 1 and 2 agricultural lands and plant trees (agroforestry and afforestation) in classes 3 to 6 (about 46 million ha), we will provide significant amounts of new carbon sinks for Canada.
In the context of introducing trees into agricultural landscapes, there are 6 temperate agroforestry systems that I would recommend. These systems are:
- Tree-based intercropping systems;
- Riparian buffer systems;
- Windbreak systems;
- Silvopastoral systems;
- Biomass production systems;
- Forest farming systems.
Overall research findings:
Irrespective of the type, all agroforestry land-use systems can contribute towards climate change mitigation and adaptation while providing ecosystem services such as, soil conservation, soil erosion control, biodiversity enhancement, and water quality maintenance. These systems can also show resilience to climate change through micro-climatic modifications (soil moisture retention, low soil temperature, less evapotranspiration rates) that are often seen in the tree-crop interface. Agroforestry systems are not a choice of environment or economics, as they enhance both. Agroforestry systems are not a choice of food or wood fibre. If properly integrated into agricultural systems, they provide both. Therefore, I have listed some of the major outcomes, both economic and environmental, that can be derived by adopting these land-use systems in Canadian agricultural landscapes:
- Enhanced system-level carbon sequestration; 200 to 300% (Soil).
- Better utilization of soil nutrients via nutrient cycling mechanisms that result in less residual in-organic soil nitrogen, which is a precursor for nitrous oxide emissions (Air).
- Nutrient leaching reduction, which contributes towards maintaining water quality. It has been shown that up to a 50% reduction of nitrate-N leaching in tree-based intercropping systems can be achieved (Dougherty, 2009) (Water).
- Enhanced biodiversity; plants, micro and macro faunal diversity, bird diversity – this contributes to climate change adaptation and also enhances resilience to climate change. (Biodiversity)
- Creation of climate-smart and resilient land-use systems, thereby increasing economic returns to the farming communities across Canada. (Economic growth)
Globally, the Intergovernmental Panel on Climate Change (IPCC), in the recent COP22 conference held in Morocco in November 2016, highly recommended agroforestry land-use systems to be adopted in developing countries in order to promote climate-smart agricultural systems while contributing to climate mitigation efforts by sequestering carbon in trees and in soils. The same sentiment has also been expressed in a FAO policy paper (2013).
Challenges and Opportunities for Canada:
- Canada has no specific and targeted policy in place for agroforestry land-use systems. As such Agroforestry adoption rates in Canada irrespective of government’s commitment to research in temperate agroforestry, are very low. Whereas, in the US, there is a targeted policy put in place by the USDA – “Agroforestry Strategic Framework; Enriching our lives with trees that work”.
- As I speak, field shelterbelts / windbreaks are being removed in the prairies. Field windbreaks have become a farm operational issue and in some cases trees in the windbreak are also dying. This trend needs to be addressed with urgency.
- Similarly, in Ontario windbreaks and riparian buffers are being removed in order to create additional agricultural land areas. This is more prevalent in the south western part of Ontario (Essex and Kent counties).
- There is a lack of riparian plantings along agricultural streams across Canada, especially in Eastern Canada where heavy non-point sources of pollutants and soils are entering water bodies.
- Non-agricultural lands are currently either pastured or abandoned; tree integration should be considered in order to create additional terrestrial carbon sinks. Ample land areas are available to execute this.
- Niche markets need to be nurtured for Canadian-produced agroforestry value-added products such as, nuts, fruits, syrup, mushrooms, and non-timber forest products.
- Tree-based farming systems are historically familiar to many First Nations communities. Therefore, a concerted effort should be taken to initiate dialogue with them in order to re-introduce agroforestry land-use systems in First Nations lands in order to bring about food and income security for them.
- Introduction of silvopastoral systems in the developing agricultural lands of the clay belt regions of Ontario and Quebec (about 29 million acres) should be given urgency to enhance terrestrial carbon sequestration.
- A Canadian agroforestry strategic framework policy is required. This should be led by the federal government in consultation with researchers across Canada, federal and provincial government officials, First Nations communities, conservation authorities / agencies, and landowners. This document is required to provide the strategic guidance for science, adoption and integration of agroforestry practice into agricultural landscapes.
- Federal leadership in Agroforestry is required, such as that provided by the former AAFC’s Agroforestry Development Centre at Indian Head, Saskatchewan.
- Programs that promote the integration of trees into agricultural landscapes are needed if Canadians wish to economically and environmentally benefit. Referencing the agroforestry knowledge continuum; discover, develop, determine, demonstrate and direct, Canadian agroforestry researchers have fulfilled the first 3 stages of the knowledge continuum but Canada-wide adoption will only materialize if the Government of Canada (and the provincial governments) introduce and execute agroforestry-friendly policies and incentives. This will facilitate the last two stages of the knowledge continuum, demonstrate and direct agroforestry land-use systems in Canada, thereby contributing directly to climate change mitigation and adaptation and the maintenance of ecosystem services across Canadian agricultural landscapes.
- Appropriate agroforestry education, research, training and knowledge transfer (extension) protocols / activities should be developed to promote sustainable agroforestry systems in Canada.
Thank you once again for the invitation and for the opportunity given to make this presentation.
Dougherty MC, Thevathasan NV, Gordon AM, Lee H and Kort J (2009). Nitrate and Escherichia coli NAR analysis in tile drain effluent from a mixed tree intercrop and monocrop system. Agriculture, Ecosystem and Environment.131:77-84
FAO (2013). Advancing Agroforestry on the Policy Agenda: A guide for decision-makers, by G. Buttoud, in collaboration with O. Ajayi, G. Detlefsen, F. Place & E. Torquebiau. Agroforestry Working Paper no. 1. Food and Agriculture Organization of the United Nations. FAO, Rome. 37 pp.
Fortier J, Gagnon D, Turax B, and Lambert F (2010). Biomass and volume yield after 6 years in multiclonal hybrid poplar riparian buffer strips. Biomass and Bioenergy 34: 1028 – 1040
Fortier J, Turax B, Gagnon D, and Lambert F (2013). Mature Hybrid Poplar Riparian Buffers along Farm Streams Produce High Yields in Response to Soil Fertility Assessed Using Three Methods. Sustainability 5: 1893-1916.
Gordon AM, and Thevathasan NV (2004). How much Carbon can be stored in Canadian Agroecosystems Using a Silvopastoral Approach? In: Silvopastoralism and Sustainable Management. p.210-218. Eds: M.R. Mosquera-Losanda, A. Rigueiro-Rodriguez and J. McAdam, CABI Publishing. 429pp.
Griscom BW. et al. (2017). http://www.pnas.org/content/114/44/11645
Oelbermann M and Beverly AR (2015). Riparian Land-Use and Rehabilitation: Impact on Organic Matter Input and Soil Respiration. Environmental Management 55: 496-507.
Peichl M, Thevathasan NV, Gordon AM, Huss J, and Abohassan R (2006). Carbon sequestration potentials in temperate tree-based intercropping systems, Ontario, Canada. Agroforestry Systems 66:243-257
Thevathasan NV, and Gordon AM (2004). Ecology of tree intercropping systems North temperate region: Experiences from southern Ontario, Canada. Agroforestry Systems 61: 257-268.
Wotherspoon A, Thevathasan NV, Gordon AM and Voroney RP (2014). Carbon sequestration potential of five tree species in a 25-year-old temperate tree-based intercropping system in southern Ontario, Canada. Agroforestry Systems: DOI 10.1007/s10457-014-9719-0