My name is Ben Dube, and I am a PhD student in Natural Resources at the University of Vermont. I’m interested in the public environmental benefits (for example: protection of surface waters, habitat for wildlife, & sequestration of carbon) of alternative agricultural techniques especially as relates to livestock and grazing. and part of my work involves helping on an innovative silvopasture project in Southern Brazil.
I’m in the early stages of thinking about how to apply this work in Vermont and the Northeast US, and would greatly appreciate any feedback or thoughts, including, but not limited to: observations from your or other’s farms & questions that you have wondered about. Keep in mind that while I’m most interested in the “public” aspects, they are usually just different parts of the same processes that create the “on-farm” ecological benefit. For instance, improved drought resistance from rainfall infiltration and storage is the on farm benefit, but runoff prevention is the public benefit.
Thanks so much for your comments!
A lot of thoughts run through my mind while thinking about this. I'll start with my personal belief:
Silvopasturing (and any other agroforestry system) should (or at least has the potential to) generate greater net benefits to the land, public and producer than managing the same area as just forest or field. This is due to factors like: optimized (vs. maximized) production; symbiosis and synergy; and managing a system that is more natural, diverse and resilient.
Any forestry or agricultural production system/model has the potential for greater or fewer net benefits depending on the skill by which it is managed and how appropriately it is implemented for a given situation. Therefore, I don't feel that it's correct to make statements like: "agroforestry is always better than a more focused forestry or agricultural system". No matter what is being done, it still has to be done well.
I'm going to add a couple of recent news stories below that touch on various aspects of your overall question, then will attempt to evaluate the benefits of silvopasturing for specific resources (water, soil, wildlife, etc.) over the coming days.
Bridging the gap between forestry and ag
ROME — While agriculture remains the most significant driver of global deforestation, there is an urgent need to promote more positive interactions between agriculture and forestry to build sustainable agricultural systems and improve food security. This is the key message of the FAO’s flagship publication The State of the World’s Forests, presented today at the opening of the 23d Session of the FAO Committee on Forestry.
Forests play a major role in sustainable agricultural development through a host of channels, including the water cycle, soil conservation, carbon sequestration, natural pest control, influencing local climates and providing habitat protection for pollinators and other species.
“The 2030 Agenda for Sustainable Development, as well as the Paris Agreement on climate change, recognizes that we can no longer look at food security and the management of natural resources separately,” said FAO Director-General José Graziano da Silva in his opening remarks to the Committee on Forestry.” Both agreements call for a coherent and integrated approach to sustainability across all agricultural sectors and food systems. Forests and forestry have key roles to play in this regard.”
“The key message from SOFO is clear: it is not necessary to cut down forests to produce more food,” he added.
Agriculture accounts for the lion’s share of the conversion of forests. According to today’s report, in the tropics and subtropics large-scale commercial agriculture and local subsistence agriculture are responsible for about 40 percent and 33 percent of forest conversion, respectively, and the remaining 27 percent of deforestation happens due to urban growth, infrastructure expansion and mining.
On the flip side of the coin, the report stresses that forests serve many vital ecological functions that benefit agriculture and boost food production.
“Food security can be achieved through agricultural intensification and other measures such as social protection, rather than through expansion of agricultural areas at the expense of forests,” said Eva Müller, Director of FAO’s Forestry Policy and Resources Division. “What we need is better cross-sectoral coordination of policies on agriculture, forestry, food and land use, better land use planning, effective legal frameworks, and stronger involvement of local communities and smallholders.”
“Governments should provide local communities not only with secure land tenure but also with secure forest tenure rights,” she said. “A farmer knows best how to manage his or her own resources but often lacks legal instruments to do so.”
Improving food security while halting deforestation
Well-managed forests have tremendous potential to promote food security. Besides their vital ecological contributions, forests contribute to rural livelihoods and poverty alleviation through income generated by engaging in the production of forest goods and environmental services. About 2.4 billion people rely on wood-fuel for cooking and water sterilization. And forest foods provide protein, minerals and vitamins to rural diets and can also serve as safety nets in periods of food scarcity.
According to SOFO, since 1990, over 20 countries succeeded in improving national levels of food security while at the same time maintaining or increasing forest cover — demonstrating that it is not necessary to cut down forests to produce more food. Twelve of these countries increased forest cover by more than 10 percent: Algeria, Chile, China, the Dominican Republic, the Gambia, Islamic Republic of Iran, Morocco, Thailand, Tunisia, Turkey, Uruguay and Vietnam.
Their successes all relied on a similar set of tools: effective legal frameworks, secure land tenure, measures to regulate land-use change, policy incentives for sustainable agriculture and forestry, adequate funding, and clear definition of roles and responsibilities of governments and local communities.
Successful case studies
The report cites case studies from seven countries – Chile, Costa Rica, The Gambia, Georgia, Ghana, Tunisia and Vietnam — that illustrate the opportunities for improving food security while increasing or maintaining forest cover. Six of these countries achieved positive change in the period 1990-2015 in two food-security indicators — the prevalence of undernourishment and the number of undernourished people — as well as increases in forest area. The Gambia, the only low-income country among the seven, succeeded in achieving the first goal of halving the proportion of hungry people within the same period.
Vietnam, for example, has implemented a successful land reform to provide secure land tenure as a way of encouraging long-term investment. This process was accompanied by a shift from state forestry to multi-stakeholder forestry with the active participation of local communities including a forest land allocation program and forest protection contracts with local households. The land reform was also coupled with policy instruments to increase agricultural productivity, including land tax exemptions, soft loans, export promotion, price guarantees, support for mechanization and reductions in post-harvest losses.
In Costa Rica, deforestation reached its peak in the 1980s, mainly due to the conversion of forest cover to pastures. The country has since reversed this trend largely due to the forest law, which now prohibits changes in land use from natural forest, and its system of Payments for Environmental Services, which provides farmers with incentives to plant trees, and supports forest conservation. As a result, forest cover has increased to nearly 54 percent of the country’s land area in 2015.
In Tunisia national development plans recognize the beneficial role of forests in protecting land against erosion and desertification. Agricultural production has increased through intensification that makes better use of existing agricultural land through irrigation, fertilizers, mechanization, improved seeds and better farming practice. Incentives for establishing forest plantations in the country include free seedlings and compensation for the loss of agricultural income.
Land use in the world’s drylands
(Brett's note: although many areas where silvopasturing is practiced is not considered "dry lands", all areas are prone to prolonged and damaging droughts - as is currently being experienced in much of the Northeast)
ROME — A new FAO report helps to fill a significant knowledge gap on the presence and extent of forests and trees in the world’s drylands, where the food security and livelihoods of millions of people, already precarious, are increasingly being threatened by climate change.
Issued today, the study’s preliminary findings – the full report will be launched later this year – show that trees are present with hugely varying densities on almost one-third of the world’s 6.1 billion hectares of drylands, which cover an area more than twice the size of Africa. Almost 18 percent of this area contains forests.
An estimated 2 billion people, 90 percent of whom are in developing countries, live in drylands. Recent studies have indicated the need to restore these areas to cope with the effects of drought, desertification and land degradation.
In particular, water availability in drylands is expected to decline further due to changes in climate and land use. Poor people living in remote rural areas will be most vulnerable to food shortages, which combined with violence and social upheaval, are already leading to forced migration in dryland regions in Africa and western Asia.
Until now, there has been little statistically based knowledge on dryland trees – particularly those growing outside forests – despite their vital importance to humans and the environment.
The leaves and fruit of trees are sources of food for people and fodder for animals; their wood provides fuel for cooking and heating and can be a source of income for poor households; trees protect soils, crops and animals from the sun and winds, while forests are often rich in biodiversity.
New data, technology made large-scale study possible in record time
As the first statistical sampling-based assessment of land use in the world’s drylands, the FAO study provides a baseline for monitoring changes in dryland forests, tree cover (density), and land use. It provides governments, donors and other stakeholders in sustainable development with a valuable tool to guide policy-making and targeting investments.
Using satellite images available publicly through Google Earth Engine, Bing Maps and other sources, FAO’s study draws information from over 200,000 sample plots each measuring approximately 0.5 hectares. The sampling error for the estimate of the total forest land for all drylands is about +/- 1 percent.
The satellite images were interpreted using Collect Earth, a tool in the Open Foris suite of free, open source software developed by FAO’s Forestry Department to make it easier for experts from around the world to collect, analyse, report and share data.
FAO stresses the participatory nature of the assessment, which was conducted as a series of regionally focused training, and data-collection workshops organized in collaboration with partners including universities, research institutes, governments and non-governmental organizations worldwide. This approach, coupled with the use of the new software developed by FAO, Collect Earth, permitted a massive study to be undertaken in the previously unthinkably short time-span of less than a year
Drylands are divided into four aridity zones (see map): the dry subhumid zone – the least arid of the four zones – and consists mostly of the Sudanian savanna, forests and grasslands in South America, the steppes of eastern Europe and southern Siberia, and the Canadian prairie. Most dryland forests occur in this zone, as do some large irrigated, intensively farmed areas along perennial rivers; at the other extreme, the hyperarid zone is the driest zone and it is dominated by desert – the Sahara alone accounting for 45 per cent, and the Arabian desert forming another large component.
The study indicates that grassland constitutes 31 per cent of land use in drylands, forests 18 percent, cropland 14 per cent, wetland 2 percent and human settlements 1 percent. The largest portion, 34 percent, which is categorized as “other land”, consists largely of bare soil and rock.
While the new study reports results on global and regional levels, FAO is ready to assist in adapting the methodology for country-level assessments on request. These in turn could enhance the ability of governments to track progress made in achieving the Sustainable Development Goals (SDGs), in particular SDG 15, which focuses on sustainably managing forests, combating desertification, halting and reversing land degradation and halting biodiversity loss.
Restoring tree-based systems and other fragile ecosystems in drylands
The study methodology is being already used for the baseline assessment and monitoring in the FAO-implemented project, “Action Against Desertification” an initiative of the African, Caribbean and Pacific Group of States (ACP).
Over four years, until 2019 ACP, the European Union, FAO, the African Union Commission and other partners will support six African countries – Burkina Faso, Ethiopia, the Gambia, Niger, Nigeria and Senegal – as well as Fiji and Haiti in improving the condition and productivity of land affected by degradation, drought and desertification.
A good overview of ecological benefits from incorporating trees in pasture systems by Rutgers U Extension Specialist Joseph Heckman
some water quality resources related to this discussion:
· https://blogs.cornell.edu/ccednrpublications/files/2015/03/Ecosystem_services_silvopasture_G.Garrett.UMCA-2b0vnxc.pdf (note that Dr. Garrett’s presentation from the 2011 Northeast Silvopasture Conference included some less talked about services like the rhizodegradation of animal antibiotics and herbicides)
· www.stroudcenter.org - extensive research showing that forested riparian buffers (which could also mean silvopastures vs. tree-less pastures) improve the health of watersheds. In addition to being filters, trees also improve stream morphology, help feed beneficial aquatic organisms, reduce thermal pollution, reduce wind-born contaminants from entering the water body, contribute to beneficial habitat structure within streams, etc.