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Agroforestry Past and Present


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Working Trees for Vermont Landowners:

Planting for Productivity and Land Restoration




By Andrea Haney

abhaney@uvm.edu

Agroforestry

Past and Present
Agroforestry is a contraction of the words agriculture and forestry. This practice is a dynamic land management system that integrates trees and/or shrubs with crops and/or livestock. Not a new concept, agroforestry has been practiced for centuries around the globe, mainly in tropical and sub-tropical regions. This is not to say that our climate isn’t capable of supporting these practices. To the contrary Vermont landowners and farmers will find many species that are well suited to agroforestry practices. For those looking to diversify their lands potential, as well as improve their lives in social, economic, and environmental ways this is the ideal alternative to monoculture farming.
During the early 1900’s the use of permanent tree systems in order to maximize production on arable lands was advocated by a few early farmers in the U.S. However, political and agricultural groups at the time opposed these biologically pragmatic ways deeming them too radical. The onset of the 1930’s depression along with the devastation “Dust Bowl” in the mid west forced political leaders to reconsider standard policy, and they began to support new agricultural research. Unfortunately, this innovative research ended with the post-war economic boom of the 1950’s and the introduction of fossil fuels, chemical fertilizers and the industrial technology. For a brief time during the oil crisis of the 1970’s there was renewed interest in trees and their potential role in food production. Innovators like Bill Mollison introduced concepts such as permaculture which then spurred grassroots ecological farming movements. Four main reasons for the renewal in agroforestry were:


  • Environmental and ecological concerns

  • Decreasing availability and increasing cost of fossil fuels

  • Soil erosion and its direct effect on food production

  • Increase in world population and subsequent demand for increased output

These issues apply today but on an even greater scale, and alternative agricultural methods are again being reconsidered. Vermont landowners will find many benefits to integrating agroforestry into local farms, and even urban communities. Appropriate use of agroforestry methods enables farmers and landowners to integrate productive profitable landscapes with healthy sustainable agricultural systems. Specifically these practices will:




  • Protect crops and livestock

  • Increase productivity of agricultural and horticultural crops

  • Reduce inputs of energy: physical, chemical and/or biological

  • Increase water use efficiency

  • Diversify local economies

  • Enhance biodiversity, and ultimately the quality of life for people

Planting select trees with a design approach can also add an aesthetically pleasing view to your property. This labor of love provides long lasting results that can be passed down to future generations.


The following strategies are flexible tools that can be tailored based on which ones fit best with the resources you have to work with. Understanding the lay of your land, and the differences among these systems is the first step toward implementing these technologies.

Windbreaks


Windbreaks are rows of vegetation used to reduce and redirect wind. Field windbreaks improve crop yields by improving water use efficiency, and reduce wind erosion. Worldwide data selected by the USDA National Agroforestry Center shows crop yields can be improved anywhere from 5 to 45 percent. Most of these yield increases can be attributed to better water use by the protected crop.


Climate stress is reduced when livestock are surrounded by vegetation. These natural buffers have been known to alter the amount of food animals consume, and reduce visual impacts. Windbreaks also provide nesting habitat for numerous bird species and small mammals.
Surrounding your property with windbreaks can add value to your home, create privacy, and help conserve energy. The NAC reports that buffers planted in the correct locations can yield annual energy savings ranging from 10 to 40 percent. Key design issues are to manage for shade and wind.

Riparian Forest Buffers
This technique is similar to windbreaks but instead the trees and vegetation grow adjacent to streams, pond and wetlands. Doing so buffers these water bodies from negative impacts that originate from adjacent land-use practices, such as agriculture, urban, and industrial areas. Natural or restored streamside forests can create results in the following ways:

  • Stabilize streambanks and protect floodplains

  • Provide necessary ecological functions

  • Reduce non point source pollution

  • Enhance aquatic and terrestrial habitat by increasing biodiversity


Silvopasture


Silvopasture combines trees with forage and livestock production. A contraction of the words silviculture and pasture it is managed as a single integrated system. Hardwood stands can be managed for long term, high value sawlogs while the understory is managed for forage production to support livestock. Grazing by farm animals can also provide an alternative to mowing, nut and fruit orchards are ideal. Potential livestock choices include: cattle, sheep, goats, pigs, horses, turkeys, chickens. The selected livestock system must be compatible with tree, forage, environment and land use regulations. For example, poplar trees provide leaves and branches for cows. Oaks, walnuts, hazelnuts, chestnuts and hickories are suitable for pigs. Livestock farms that graze their animals could definitely take advantage of this multiuse approach.



Alley Cropping


When agricultural crops are grown in the alleys between widely spaced rows of trees thus defines alley cropping. The main difference between alley cropping and silvopasture is the absence of livestock. Annual income is provided through ground cover crops while the trees produce long term income. For example, hardwoods such as, walnut, oak, ash and pecan are favored for their high value lumber and veneer logs. Nut crops are often used as an intermediate tree product. There are many factors to consider depending on the lay of the land these include:





  • Maintenance of timing & methods

  • Size of farming equipment

  • Possibility of attracting unwanted wildlife

  • Light requirements of companion crops

  • Chemical interactions between trees and companion crops


Forest Farming


Forest farming is created when high value specialty crops are cultivated under the protection of the forest canopy. Forest stands can be pruned to provide the desired amount of shade. Crops such as, ginseng, shitake mushrooms and decorative ferns are often sold for medicinal, culinary and ornamental uses. This method is similar to alley cropping but in a more natural setting. Some products especially medicinal and botanicals can have tremendous economic value, while others provide lower but steady income. For example, high quality northern forest cultivated ginseng has been known to fetch $800 a pound and shitake mushrooms average a steady $10 to $12 a pound.




Special Note on Non-Native Species
It is important when cultivating any crop that you consider the ecological components of various exotic/non-native species. Invasive species have expansive and/or dispersive tendencies that often have long term detrimental effects on native ecosystems. When we consider the native origins of the vast majority of our cultivated crops, it becomes clear that many non-native species play a critical role in our everyday lives. That said, in order to promote sustainable stewardship through agroforestry one should be well informed of the invasive properties some non-natives carry.

The following are a list of suggested species their habitats and possible uses. Keep in mind that many of these species have several suitable varieties within each family.



Alnus glutinosa – Alder

Range – Europe and North America

Habitat – Wet soils in woods lakes and stream shores

Primary uses – Nitrogen fixer, pioneer, soil stabilizer, timber, coppice material, charcoal windbreak, fire protection, honey, biomass, livestock fodder, fiber, insecticide, edible – seeds, flowers and seed pods

Sorbus Americana – American Mountain Ash



Range – Eastern North America

Habitat – Rocky slopes and higher elevations

Primary uses – Windbreak, edible fruits, medicine, winter bird forage, timber



Robina pseudoacacia – Black locust



Range – Eastern North America

Habitat – Woods, thickets, and deep well drained calcareous soils

Primary uses – Nitrogen fixer, pioneer, soil stabilizer, timber, coppice material, charcoal, windbreak, fire protection, honey biomass, livestock fodder, fiber, insecticide, edible seeds, flowers and seed pods



Juglans nigra – Black walnut

Range – North America

Habitat – Moist, rich, well-drained soils, bottomlands, floodplains, low mixed deciduous forest

Primary uses – Edible nuts and oil, timber, insect repellent, livestock fodder, stain, wood polish

Castanea dentate – Chestnut

Range – North America

Habitat – Sterile soils, dry, gravelly, or rocky, moistly acidic soils

Primary uses – Edible nuts and oil, flour, timber, coppice material, tannin, livestock fodder

Sambucus Canadensis – Elderberry





Range – Native to Eastern North America

Habitat – Damp rich soil, moist fields, woods, around marshes, stream and riverbanks, and fencerows

Primary uses – Edible flowers, buds, and berries, wine, insect repellent, hedge, windbreak, wildlife forage

Corylus – Beaked/American hazelnut

Range – North America

Habitat – Rich thickets, clearings, forest borders, dry or moist woodlands, hills or mountain slopes

Primary uses – Edible nuts and oil, hedge, fiber, coppice material, wildlife habitat, livestock fodder

Crataegus – Hawthorn

Range – North American and European natives

Habitat – Stream banks, old fields, woodland openings, bottomlands

Primary uses – Hedge, windbreak, and livestock forage, edible fruits and leaf shoots, coppice material, wildlife habitat/forage, medicine, wine

Viburnum trilobum – Highbush cranberry

Range – North American native

Habitat – Stream banks, wet thickets, and moist woodlands

Primary uses – Wildlife/bird forage, edible fruits, hedge, ornamental, medicine

Gleditsia triacanthosHoney locust

Range – Eastern and North America

Habitat – Floodplains, riverbanks, pastures, fencerows, abandoned fields

Primary uses – Livestock fodder, windbreak, soil stabilizer, timber, coppice material, fuel, and sugar, edible seeds, pulp and pods
Morus – Mulberry

Range – Widely distributed throughout U.S. native to Asia

Habitat – Red Mulberry: rich woods, river valleys, floodplains, lower hill slopes, and rich moist soils. White Mulberry: fencerows, roadsides, abandoned fields, woodlands

Primary uses – Edible berries, juice, windbreak, livestock fodder, timber, bird forage




Quercus – Oak

Range – North American natives

Habitat – White Oak: mixed deciduous forest, sandy, gravelly, loamy soils

Northern Red Oak: valleys, ravines, lower and mid slopes of hill and mountains

Primary uses – Edible nuts, coffee, flour, timber, firewood, windbreak, insect repellent, coppice material, livestock/wildlife fodder



A
simina triloba
– Paw Paw

Range – North American native distributed throughout South Central and South Eastern U.S.

Habitat – River valleys, bottomlands, deep rich moist soils, understory

Primary uses – Edible fruit, insecticide, fungicide, timber, cordage

Pyrus communis – Pear

Range – Asian and European natives widespread throughout U.S.

Habitat – Woods, thickets, deep well drained calcareous soils

Primary uses – Edible fruit, timber, livestock forage, shelterbelt

Malus coronaria – Apple

Range – North American, Asian and European natives; widespread throughout U.S.

Habitat – Woods, hedgerows

Primary uses – Edible fruit, pectin source, hedge, pollinator, timber, firewood, rootstock, livestock fodder, wildlife forage


Prunus domestica – Plum

Range – Chinese, European and American natives; widespread throughout U.S.

Habitat – Praries, woodlands, pastures, roadsides, riverbanks

Primary uses – Edible fruit, hedge, windbreak, soil stabilizer, bee forage, medicine, timber, fire protection

Carya Ovata – Shagbark Hickory



Range – North American native; widespread throughout north east and mid west

Habitat – Rich woods, well drained bottomlands, dry upland slopes

Primary uses – Timber, firewood, charcoal, edible: nuts, oil, sap and syrup, windbreak, livestock fodder



Amelanchier – Serviceberry





Range – North American natives; widely distributed throughout northeastern U.S.

Habitat – Tidal stream banks, rocky slopes, barrens, open woods, waste areas

Primary uses – Edible berries, wildlife forage, windbreak, hedge, timber, basketry


Salix – Willow



Range – North American and European natives; widely distributed throughout U.S.

Habitat – Damp fertile bottomlands, stream edges, lake rims

Primary uses – Soil stabilizer, fiber, basketry, coppice material, biomass, fuel, rooting hormone, fire protection, timber, livestock fodder, medicine



Bibliography
Mollison, Bill (1993). Pig raising and free range forage species. Permaculture Paper #19 Yankee Permaculture

The New American Farmer, Profiles of Agricultural Innovation, SARE publication, 2002, p. 83-85, Walnut Meadow Enterprises, West Virginia

Working Trees for Agriculture (1999). USDA National Agroforestry Center

Photos: Flickr.com, National Agroforestry Center


Special Thanks

Mark Krawczyk and Mike Blazewicz from Burlington Permaculture






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