Agroforestry in Argentine Patagonia
Agroforestry in Argentine Patagonia
Agroforestry is relatively common in Argentina, due to both wood scarcity and a climate favorable to many tree crops. Patagonia is a vast expanse of forests and grasslands that stretches across the southern cone of South America, on both the Chilean and Argentine sides of the Andes. Precipitation falls as rain and snow, but ranges from 8 to 45 inches per year on the Argentine side, to 80 inches in Puerto Montt, Chile. Fruit and meat are abundant, but so too are fires.
Three core takeaways:
Silvopasture makes a lot of economic sense, because wood is expensive.
Windbreaks are common and useful.
Apples, cherries, and walnuts produce large crops with minimal pest management.
Hybrid poplar windbreaks tower over the irrigated fruit growing regions of the Patagonian steppe.
The agricultural context:
Climate: Patagonia ranges from a hospitable Temperate oceanic climate with ample precipitation and dry air (Cfb), to a hostile cold semi-arid climate (BSk) where evaporation often exceeds rainfall. Politically, Argentina is dynamic, to say the least. In the 20th century, the country saw 80 years without a democratic change of power from one political party to another, and periodic hyperinflation is common. Rural salaries are roughly 25% of what they are in the United States, and we could compare the standard of living in rural Patagonia to that of Rural New England or Rural New York State in the late 1960’s.
Geography: Soils range from sandy and gravelly to loamy, with low clay content. Far away from markets with a high willingness to pay, Patagonia is sparsely populated, with 2-3 million people in total, compared to 55 million in the Northeast United States, and 22 million in the Pacific Northwest.
Water: Precipitation varies drastically, and irrigation for trees and livestock is often a constraint. Ponds are less common than stock tanks. Massive dams in the dry regions serve to flood-irrigated river valleys full of fruit, forestry, cereals, and livestock.
Access: Main highways and downtown roads are paved, with rural roads in Argentina similar to the lower-standard dirt logging roads of Maine or Vermont.
Forestry: Wood is 5-6x as expensive in rural Patagonia as it is in rural New York, so it makes much more economic sense to plant and manage trees for lumber. With the dry air, apples and stone fruit thrive, and walnuts and European chestnuts consistently produce heavy crops.
Windbreaks
Dry winds rip across the Patagonian steppe. In regions such as Neuquén, they desiccate fruit crops, and a windbreak will increase the yield of Grade A fruit by 19%. Windbreaks mainly consist of hybrid poplar, which is also harvested and sawn into lumber for crates, pallets, and furniture. Producers also plant black locust windbreaks, known there as white acacia. The locust windbreaks are eventually harvested for fenceposts. Black locust is not viewed as aggressive in Argentina, and doesn’t raise much invasion concern. Thorned honey locust, spread by cattle, is despised and labeled as invasive.
A black locust windbreak in El Bolsón, on Chacra Humus, a organic farm that produces organic dairy and a large variety of fruit that flavor their ice cream. This windbreak is grown first for wind protection, and second for fenceposts.
A windbreak’s effectiveness is a function of its height and its density. Protected wind speed is expressed as a percentage of unprotected, open wind speed, at different distances downwind from the trees. We can expect wind protection at 5-15x the height of the trees, down wind. Denser windbreaks generally provide more protection, though a permeable coniferous windbreak is more effective than a solid wall, given that the air mass leaps up-and-down over a wall. We can benchmark deciduous windbreaks at 50% density, and coniferous windbreaks at 70% density, with a solid wall being 100% dense. Here, the coniferous windbreak will provide 30% better wind protection than a deciduous windbreak, at a distance of 10x the height of the trees, if the trees are the same height. Another way to look at this is: even though coniferous windbreaks are more effective at maturity, hybrid poplars and black locust trees grow faster and taller, compensating for their reduced density.
Silvopasture
Where sawlogs from natural forest are scarce, planting hybrid poplar makes economic sense, especially when it can shade livestock.
Silvopasture is the intentional aggregation of trees, forage, and livestock. Timber trees such as hybrid poplar and various conifers are a common overstory for livestock, sheltering cattle and sheep from intense sunlight, wind, heat, and cold. Silvopasture usually amounts to thinning existing forest to allow forage to grow or adding trees to pasture, but most notable in Argentina is establishing both trees and pasture at the same time. Planting trees as a long-term timber asset makes more sense here, because wood is scarce expensive.
The most potent comparison we can make between rural New York and rural Patagonia is the number of hours a laborer would need to work in order to buy firewood or lumber. Douglas Fir lumber in El Bolsón is priced at $1.40/board foot, compared to $1.00/board foot in the United States, or 40% more expensive. However, with a rural labor rate of $5/hr vs. $20/hr respectively, a laborer would need to work 5.6x as many hours to buy the same wood. As a result, using small diameter pole wood is much more common in Patagonia.
Culturally, cattle ranching is a mainstay of the region. Organizations such as Ovis 21 and Ruuts help ranchers utilize Holistic Planned Grazing, which drastically increases productivity. Silvopasture, the incorporation of trees, forage and livestock, takes the form of planned grazing in forest plantations. The practice is seen as agronomically advantageous, outside of any ecological impetus.
Fruit
Apples, Persian walnuts, and peaches all originated in Western and Central Asia, where the air is dry. Apples, cherries, and plums grown in New York State are faced with bacterial and fungal pathogens that thrive in humid air, but the humidity of Patagonia enables extraordinary fruit production, along with small walnut and European chestnut industries. In the same vein as lumber being time-expensive in Patagonia, food is currently expensive relative to wages. Hence: it makes more sense to grow your own food.
Ecological Succession and Native Fruits of Patagonia
Understanding the agroforestry context of a place wouldn’t be complete without a review of native fruit trees and forest dynamics. Native pioneer species largely consist of large woody shrubs. Three nitrogen fixers, specifically Discaria chacaye, Colletia hystrix, and Retania trinervia, all have spines and thrive in poor soil. Willow, poplar, and black locust fulfill their usual niches in Patagonia, and they are neither native to the region nor vilified for being foreigners. There is much more discontent around honey locust (Gleditsia triacanthos) and sweet briar (Rosa eglanteria).
Native fruits mostly consist of small berries, many with spines as well.
Calafate (Berberis microphylla), pronounced cah-lah-fah-tay is a barberry that produces small, sweet blue berries. Similar to Saskatoon, Saskatchewan, the city of El Calafate is named after the berry. Local legend says that those who eat the berry will return to Patagonia.
Michay (Berberis darwinii) is another barberry, with a flavor more sour than calafate.
Maqui (Aristotelia chilensis) is another dark purple native fruit, used in jams and ice cream.
Parilla (Ribes magellanicum) is a native currant, and is tolerant of moderate shade.
Murtilla (Ugni molinae) is a berry that grows abundantly on the Chilean side, and is more common as you hike into the mountains.
Luma (Amomyrtus luma) is a myrtle with tasty fruits, and is moderately shade tolerant.
Pitra (Myrceugenia exsucca) is a small tree with edible but seedy berries, also moderately shade tolerant.
Chaura (Gaultheria mucronata) is a native wintergreen.
Calafate seems to be the most appealing. It is rare in North America, though it has been imported.
Challenges and Conclusions
These beautiful windswept forests come with massive fires. This year, the summer dryness and intense winds (and talk of arson) brought the Confluencia fire to burn 9,000 acres outside of El Bolsón, and 30,000 acres throughout the region. Planning for fire and protecting against it is a gargantuan task. Public infrastructure is important, but may not be dependable. Land planning with adequate water infrastructure is vital, but expensive. A topic for another day: The Regrarians Handbook dives into fire protection in Chapter 3: Water. Author Darren J. Doherty, an Australian, is passionate about planning for fire.
Learning from different climates helps us understand our own. Both the abundances and challenges of elsewhere can help us manage and plan our own society and farms should they reach such extremes. Australians must manage fire and poisonous animals but have very mild winters. The English fear famine but have excellent access to capital. Argentines have abundant fruit and meat, but their county exudes beauty and chaos simultaneously.
Sometimes, some grass is greener. Argentine Patagonia shows us bottomless stock tanks, great windbreaks, extensive irrigation canals, silvopasture, and above all: persistent and pervasive creativity. We cannot bring plants with us through customs, but we can bring ideas.