The dehesa is a landscape of beautiful harmony. Holm oak and cork trees, grasses, and aromatic plants thrive in an ecosystem maintained by humans for many centuries as a foraging ground for cattle, sheep, fighting bulls and Ibérico pigs. It is also an especially important reserve for aromatic plants such as thyme or rosemary and a wide variety of wild mushrooms. This exceptional habitat provides a natural and balanced diet to the Ibérico pig, key to achieving the sensory quality of Jamón Ibérico de Bellota.
In ancient times a huge Mediterranean forest once stretched over vast portions of Spain. Over the millennia much of the forest was cleared, but a large portion still survives called the dehesa. This ancient rangeland coveres 20,000 square kilometers of southwestern Spain.
This pastureland dotted with holm oak and cork trees forms a unique bio-diverse ecosystem, which covers almost five million acres of western Spain and Portugal. Each tree takes between 30 and 40 years to grow to maturity and can live for hundreds of years.
Source: https://www.jamon.com/pig-raising.html
This is the area on which the Black Iberian pig feeds on acorns a minimum eight months before slaughter and from which the famous and exclusive jamón ibérico de bellota (bellota = acorn) comes. Dan Barber, the American chef and food author writes about this unique region in Spain in his inspiring book, ‘The Third Plate’.
The dehesa system originated during the Middle Ages. By 1300 the Reconquista of Spain had reclaimed the area of Extramadura from the Muslims, and the uncultivated landscape represented thousands of miles of potential pastureland for the Merino sheep. The influx of livestock prompted the destruction of the area’s thick forests, resulting in the spase oak population that can be seen today. The word dehesa comes from the Latin defensa (defence) as the peasant farmers built stone walls around the sheep’s grazing area to protect against predators.
These sheep were so integral to the dehesa system that when the price of wool fell, milk replaced the wool. Eventually cheaper competition from the New World undermined the industry and the lucrative Spanish wool indstry collapsed. However, sheep are still reared and two sheep’s-milk cheeses are still produced from the area – the Torta del Casar (“gamy, acidic and somewhat smoky flavour”) and La Serena. However, as Barbar says, “The investment in the dehesa’s ecosystem did not stop paying dividends. It adapted to the changing times with other breeds of animals – especially the black Iberian pigs, which were equisitely suited to the land.”
However, not all went smoothly. According to Svein Inge Meland in his article, ‘How a black pig created an entire industry’,
The 20th century was a painful century for both the Iberian pig and its oak forests. When the country switched to industrial meat production, many of the oak forests were cut down and turned into fields for grain cultivation for animal feed. In the 1960s, the Iberian pig population was afflicted with African swine fever, a viral disease.
Iberian ham and sausage production stayed small-scale and local, with limited availability. By 1980, the pig population had shrunk so much that authorities initiated a rescue operation. At the same time, UNESCO started a programme to save what was left of forest pastures in Europe. In southwestern Spain, the old oak groves (dehesa) were decimated by illegal logging.
In the 1990s, the EU allocated funding to replant oak forests in the province of Badajoz, and in 2002, UNESCO and the Spanish authorities created a biosphere reserve in the Sierra de Aracena, providing protected status for large forest pasturing areas.
The rescue operations for the Ibérico pig and oak grove pasturelands laid the groundwork for industrializing Iberian pork production after 1990. The capacity of the oak groves puts clear limitations on the production quotas of pure-bred pigs that can fatten up on acorns. These animals account for the most exclusive and expensive cured ham. Only five per cent of Ibérico production attains this top quality classification.
“The pure-bred Iberian pig, with a black label, tops the list. For at least 60 days before slaughter, a pig herder takes the pigs to the oak groves where they feed exclusively on acorns, mushrooms and herbs. The exercise they get is important for the quality of the meat. After salting and drying, the ham ages for up to four years…”
Barber describes the raising of the black Iberian pigs in more detail:
“Up until the fall, the Iberian pig feeds on grass, seeds, and grain naturally found in the dehesa – just enough calories to grow larger but far fewer than in conventional operations. By late October they’re ravenous, which conveniently marks the beginning of the montanera phase, roughly between November and March, when the acorns have fallen from the trees. In the space of four months, the pigs gorge enough to put on 40 percent of their slaughter weight, acquiring a band of fat as thick as a down comforter”.
There are two common types of oak trees in the dehesa – the holm oak and the cork oak. The holm oaks produce the sweeter acorn – the pigs’ preferred meal – but cork oaks produce later in the season, extending the supply. Both acorns are unique for their large size, which is another plus in terms of the dehesa’s ecology. The original intent for spacing of the oak trees may have been to provide shade cover, but Barber explains it also enabled the development of deep root systems. Withput competition in terms of soil nutrients and water, the latter being a scarce resource, the oaks grow to be enormous and robust, producing larger and sweeter acorns. To promote even more production, they trees are periodically pruned.
The pigs are forced to move from tree to tree with mouthfuls of grass along the way, and this represents intense exercise for the animal, and it is the exercise that creates oxygenated muscles and thus the deep flavour associated with jamón ibérico. Excercise also creates space within the muscles for fat deposits – it is this space and the muscle mass itself from all the exercise that enables the meat to integrate the oleic acid from the acorns. Seventy percent of the fat is unsaturated, which sometimes leads to the pigs being referred to as “olive trees on four legs”.
There are also cows local to the dehesa, the relatively unknown Morucha breed. These cattle were once used as fighting bulls, and since they originated from the Black Iberian cattle, they have evolved to forage on the dehesa. As Barber states, “The cattle are constantly in motion whch, just as with the Iberian pigs, oxygenates the muscles and yields bold, flavorful, meat, darker than most steaks”.
At the centre of the dehesa economy are the oak trees – not the acorns but the cork. The bark is carefully stripped from the tree trunks, and nearly a quarter of all wine corks in the world originate from the dehesa.
Barley, oats and rye are also grown which cuts down on the import of feed for livestock. Also dissecting the open pastures are thick forest stretches that are thinned out appropriately for the charcoal production industry.
The regenerative grazing aspect of the dehesa
Without the pigs moving, the grasses between the trees would suffer. THe pig eat just some of the grass, which represents a collateral feast on their way to the next targeted acorn tree. The cattle follow behind the pigs and it is they who do the real grazing given that they’re herbivores. After the pigs and the cattle, the sheep eat the leftovers i.e. the grasses that the other animals either don’t want or can’t get at on account of the size of their mouths.
All this grazing actually improves the grass as the manure – spread out by the abundant wildlife – fertilises the grassland. The trampling of the hooves also helps to break down materials such as fallen leaves. Returned to the ground, this organic matter helps to sustain the billions of soil organisms and conspires to make as Barber calls it “the famously delicious assortment of grasses”. It’s the variety that is key to the health of the animals, and to the larger ecosystem in general. All this grass diversity increases the numbers of insects, such as butterflies, ants and bumblebees, which in turn supports the animals that prey on these insects, such as lizards and snakes. There is also an abundand wild bird population – e.g. red kites, booted eagles and short-toed eagles – that all provide a built-in insect and rodent population control.
