Collapse_ How Societies Choose to Fail or Succeed - Jared Diamond [139]
1. The site should have a large area of flat or gently sloping lowlands (at elevations below 700 feet above sea level) to develop as a productive infield, because lowlands have the warmest climate and longest snow-free growing season, and because grass growth is poorer on steeper slopes. Among Greenland Norse farms, the cathedral farm of Gardar was preeminent in its expanse of flat lowlands, followed by some of the Vatnahverfi farms.
2. Complementary to this requirement for a large lowland infield is a large area of outfield at mid-elevations (up to 1,300 feet above sea level) for producing additional hay. Calculations show that the area of lowlands alone at most Norse farms would not have yielded enough hay to feed the farm’s number of livestock, estimated by counting stalls or measuring areas of ruined barns. Erik the Red’s farm at Brattahlid was preeminent in its large area of usable upland.
3. In the northern hemisphere, south-facing slopes receive the most sunlight. That’s important so that the winter’s snow will melt off earlier in the spring, the growing season for hay production will last more months, and the daily hours of sunlight will be longer. All of the best Norse Greenland farms—Gardar, Brattahlid, Hvalsey, and Sandnes—had south-facing exposures.
4. A good supply of streams is important for watering pastures by natural stream flow or by irrigation systems, to increase hay production.
5. It’s a recipe for poverty to place your farm in, near, or facing a glacial valley off of which come cold strong winds that decrease grass growth and increase soil erosion on heavily grazed pastures. Glacial winds were a curse that ensured the poverty of farms at Narssaq and in Sermilik Fjord, and that eventually forced the abandonment of farms at the head of Qoroq Valley and at higher elevations in the Vatnahverfi district.
6. If possible, place your farm directly on a fjord with a good harbor for transporting supplies in and out by boat.
Dairy products alone were not enough to feed the 5,000 Norse inhabitants of Greenland. Gardening was of little use in making up that resulting deficit, because growing crops was so marginal in Greenland’s cold climate and short growing season. Contemporary Norwegian documents mentioned that most Greenland Norse never saw wheat, a piece of bread, or beer (brewed from barley) during their entire lives. Today, when Greenland’s climate is similar to what it was at the time that the Norse arrived, I saw at the former best Norse farm site of Gardar two small gardens in which modern Greenlanders were growing a few cold-resistant crops: cabbage, beets, rhubarb, and lettuce, which grew in medieval Norway, plus potatoes, which arrived in Europe only after the demise of the Norse Greenland colony. Presumably the Norse, too, could have grown those same crops (other than potatoes) in a few gardens, plus perhaps a little barley in especially mild years. At Gardar and two other Eastern Settlement farms I saw small fields at sites that might have served as Norse gardens, at the base of cliffs that would have retained the sun’s heat, and with walls to keep sheep and winds out. But our only direct evidence for gardening by the Greenland Norse is some pollen and seeds of flax, a medieval European crop plant that was not native to Greenland, hence that must have been introduced by the Norse, and that was useful for making linen textiles and linseed oil. If the Norse did grow any other crops, they would have made only an extremely minor contribution to the diet, probably just as an occasional luxury