Forests after Rome

In the Mediterranean, the Roman Empire (27 B.C.E.-394 C.E.) focused agriculture in the lowlands and protected the wooded uplands. But this broke down as the Empire declined, starting around 300 C.E. as large-scale lowland agriculture was abandoned in favor of small upland farms. Some historians have claimed that this caused the subsequent increase in forest clearing (removal of trees), with a need for more small farms, and more grazing animals like sheep and goats (which eat young trees and green shoots). However, others consider this conclusion something of an exaggeration, as it overstates the extent to which widespread forest use meant forest clearance. Even in the absence of government control and supervision, many forces limited the exploitation of woodlands. Wooded land is valuable and likely to attract the interest and protection of powerful people whether they are figures of authority or not, so dense forests and sizable woodlands would typically have been off-limits to random exploitation. Jobs like building ships and roofing large structures require big forest trees. Demand was low, since shipbuilding was pointless when commerce was virtually nonexistent, and large structures are more usually built when population is increasing and cities are growing. Even where demand existed, transport remained a problem. The high cost and difficulty of cutting down a great tree was negligible compared with the expense and challenge of moving wood overland from the forest where it was harvested to the shipyard or building site where it was to be used.

A factor that is harder for us to appreciate in an age when chain saws and wood splitters are widely available is the technological limitation on harvesting forest giants. Big trees contain many times the potential heat energy of small trees, but harvesting them and reducing them to wood that is useful for burning is a formidable task; the small hand tools that most villagers possessed were hardly up to the job. A householder was better off gathering and using small pieces of wood. For fires, fallen or hanging branches that had dried out over the course of a year or so were preferable.

Two forest management techniques that Roman writers on farming advocated continued to be widely used after the fall of Rome. They survived not because they were mandated but because they were practical methods of producing renewable supplies of the small-dimension wood that met the needs of farmers. These techniques, known as coppicing and pollarding, are occasionally still practiced today, and many Mediterranean forests still bear the marks of this kind of cultivation. The purpose of coppicing is to transform a single-trunked tree into a producer of multiple fast-growing branches that can be harvested periodically. Mature trees are cut to the ground then allowed to sprout multiple trunks. A coppiced woodland is typically divided into sections that are harvested on a rotating basis. The length of the rotation depends on the speed with which the trees grow and the use to which the branches are to be put. Fast-growing trees might be harvested every four years; slower-growing trees, like oak, might require a fifty-year rotation. Instead of big trunks difficult to harvest and slow to regrow, coppiced woods produce multiple small-diameter sticks and poles. Pollarding works on the same principle as coppicing, but trees that are pollarded are cut back to a main trunk rather than to the ground. Where wild or domestic animals graze in forests, the new branches that grow from coppiced trees at ground level are likely to be eaten. With pollarded trees the productive source of new growth is raised above the level where animals browse.

Neither deforestation nor upland erosion was widespread after the fall of Rome. Upland soils were enriched rather than depleted. Those who continued to live in the area appear to have adapted well to changed conditions. They relied on the time-tested technologies of simple, minimally destructive agriculture, cultivating olives, figs, and grapes and herding sheep. Grain, the largest Roman crop, continued to be raised on small plots or on flat areas cut out of the hillside shaded by olive trees or vines. This type of farming decreases erosion and surface water runoff. The sustainable agriculture that had characterized the region before the great Roman explosion once again served the inhabitants.