Vegetation

Climbing to higher altitudes in the Mediterranean produces effects comparable to traveling northwards toward the Arctic, passing out of Mediterranean into temperate, then continental and finally to subarctic climates (Admiralty 1944, Bintliff 1977, Rackham 1983, Kautzky 1993). Average annual temperatures decline, and although summers can be hot they are milder than in coastal lowlands; autumn, spring, and winter are colder and rainier; finally, winter frost and snow increase with height above sea level. The position of the uplands relative to rain-bearing autumn and spring Westerlies modify these effects, also true for the winter cold climate cells which derive from the Balkans. Thus when traveling west and north from the Mediterranean climate zone of the Southeast Mainland coast and its offshore islands, or merely inland and up into the hill land and then mountains, we observe a succession of natural vegetation zones which are related to the main vegetation zones of Europe from its far south to its far north.

Evergreen trees (oaks, olives) give way to mixed evergreen and deciduous trees and shrubs, then deciduous vegetation is gradually displaced by hardy coniferous trees, until finally in the highest or rockiest mountain peaks trees decline and Alpine grasses and low plants dominate. However, this is a picture of typical conditions throughout Greece in the middle of an Interglacial period, and for the Holocene this has been much modified by human impact.

Since people colonized the Greek landscape in large numbers, from the Late Neolithic (ca. 5000 Bc), they have modified natural vegetation to assist their farming-herding economy, whilst from the mature

Figure 1.4 The vertical zonation of crops in the Mediterranean lands.

J. M. Houston, The Western Mediterranean World. London 1964, Figure 28. Courtesy ofJ. M. Houston.

Iron Age onwards (ca. 800 bc) intensified mining and timber extraction has increased human impact. In some regions and periods in the past, natural woodland disappeared or was reduced to a patchwork amid a landscape of fields, pastures or mere wasteland. Photographs for much of Greece from the late nineteenth to early twentieth centuries frequently portray treeless, almost lunar landscapes. Fortunately the Greek government in recent decades has implemented increasingly effective reafforestation and woodland preservation programs. Redirection of the economy away from extensive sheep and goat raising has dramatically allowed uplands to regenerate tree cover. European Union agricultural policies, and internal pressure to focus Greek farming on highly commercial forms of land use, are also creating divergent paths in the previously cultivated landscape. Open lowlands and areas with plentiful pumped irrigation water are now intensively farmed throughout the year for multiple crops. In contrast, vast areas of hill country where motor and irrigation access are restricted, and fields small, are swiftly reverting to scrubland and bushes. Areas suitable for archaeological landscape survey are increasingly confined by this polarization of land use.

However, human impact from later prehistoric times onwards has always been regionally diversified,

As the “agropastoral” (farmer-herder) economy adapted to local climate and topography (Figure 1.4). In the lowlands and hill lands, to several hundred meters above sea level, natural Mediterranean evergreen woodland, alternating with dry steppe and shrubs where stoniness or aridity prevented tree cover, has become a cultivated “woodland” of evergreen olives, figs, vines, and (after Medieval importation) citrus fruits. Natural grasses and bulbs have been replaced by the favored bread grasses wheat, barley, and the root crops beans, lentils, and melons. From the sixteenth to seventeenth centuries AD onwards, the versatile exotic maize and exotic commercial shrubs cotton and tobacco spread widely. In the cooler hill lands, fruit and nut trees, which were a natural component of the European mixed deciduous-evergreen vegetation, have been favored, such as apples, whilst the milder, wetter climate suited native vegetables and Early Modern imports such as potatoes. In the higher uplands more open landscapes due to climate, culminating in high level grass-bulb landscapes, have been drastically enhanced by human clearance (by fire, axe, and grazing) to make pasture-lands, where cooler summers compared to the lowlands have encouraged specialist herders to bring seasonally transhumant domestic flocks.

Vegetation

The zonal vegetation map of Greece (Color Plate 1.4) demonstrates that topography, geology, and climate collaborate to produce a clear trend in the distribution of typical natural vegetation during a warm period such as our current Interglacial. The drier coastlands and islands, mainly in the South and especially the Southeast, display Mediterranean evergreen, drought-resistant plants. If unaffected by fire, grazing, and cultivation (a minority of the landscape!) one would find savannah or woodland composed of trees like evergreen oak, Aleppo pine, and wild olive. Moving away from the Southeast Mainland coasts and islands, north and west, higher rainfall and often higher relief support mixed Mediterranean evergreen and deciduous woodland species, deciduous oaks, beech, and chestnut. Such mixed vegetation would in the natural state typify higher land in the South and much of the lower land in the North. Within the great upland zones which constitute Mainland Greece’s rugged interior, Mediterranean vegetation disappears and we find deciduous and increasingly with altitude more continental tree species, such as hardy conifers, the latter dominant as we ascend the mountains. Even without human interference there would be small zones in the uppermost mountain belts with Alpine, non-tree grassland and other low plants. Given the fact that in Greece one can move within a short distance from the dry coastland up into fringing mountains, it is often possible in many parts ofGreece to walk in a day from Mediterranean evergreen brushland through deciduous, then coniferous, woodland and see ahead the bare Alpine-plant zone on the crests of the mountains.

A Alpine vegetation zone D B Mediterranean montane forest zone C Deciduous forest zone

D Deciduous forest zone with elements of evergreen forest E Eu-Mediterranean evergreen forest zone

Cover was first removed on a large scale by later Neolithic and Bronze Age times, and the cultivable landscape is considered to have already possessed its Early Modern appearance by Classical Greek times (Bintliff 1977, 1993): a mosaic of open land (dominated by grain crops) and cultivated olive and fig orchards and vineyards. In place of woodland, where agriculture is not found, human impact by fire and grazing, or natural climatic aridity, give rise to three levels of sub-woodland vegetation, in decreasing order of size and ground surface cover (Rackham 1983): degraded evergreen woodland becomes low shrubland (“maquis”), predominantly prickly oak bushes. More heavily degraded land, or where bare rock is very prominent, supports thin grassland mixed with spiky plants (“steppe”). Finally in the least vegetated zones, the result of maximum human impact or the dominance of bare rock, we find very low, widely-spaced “phrygana” or “garri-gue” vegetation, notable for aromatic fragrances and valued by bees and humans for nourishment and cuisine respectively (sage, thyme).

Pollen analysis documents the evolution of vegetation in Greece, taken from lake and coastal corings. A prediction for a warm epoch or Interglacial, such as our Holocene period, without human interference, comes from a deep boring at Philippi in Northeast Mainland Greece which covers the last million years (Wijmstra et al. 1990). A warm, wet early phase, with mixed deciduous and evergreen open woodland, would by mid-interglacial in the lowlands give way to a drier Mediterranean climate, encouraging denser evergreen woodland, then be succeeded, as the era moves toward a new glacial, by a cooler and wetter climate encouraging a rise in deciduous vegetation. This reconstruction agrees with early-mid Holocene pollen cores from the drier Southern Greek climate. Here Bottema (1990) noted increasingly drier climate through the early farming eras of the later Neolithic and Bronze Age, in Middle Holocene times (more pronounced from 5000 to 4000 Bc), then a postulated rise in rainfall, or aridity decline, in Late Holocene times (from the Iron Age on, ca. 1000 Bc). Nonetheless, since the Middle-Late Holocene era coincides with several phases of major human impact on the landscape, through woodland clearance and the expansion of cultivated crops and managed grazing, it becomes difficult to separate out vegetational changes due to climate and those under anthropogenic (human-inspired) influence. Combinations of natural and human factors, as with soil erosion, seem preferable to comprehend Greek landscapes for these recent millennia (Rackham 1982, Atherden and Hall 1994).

From the Bronze Age till Medieval times, the natural climate seems to have been mostly warm and dry. The Mesolithic hunter-gatherers (see Time Chart in Introduction) would experience the rather different climate of the early interglacial model, whilst the Neolithic farmers would experience a transition to increasingly drier conditions. Although the Earth had probably not begun to shift definitively toward a late interglacial climate, before human-induced Global Warming overrode any natural cyclical patterns, climatologists argue that during the last 2000 years the Earth has experienced several shorter phases of wetter, colder climate. The classic example is the Little Ice Age between Late Medieval and Early Modern times (Bintliff 1982, Grove 2004). Furthermore, within the warm, dry mid-interglacial mode, and the early wetter but warm mode, climatologists have also identified large-scale episodes of intense drought, around 6200 and 2200 BC, both considered as particularly significant for the Eastern Mediterranean region (Weiss 1993, Rosen 2007).

The vegetation of the Aegean has certainly altered over the last 10,000 years, in the first place responding to global climatic changes. These changes form longterm cycles, over which are superimposed smaller interruptions. Human impact, through progressive clearance, but also cyclical, as human populations waxed and waned, are a further factor impacting on the degree of natural vegetation and its type, but we now see that visible alterations may be as much due to natural as to anthropogenic causes, most frequently it seems a combination of these.