Cambridge Histories Online http://universitypublishingonline.org/cambridge/histories/ The Cambridge History of Early Inner Asia Edited by Denis Sinor Book DOI: http://dx.doi.org/10.1017/CHOL9780521243049 Online ISBN: 9781139054898 Hardback ISBN: 9780521243049 Chapter 2 - The geographic setting pp. 19-40 Chapter DOI: http://dx.doi.org/10.1017/CHOL9780521243049.003 Cambridge University Press The geographic setting The areal extent and diversity of the natural landscapes of Inner Asia impel a survey of the geographic background of this region to concentrate on the environmental characteristics which seem to contribute most to an under­ standing of the even greater complexities of the human use of these lands. To this end, attention will be focused initially on five general geographic features of Inner Asia: its size; the effects of distance from maritime influences on movement and climate; the problems of its rivers; geographic diversity and uniformity; and, the limited capabilities for areally extensive crop agriculture. This will be followed by a discussion of the major environmental components of the natural zones of Inner Asia. General geographic characteristics The Inner Asian region occupies an immense area in the interior and northerly reaches of the Eurasian land mass and encompasses a territory of more than eight million square miles or about one-seventh of the land area of the world. The east-west dimensions of this region extend some 6,000 miles, which is slightly more than twice as long as the maximum north-south axis. These distances are comparable to those traversed by only a few of the most adventurous maritime vessels in the European "Age of Discovery." Within Inner Asia, however, the pre-eminent means of long-distance communication has been overland movement inasmuch as no region on earth is as landlocked by the absence of feasible maritime alternatives. The major movements of peoples, cultural innovations, and goods has been on Inner Asian land routes far removed from the Pacific, the ice-covered Arctic and the Indian Ocean.1 In the European portions of this region, substantial use has been made of Black 1 It might be noted, however, that parts of the early Silk Road traffic was channeled through Indian Ocean ports. See Boulnois, 1966, pp. 40-60. 19 Cambridge Histories Online © Cambridge University Press, 2008 Downloaded from Cambridge Histories Online by IP 128.103.149.52 on Thu Jan 30 15:48:10 GMT 2014. http://dx.doi.org/10.1017/CHOL9780521243049.003 Cambridge Histories Online © Cambridge University Press, 2014 20 The geographical setting Sea and Caspian Sea routes, but this has been confined essentially to the margins of Inner Asia. In addition to the limited role of maritime routes, the use of rivers as an alternative to land movement has been constrained by a number of serious problems. The most obvious of these is the absence of navigable waterways over a large part of the arid and semi-arid zones. Moreover, the extensive areas of interior drainage in Inner Asia extending from the Caspian Basin in the west to the Khingan ranges in the east do not provide a river approach to the world ocean. Unfortunately, some of the rivers which reach oceans flow in directions which scarcely are conducive to a major transport role. The most important examples are the massive rivers of Siberia, including the Ob-Irtysh, Yenisey, and Lena systems, which empty into the Arctic Ocean, which is ice­ bound most of the year. Even the eastward flowing Amur bends to the north rather than the south at Khabarovsk and flows into the Taiga rather than southwards through the fertile Ussuri-Khanka lowlands which terminate at the excellent natural harbors of Vladivostok and Nakhodka. Fortunately, the northward flowing Ussuri River tributary of the Amur passes through these lowlands. To a considerable extent, movement in the Siberian and European portions of Inner Asia has been able to compensate for these directional debilities by use of land routes between river systems. Relatively short portages connected the long, latitudinally oriented tributaries of the major north-flowing Siberian rivers to form east-west avenues of movement. Although the limited navigational season on these rivers, ranging from six months in southern Siberia to only three months in the northern parts, also was a serious handicap to transportation, pathways formed by the frozen surfaces of rivers frequently were used for overland type movement. West of the Urals, the rivers of the Volga Basin draining into the enclosed Caspian Sea are linked to the other river systems flowing through the Russian Plains by easily traversed land routes. The Volga, however, is blocked by ice from three to five months a year. By contrast, passage through most of the extensive interior zone of arid and semi-arid lands could not employ river and portage routeways and overland transportation had virtually unchallenged pre-eminence. Fortunately, the grasslands of Inner Asia have few natural obstacles to movement. In many ways, the elongated steppe zones, the isolated oases, and the major mountain passes and corridors of Inner Asia have been the overland equivalents of ocean routes, ports-of-call, and canals. From a different point of view, the modest importance of maritime influ­ ences and the northerly latitudes of Inner Asia have a far-reaching effect on its Cambridge Histories Online © Cambridge University Press, 2008 Downloaded from Cambridge Histories Online by IP 128.103.149.52 on Thu Jan 30 15:48:10 GMT 2014. http://dx.doi.org/10.1017/CHOL9780521243049.003 Cambridge Histories Online © Cambridge University Press, 2014 General geographic characteristics 21 climate. This region is characterized by the highest degree of continentality on the surface of the earth, which means that the greatest differences in average temperatures between cold and warm seasons are encountered here. The winters in most of Inner Asia are cold or extremely cold and the summers are either warm or hot. The distance from oceans in conjunction with mountain barriers has impeded the flow of maritime air masses and has led to a pervasive deficit of moisture in the parts of Inner Asia south of the forest zone. To make the aridity and temperature problems worse, the interior portion of the Eurasian land mass is the site of the annual winter appearance of a massive and stable zone of high pressure centered on Mongolia which brings clear skies, sub-zero temperatures, and precipitation-free weather. Dry and cold winds emanate from this high pressure ridge and influence the winter weather of a large part of Inner Asia. As could be anticipated from an awareness of the imposing physical dimensions of this region, Inner Asia embraces a wide variety of physical- geographic landscapes between the barren deserts and snow-covered peaks on its southern margins to the desolate, tundra-fringed shores of the Arctic Ocean in the north. The forests, steppes and deserts, which are separated by transitional areas, are aligned in broad, latitudinally oriented natural zones. It is difficult to imagine two areas which differ more in appearance than the waterlogged forests of the West Siberian Taiga and the bare sand dunes of the Taklamakan desert. In addition to locational factors, the geographic diversity of Inner Asia is intensified by the effects of mountainous terrain. The broad ecological zonation of the natural features distributed over geographic space is encoun­ tered on a condensed vertical scale in the mountains of this region where altitudinal differences in vegetation, soils, and moisture combinations replace the latitudinal variations in natural zones. The northern ranges of the eastern T'ien Shan exemplify the vertical zonation of landscapes.2 On the windward, or northern slopes of these mountains, the steppe grasses on the lower slopes are found up to elevations of 1,600 meters where they mix with scattered stands of trees. This pattern is replaced farther up the slopes by a solid band of coniferous trees which continues up to the tree line of 2,600 meters. Above that elevation, the vegetation cover begins to diminish and changes from alpine meadows to a zone of barren rock and primitive mountain soils above 3,600 meters which is covered by a permanent cap of snow on the highest peaks and ridges. On the dry leeward, or southern side of these same ridges, 2 Institute of Geography, 1969, vol. 1, pp. 236-7. Cambridge Histories Online © Cambridge University Press, 2008 Downloaded from Cambridge Histories Online by IP 128.103.149.52 on Thu Jan 30 15:48:10 GMT 2014. http://dx.doi.org/10.1017/CHOL9780521243049.003 Cambridge Histories Online © Cambridge University Press, 2014 22 The geographical setting deserts rise up the slopes to elevations comparable to the start of forests on the opposite, windward side. These high-altitude deserts yield to subalpine steppes and eventually slopes devoid of vegetation. In addition to the formation of vertically layered natural zones and, of course, the striking differences in relief caused by mountains rising far above adjacent basins, the mountains of Inner Asia have added to the geographic variety of this region by contributing to the formation of the commonly encountered landscapes in the dry zones in which verdant oases on rivers flowing down from adjacent mountain ranges stand in sharp contrast to surrounding deserts or steppes. This type of landscape is most evident on the margins of the Tarim Basin, the plains of Zungaria next to the northern slopes of the T'ien Shan, and on the loessial piedmont plains which fringe the southern mountain borders of Central Asia. The oases of Inner Asia depend primarily on the mountains for their water lifelines. When air masses which yield little or no precipitation over the plains rise over the windward slopes of mountains, they cool and acquire a lower saturation point which often leads to heavy precipitation on these slopes and in the core of the mountains with relatively little precipitation on the leeward side.