For that matter, the population history of the Czech Republic has been characterized by decline, or at least by a rate of population growth never able to make up for the losses of the Second World War. The Czech population reached its post-1945 peak population in 1991 of 10.3 million people, but even there there were still 300 thousand fewer people living in the Czech lands than in 1930. War casualties and the Holocaust played a role, but not much of one since the Czech lands were lightly touched by the Second World War. By far the most important reason for the Czech population shortfall is the expulsion of the Sudeten Germans after the Second World War, as punishment for the almost three million Germans' enthusiastic support for the Nazis and in revenge for their unhappiness with their inclusion in the Czechoslovak state after the collapse of Austria-Hungary. As Philipp Ther notes in his review of Nationale Frage und Vertreibung in der Tschechoslowakei und Ungarn 1938-1948: Aktuelle Forschungen,
the six years of German occupation in the Czech lands [. . .] resulted in "total exclusion and total separation." Although the occupational regime was less harsh than in Poland and in Serbia, it still created such hatred against Germans that the vast majority of Czechs demanded their expulsion to Germany. In his article, Suppan implicitly criticizes the position of prominent Sudeten German historians. He does not demand an explanation by the Czechs as to why they expelled the Sudeten Germans, but instead he explains the change of attitudes among Czechs during the war which caused the expulsion.
[. . . In] Czechoslovakia, where almost 6 million hectares of land, 11,200 factories, and 55,000 small businesses were dispossessed. The property of the expellees fell into the hand of the states that "transferred" them. This gave the new regimes in East Central Europe ample possibilities to build up political allegiances among the populace and to transform society.
The expulsion remains an active issue in the Czech Republic and between the Czech Republic and Germany, but the assimilation of the Sudeten Germans into post-War West German society has mostly neutralized the issue. Its legacies remain in the Czech lands, where regional population statistics demonstrate that the effects of the deportation were not uniform across the Czech lands. The region of Moravia, for instance, saw a slight increase in its population over its 1930 peak. The former Sudetenland, located in the north and west of Bohemia adjacent to Germany, is particularly underpopulated, never having regained its previous heights.
Under Communism, northern Bohemia not only became a major industrial centre, but it gained fame as one of the most heavily-polluted areas of the world thanks to policies which maximized energy consumption and industrial production at the expense of the natural environment. The summary of Eagle Glassheim's 2004 presentation paper "Ethnic Cleansing, Communism and Environmental Devastation in Post-War Czechoslovakia" (Word format) raises interesting issues as to why northern Bohemia fared so badly.
Some observers have suggested a link between the expulsion of the Sudeten Germans and the subsequent environmental devastation of the region. Writing under a pseudonym in the 1980s, the dissident Petr Príhoda argued that new settlers lacked a sense of place. In contrast, the long-established Sudeten Germans had held strong regional identifications, tied closely to the built and natural landscape (their "Heimat" or homeland). According to Príhoda, Czech newcomers were alienated from the land and each other, allowing easy control by a Communist Party intent on exploiting the region’s natural resources and industry, regardless of the human and environmental costs.
[. . .]
Contrary to Príhoda, I have found that a strong regional identity did develop in north Bohemia during and after resettlement in the latter half of the 1940s. In contrast to Sudeten German romantic, pastoral and historical visions of homeland, however, Czech settlers and settlement officials stressed a modern, production-oriented, materialist identity. Rather than a lack of solidarity and identification, then, it was these new visions of an industrial landscape that contributed to the region’s infamous environmental mess in the 1960s and beyond.
Glassheim concluded that northern Bohemia became such a mess not because the Czechs who resettled the area were unattached to the land, but because the land was presented as a space where industrial modernity could operate untrammelled by tradition, as a site for mass production and mass consumption regardless of the human and environmental cost.
Northern Bohemia after 1945 was a tabula rasa for Communism. It will be interesting to see what this region, with its new history and the cautious relationship to its old one, will become in the context of a uniting Europe even now that its inclusion within the Czech lands is beyond any doubt.