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Analysis of Land Use Change: Theoretical and Modeling Approaches
Helen Briassoulis, Ph.D.

2 BRIEF HISTORICAL OVERVIEW OF STUDIES OF LAND USE CHANGE

2.1. Introduction
2.2. The early period -- von Thunen and George Perkins Marsh
2.3. The first half of the 20th century
2.4. The other (last) half of the 20th century
2.5. The new millennium


2.1. Introduction

The first thing people ever used to meet their needs was land – to move around, to rest, to settle, to feed themselves. Hence, the relationship of people with land has the same origin as their appearance on earth. But the widespread concern over this relationship expressed in diverse scientific quarters since ancient times focuses on its negative facets – either the adverse effects of human activities on land and environmental resources or the adversities humans experience due to constraints and hazards originating in land and the environment. As a full-blown historical review of this relationship is beyond the scope of this contribution, this chapter overviews briefly studies of land use change over time and across space with the purpose of providing a backdrop for the examination of the evolution of the theoretical and modeling approaches to land use change which is the core subject of this project. The changing modes of theorizing on and modeling land use change are paralleled to two broad streams of changes; first, in the conceptualization of land and land use which are affected by changes or differences in socio-cultural values, technology, economic organization, and magnitude of environmental problems associated with land use change, among others; and, second, changes in the modes of theorizing and modeling in the disciplines of the natural and the social sciences that engage in the study of land use change.

The present overview covers mainly studies of global, regional (in particular countries or in groups of countries) and local (in particular places within countries or in natural areas) land use change of the last 150 years of the second millennium. For the purposes of this presentation, three time divisions are introduced: (a) the "pre-industrial" period, (b) the first half of the 20th century, and (c) the second half of the 20th century. A perspective on the third millennium is based on current trends and expectations. Within each time division, the issues examined include: the purpose of a particular study, the spatial scale and the time frame of reference, the (implicit at least) epistemological basis and the contributing disciplines. The assumption is that the view of land and land use a study espouses is critically influenced by the latter two characteristics and, in its turn, influences the mode of theorizing and modeling land use change.

Before examining particular studies, the three generic approaches usually taken for the study of land use change which the "Implementation Strategy" of the Land Use and Land Cover Change project (LUCC 1999) names very lucidly "perspectives of understanding" should be mentioned. These are "the narrative, the agent-based, and the systems approach. The narrative perspective seeks depth of understanding through historical detail and interpretation. It tells the LUCC story, providing an empirical and interpretative baseline by which to assess the validity and accuracy of the other visions. It is especially beneficial in identifying stochastic and random events that significantly affect land-use/land-cover changes but might be missed in approaches employing less expansive time horizons or temporal sampling procedures. Both the agent-based and the systems approaches depend on explicit model development and empirical testing. The former (agent-based perspective) seeks to distill the general nature and rules of individual agents’ behavior in their daily decision making. The forms of the distillation are many, ranging from the rational decision making of the average or typical actor in neo-classical economics to household, gender, class, and other such formations …. Central to this perspective, however, is the significance given to human agents in determining land-use decisions and the search for generalizations about this behavior. The systems/structures perspective, in contrast, finds understanding in the organization and institutions of society that establish the opportunities and constraints on decision making (Ostrom 1990). These structures operate interactively at different spatial and temporal scales, linking local conditions to global processes and vice versa (Morán, Ostrom and Randolph, 1998). The systems or structures may manifest themselves in unforeseen and unintended ways. Some institutions are direct drivers of change. Others, such as markets, are intricately linked to individual decisions – they affect these decisions and at the same time are the aggregate result of these decisions" (LUCC 1999, 14). In addition, LUCC (1999) stresses also that the study of land use change should strive to reconcile and integrate the three epistemological traditions: "(i) ‘to observe and describe to understand’ (i.e. inductive approach); (ii) ‘to model to understand’ (i.e. deductive approach); and (iii) ‘to integrate to understand’" (i.e. dialectic approach)" (LUCC 1999, 14).


2.2. The Early Period – George Perkins Marsh and von Thunen

Among the most well known pioneers of the study of land use change are George Perkins Marsh in the U.S.A. and J.H. von Thunen in Germany. They approached the same issue from different perspectives and in different continents. The former, a (prescient) scholar and diplomat, examined in his seminal book Man and Nature; or, the Earth as Modified by Human Action (Marsh 1965; originally published in 1864) the extent and magnitude of impacts of human actions on the natural environment through the ages in various parts of the world. This study, while mainly descriptive, attempted to provide explanations of the environmental transformations observed and recorded as well as prescriptions of man’s position vis-a-vis nature. The issue of land use is central (implicitly, at least) in Marsh’s work as all human activity takes place and modifies space for particular uses. In the words of Kates et al. (1990) "The importance of Man and Nature lies less in the individual impacts that it catalogued ….. than in a grouping and wide-ranging synthesis that emphasized their interrelations and traced the innumerable distant effects of human action. The work was cited by many early conservationists…and influenced the views of nature-society relationships well beyond Marsh’s native shores…..Marsh stressed the breadth and gravity of the unintentional human impacts, and thus the need to understand the complex interactions of natural processes prior to human intervention…Marsh also saw the transformation of the environment, if properly done, as almost entirely desirable….." (Kates et al. 1990, 3).

Somewhat earlier than G.P. Marsh, in 1826, from the other side of the Atlantic, a North German estate owner, J.H. von Thunen, "set for himself the problem of how to determine the most efficient spatial layout of the various crops and other land uses on his estate, and in the process developed a more general model or theory of how rural land uses should be arranged around a market town. The basic principle was that each piece of land should be devoted to the use in which it would yield the highest rent" (Hoover and Giarratani 1984, 142-143). Von Thunen viewed land as an economic resource whose main attribute worth considering was productivity and the landscape within which agricultural activity was taking place was flat and uniform in all directions. His purpose was utilitarian and the analysis of the "optimum" land use patterns static. The mechanism of land use change is implicit and can be derived from the assumptions of the theory; the only variable factor affecting location of a land use (and, presumably, its change) being the value of the associated product. Von Thunen’s agricultural land use theory and model are discussed further in Chapter 3.

The two early studies just described represent the first diametrically opposed approaches to the study of land use change. In the decades that followed, a broad variety of studies covering the whole range between these two extremes appeared but Marsh’s and von Thunen’s legacy marked the two opposing currents along which theorizing on and modeling land use change developed in the 20th century. Marsh’s comprehensive view of land, the natural environment and man’s role in causing environmental change is in the core of a host of nature-society theories and integrated models proposed in the years that followed and that are much in vogue in the present. Von Thunen’s economic, rational man producing economic goods for sale in a uniform, static and orderly landscape whose change is not a central issue founded the theories and models of mainstream urban and regional economics in the 20th century.


2.3. The First Half of the 20th Century

The first decades of the 20th century saw significant changes in the uses of land brought about by industrialization and urbanization in the western world not to mention by the two world wars and other major socio-economic events and technological progress. These changes were documented in studies of this period – most of which are not easily accessible, however – as well as in studies conducted in the second half of the century. They refer mostly to countries or geographic regions as well as to uses of land experiencing the most rapid and important changes such as urban areas in Europe and the USA, forests and agricultural areas in Europe, Russia, and the USA (e.g. the American Great Plains), coastal areas such as the Mediterranean basin and so on (see, for example, Braudel 1966, Kates et al. 1990, Bouwer et al. 1991). The most important trait of these studies is the establishment of the systematic and "scientific" analysis of land use change based on theories and models drawn from a variety of scientific fields – mainly, economics, sociology and geography. In fact, this trait is a reflection of a broader and more general development of this period: the emergence and development of dominant modes of theorizing and modeling on land and land use in the related fields of the social sciences: urban and regional economics, urban sociology, economic and social geography.

In the economics-oriented fields, central concepts and theories appeared in this period that relate directly or indirectly to the study of land use change. In 1933, Christaller (1966) formulated the Central Place Theory to offer a theoretical account of the size and distribution of retail establishments within an urban area employing two main concepts: the "range" of a good and the "threshold" for a good. In the 1940s, Losch (1954) used the conceptual framework of Central Place Theory to offer a more general account of the patterns of "central places" in a continuous space that accounted for other urban functions in addition to retailing. Extended to the level of an urban system, Central Place Theory accounts for the size and distribution of settlements within this system. The hexagonal hierarchical patterning of places is the distinguishing characteristic of both Christaller’s and Losch’s (and subsequent) versions of Central Place Theory. It should be noted, however, that these theorists dealt more with location in space rather than with land use per se and this is why the genre of location theory deriving from these founding fathers are not considered in the present contribution (see Chapter 3). Another concept drawing from concepts of social physics was that of human "interaction in space" (Stewart 1947, Zipf 1949) and the related notion of "accessibility" which was reflected mainly in the variability of transportation costs from some constant point in space (Haig 1927 cited in Korcelli 1982, p. 98-99). These latter concepts provided the foundations, in the latter half of the 20th century, for the development of the spatial interaction theoretical and modeling approaches which are discussed extensively in Chapters 3 and 4.

In the sociology-oriented fields, the development of the school of "human ecology" by sociologists of the Chicago School in the 1920s has had the greatest impact on the analysis of the land use structure and change of urban (and other) regions in this and subsequent periods (see, for example, Park et al. 1925, Chorley and Haggett 1967). The principal concepts of human ecology are drawn directly from the field of ecology and they are used to describe and explain the physical patterns observed in an urban region as well as the economic and social processes underlying them. Among them, the notions of "community", " competition ", " invasion ", " succession ", "conflict", " climax equilibrium " constitute central descriptive and explanatory conceptual devices (for definitions of some of these terms see, among others, Johnston et al. 1994). The concepts advanced to describe urban patterns, routinely mentioned in most texts of urban and regional studies and planning, are the "concentric zone" hypothesis (see, among others, Park et al. 1925, Romanos 1976), the "radial sector" theory (Hoyt 1939) and the "multiple nuclei" concept (McKenzie 1933, Harris and Ullman 1945). In the same vein, the notion of "sequent occupance" was proposed to describe the geography of an area as "a succession of stages of human occupance which establishes the genetics of each stage in terms of its predecessors" (Whittlesey 1929 cited in Johnston et al. 1994, 549). A well known application of this notion is Broek’s study of the Santa Clara Valley, California (Broek 1932). The first human ecological studies that appeared in the first half of the 20th century marked the beginning of a long procession of similar studies undertaken in the following decades.

The concepts and theories discussed above share some common characteristics that bear importantly on the analysis of land use change. Firstly, most of them are functionalist approaches to the study of urban and regional structure and change – i.e. they reflect "an epistemological position in which teleological as distinct from causal explanatory forms are stressed" (Cooke 1983, 72). They look for "repeatable and predictable regularities in which form and function can be assumed to be related" (Bennett and Chorley cited in Johnston et al. 1994, 209). Second, some are predominantly descriptive (mostly the human ecology-based approaches) while some others are normative and prescriptive (Central Place Theory). Land, and space in general, does not have intrinsic properties. It is abstract and amorphous – an isotropic medium with uniform (though unspecified or highly abstract) qualities in all directions within which social and economic processes take place. Population and human activities and the uses of land associated with them are treated as though they do not extend over space but are points on a map. Even the city center is a point –simply, the center of a circle or a hexagon. The emphasis is on the location of human activities in space and on the form of the patterns produced – be they concentric rings or hexagonal market areas. Change in the uses of land – when it is a direct object of analysis in these frameworks – is a mechanistic and predictable response to changes in distance or transport cost, a natural consequence of the functionalism of these approaches.


2.4. The Other (Last) Half of the 20th Century

The scientific analysis and studies of land use change boomed after World War II along the lines of several of the approaches that had been formulated earlier. The numbers and diversity of extant studies make a complete and comprehensive overview impossible. Even a simple enumeration is difficult. The studies cover the whole range from the local (urban) to the global level. The approaches adopted stem from urban and regional economics, urban and rural sociology, geography and planning as well as from the natural sciences. In addition to the mono-disciplinary, a multitude of interdisciplinary approaches have appeared especially after the 1970s. Hence, this section attempts a selective overview of a vintage of the most important categories of studies the emphasis being on those where land use change is more or less the direct object of analysis.

The proliferation of studies and the particular directions pursued in the analysis of land use change are not unrelated to the broader theoretical and methodological changes in the disciplines that contributed to these studies as well as in the required supporting technology. The most important of them is perhaps the so-called "quantitative revolution" in geography but also in economics, sociology and planning in the 1950s and 1960s. Formal models and theories of land use and land use change were proposed in that period to be rejected – but not abandoned – later when their limitations became evident and their epistemological foundations were seriously questioned. The parallel progress in computer and data processing technology initially reinforced the quantitative orientation of the studies under consideration. Later on and at present, this technology appears to have an emancipating effect on the analysis of land use change in the sense that it facilitates the application of less quantitative (in the sense of the 50s and 60s), more qualitative and heuristic approaches that are not constrained by the frequently unrealistic assumptions of the earlier quantitative theoretical and modeling formulations.

Deeper changes in the epistemological perspectives of the scientific fields involved in the study of land use change at large have played and are playing also a catalytic role in directing the analysis towards particular paths and approaches as the current (beginning of the 21st century) diversity of land use change studies testifies. Finally, the recent policy interest in the (negative) implications of global environmental change – one component of which is land use change – may be exerting an influence on the orientation of the studies of land use change as practical approaches and decision support instruments are sought to guide policy making for sustainable land use.

The systematic and scientific analysis of land use change that had started in the first half continued in the second half of the 20th century in the same fields as before – urban and regional economics, regional science, sociology, geography and planning – in several of which the related theories and models were moving to or had reached mature stages. Again, land use and its change are not always the direct object of analysis in many fields reflecting the different focus of emphasis on particular aspects and dimensions of spatial change. However, the links to land use change are rather straightforward although not always obvious and explicitly elaborated. In addition, studies of land use change from particular fields of the natural and the applied sciences – forestry, agronomy, biology, ecology, remote sensing, environmental sciences – are not uncommon as well as studies attempting interdisciplinary approaches to the subject. Three main bundles of studies are presented below. The first originates in the economics-oriented fields such as urban and regional economics and the relevant subfields of regional science, geography and urban and regional planning. The second bundle draws from the sociology-oriented fields like urban and rural sociology and the relevant subfields of regional science, geography and urban and regional planning. A third bundle contains a multifarious collection of studies originating in the same fields as before but bearing the influence of the natural sciences and opting for integrated analysis of land use change.

The economics-oriented fields generated impressive numbers of theoretical, modeling and empirical studies of urban and regional spatial structure in the post war years. Broadly, they can be divided into those concerned with the urban and intra-urban spatial (economic) structure and those referring to larger than the regional scale areas. Most of the studies that explicitly account for land use change belong to the first group, the land-using activities more frequently analyzed being residential, commercial, transportation and, to a lesser extent, public and other services. A major stream of research is founded on neo-classical economics informed by spatial concepts; mainly the "friction of space" as measured by the distance among the location of activities. Alonso’s (1964) urban land market theory and model (borrowing concepts from von Thunen’s analysis) is considered the landmark study from which a series of urban economic models followed sharing a common characteristic: the description and explanation of urban spatial structure based on land rent and transportation costs and the assumption of utility maximizing individuals. For a selection of theories and models in this direction the reader is referred to Nijkamp (1986). In a related spirit, the 1960s saw applications of Central Place Theory to the location of retail centers, among others (Berry 1967). Another major stream of studies developed in the 1970s around the notions of spatial interaction and accessibility – already introduced in the 1940s and even earlier. It provided a theoretical framework as well as a "family of spatial interaction models" (Wilson 1974) to account for the location and allocation of activities in space taking into account the transportation network. Integrated land use-transportation models were built also to account for the simultaneity of changes in land use and accessibility (Putman 1983, Wegener 1986). Several variants of these models have appeared each attempting to relax the unrealistic and introduce more plausible assumptions regarding spatial economic behavior in space (for a review of such attempts, see, for example, Batten and Boyce 1986).

In a macro-economic perspective, regional equilibrium and disequilibrium theories and models, among others, developed in this period, too, to describe and explain processes of regional change (growth or decline) but their treatment of land uses is abstract and vague at best . The theoretical and analytical framework of general equilibrium and neo-classical welfare analysis has been employed to produce Pareto optimal solutions to social welfare maximization problems where land is one of the production factors together with labor and capital (see, for example, Cooke 1983, Andersson and Kuenne 1986, Clark and van Lirerop 1986, Miyao 1986, Takayama and Labys 1986, Fischer et al. 1996a). Finally, empirical analyses of land use changes in urban and rural areas were conducted responding, more or less, to pressing problems such as urban decline, rural-urban land conversion (especially on the fringe areas of metropolitan regions), urban sprawl, etc. (see, for example, McDonald 1984, Simon and Sudman 1982). These have a more practical orientation focusing on detailed typologies of land uses that capture the qualitative, and not only the quantitative, intricacies of land use change (see, for example, Bourne 1978).

The economics-oriented analyses of land use change share common traits the most important of which is the emphasis placed on the price mechanism (land and transportation costs) as the principal determinant of the location of human activities in space. They are functionalist , quantitative, sometimes highly mathematical, approaches relying on frequently very restrictive assumptions with respect to the nature of land, land use, land use change as well as the characteristics and preferences of the users of space. They attempt both to describe (directly or indirectly) land use patterns and their changes as well as to prescribe optimal land use configurations that satisfy set goals.

The sociology-oriented fields continued the tradition of human ecology developed in the first half of the 20th century producing quantitative, empirical studies of urban spatial and social structure especially in the 1960s and 1970s. Starting with the theory and technique of social area analysis and later moving to the more sophisticated inductive techniques of factorial ecology (Johnston et al. 1994, 558), studies of land use and its change focused on such variables as socio-economic, family, and ethnic status to provide explanations for observed differences in the location of particular activities – mainly, residential areas occupied by groups of varying socio-economic traits. The characteristic of human ecological studies of this period is best summarized in Johnston et al. (1994): "Later systematizers of sociological human ecology, such as Hawley (1950, 1986), have tended to play down the spatial focus of the Chicago School…..in favor of an emphasis on the demographic and institutional dimensions of society (Saunders 1981) although at the same time they have shown a strengthened interest in human interaction with the physical environment" (Johnston et al. 1994, 258). In fact, most sociological analyses see the urban spatial structure as an expression of the underlying social structure and the associated processes (see, for example, Suttles 1975, Korcelli 1982).

Within the broader realm of sociology-oriented studies of land use change, two particular approaches have developed: the behavioral and the institutional. The first attempts to describe and explain land use patterns as a function of factors influencing human behavior and decision making and focuses on human activity systems (see, for example, Chapin 1968, Chapin and Kaiser 1979, Korcelli 1982, Johnston 1982, Webber 1964a). A idealistic variation of this approach emphasizes the ways people perceive and experience the world around them and act correspondingly (Tuan 1975, 1976, Hugill 1975, Buttimer 1976 cited in Johnston 1982). The second (also called "radical" or " structuralist ") places emphasis on the constraints imposed on human behavior by societal institutions in the effort to explain spatial patterns in urban and other areas. The central concept of this approach is "power", especially economic power, and a correlate concept is ‘conflict’, usually between unequals, or class conflict (Johnston 1982).

These latter approaches belong to a long repertoire of approaches developed in the 1970s and beyond when geography and planning showed an interest in and were heavily influenced by social theory. Developed frequently as attacks on the empiricism and positivism characterizing most post-war descriptions and explanations of spatial structure and change, alternative approaches appeared that offered explanations of social and spatial phenomena drawing from diverse philosophical and epistemological positions. Historical materialism provided a framework within which patterns of spatial and environmental change are explained as the result of the specific social relations of the capitalist or other modes of production (see, among many others, Harvey 1973, 1985; for an application to land use change, see, Hecht and Cockburn 1990). Structuralist approaches sought for the truth beneath the surface of the "facts" and the "taken-for-granted" categories by means of which social life was usually comprehended (Johnston et al. 1994, 599). Realist perspectives oriented themselves towards the identification of the causal mechanisms underlying specific (social and spatial) structures which occur under specific (contingent) conditions (see, for example, Sayer 1982, 1985b). Giddens’ "structuration theory" sought to explore the time-space constitution of social life (see, for example, Giddens 1984). Symbolic interactionism emphasized the social construction of reality while phenomenology stressed the individuals’ experiences of the world in a more or less similar fashion as existentialism which stressed the centrality of the human subject’s existential being in the world (see, for example, Berger and Luckmann 1967, Relph 1976, Buttimer 1974). Ethnomethodology has taken an even more extreme stance emphasizing the unique and the idiographic and rejecting any attempt at generalizations (Jonhston et al. 1994, 175).

A striking characteristic of all these sociology-oriented approaches which deal, in one way or another, with space, spatial structure, spatial and social relations is that they treat space and the human subjects that exist within it and interact with it in an abstract fashion; i.e. they make no explicit reference to actual land use and its changes within the context of the causal social relations studied. Moreover, frequently they lack spatial and temporal explicitness and concreteness even when they refer to the urban, regional or international level and when they deal with real world applications. In addition, several of these approaches apply to particular socio-political and cultural settings and they cannot be transferred easily and without violating their very assumptions to other contexts. Overall, in their present form and orientation, they can inform the analysis of land use change very little in practical terms.

Besides economics-oriented and sociology-oriented, a host of other approaches to the study of land use and its change borrowing from ideas and concepts of the past developed in the second half of the 20th century. They combine elements of both the natural and the social sciences and they are based, broadly, on the notion of ecological equilibrium which attributes changes in a region to changes in the dynamic interaction of four sets of factors: population, resources, technology and institutions (see, for example, Coccossis 1991, Meyer and Turner 1996). Although not directly concerned with land use change, Ian McHarg’s (1969) ecological method for land use and landscape planning is worth noting here. On the one hand, it bears the influence of past streams of thought on the man-environment relationship and, on the other, it has marked, in its turn, the way of thinking about the relationship between human activities and nature and of planning for their harmonious symbiosis. The ecological method he had advocated was an appeal to consider the life processes as constraints and opportunities for land use planning. His was a holistic approach as the following statement reveals: "The social value of a given environment is an amalgam of the place, the people, and their technology. People in a given place with opportunities afforded by the environment for practicing a means of production, will develop characteristic perceptions and institutions. These institutions will have perceptions and values that feed back to an understanding of the environment … and that have a modification of technology" (McHarg 1979, 14).

Ecosystem-based theoretical approaches and integrated environment-economy-society models became widespread in the last half of the 20th century and especially after the 1970s. The broader climate of this period is marked by the growing appreciation of and concern about the environment in policy and academic circles as well as and among laypersons which created a demand for approaches and tools of analysis of the related problems. Land use and its changes came to be recognized as important elements of the broader nature-society system and non-trivial contributors to global environmental change whose study was a prerequisite for taking action (see, for example, Slocombe 1993, Lutz 1994, Fischer et al. 1996a, Manning 1988, 1991). What distinguishes these approaches from the previous two groups is the treatment of land and land use as having intrinsic and variable environmental (and not only economic and socio-cultural) properties, attributes and capabilities that influence and are influenced by human activities and actions. Hence, land use change is analyzed within a meaningful setting of nature-society interactions which appears to be more promising in handling policy and decision making issues in an integrated manner than the more uni-dimensional approaches discussed before which focus on only one dimension of the subject.

In addition to theoretical and methodological studies, a host of empirical studies have been and are undertaken at both the international and lower levels to identify and record changes in major uses of land, mostly when and where these changes have grave ecological (and economic) consequences as in agricultural, forest, and urban areas. Turner et al. (1990) and Meyer and Turner (1994) provide historical accounts of global studies and present the current trends in this perspective. Besides global level assessments of land use changes, land use change research in individual countries has provided stock taking of major land use changes on a variety of spatial scales as input to both research and policy activities (see, for example, Brouwer 1991, Jongman 1995, CLAUDE 1996). Technological progress in the domain of (spatial) data management and remote sensing has spurred major projects on observing and recording land use changes. Powerful earth observation systems covering the globe (e.g. those utilized in programs such as GCOS, GCTE, GOOS, GTOS, LANES, TREES to name but a few) together with advanced spatial data management systems (mainly, Geographical Information Systems) offer the possibility to monitor and map land cover (not land use necessarily) changes at very disaggregate levels of spatial and temporal resolution. In addition, they facilitate data storing and processing for use in various contexts such as in scientific research, policy making, and implementation of related programs (see, for example, Liverman et al. 1998). Technology is a significant – but not the sole and most important – contributor to the comprehensive and timely analysis of land use change and the fast dissemination of the information and knowledge produced. Despite the more impressive outputs it can produce, such as fancy and colorful satellite images and maps, it will never become a substitute for theoretically informed and methodologically sound analyses of land use change.


2.5. The New Millennium

Standing at the doorstep of the new millennium, it is natural to ask where the study of land use change is now and to where it is heading (or, to where it should head). This section takes a brief look at the current status of outlook, theorizing, modeling, tools, and initiatives on the subject based on the foregoing presentation.

In the last decade of the second millennium, the 1990s, the study of land use change could be no exception to the sweeping impact of the Brundtland report and the sustainable development movement. An almost universal concern with global environmental change had already gained ground also and had spurred a large number of research and policy initiatives around the globe especially after the Rio Summit of 1992. Examples include the research initiatives of IGBP, IHDP, the FAO, the European Environment Agency (EEA) as well as the UN Conventions on Climate Change (UNCCC), Desertification (UNCCD), and so on. Land use change was soon recognized as a significant component of the global environmental system as "the lands of the earth bear the most visible, if not necessarily the most profound, imprints of humankind’s actions" (Kates et al. 1990, 6) and specific research initiatives, such as LUCC, were formed. At the same time, the scientific fields contributing to the analysis of land use change had matured more or less in terms of theories, models and tools (technology). Interdisciplinary research was undertaken both within broad scientific realms (e.g. the environmental sciences) as well as between scientific realms on the society-environment interface as it was beyond question that the answers to almost all environmental and social problems could not be provided within the narrow confines of any discipline.

As a result of these developments, among many others, the outlook on the subject has broadened and the approaches advanced are more holistic than they were in the past. Despite the persistence and inertia of strong disciplinary boundaries, new forms of scientific cooperation are promoted under the call for "transdisciplinarity". A return to the view of land as a multi-faceted resource and of land use as the wise manipulation and stewardship of this resource is encouragingly visible, echoing the legacy of the past, although it cannot be claimed that it is the dominant view yet.

In fact, it may be difficult to speak of a dominant view and approach on the subject as, at the time of this writing, at least the economics-oriented and the natural-sciences-oriented fields as well as the interdisciplinary research orientation are raising strong voices and claims with respect to theories and models. Only the sociology-oriented fields are still lagging behind despite the strides they are making recently on the subject of land use change. The result of this imbalance is that, from the epistemological point of view, most approaches to the analysis of land use change move, more or less, along empiricist and positivist lines (cf. remote-sensing and GIS applications, integrated models, the neo-classical economic welfare maximization approach). The critique and alternative views to this epistemology which developed in particular disciplines of the social sciences have not found their way yet into the practical analysis of land use change where they may have potentially a beneficial impact in contributing to the development of more socially-informed and responsive theoretical schemata.

Studies of land use change cover the whole spectrum from the global to the local. But, in most cases, studies at particular spatial levels are usually conducted in isolation from one another and, frequently, they fall within the purview of particular disciplines (e.g. urban economics, geography, environmental sciences, forestry, etc.). This kind of scientific segregation inhibits the exchange of concepts, theories, tools, and results among spatial levels. Global level land use change studies have received greater publicity compared to the other levels given the stronger interest, in general, in global environmental change and the requirements of global policies such as UNCCC and UNCCD. It is recognized, however, that many of the global impacts of land use change result mostly from the many, incremental local level decisions and actions of the actual users of land. Hence, the heightened recent interest on integration – among spatial scales, of local with regional and global level analyses, of urban with rural analyses. Integrated analysis is a relatively under-researched area in most disciplines given, among others, the problems with integrating/synthesizing theoretical and methodological frames of analysis from different disciplines as well as the more mundane but hoary "data problem". Judging from the LUCC Implementation Strategy (LUCC 1999), however, it seems that future studies of land use change will be increasingly characterized by integrated, interdisciplinary approaches to address the issues associated with the management of land use change. This task is expected to be facilitated greatly by further advances in the systems of data collection, compilation and management assuming that the currently high costs and long times associated with the provision of the required data will be reduced to reasonable levels.

The following chapters present in greater detail available theoretical frameworks (Chapter 3) and modeling approaches (Chapter 4) developed for the analysis of land use change. The last chapter (Chapter 5) discusses the links between theories and models over time and identifies future research needs.