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Institute
Intelligent Product Design
(2012)
The aim of this thesis is to generate reality-based hypotheses about the opportunities and obstacles that create the implementation of Cradle to Cradle for the companies Jules Clarysse NV and Steelcase Inc. It discusses further which marketing-mix is appropriate for Cradle to Cradle products. Therefore exploratory expert interviews have been conducted with both companies. The empirical part is introduced by a literature study. From marketing perspective, the Cradle to Cradle approach for product design is investigated while taking into account that academic literature categorizes the concept on the one hand as consistent sustainability strategy, on the other hand as sustainable design. Moreover, the broad use of the expression design, within the literature of the Cradle to Cradle founders, is analyzed. Here, Cradle to Cradle design is holding out the prospect of Triple Top Line growth, rather than meeting only the economic bottom line. In regard of aesthetics, Cradle to Cradle aspires diversity in contrast to prevailing principles of Functionalism and universal design solutions. The ‘hidden‘ design assignment of Cradle to Cradle, service design, is highlighted as sphere that should be progressed. All these considerations form the interview guideline. The interviews serve as reality check whether there result Triple Top Lines and new service models for the companies and explore how aesthetics and tools of the marketing-mix are handled in Cradle to Cradle practice.
The dissertation deals with the impact of nitrogen deposition on the functioning of heathland ecosystems. Special interests were the displacement of heather (Calluna vulgaris) by the purple moor-grass (Molinia caerulea) as well as the fate of nitrogen loads in dry heathland ecosystems. The results of the studies undertaken in the field and in the greenhouse are presented as five individual journal articles. The nature of nutrient limitation was studied by means of fertilisation experiments with nitrogen (N) and phosphorus for heather and purple moor-grass (Articles I and II). The impact of nitrogen deposition on the outcome of competition between these two species was analysed during a competition experiment in the greenhouse (Article III). The aim of a 15N tracer experiment was to determine the fate of nitrogen deposition as well as allocation patterns (Article IV). In addition, the response of purple moor-grass to the combined effects of nitrogen deposition and summer droughts was investigated in a second greenhouse experiment (Article V). The fertilisation experiments showed that the growth of heather as well as of purple moor-grass is predominantly limited by N (Articles I and II). However, the results of the competition experiment demonstrated that only purple moor-grass has the ability to benefit from additional N loads, which in turn gives the grass the opportunity to displace heather (Article III). Drought treatment resulted in strikingly reduced biomass production of purple moor-grass in N-fertilised pots, mainly as a result of dying aboveground biomass during dry periods (Article V). This striking susceptibility of purple moor-grass to the combination of nitrogen deposition and drought must be taken into account, when predicting future developments of dry heathlands. The results of the 15N tracer experiment showed that the investigated heath is still in an early stage of N saturation, as indicated by a high immobilisation capacity and negligible leaching losses of 15N (Article IV). The findings of the dissertation contribute to a better understanding of the processes underlying the encroachment of purple moor-grass in dry heathlands and can enhance heathland management. The results can also be used to to evaluate the current and future status of this ecosystem particularly with regard to the various stages of N saturation as well as in the determination of “Critical Loads”.
The world wide population growth and the increasing water scarcity endanger more and more the human society. Water saving measures alone will not be sufficient to solve all associated problems. Therefore, people in arid countries might come back to any kind of water available. In this context the way people regard wastewater must change in terms that it has to be recognized as a water resource. The reuse of wastewater, treated and untreated, for irrigation purposes in agriculture is already established in some semi-arid and arid countries. Countries with absolute water scarcity like Israel might not only be forced to reduce their water consumption, but even to transfer reused water to other sectors. Concerns of authorities and the general public about potential health risks are completely understandable. The health risks of wastewater are mainly originating from pathogens which are negatively correlated with its treatment. Therefore, the quality of a wastewater effluent derived from mechanical-biological treatment can be further improved by additional treatment steps like soil aquifer treatment (SAT). This process is adopted at the Israeli Shafdan facility in the south of Tel Aviv. Conventionally treated wastewater is applied on surface basins from where it percolates into the coastal plain aquifer which supplies approximately one quarter of Israel ́s drinking water. After a certain residence time in the subsurface the water is recovered by wells surrounding the recharge area. Although the pumping regime creates a hydraulic barrier to the pristine groundwater, concerns exist that a contamination of the surrounding drinking water wells could occur. So far, little is known about the removal of organic trace pollutants during the SAT process in general and for the Shafdan site in particular. Consequently, the need arose to study the purification power of the SAT process in terms of the removal of organic trace pollutants. For this purpose reliable wastewater tracers are essential to be able to differentiate between degradation and sorption processes on the one hand and dilution with pristine groundwater on the other hand. Based on their chemical properties, their worldwide usage in a variety of foodstuffs and beverages, and first data about the fate and occurrence of sucralose, artificial sweeteners came into the focus as promising tracer candidates.
Thus, in the present work an analytical method for the simultaneous determination of seven commonly used artificial sweeteners in different water matrices, like surface water and wastewater, was developed (see chapter 2). The method is based on the solid phase extraction (SPE) of the analytes by a styrene-divinylbenzene (SDB) copolymer material, and the analysis by liquid chromatography-electrospray ionization tandem mass-spectrometry (LC-ESI- MS/MS). The sensitivity in negative ionization mode was considerably enhanced by postcolumn addition of the alkaline modifier tris(hydroxymethyl) aminomethane. In potable water, except for aspartame and neohesperidine dihydrochalchone, absolute recoveries >75 % were obtained for all analytes under investigation, but were considerably reduced due to matrix effects in treated wastewater. The widespread distribution of the artificial sweeteners acesulfame, saccharin, cyclamate, and sucralose in the aquatic environment was proven. Concentrations in two German wastewater treatment plant (WWTP) influents ranged up to 190 μg/L for cyclamate, several tens of μg/L for acesulfame and saccharin, and about 1 μg/L for sucralose. For saccharin and cyclamate removal rates >90 % during wastewater treatment were observed, whereas acesulfame and sucralose turned out to be very persistent. As a result of high influent concentrations and low removal rates in WWTPs, acesulfame was the dominant sweetener in German surface waters with concentrations up to 2.7 μg/L. The detection of acesulfame and sucralose in recovery wells in the Shafdan SAT site in Israel in the μg/L range was a promising sign for their possible use as anthropogenic markers. As acesulfame and sucralose showed a pronounced stability in WWTPs and were detected in recovery wells of the SAT site in Israel it became worthwhile to assess their tracer suitability compared to other organic trace pollutants suggested as anthropogenic markers in the past (see chapter 3). Therefore, the prediction power of the two sweeteners was evaluated in comparison with the antiepileptic drug carbamazepine (CBZ), the X-ray contrast medium diatrizoic acid (DTA) and two benzotriazoles (1H-benzotriazole (BTZ) and its 4-methyl analogue (4TTri)). The concentrations of these compounds and their ratios were tracked from WWTPs with different treatment technologies, to recipient waters and further to river bank filtration (RBF) wells. Additionally, acesulfame and sucralose were compared with CBZ during advanced wastewater treatment by SAT in Israel. Only the persistent compounds acesulfame, sucralose, and CBZ showed stable ratios when comparing influent and effluent
concentrations of four German WWTPs with conventional wastewater treatment. However, by the additional application of powdered activated carbon in a fifth WWTP CBZ, BTZ, and 4-TTri were selectively removed resulting in a pronounced shift of the concentration ratios towards the nearly unaffected sweeteners. Results of a seven months monitoring program along the rivers Rhine and Main showed an excellent correlation between CBZ and acesulfame concentrations (r2 = 0.94), and still good values when correlating the concentrations with both benzotriazoles (r2 = 0.66 - 0.82). In RBF wells acesulfame and CBZ were again the compounds with the best concentration correlation (r2 = 0.85).
Nongovernmental organisations often criticize the working conditions at foreign suppliers – especially those in Asia and Latin America – of Western brands. In response, many brands have established codes of conduct in order to set binding social standards for their suppliers. Audits are conducted to monitor their implementation; however, substantial improvement of labour conditions has not been achieved. Therefore, brands are increasingly shifting their efforts towards building the capacity of their suppliers themselves to enhance the implementation of social standards. The creation of participative organisation structures that involve workers in decision-making processes regarding working conditions is often a focus of such novel training programmes. In light of these developments, this study will examine if a positive relationship exists between worker participation initiated by management and the improvement of working conditions in factories. In the theoretical part of the study, motivational and cognitive models as well as aspects of power-sharing and decision-making processes are used to examine the influence of participation on working conditions. Moreover, requirements for successful participation structures are developed. The Western discourse on influence mechanisms is complemented by political, economic, legal and cultural conditions in China related to participation and the implementation of social standards. The case study in this dissertation is based on research at seven garment factories in China which took part in the public-private-partnership project „Worldwide Enhancement of Social Quality“ initiated by the German retailer Tchibo GmbH and the Gesellschaft für Internationale Zusammenarbeit, a German federal enterprise for international cooperation in the field of sustainable development. The goal of the three-year project was to initiate participative dialogue structures and to provide technical knowledge regarding the implementation of social standards in 40 factories in China, Bangladesh and Thailand. In order to examine the influence of worker participation in the Chinese facilities, a quantitative survey of 390 workers and 70 worker representatives, as well as interviews with 15 managers, nine project members and one representative from the International Labour Organisation China were conducted. The research results indicate that worker involvement contributes to the improvement of the economic and social performance of factories. In particular, the rise in trust between management and the workforce, and the inclusion of workers’ valuable input contributed to the positive change. In order to make full use of the potential of participation, workers’ and managers’ motivation, key competences for participation, training activities as well as time resources are of importance. China is undergoing a period of transformation. Although until now no independent unions are allowed in China, employee involvement offers the opportunity for workers to become part of decision-making processes in the factories, thereby supporting democratisation tendencies in the country.
Halogenated flame retardants (HFRs) have been applied since the 1960s in various industrial and consumer products to protect humans as well as private and public possessions. In the past decade polybrominated diphenyl ethers (PBDEs), formerly the major applied HFRs were widely restricted and adopted as Persistent Organic Pollutants (POPs) in the Stockholm Convention due to their adverse effects on humans and the environment as well as their ubiquitous occurrence in the global environment. Besides PBDEs, various alternative HFRs have been applied for decades as well, or were recently developed to replace PBDEs. However, their potential adverse properties, environmental distribution and fate are largely unknown. Therefore, this thesis addresses the global occurrence, distribution and transport of alternative HFRs versus PBDEs in the marine atmosphere and seawater toward the Polar Regions in order to examine their longrange atmospheric transport (LRAT) potential. This thesis presents the first data on alternative HFRs in the atmosphere of the marine environment and the Polar Regions. Alternative brominated flame retardants (BFRs), Dechlorane compounds and PBDEs were investigated in high-volume air and seawater samples taken along several sampling transects in the Atlantic Ocean, Pacific Ocean and Indian Ocean toward the Polar Regions of the Arctic and Antarctic. In addition, three sampling cruises were conducted in the German Bight, North Sea. Several alternative HFRs were detected in the global marine atmosphere and seawater with hexabromobenzene (HBB), pentabromotoluene (PBT), pentabromobenzene (PBBz), 2,3- dibromopropyl-2,4,6-tribromophenyl ether (DPTE) and Dechlorane Plus (DP) being the predominant compounds which were observed in concentrations similar or even higher than PBDEs. Total atmospheric concentrations ranged from <1 pg m-3 over the open oceans up to 42 pg m-3 over the East Indian Archipelago. Seawater concentrations ranged from <1 pg L-1 in open ocean seawater up to 21 pg L-1 in coastal regions, while estuarine concentrations reached up to 6800 pg L-1. Overall, the comparison revealed that alternative HFRs dominate versus PBDEs in air and seawater, both in coastal regions as well as the Polar Regions, showing a shift from PBDEs toward alternative HFR in the marine atmosphere and seawater. The distribution in the global atmosphere was strongly influenced by the proximity to potential source regions and the pathway of the sampled air masses. Highest concentrations were observed in continentally influenced air masses, while low background concentrations occurred during sampling of oceanic remote air masses. In general, Western Europe, East and Southeast Asia but also Africa were identified as source regions for the marine environment, especially for alternative HFRs as well as BDE-209. In contrast, relatively low peak concentrations of the PBDE congeners of the Penta- and OctaBDE mixtures under continental influence were observed, indicating limited emissions of legacy PBDEs. The dry air-seawater gas exchange estimation showed that the atmosphere is a source for seawater resulting in net deposition into the global oceans after atmospheric emissions and transport, both in coastal regions as well as in the open oceans. Besides atmospheric depositions, riverine discharge was shown to act as source for coastal environments. The investigation of sampling transects toward the Polar Regions revealed that several alternative HFRs – in particular HBB, PBT, DPTE, PBBz and DP – undergo LRAT toward the Polar Regions in an extent similar to PBDEs and, therefore, meet the LRAT criterion of POPs under the Stockholm Convention. DP was found to undergo LRAT attached to airborne particles whereby stereoselective LRAT differences were shown for the two DP stereoisomers. With respect to LRAT, the results of this thesis therefore imply that alternative HFRs – in particular HBB, PBT, DPTE and DP – aren’t suitable replacements for PBDEs, but chemicals of emerging global environmental concern and possible future POPs.
All of the papers contained in this thesis address the topic of population economics, especially in relation to labor markets. The first chapter, Introduction, gives an overview of the papers discussed in this thesis. In the second chapter, Age and Gender Differences in Job Opportunities, job opportunities for older workers are analyzed. Newly-employed women and men who are older than the age of 55 are more limited in their occupational choices than younger women and men. Different measures of segregation such as the Duncan Index and Hutchens Index show unequal distribution of jobs over age. Older women in particular face the highest segregation. Several years of the IAB Employment Sample are used in the analysis. In the third chapter, Explaining Age and Gender Differences in Employment Rates: A Labor Supply Side Perspective, the labor supply of older individuals is analyzed. The comparison of reservation wages and entry wages shows age- and gender-specific differences. Nonemployed individuals at the age of 55 and older have the highest reservation wages. Reservation wages for females are always higher than those for males. Entry wages increase with age for males, but not for females. Furthermore, the job satisfaction of women decreases with age while satisfaction with leisure tends to increase. This may explain why employment rates for females are lower than for males. The German Socio-Economic Panel (GSOEP) data is used in the paper. In the forth chapter, Somewhere over the Rainbow: Sexual Orientation Discrimination in Germany, sexual orientation-based differences in income are analyzed. Although Germany has an anti-discrimination law that has explicitly prohibited discrimination on the basis of sexual orientation since 2006, there are significant income differences for gay men and lesbian women. While gay men have an income discount of 5 to 6 percent relative to married heterosexual men, lesbian women have an income premium of 9 to 10 percent relative to heterosexual married women. These differences within the gender types can be explained partially by selection into specific occupations and sectors. One wave of the German Mikrozensus data is used in the analysis. The fifth chapter, A Note on Happiness in Eastern Europe, is no more related to Germany, but takes an international position. Estimations on life satisfaction show typical results, such as a u-shaped effect in relation to age. Marriage and a good state of health have positive effects on life satisfaction or utility, while individual unemployment has a negative effect. Several years of the European Values Study (EVS) and the World Value Survey (WSV) are used in the paper. The thesis is finished by a final chapter, Conclusion
Conflicts between intragenerational and intergenerational justice in the use of ecosystem services
(2012)
The principle of sustainability contains two objectives of justice regarding the conservation and use of ecosystems and their services: (1) global justice between different people of the present generation ("intragenerational justice"); (2) justice between people of different generations ("intergenerational justice"). International sustainability policy attaches equal normative importance to both objectives of justice. Accordingly, environmental philosophers ethically justify that people living today and people living in the future have equal rights to certain basic goods, including ecosystems and their services (e.g. Feinberg 1981, Visser’t Hooft 2007). Whereas ideal theories of sustainability and justice do not recognize interdependencies between intragenerational and intergenerational justice, conflicts in attaining the justices possibly arise in policy implementation. Identifying and preventing such conflicts is fundamental to devise an ethically legitimate, politically consistent and actually effective sustainability policy. This dissertation systematically investigates conflicts between intragenerational and intergenerational justice in the use of ecosystem services. Human wellbeing depends on the services provided by ecosystems. Yet, humans substantially degrade world’s ecosystems, and therewith cause the loss of important ecosystem services (MEA 2005: 26ff.). The idea of sustainability demands to use ecosystem services in accordance with the two objectives of intragenerational justice and intergenerational justice. Reality, however, is far from attaining these objectives: Both today’s global poor and future persons are, resp. will be, disproportionately affected by the loss of vital ecosystem services (MEA 2005: 62, 85). Especially severe affected are the rural poor who directly depend on local ecosystem services for food, income and health. The political discourse on the relationship between the objectives of intra- and intergenerational justice in the use of ecosystem services (‘justice-relationship’) is blurred. Further, the political discourse lacks a common understanding of justice in ecosystem-use and a systematic reflection on the actual ‘justice-relationship’, such as on the factors that cause conflicts between the two justices. In this dissertation, I investigate the ‘justice-relationship’ along three central questions: • What conception(s) of justice can adequately address the distribution of access rights to ecosystem services? • How must sustainability policy be designed to enhance both intragenerational and intergenerational justice in the use of ecosystem services? • (How) Can economics be helpful for characterizing and assessing trade-offs between the two justices? I approach these questions both generally and by the example of a case study, the MASIPAG farmer network in the Philippines. Methodologically, I combine a normative and a positive analysis of the relationship between intra- and intergenerational justice in the use of ecosystem services: The normative analysis serves the explication, justification and reflection of the norms underlying the ‘justice-relationship’; the positive analysis serves the description of the ‘justice-relationship’ in the sustainability discourse and in practical contexts, as well as the provision of explanations on the determinants of the ‘justice-relationship’. As methodological approach, I apply the “comprehensive multi-level approach” as developed by Baumgärtner et al. (2008) – investigating the ‘justice-relationship’ simultaneously on the three levels of (i) concept, (ii) model and (iii) case study.
Due to the financial markets disturbances of 2007/2008, a considerable number of financial intermediaries such as banks, credit institutions and asset management companies noticed substantial liquidity shortages, difficulties to refinance their operations as a result of a drying out of appropriate refinancing sources, and withdrawals of deposits by consumers. These turbulences in the financial markets forced governments and central banks to increase liquidity provisions to ensure a sufficient aggregate liquidity of the financial industry. Furthermore, policy-makers decided on bailouts of banks or on supporting financial intermediaries by governmental warranties or liquidity provisions to avoid a substantial number of insolvencies of banks and other financial institutions that may have rapidly deteriorated the global financial industry. In the aftermath of the crisis, politicians and economists discussed these decisions controversially because interventions by governments and central banks appear to have a deep impact on the global economy particularly in the financial industry. Moreover, legislative and regulatory authorities decided on increasing their vigilance, particularly with focus on principal-agent problems within certain sectors of the financial industry. A considerable amount of recent research papers has focused on the dynamics of liquidity shortages that suggest the recent crisis being related to both an increasing funding liquidity risk and an emerging market liquidity risk. Self-amplifying interdependencies appear to connect these two dimensions of liquidity risk that during the period 2007 to 2008 have led to the contagion effects in the global financial industry. Only little research work so far has provided evidence from the financial crisis in 2007/2008 while focusing on the German financial industry. Thus, my doctoral dissertation covers three research papers that address the occurrence of substantial liquidity risk and default probability within the German financial industry over the course of the financial crisis of 2007/2008. My first publication co-authored with Daniel Schmidt, Leuphana University of Lüneburg, entitled ‘Consumer reaction to tumbling funds - Evidence from retail fund outflows during the financial crisis 2007/2008’ focuses on funding liquidity risk of German retail funds. Contrary to the findings reported in some of the extant literature, our study indicates that over the past few years a change in investors’ behavior patterns means that investment decisions are made at short notice, and that shares are redeemed in a discriminatory manner when funds perform poorly. By using data assembled from 1672 retail funds in Germany over the period March 2008 to April 2010, we are able to show that in general, both the prior fund performance and prior net redemptions have a statistically significant influence on fund outflows. Moreover, there are indications that in recent crises situations that have resulted in the withdrawal of shares investors react fast to market signals. My second research paper entitled ‘Leveraging and risk-taking within the German banking system: Evidence from the financial crisis in 2007 and 2008’ examines the risk-taking attitudes of distinguishable German banking sectors. This study intends to examine whether the German banking system displays pro-cyclical behavior during 2000 to 2011, and to what extent specific sectors of the German banking system show significant balance sheet operations to increase their leverage during years of booming asset prices. The results of this study demonstrate that different sectors of the German banking system did operate their business more or less pro-cyclical. It also provides empirical evidence that certain banking sectors did favor refinancing their assets by short-term borrowing in the interbank market to increase their leverage during periods of extraordinary high returns in financial markets. Moreover, this study shows that banks, which operate above average leverages, tend to report a high volatility of return on assets and low distances-to-default. Finally, my third paper entitled ‘Are private banks the better banks? An insight into the ownership structure and risk-taking attitudes of German banks.’, and co-authored with Thomas Wein, Leuphana University of Lüneburg, tries to enlighten the influence of the different principal-agent relationships on the risk-taking attitudes of German banks. In this study, we propose our hypothesis that the distinguishable principal-agent relationships of German banks are significantly influencing the risk-taking attitudes of bank managers. Particularly, we intend to substantiate the theory that banks owned by dispersed shareholders or federal state authorities face a higher relevance of principal-agent problems than other banking sectors due to a missing ability to monitor bank managers. Our results underline that these problems appear to mislead bank managers showing an unreasonable risk-taking behavior. In a first stage, we rely on a theoretical model explaining that from the bank owners’ viewpoint three factors of the principal-agent relationships are determining the probability of choosing the optimal portfolio of risky assets. These factors cover the ability to control bank managers, the risk pooling capabilities of bank owners and bank managers, and the incentives of seeking high returns. To support our hypothesis we apply an empirical study to the distances-to-default of different German banking sectors. This demonstrates that risk-taking attitudes of banks are closely related to banks’ ownership. Consequently, our findings offer evidence, that legislative and regulatory authorities should increase their vigilance in terms of principal-agent problems within certain sectors of the banking industry.
Entrepreneurs and entrepreneurial firms are a frequent research topic in psychological research. However, the focus of this research has largely been on the entrepreneur as a person and on the entrepreneurs’ strategy for the business. By contrast, the entrepreneur as a leader and the entrepreneurial firm as a work environment for employees have received little attention. Therefore, this dissertation aims to integrate theoretic thoughts from organizational behavior research into entrepreneurship research. Specifically, I will focus on novelty creation within entrepreneurial firms and organizational phenomena which provide a context for employees in novelty creating activities. This dissertation adds to the literature as it provides insight in the effects of work environment facets on employees’ engagement in novelty creating activities in entrepreneurial businesses. In three empirical chapters, I will focus first on the effects of entrepreneurial orientation on efficiency of employee work in innovation projects. Second, I will look at a facet of organizational culture, the error management culture, and its effects on individual learning of employees. Last, I will focus on occupational roles of employees within small businesses and effects of these roles on responses to a questionnaire and on work in innovation projects. In all three empirical chapters I test my hypotheses in a sample of N = 40 entrepreneurial businesses and employees within these businesses. For my chapter on occupational roles this sample is complemented by two additional samples of college students. In sum, results indicate that the entrepreneurial business in all three chapters exerts significant influences on employee work. Furthermore, I show that employee participation in novel activities is positive for entrepreneurial businesses (Chapter 2: Correlation between employees’ and entrepreneurs’ evaluation of innovation project effectiveness: r = .44; p < .01; Chapter 3: Correlation between organizational level leaning and organizational growth in sales: r = .35; p < .01). Therefore, I suggest that research on the entrepreneurial firm as a context for work may contribute to our knowledge on success factors in entrepreneurship, and may therefore be a relevant direction of future research. Especially, it may be fruitful to investigate aspects of work in which entrepreneurial firms may differ from other, less entrepreneurial organizations.
The role of tree diversity for individual tree growth, crown architecture and branch demography
(2012)
In the light of the concurrent loss of biodiversity, biodiversity and ecosystem functioning (BEF) research attracted a great deal of attention and emerged as one of the important fields of research in ecology. Since important ecological interactions such as competition occur between individuals, the understanding of individual tree growth was considered to be fundamental for forest related BEF research. Individual tree growth is determined by the above- and belowground interactions of a tree individual with its local neighbourhood. To obtain a deeper understanding of BEF relationships, I broadened the focus from individual tree growth (usually measured as diameter or biomass increment) to the arrangement and dynamics of the above-ground modules of trees in dependence of their local neighbourhood. More precisely, the main objective of the present thesis was to analyse the impact of tree diversity on individual tree growth, crown architectural and branch demographic variables. Thereby I considered crown architectural variables as important indicators of the competition for light. In addition, crown architectural variables impacted ecosystem services such as erosion control. Furthermore, the results of the present thesis contributed to the current discussion on species coexistence theories, which may be differentiated by two opposing views: one that relies on neutral processes and one that implicates a role for meaningful differences in the ecological strategy (niche) of co-occurring species. The studied forest ecosystems were the subtropical broad-leaved evergreen forests of southeast China, which have been under high human pressure due to a long history of intensive land-use. The area is of particular interest for BEF research due to the high species richness of woody plants, including many, yet poorly studied species, and due to the rough terrain with steep slopes, which cause severe soil erosion. The present thesis combines three observational with two experimental studies, applying the local neighbourhood approach along an age gradient from tree saplings to mature trees. In the Gutianshan National Nature Reserve (GNNR), I conducted two observational studies on permanent plots which were chosen according to a space-for-time substitution design. The aim of the first study was to reveal the effects of diversity (species richness, functional diversity) together with other biotic and abiotic variables on morphological growth parameters (crown area, crown displacement and stem inclination) of target trees of four tree species (Castanea henryi, Castanopsis eyrei, Quercus serrata and Schima superba). In the second study, the same target trees together with their neighbours were used to analyse the relation between stand related functional diversity and the horizontal and vertical structure of the canopy. The third study was conducted in a young secondary broad-leaved evergreen forest. Using two target species (Castanopsis fargesii and Quercus fabri), the role of diversity, intra- vs. inter-specific competition and the mode of competition (symmetric vs. asymmetric) on the target individuals was tested by analysing five-year radial growth increments. The two other studies were carried out in an experimentally established plantation, using saplings of four tree species (C. henryi, Elaeocarpus decipiens, Q. serrata and S. superba), which were planted in monoculture, twoand four-species combinations and in three densities. The fourth study focused on mechanisms of coexistence and the role of species richness, species composition, species identity and density on sapling growth. The fifth study tested the effect of sapling density and identity on the througfall kinetic energy, which represents a measure for the erosive power of rain. It was found that functional diversity does affect crown architectural and canopy related parameters of forests in the GNNR. However, no effects of species richness on radial-growth were detected in the younger forest. Since I also did not find strong effects of species richness on saplings in the experimental plantation, diversity effects may evolve at a later age stage. The importance of the diversity effect may be related reversely to that of species identity in an age gradient of forest stands. The findings suggest that different mechanisms of coexistence operate simultaneously but that their relative importance may shift through the life stages of trees. During the sapling stage, species-specific differences in growth and architectural traits support niche theory. In older forest stands, no species-specific differences in growth parameters could be detected. However, I did find effects of functional diversity on horizontal canopy structure. I conclude that mechanisms of coexistence may not only change with forest stand age, but may also differ for distinct traits. The present thesis, being the first to apply the local neighbourhood approach with regard to crown architecture and branch demography within the BEF field of research, stresses the importance of this individual based approach. Although the observed forest systems are very complex, crown architectural and canopy structural variables were found to be affected by diversity. The finding that the degree of erosive power of rain could be elucidated by crown architectural variables, encourages further studies to reveal possible relations between biodiversity and other ecosystem functions or services, which might be mediated by crown architectural and canopy structural variables.