RTG 2300: Enrichment of European beech forests with conifers: impacts of functional traits on ecosystem functioning

The societal demands for ecosystem goods and services are globally increasing. One possibility to meet this challenge is to manage forests in such a way that aspects of wood production and forest conservation are combined. Against this background, mixed forest stands composed of locally occurring native tree species and highly productive tree species growing outside of their native range are of particular interest. Despite the importance of native-non-native tree species mixtures, their impact on ecosystem functioning has rarely been studied. It is generally assumed that presence, abundance, distribution, and diversity of functional traits are more important for ecosystem functioning than species diversity per se. To study this assumption in further detail, the RTG 2300 aims at identifying the functional traits and associated mechanisms that control ecosystem functioning in pure and mixed stands of European beech (Fagus sylvatica, a deciduous tree species which would be the dominant tree species in Central Europe under natural conditions), Norway spruce (Picea abies, a native conifer species mainly cultivated outside its natural range) and Douglas-fir (Pseudotsuga menziesii, a non-native conifer species, which originates from the Pacific Northwest of North-America). It is hypothesized that mixtures of European beech with conifers show higher functional diversity than pure European beech stands and that the effects of admixed conifers on ecosystem functioning are more pronounced in mixtures with Douglas-fir.

40 forest stands differing in tree species composition and site quality have been selected. Eleven closely linked subprojects focus on key functional traits of the tree species and associated biota and the mechanisms that link them with ecosystem functioning. The interdisciplinary research approach requires close cooperation between students and supervising scientists which will be facilitated by different team building activities. The concept of qualification is based on an ambitious and clearly structured programme of intensive interdisciplinary research and supervision, which will support top-class PhD studies. Special options for further qualification and support for career planning are offered to a postdoctoral researcher. The comprehensive programme will expose the students to a broad array of methods, ranging from molecular genetics, over ecophysiology and isotope analyses to sophisticated regression modelling. The systematic and profound research-oriented qualification will generate highly skilled natural resource managers with topical knowledge and skills that cross disciplinary boundaries and provide key qualifications for careers in academia, the public sector and enterprises.