Kurzbeschreibung
(Englisch)
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In Europe, traditional single-species forest plantations are increasingly being replaced by mixed-species forests. Mixed forets are thought to have several advantages over single-species forests, particularly with respect to the provision of multiple ecosystem goods and services (EGS) including higher resistance and resilience to disturbances and future climate change. However, empirical studies that quantify and compare these proposed benefits between forest types are rare. Dynamic landscape models have reached a high degree of sophistication regarding the quantification of climate impacts, disturbance dynamics, management constraints, and the provision of EGS. We propose to use the forest landscape model LandClim to address the above questions. LandClim simulates local forest succession in conjunction with landscape level disturbances and management. Our research has two main goals. First, we will use LandClim to simulate single-species and mixed-species forests under identical climatic and edaphic conditions and quantify the difference in productivity, ecosystem resistance/resilience, and provisioning of EGS. Second, we will identify potential future forest states that are most suited for a continual provisioning of EGS under various climate change scenarios and disturbance regimes. This project will help to clarify the benefits of mixed-species forests and offer possible conversion strategies for forest managers and conservationists.
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Abstract
(Englisch)
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European forestry is currently in transition, with an increasing number of single-species coniferous forest being converted into mixed-species forests. Proposed benefits include an increase in productivity, increased resilience to disturbances, higher resistance to climate change, as well as the provisioning of a wider range of ecosystem services (ES). Although mixed-species forestry appears to be a promising approach for creating productive and resistant forests for the future, the influence of species composition, mixture level or age classes remains unclear. The project uses a modeling approach to evaluate the putative benefits of mixed-species forests over monocultures. Due to the flexibility of simulation modeling, it is possible to examine a very wide range of multispecies combinations and age structures (single vs. mixed-species, even-aged vs. uneven-aged) compared to experimental approaches. Also, the modeling approach allows us to quantify those forest characteristics that are important for providing various ES. The selected ES are: (1) tree biomass production, (2) protection against gravitational natural hazards, and (3) conservation issues such as habitat quality for birds. In the present reporting period, in-depth simulation studies were conducted in two mountain case study landscapes, and the results were analyzed with respect to the suitability of single-species vs. mixed-species forests to provide a portfolio of ecosystem services demanded by society (e.g., biodiversity, timber production, protection from natural hazards). The results suggest that multi-species mixtures are often, but not always more suitable for providing ecosystem services; however, for multiple services demanded from the same area, multispecies mixtures are always outperforming single species. A manuscript describing these insights has been submitted to an international journal. In addition, we have started a detailed evaluation of the two key processes that determine species diversity, i.e. competition and regeneration. A new version of the model LandClim was developed that allows us to evaluate these relationships for both current climate as well as for records of past vegetation dynamics (pollen data). These investigations are currently ongoing, and results will be available with the next report.
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