Search Results
Fire, late frost, nun moth and drought risks in Germany's forests under climate change
2016, Lasch-Born, Petra, Suckow, Felicitas, Gutsch, Martin, Hauf, Ylva, Hoffmann, Peter, Kollas, Chris, Reyer, Christopher P.O.
Ongoing climate change affects growth and increases biotic and abiotic threats to Germany's forests. We analysed how these risks develop through the mid-century under a variety of climate change scenarios using the process-based forest model 4C. This model allows the calculation of indicators for fire danger, late frost risk for beech and oak, drought stress and nun moth risk. 4C was driven by a set of 4 simulations of future climate generated with the statistical model STARS and with 10 simulations of future climate based on EURO-CORDEX model simulations for the RCP2.6, RCP4.5 and RCP8.5 pathways. A set of about 70000 forest stands (Norway spruce, Scots pine, beech, oak, birch), based on the national forest inventory describing 98.4 % of the forest in Germany, was used together with data from a digital soil map. The changes and the range of changes were analysed by comparing results of a recent time period (1971–2005) and a scenario time period (2011–2045). All indicators showed higher risks for the scenario time period compared to the recent time period, except the late frost risk indicators, if averaged over all climate scenarios. The late frost risk for beech and oaks decreased for the main forest sites. Under recent climate conditions, the highest risk with regard to all five indicators was found to be in the Southwest Uplands and the northern part of Germany. The highest climate-induced uncertainty regarding the indicators for 2011–2045 is projected for the East Central Uplands and Northeast German Plain.
Tackling unresolved questions in forest ecology: The past and future role of simulation models
2021, Maréchaux, Isabelle, Langerwisch, Fanny, Huth, Andreas, Bugmann, Harald, Morin, Xavier, Reyer, Christopher P.O., Seidl, Rupert, Collalti, Alessio, Dantas de Paula, Mateus, Fischer, Rico, Gutsch, Martin, Lexer, Manfred J., Lischke, Heike, Rammig, Anja, Rödig, Edna, Sakschewski, Boris, Taubert, Franziska, Thonicke, Kirsten, Vacchiano, Giorgio, Bohn, Friedrich J.
Understanding the processes that shape forest functioning, structure, and diversity remains challenging, although data on forest systems are being collected at a rapid pace and across scales. Forest models have a long history in bridging data with ecological knowledge and can simulate forest dynamics over spatio-temporal scales unreachable by most empirical investigations.We describe the development that different forest modelling communities have followed to underpin the leverage that simulation models offer for advancing our understanding of forest ecosystems.Using three widely applied but contrasting approaches - species distribution models, individual-based forest models, and dynamic global vegetation models - as examples, we show how scientific and technical advances have led models to transgress their initial objectives and limitations. We provide an overview of recent model applications on current important ecological topics and pinpoint ten key questions that could, and should, be tackled with forest models in the next decade.Synthesis. This overview shows that forest models, due to their complementarity and mutual enrichment, represent an invaluable toolkit to address a wide range of fundamental and applied ecological questions, hence fostering a deeper understanding of forest dynamics in the context of global change.
Verbundprojekt OakChain - "Eichen-Kiefern-Mischbestände" : Abschlussbericht 2010 ; TP 2.2: Modellgestützte Analyse von Eichen-Kiefern Mischbeständen im subkontinentalen Nordostdeutschen Tiefland unter Klimawandel
2010, Suckow, Felicitas, Gutsch, Martin, Lasch, Petra, Badeck, Franz
[no abstract available]
Balancing trade-offs between ecosystem services in Germany's forests under climate change
2018, Gutsch, Martin, Lasch-Born, Petra, Kollas, Chris, Suckow, Felicitas, Reyer, Christopher P.O.
Germany's forests provide a variety of ecosystem services. Sustainable forest management aims to optimize the provision of these services at regional level. However, climate change will impact forest ecosystems and subsequently ecosystem services. The objective of this study is to quantify the effects of two alternative management scenarios and climate impacts on forest variables indicative of ecosystem services related to timber, habitat, water, and carbon. The ecosystem services are represented through nine model output variables (timber harvest, above and belowground biomass, net ecosystem production, soil carbon, percolation, nitrogen leaching, deadwood, tree dimension, broadleaf tree proportion) from the process-based forest model 4C. We simulated forest growth, carbon and water cycling until 2045 with 4C set-up for the whole German forest area based on National Forest Inventory data and driven by three management strategies (nature protection, biomass production and a baseline management) and an ensemble of regional climate scenarios (RCP2.6, RCP 4.5, RCP 8.5). We provide results as relative changes compared to the baseline management and observed climate. Forest management measures have the strongest effects on ecosystem services inducing positive or negative changes of up to 40% depending on the ecosystem service in question, whereas climate change only slightly alters ecosystem services averaged over the whole forest area. The ecosystem services 'carbon' and 'timber' benefit from climate change, while 'water' and 'habitat' lose. We detect clear trade-offs between 'timber' and all other ecosystem services, as well as synergies between 'habitat' and 'carbon'. When evaluating all ecosystem services simultaneously, our results reveal certain interrelations between climate and management scenarios. North-eastern and western forest regions are more suitable to provide timber (while minimizing the negative impacts on remaining ecosystem services) whereas southern and central forest regions are more suitable to fulfil 'habitat' and 'carbon' services. The results provide the base for future forest management optimizations at the regional scale in order to maximize ecosystem services and forest ecosystem sustainability at the national scale.
The PROFOUND Database for evaluating vegetation models and simulating climate impacts on European forests
2020, Reyer, Christopher P.O., Silveyra Gonzalez, Ramiro, Dolos, Klara, Hartig, Florian, Hauf, Ylva, Noack, Matthias, Lasch-Born, Petra, Rötzer, Thomas, Pretzsch, Hans, Meesenburg, Henning, Fleck, Stefan, Wagner, Markus, Bolte, Andreas, Sanders, Tanja G.M., Kolari, Pasi, Mäkelä, Annikki, Vesala, Timo, Mammarella, Ivan, Pumpanen, Jukka, Collalti, Alessio, Trotta, Carlo, Matteucci, Giorgio, D'Andrea, Ettore, Foltýnová, Lenka, Krejza, Jan, Ibrom, Andreas, Pilegaard, Kim, Loustau, Denis, Bonnefond, Jean-Marc, Berbigier, Paul, Picart, Delphine, Lafont, Sébastien, Dietze, Michael, Cameron, David, Vieno, Massimo, Tian, Hanqin, Palacios-Orueta, Alicia, Cicuendez, Victor, Recuero, Laura, Wiese, Klaus, Büchner, Matthias, Lange, Stefan, Volkholz, Jan, Kim, Hyungjun, Horemans, Joanna A., Bohn, Friedrich, Steinkamp, Jörg, Chikalanov, Alexander, Weedon, Graham P., Sheffield, Justin, Babst, Flurin, Vega del Valle, Iliusi, Suckow, Felicitas, Martel, Simon, Mahnken, Mats, Gutsch, Martin, Frieler, Katja
Process-based vegetation models are widely used to predict local and global ecosystem dynamics and climate change impacts. Due to their complexity, they require careful parameterization and evaluation to ensure that projections are accurate and reliable. The PROFOUND Database (PROFOUND DB) provides a wide range of empirical data on European forests to calibrate and evaluate vegetation models that simulate climate impacts at the forest stand scale. A particular advantage of this database is its wide coverage of multiple data sources at different hierarchical and temporal scales, together with environmental driving data as well as the latest climate scenarios. Specifically, the PROFOUND DB provides general site descriptions, soil, climate, CO2, nitrogen deposition, tree and forest stand level, and remote sensing data for nine contrasting forest stands distributed across Europe. Moreover, for a subset of five sites, time series of carbon fluxes, atmospheric heat conduction and soil water are also available. The climate and nitrogen deposition data contain several datasets for the historic period and a wide range of future climate change scenarios following the Representative Concentration Pathways (RCP2.6, RCP4.5, RCP6.0, RCP8.5). We also provide pre-industrial climate simulations that allow for model runs aimed at disentangling the contribution of climate change to observed forest productivity changes. The PROFOUND DB is available freely as a “SQLite” relational database or “ASCII” flat file version (at https://doi.org/10.5880/PIK.2020.006/; Reyer et al., 2020). The data policies of the individual contributing datasets are provided in the metadata of each data file. The PROFOUND DB can also be accessed via the ProfoundData R package (https://CRAN.R-project.org/package=ProfoundData; Silveyra Gonzalez et al., 2020), which provides basic functions to explore, plot and extract the data for model set-up, calibration and evaluation.
Description and evaluation of the process-based forest model 4C v2.2 at four European forest sites
2020, Lasch-Born, Petra, Suckow, Felicitas, Reyer, Christopher P. O., Gutsch, Martin, Kollas, Chris, Badeck, Franz-Werner, Bugmann, Harald K. M., Grote, Rüdiger, Fürstenau, Cornelia, Lindner, Marcus, Schaber, Jörg
The process-based model 4C (FORESEE) has been developed over the past 20 years to study climate impacts on forests and is now freely available as an open-source tool. The objective of this paper is to provide a comprehensive description of this 4C version (v2.2) for scientific users of the model and to present an evaluation of 4C at four different forest sites across Europe. The evaluation focuses on forest growth as well as carbon (net ecosystem exchange, gross primary production), water (actual evapotranspiration, soil water content), and heat fluxes (soil temperature) using data from the PROFOUND database. We applied different evaluation metrics and compared the daily, monthly, and annual variability of observed and simulated values. The ability to reproduce forest growth (stem diameter and biomass) differs from site to site and is best for a pine stand in Germany (Peitz, model efficiency ME=0.98). 4C is able to reproduce soil temperature at different depths in Sorø and Hyytiälä with good accuracy (for all soil depths ME > 0.8). The dynamics in simulating carbon and water fluxes are well captured on daily and monthly timescales (0.51 < ME < 0.983) but less so on an annual timescale (ME < 0). This model–data mismatch is possibly due to the accumulation of errors because of processes that are missing or represented in a very general way in 4C but not with enough specific detail to cover strong, site-specific dependencies such as ground vegetation growth. These processes need to be further elaborated to improve the projections of climate change on forests. We conclude that, despite shortcomings, 4C is widely applicable, reliable, and therefore ready to be released to the scientific community to use and further develop the model.
Modeling of two different water uptake approaches for mono-and mixed-species forest stands
2015, Gutsch, Martin, Lasch-Born, Petra, Suckow, Felicitas, Reyer, Christopher P.O.
To assess how the effects of drought could be better captured in process-based models, this study simulated and contrasted two water uptake approaches in Scots pine and Scots pine-Sessile oak stands. The first approach consisted of an empirical function for root water uptake (WU1). The second approach was based on differences of soil water potential along a soil-plant-atmosphere continuum (WU2) with total root resistance varying at low, medium and high total root resistance levels. Three data sets on different time scales relevant for tree growth were used for model evaluation: Two short-term datasets on daily transpiration and soil water content as well as a long-term dataset on annual tree ring increments. Except WU2 with high total root resistance, all transpiration outputs exceeded observed values. The strongest correlation between simulated and observed annual tree ring width occurred with WU2 and high total root resistance. The findings highlighted the importance of severe drought as a main reason for small diameter increment. However, if all three data sets were taken into account, no approach was superior to the other. We conclude that accurate projections of future forest productivity depend largely on the realistic representation of root water uptake in forest model simulations.