Forest simulation models in Netherlands: main developments and challenges WG1 Gert-Jan Nabuurs, Koen Kramer, MartJan Schelhaas, Isabel vd Wyngaert, Geerten Hengeveld, Frits Mohren COST ACTION FP0603: Forest models for research and decision support in sustainable forest management 1st Workshop and Management Committee Meeting. Institute of Silviculture, BOKU. 8-9 of May 2008 Vienna, Austria

Main features of Dutch forests Forest cover (total/share): ha / ~10% of the land Growing stock, annual growth and cuts: 65 Mm3, 2.5Mm3, 1.2 Mm3 Main species: scots pine, pedunculate oak, beech Main non-wood products and services: recreation/ landscape Main risks: storm damage Management and silvicultural characteristics: a strong trend towards nature oriented management started already late seventies. This was initiated by storms of 1970’s, and partly because the ownership was fragmented, and not profitable anyway. One third of forest is owned by nature conservation organisations

Forest modelling approaches and trends Empirical models Main empirical models are growth functions underlying the yield tables. Permanent plots are hardly maintained. A national inventory is carried out on 3000 plots in a cycle of 5 years Netherlands is included in the empirical model EFISCEN, covering whole of Europe. This is an area matirx model, covering some 5000 forest types across EU 27. EFISCEN is being improved to high resolution empirical model for whole of EU27 (EFISCEN-space). Harvest/increment ratio in 2040 by region

Mechanistic models Forgem (individual tree, process based with genetics) (Kramer et al) Forspace (landscape scale, process based, emphasis on disturbances and herbivory) Forest modelling approaches and trends

Models for predicting risk of hazards -a semi mechanistic storm damage module was build in FORGEM (Schelhaas). This will be improved in efiscen-space - Storm risks were scaled up in the previous regional version of efiscen gravity wind Resistance against breaking Resistance against uprooting wind

Simulators and information systems Forest level decision support systems ~ possibly EFISCEN can be seen as a decision support system.

Research highlight - Netherlands in a European context as simulated with efiscen - Coupling of mechanistic aspects, management, and genetics in forgem - Spatial aspects in relation to herbivory in forspace - disturbance chances, mechanistic aspects of storms, and relation to beetle attacks - European forests as covered by 260,000 inventory plots and its options to simulate impacts of climate change, using GIS material. Application to natura 2000, wood supply, distance to industry, carbon sequestration in relation to climate impacts

Future challenges Maintain and further develop model series of forgem- forspace and Efiscen-space Detailed models: gain insight in processes and functional relations (with aspects of management, and disturbances under environmental changes) Larger scale model (efiscen): support strategic choices concerning wood availability, biomass, biodiversity, carbon sequestration under climate change Efiscen-space allows upscaling exercises and improved links to detailed models: overlays of e.g. Natura 2000, transport distance questions, and improved analyses of impact of disturbances under climate change

Innovative references Kramer, K., Werf, B. van der, Schelhaas, M.J., & Wijdeven, S.M.J. (2004). Scenario evaluation for the optimisation of adaptive potential and conservation of diversity. In K. Kramer (Ed.), Effects of silvicultural regimes on dynamics of genetic and ecological diversity of European beech forests; impact assessment and recommendations for sustainable forestry (pp ) [S.l.]: [s.n.].. Nabuurs, G.J., R. Päivinen, A. Pussinen & M.J. Schelhaas: Development of European forests until 2050; a projection of forest resources and forest management in thirty countries. Leiden/Boston, Brill, Eur. Forest Inst. Res. Rep. 15, 242 pp. Schelhaas, M., Nabuurs, G.J.M.M. & Schuck, A. (2003). Natural disturbances in the European forests in the 19th and 20th centuries. Global Change Biology, 9(11), Nabuurs, G.J., J. van Brusselen, A Pussinen. M.J. Schelhaas Future harvesting pressure on European forests. European Journal of Forest Research. 126: 391–400