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Conference paper2008Peer reviewed

Adjustment of an emperical growth and yield model to account for effects of climate change on forest production

Freeman Michael, Wikström Peder, Elfving Björn Olov


In forest management planning, it should be possible to handle that climate change is currently altering the environmental conditions for forest growth and will continue to do so in the future. Traditionally, empirical growth and yield models based on historical growth data and historic environmental conditions have been used to reliably predict forest timber production. The weakness of these models is, though, that they do not incorporate a mechanistic description of the interaction with the environment and, thus, their predictions in a changing climate become less reliable. We present a method using process-based modelling for adjusting an empirical growth and yield model to be responsive to climate change. The relative effect of climate change simulated by the process-based model is used to adjust the prediction of the empirical model for every 5-year period according to actual stand condition. The responsiveness is primarily based on simulations driven by GCM-scenario data; ECHAM4 and HadAM3 with emission scenarios A2 and B2 from IPCC’s SRES, regionalised by the Swedish Meteorological and Hydrological Institute. The study area is Sweden but the principles are general. Effects of elevated CO2 and temperature, changed patterns of precipitation, as well as feed back on tree growth from soil fertility and soil water availability, are considered. The end-use of the adjusted empirical model does not require any additional data to those already found as input or output in the original empirical model. This is in contrast to many other methods in literature, where requirements of substantial amounts of additional input data represent a hinder for its practical use. The method of adjustment that we present is applicable to stands, whether they are already present at the year of inventory, established at the year of inventory, or planned to be established in the future. The response of forest stands to changes in climate predicted by the adjusted empirical model is sensitive to management. For stands already present at the year of inventory we show the importance of stand management history for the predictions of future growth


climate change; forest management planning; process-based modelling; scenarios

Published in


Adaptation of Forests and Forest Management to Changing Climate with Emphasis on Forest Health: A Review of Science, Policies and Practices