Forest growth response to changing climate between 1961 and 1990 in Austria

Using 30 years of climate records from 20 weather stations, we investigate the magnitude of temperature and precipitation change, and change in the le ngth of the growing season between 1961 and 1990. Special attention is paid to the period between 1981 and 1990, because recent research suggests that , during this time-span, forest productivity may have increased in the nort hern latitudes. In order to understand the importance of changes in climate on forest growth, we use the ecosystem model FOREST-BGC as a diagnostic to ol to predict the annual net primary production (NPP). The results of our s tudy indicate: no change in precipitation between 1961 and 1990; a signific ant (alpha = 0.05) increase in mean annual temperature of 0.72 degrees C, m ean annual minimum temperature (0.80 degrees C), winter temperature (2.36 d egrees C) as well as an increase in the length of the temperature controlle d growing season by 11 days, resulting in a significant increase in diamete r increment obtained from 1179 cores of Norway spruce across Austria. The t rends in NPP are consistent with observed increment rates validating the us e of biogeochemical modeling as a diagnostic tool to search for possible ca uses on changing environmental conditions. (C) 1999 Elsevier Science B.V. A ll rights reserved.