BIONÆR-Bionæringsprogram

Dieback of 40-60 years old Norway spruce trees (Picea abies L. Karst.) is frequently observed in vigorously growing stands in the lowlands of SE Norway. The symptoms typically appear in productive mature stands and often on former agricultural sites. Drou ght stress is a limiting factor for Norway spruce growth in this region and a possible driving factor of the observed damage. The damage inflicts a cost on forest owners and raises serious concerns for the future under climate change. The objectives of th is project are to identify possible risk factors, propose the mechanisms of dieback, and outline relevant alternatives for future management. In the project we aim to i) describe and diagnose the observed damage, ii) identify the most likely mechanisms ii i) project the effect of climate change, iv) facilitate a discussion. The overarching hypothesis is that the projected increase in summer temperature and decrease in precipitation will move the southern range of Norway spruce north. We will combine tradit ional and novel methods i.e. large-scale statistical methods, eco-physiological investigations and remote sensing. The project will increase the scientific competence on i) automatic detection of damage in aerial photographs and extraction of climate resp onses in MODIS satellite data, ii) stable isotope- and wood anatomical techniques to link physiological stress to site factors and stand productivity. It will 1) identify site factors that explain the contrasting responses of trees, 2) map the extent of d amage, 3) evaluate the effect of site and stand factors predisposing trees to drought stress, 4) forecast the potential growth reduction and drought related stress in Norway spruce based on projected climate change, 5) discuss and interact with practition ers to identify a strategy for adaption. The project will help forest management to decide on site suitability and how to manage Norway spruce as well as broadleaved forests in SE Norway under climate change.