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Dieback in Norway Spruce - Causality and future Management Strategies

Project Leader
Godbold Douglas L., BOKU Project Leader
Type of Research
Applied Research
BOKU Research Units
Institute of Forest Ecology
Funded by
Norwegian Research Council, Norway
PART 1: The KMB project
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 (southeast) Norway. The symptoms typically appear in dominant or co-dominant trees in productive mature stands and often on former agricultural sites. They show top dieback, stunted growth and needle discoloration often associated with nutrient difficiency, bark beetle infection or Armillaria spp. attack. Trees die 1-4 years after the first symptoms appear. Drought stress is a limiting factor for Norway spruce growth in this region (Andreassen et al. 2006) and a possible driving factor of the observed damage. The damage inflicts a cost on forest owners as they need to harvest earlier than at the optimum rotation age and raises serious concerns about how to manage these forests for the future.
1. Objectives
The main objectives of this project are to identify possible risk factors, propose the mechanisms of dieback, and outline relevant alternatives for the future management of forests in SE Norway, particularly regarding drought stress in Norway spruce. In the project we aim to
• describe and diagnose the observed damage: We will describe the symptoms, identify the role of biotic agents and create maps displaying the geographical extent of the damage,
• identify the most likely mechanisms: Through field studies and analyses of long term data set, damage, growth and mortality as well as other measures of stress in Norway spruce will be related to site- and stand factors and to the severity of drought,
• project the effect of climate change: Using the REGCLIM climate scenario for Norway, we will forecast the areal extent of drought related stress as a response to a warmer and drier climate.
• facilitate a discussion on the silvicultural alternatives in SE Norway: A group of silvicultual specialists will be formed. Work shop-discussions with practitioners will focus on how to adapt Norway spruce management and tree species selection to the uncertainties of the future climate.
forest ecology;
fine roots; Spruce decline; mycorrhizas;
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