1. Forest damage in a changing climate
Anna Maria Jönsson and Lars Bärring
Dept. of Physical Geography and Ecosystem Analysis
Geobiosphere Science Centre, Lund University

2. Forest damage in a changing climate
Predisposing factors
Climate change, Tree species and Provenances
Forest management, Nutrient availability, Air pollution
Triggering factors
Weather events exceeding tree acclimatization capacity
Often causing visible damage
Contributing factors
Attacks by pests and pathogens
Often the cause of mortality

3. Extreme weather event ≠ Extreme situation for the tree
Acclimatization
The ability to adjust to changing weather conditions
Tolerate non-optimal conditions
Threshold values could be more important than extreme values
Affected by Example
Seasonality Spring backlashes
Intensity Flooding
Duration Dry spells
Frequency Wind storms
Combination Spring frost followed by drought

4. Tree nutrient availability
decomposition, weathering, mycorrhiza, leakage
Climate change
temperature
dry spells during summer
flooding episodes
storm frequency
Tree damage
frost damage
drought stress
root oxygen deficiency
wind throw, root damage
CO2
Pests and Pathogens
Photosynthesis: growth - repair - defence - respiration
NPP
+10-20%

5. Ongoing activities within ENSEMBLES
related to task 6.2.2, 6.2.3, and
Spring backlash index: Frost damage projections
SBI has been calculated for Sweden, is currently applied to European conditions using the PRUDENCE dataset, and will use ENSEMBLES RCM data.
A Frost hardiness and damage sub-module is incorporated to the vegetation model LPJ-GUESS.
2) Modelling the temperature dependent development of the
spruce bark beetle Ips typographus
The model has been applied to south Swedish conditions, and will be applied for Northern European spruce forests using ENSEMBLES RCM data.

6. Start of dehardening in Norway spruce
5 consecutive days with a mean temperature above 5°C
Scenario B2
Scenario A2 1 2 3 4 5
month
Climate data: HadRM3

7. Frost events after the start of dehardening over 30-years
Control period
Scenario B2 - Control
Scenario A2 - Control
Number of events
Difference

8. Temperature dependent annual cycle of Ips typographus
Egg development
Summer swarming?
>
Spring swarming
Egg development?
Winter mortality
Almost 100% for not completely
developed bark beetles

9. Development of Ips typographus in Växjö
April May June July August September
Scenario B2
Scenario A2
Spring swarm Completed development

10. Temperature dependent summer swarming
of Ips typographus
Data from RCA3
Scenario A2