Workshop “Silviculture in
Changing Environment“
November 24-25, 2014
Kirkkonummi, Finland
Changes of coniferous timber and tree
lines in Finnish Lapland during 1983-2009
Anna Franke, Pasi Aatsinki, Ville Hallikainen, Esa Huhta,
Mikko Hyppönen, Vesa Juntunen, Kari Mikkola,
Seppo Neuvonen and Pasi Rautio
Research group, in addition to authors
Tarmo Aalto
Hannu Herva
Jari Hietanen
Esko Jaskari
Heikki Kauhanen
Mikko Kukkola
Kari Mikkola
Kuisma Ranta
Katja Sippola
Raija Vainio
Pekka Välikangas
Contents of the presentation
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Forest timber line research in Metla
About the experiment
Aim of the monitoring study
Material and methods
Results
Discussion and conclusions
Forest timber- and tree-line research in Metla
• The forests in timber- and tree-line area are supposed to indicate climatic
variation and changes.
• Metla administers a forest-line experiment, jointly founded by Helsinki, Oulu
and Turku universities and Metla in 1980s.
• Regeneration and success of Scots pine, Norway spruce and birch are
monitored at northern and alpine timber lines in the experiment.
• The inventory years: 1983, 1994, 1999, 2004 and 2009.
• Results of the study have been published twice (Juntunen et al. 2002, 2006).
• In addition, Metla has an official role to monitor the forest regeneration success
in the protection forest area (Forest act 1997).
Earlier reports of the experiment
• Kallio, P., Hurme, H., Eurola, S., Norokorpi, Y. & Sepponen, P. 1986.
Research activities on the forest line in Northern Finland. Arctic
39(1): 52-58.
• Juntunen, V., Neuvonen, S., Norokorpi, Y. & Tasanen, T. 2002.
Potential for timberline advance in Northern Finland, as revealed by
monitoring during 1983-1999. Arctic 55(4): 348-361.
• Juntunen, V. & Neuvonen, S. 2006. Natural regeneration of Scots
pine and Norway spruce close to the timberline in Northern
Finland. Silva Fennica 40(3): 443-458.
Protection forest area and conifer timber lines
Map: K. Mikkola, Metla
Alpine forest line area in
Pitkäsuvanto, Inari
Photo R. Jalkanen
Pine tree line in Saariselkä, Inari
Photo R. Jalkanen
Spruce tree and timber lines, Ylläs,
Kolari
Photo R. Jalkanen
Aim of the study
• To monitor the changes and variation of stem
number and volume of growing stock of conifer
species in northern and alpine forest line areas in
Northern Finland
• The monitored variables for this study
– Volume of growing stock m3 ha-1 (trees > 2 m)
– Number of trees ha-1
Monitoring
locations
and regions
Experiment
design
Examples of the monitoring areas –
Alajoenpää and Urupää, Inari
Stem number of pine
Pine snow blight (Phacidium infestans) is a
bad winter pathogen of Scots pine
Photo R. Jalkanen
Volume of growing stock of pine
Stem number of spruce
Volume of the growing stock of spruce
Temperature sum in Kevo, Sodankylä and Kuusamo
in 1976−2013
Results of earlier studies in timber-line and protection forests
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Juntunen ym. 2002: Study showed new regeneration and tree establishment in Northern Finland
during recent decades, indicating potential for an advance of timber line and tree line (timberline
monitoring).
Hyppönen ym. 2003: Climate has been relatively favourable for forest regeneration during the
recent decades. If the climate does not abruptly change in the near future no changes will be in
forest regeneration (protection forest monitoring).
Varmola et al. 2004: Temperature plays the main role in forest regeneration and the temperature
sum expresses well the location of the Scots pine timber line. Natural regeneration of pine has
been satisfactory, especially combined with soil preparation. Pine forests often regenerate in the
form of advance growth without any silvicultural action (protection forest monitoring).
Juntunen & Neuvonen 2006: Pine and spruce regenerated more or less regularly in all zones
during 1983–1999. However, seedling mortality of pine was much higher compared to spruce. The
results suggest that stand dynamics in the timberline habitats are strongly controlled by seedling
mortality due to a variety of causes (timberline monitoring).
Hyppönen et al. 2012: Climate has been favourable for the regeneration of forests in the
protection forest area and in high altitude forests. Extreme temperature conditions have
stabilized. Seedling establishment has succeeded satisfactorily and seedling mortality has stayed
low (protection forest monitoring).
Conclusions
• Stem number and volume of spruce have increased in the sprucedominated regions in all zones during the monitored period.
• Volume of pine has slowly increased in the pine regions in all zones,
as well, but instead, stem number of pine has stagnated or even
decreased in all zones.
• The results indicate a clear potential for the spruce timber and tree
lines to advance upwards and northwards.
• Spruce needs favorable conditions for regeneration but after seedling
establishment spruce seedlings seem to be more resistant against biotic and
abiotic disturbances than pine seedlings.
• Responses to environmental changes are species-specific and
hence, more favorable environmental conditions do not necessarily
lead to expansion of coniferous forest line