The basis for a healthy productive forest is the use of the right reproductive material. In Finland genetically improved seed is produced in seed orchards, located in different parts of the country. The seed from these orchards is adapted to a certain area, depending on the location of the orchard and origin of the mother trees growing in the orchards.
Until today the so called deployment area of the seed from each orchard has been defined by a rather rough estimation, based on temperature sum. It is obvious that climate change will affect the optimal deployment areas for seed orchards in the near future. The present definitions are also limited in the way that they are based on risk (i.e. survival) only.
It is obvious that climate change will affect the optimal deployment areas for seed orchards in the near future.
Nowadays we have the availability of a quite large set of data from field trials on the performance of certain seed sources in different geological and climatological areas. The first of these so called provenance trials in Finland were established already during the early 1930’s by Prof Olli Heikinheimo, but the majority of such trials was established during the 1960’s, 1970’s and 1980’s. Provenance data formed the basis for a project, in cooperation with Skogforsk in Sweden, to redefine the deployment areas for Scots pine seed orchards in Finland and Sweden. Having similar deployment areas in both Finland and Sweden, based on the same models and assumptions, will enable in the future a more smooth exchange of material between the countries.
Because a forest owner is not only interested in the survival of his newly established forest, but as much in its production capacity, the models for the new definitions will also include growth. The performance of material from seed orchards is compared with that of seed from local natural sources to ensure that within the deployment area the seed orchard material is superior.
The results show that there is indeed a trend that the optimal deployment areas shift slightly northwards as a result of climate change. However, the trend is not as strong as maybe expected. The main reason for that is that survival is mostly affected during the early stages of a newly established forest when the trees are still small and sensitive. This stage is under influence of climate conditions similar to that we have today. Growth, on the other hand, is mainly affected by a climate several decades ahead. A second reason is that material from natural sources will also be affected by climate change.
During the project stakeholders (authorities, seed producers and nurseries) have been actively involved in discussing the results, especially on the practical implications of the new deployment areas. The implementation of the new deployment areas is in Finland the task of the Finnish Food Safety Authority Evira. At the end it is the forest owner who needs to know what would be the most suitable source of reproductive material for a specific reforestation site. For them a decision supporting tool is under preparation. The work will not end with Scots pine. The modeling for Norway spruce is already on its way, covering an even larger area including Norway and maybe also some Baltic countries.