As the climate changes, so do the growing conditions of the world's pine trees. Researchers at the SMHI Rossby Centre have collaborated with the Swedish Forestry Research Institute Skogforsk to develop a large number of climate variables, which they have analysed along with data from forest field experiments with different pine saplings in different locations.
The temperature is important
The analyses show that the temperature sum is a good indication of the growth conditions for Swedish forests. At a mid-range climate change scenario, the temperature sum increases by 200–400 degree days by the year 2050.
“This would correspond roughly to transferring the climate of Skåne to Mälardalen,” says Lars Bärring, researcher at the SMHI climate research unit at Rossby Centre.
Reduces risks and increases production
Several studies have shown that it is important to consider the effects of climate change on the forest. There are excellent possibilities of reducing the risks of damage and diseases, while adaptation to a changed climate may also increase production.
In this study, the researchers selected 22 climate variables that are important to the growth and survival of the pine tree in a Nordic environment. These variables included average temperature and precipitation at various times of year, but also compound variables such as temperature sum, vegetation periods, dry periods and continentally index.
Climate data for Sweden and Finland
The researchers have used new grid-based climate data of the highest possible resolution for both Sweden (4x4 km) and Finland (10x10 km). In order to adapt these data to models that can predict future climate scenarios, a number of adjustment models were developed and applied to six different climate models in scenario A1B.
New transfer recommendations have then been developed based on these climate variables and field experiment data for both Sweden and Finland. Skogforsk is now launching a new version of its tool Plantval (the Planter’s guide) with new climate-adapted user recommendations for pine tree in Sweden and Swedish seed orchards.