Warmer Weather Leads to More Heat-Loving Trees

Due to the increased temperatures, various tree species have been able to grow further inland and higher up in the mountains in Norway over the last thirty years than before.

Different tree species have different temperature requirements for growth and thriving. The dwarf birch has the lowest temperature requirements among all Norwegian tree species. Therefore, it grows extensively in the mountains. More heat-loving tree species, such as elm, ash, beech, oak, hazel, lime, maple, and black alder, have higher demands for summer temperatures. The high heat requirement is the reason why species like ash, oak, and beech are only found in certain areas in the southern part of the country.

Over 100 years ago, botanists and plant researchers already examined the heat requirements of different tree species in Norway. Beech is the tree species in Norway that requires the highest average summer temperature, at 13.4 degrees Celsius. Spruce and pine are less demanding, being content with at least 8.4 degrees. Birch needs at least 7.5 degrees; aspen 7.6; bird cherry, rowan, and ash 7.7.

The Trees Will Grow and Thrive in a Different Climate Than Today When forest owners plan for the types of forests to focus on in the future, knowledge about how temperature changes affect tree growth in the forests of the future is essential. The tree species chosen for planting today – whether it’s spruce, pine, birch, black alder, or beech – will grow and thrive in a different climate than today.

Even for urban forests around Oslo, Bergen, and Trondheim, the choices made by forest managers today will have a significant impact on the outdoor activities and hiking areas our grandchildren and great-grandchildren will have for the next 100 years.

Increased Risk of Drought Damage and Bark Beetle Attacks Heat-loving trees like beech could extend further inland if other conditions are also present. However, anything that can affect growth will be vital for long-term agricultural planning. Higher temperatures, for instance, could increase the risk of drought damage and bark beetle attacks, as seen during the drought of 2018.