Pure and even-aged forestry of fast-growing conifers under climate change: on the need for a silvicultural paradigm shift

Pure and even-aged (PEA) forests of fast-growing conifer species have for a long time been key providers of industrial raw material. Despite recent concerns regarding their greater sensitivity to major natural disturbances, their impacts on biodiversity and their funding efficiency, PEA conifer forests could remain a major economic target given the ongoing European strategy for bioeconomy. These forests are encountered in contrasted climates and in both native and introduced contexts across Europe, giving rise to high uncertainties regarding their growth responses to current climate change. Using the French National Forest Inventory data, we studied the radial growth of eight major conifer species in European forestry across 16 regional native and introduced PEA forest systems (n > 10 000 trees). Growth trends over the 2006-2016 period exhibited a significant negative association with the absolute growth level in 2006, with the strongest negative growth trends found for emblematic PEA forestry species (e.g. Norway spruce and Douglas fir), and the strongest positive trends for pine species (e.g. Scots pine). While the greater growth rate advantage of some species may shorten rotation and lower risk exposures for future decades, their recent lowered productivity may affect the forest sector in the long run. The prevalence of PEA forests across European forest landscapes and their increasingly reported lower resilience to climate change compared to more complex forest systems call for the establishment of a long-term European forest policy strategy. Maintaining the environmental, social and economic benefits of forests should remain a priority in the European agenda, regardless of the financial costs at stake.

Automated summary

PEA forests of fast-growing conifer species have long been key providers of industrial raw material, but concerns have been raised about their sensitivity to major natural disturbances, impacts on biodiversity, and funding efficiency. Despite being a major economic target in the European bioeconomy strategy, the growth responses of PEA forests to current climate change remain uncertain. Maintaining the environmental, social, and economic benefits of forests in the long run is crucial, even with potential financial costs involved.