According to the results of the national forest inventory, the ecosystems in French forests are facing a series of crises, primarily attributed to the impacts of climate change.

French forests, renowned for their contributions to climate and biodiversity, are confronting a range of crises, resulting in escalating mortality rates, as revealed in the national forest inventory report released on October 12. The French Institut National de l'Information Géographique et Forestière (IGN) compiles an annual inventory to track the development of forest ecosystems and wood resources, drawing on data collected from 70,000 plots over the previous five years. The 2023 edition of the inventory underscores the tangible influence of climate change on forests and their overall health.

One alarming statistic is the occurrence of significant dieback in almost 670,000 hectares, equivalent to 4.1% of the total forest area. This figure equals the combined area lost to wildfires over the past 35 years. While forest dieback may not be as visually striking as winter storms or summer fires, its implications for the future are just as concerning, according to the IGN.

A timber stand is classified as undergoing dieback when at least 20% of trees with access to light have perished within a five-year period or when over 50% of their upper foliage contains dead branches. It is worth noting that the 670,000-hectare estimate likely underrepresents the actual extent of dieback, especially in cases where diseased trees are promptly removed and difficult to detect.

Additionally, tree mortality has surged by nearly 80% over the past decade, marking a significant increase compared to the 54% rise reported in the previous inventory. Photo by Romain Boukhobza, Wikimedia commons.