Oak Need Active Management in Continuous Cover Forestry

Oak forests are among the most valuable forest ecosystems. They provide timber, recreational spaces, and habitats for a vast number of species.

Because oaks can live for several centuries, they form complex forest structures that support a rich diversity of insects, fungi, lichens, mosses, and birds. This structural diversity also makes oak forests more resilient to environmental change.

Struggle in CCF

In recent years, continuous cover forestry—an approach that avoids clear-cutting and instead removes individual trees while maintaining a tree canopy—has become increasingly promoted. The method aims to preserve a varied forest structure and enhance biodiversity.

However, oaks struggle to regenerate under continuous cover management, CCF. Although large numbers of seedlings often appear, few young trees succeed in growing tall enough to become the canopy trees of the future.

Decades of decline

Long-term data from Sweden’s National Forest Inventory show that the growth rates of young oaks have steadily declined over the past 40 years. The largest decreases are found in dense forests and in places where oaks grow alongside shade-tolerant species such as spruce and beech.

In her dissertation, Nora Sophie Pohl demonstrates that selective cutting can improve short‑term conditions for young oaks in oak-dominated forests. Lower tree density was linked to more oak recruits, and forests with more open crowns or light‑permitting tree species saw better regeneration.

A second, longer-term experiment focused on a spruce- and pine-dominated forest that contained many young oaks. When competing trees—particularly spruce—were removed, the diameter growth of the oak recruits increased markedly. This treatment also improved the young oaks’ ability to compete with larger trees, enhancing their chances of responding well to future management efforts and environmental changes.

Active management needed

Together, the studies show that competition from surrounding trees severely limits the success of young oaks. Dense stands with many shade-tolerant species, high stem density, and large volumes of standing timber reduce both the number and growth of oak recruits. To support oak regeneration, targeted management is essential.

“To secure the future of oak forests, selective cutting must be used deliberately and repeated when necessary to reduce competition and ensure sufficient light,” says Nora Sophie Pohl.
“Without targeted efforts, oak forests risk being dominated by old trees without enough younger ones for the future."

Read the thesis: Oaks under continuous cover forestry - Recruitment challenges and biodiversity implications

Nora Sophie Pohl will defend her thesis on February 27th, 09:00, in the Crafoord Hall at the Swedish University of Agriculture Sciences´ campus in Alnarp. Everyone is welcome.