Van Oord and Ecowende have signed a contract for the design, construction, and installation of Tree Reefs and Oyster Hubs at the Hollandse Kust West (HKW, site VI) wind farm. Developed under Van Oord Ocean Health, these initiatives aim to support marine biodiversity in the North Sea.
Tree Reefs are circular, biodegradable reef structures made from discarded fruit trees, which are sourced from Dutch orchards when they become less productive. Originally developed by the Royal Netherlands Institute for Sea Research (NIOZ), a pilot in the Wadden Sea demonstrated that the intricate structure of these trees provides a valuable habitat for marine life. A larger-scale Tree Reef in the North Sea is expected to support a greater variety of benthic and fish species, contributing to local biodiversity.
In addition, Van Oord and Ecowende will introduce Oyster Hubs at the wind farm. Developed in collaboration with Waardenburg Ecology, these hubs use adult oysters placed on cable crossings to act as a source of larvae. The wind farm will serve as a distribution point, helping oyster larvae reach new areas and connect otherwise isolated habitats.
Installation of the Tree Reefs is planned for 2026 on four cable crossings within the wind farm, using approximately 1,000 trees. The reefs are expected to biodegrade over 10 to 20 years, gradually being replaced by natural reef-building organisms. The Oyster Hubs will be installed in 2026 or 2027 on three cable crossings.
