In April 2022, TreeReefs were deployed in the Eierlandse Gat tidal basin, north of Texel, within four tidal channels where seabed morphology is relatively stable. Each channel contained a block of eight TreeReef units, positioned five meters apart. The units were constructed from six short-stemmed fruit trees, bolted together into a pyramid shape. Three upright trees were anchored with concrete weights, while three crossbeams reinforced the structure, creating a stable triangular framework. Deployment was carried out using a crane from a vessel. 

Prior to this field placement, various prototype designs were tested near the seawall at NIOZ Yerseke, where strong tidal action provided a stress test for stability and durability. 

Monitoring focused on both sessile and mobile species. One specially reinforced tree in each block was periodically lifted to assess colonisation by benthic organisms. Fish and mobile invertebrates were studied through trap fishing, active acoustic surveys (fish finders), and passive acoustic monitoring for biological sounds. The reefs remain in place under Rijkswaterstaat’s management, with ongoing monitoring and gradual natural degradation expected to start lasting biogenic habitats such as oyster reefs and seagrass meadows.  

• Think in height: Elevated structures provide far greater habitat value than logs lying flat on the seabed. Designs such as pyramids increase vertical complexity, offering essential shelter for fish and shellfish while remaining stable on the seafloor. 
• Design for flexibility: Iterative testing has shown the value of self-righting, pyramid-shaped reefs. These can be adapted to specific project goals. For example, by attaching oyster-shell necklaces for pre-seeding or adding habitat modules like lobster houses. 
• Plan with natural decommissioning in mind: Marine woodborers gradually break down the reefs, transforming woody material into biomass and detritus. Depending on wood type and condition, structural integrity typically lasts 10–20 years, with full degradation expected within about 40 years. This natural process means active decommissioning is unnecessary, while still allowing habitat functions during the reef’s lifespan.