Belgrade's Cassette Green Roofs — From a 15m² Pilot to a 6,500m² Installation in Košutnjak Park

Belgrade-based company Green Decor developed a modular 'cassette' green-roof system using recycled-material trays filled with drought- and cold-tolerant potted plants, designed to retrofit flat roofs without major structural reinforcement. Under the 2023–2025 project 'Path to Successful Decarbonisation through Green Cassette Roofs', the Institute for Biological Research 'Siniša Stanković' (IBISS) tested nine plant species over one vegetation period, and the work was funded through the EU-backed 'EU for Green Agenda in Serbia' programme, implemented by UNDP Serbia with Serbia's Ministry of Environmental Protection, the Governments of Switzerland and Sweden, and the European Investment Bank.

IBISS tested nine plant species over one vegetation period and identified moss rose, chives and bird's-foot trefoil as the most climate-resilient performers for Belgrade's conditions. Installations range from a 15m² private terrace in central Belgrade to a 6,500m² roof in Košutnjak Park, described as the largest of its kind in the region, with New Belgrade and Konjarnik named as neighbourhoods for further rollout.

A reference 200m² installation is estimated to produce about 260kg of oxygen annually. The system is described as slowing rainwater runoff and providing seasonal thermal insulation, but no measured stormwater-retention volumes, CO2 balance or wildlife-outcome data specific to the installations have been published.

Benefits beyond the oxygen estimate and the plant-resilience trial remain qualitative; the project demonstrates a working retrofit model and has scaled from a 15m² pilot to a 6,500m² flagship installation, but rigorous ecological outcome monitoring has not yet been published.