Recycled demolition waste in engineered substrate promotes long-term urban tree growth and ecosystem services in a temperate city

• Brick-enhanced aggregates enhance growth of Tilia cordata by alleviating drought. • Aggregates with cement, mortar, and plaster reduce tree performance under drought. • Brick-enhanced aggregates increase transpiration cooling and carbon fixation. • Soil pH in recycled substrates stabilized at tree-compatible levels over time. • Selective recycling of demolition waste supports climate-resilient urban greening. Urban trees are critical for mitigating urban heat and delivering ecosystem services, yet their growth is increasingly constrained by drought stress under changing climatic conditions. Engineered substrates incorporating porous, water-retaining recycled aggregates (RA) from construction and demolition waste (C&DW) offer a promising approach to improving substrate performance while promoting resource circularity. However, the long-term effects of RA composition on tree performance remain insufficiently understood. In a four-year field study (2020–2024), we investigated the growth and ecosystem service provision of Tilia cordata planted in substrates amended with 25 %, 50 %, or 75 % (v/v) RA, derived either from brick-rich or cementitious (concrete, mortar, plaster) waste. Compared to the unamended control, substrates with 75 % brick-enriched RA increased stem diameter growth by 13.6 %, and enhanced transpiration cooling and carbon fixation by up to 42 % and 71 %, respectively. Treatment effects were strongly mediated by contrasting edaphic drought conditions during hot summer periods. In contrast, high proportions of cementitious RA induced drought stress and growth reductions. These findings demonstrate that selectively composed RA substrates—particularly those enriched with brick waste—can enhance tree performance under drought. This supports targeted recycling strategies and policy frameworks that prioritize brick-rich C&DW fractions for use in urban greening applications.