In 2020, Stewart began making monoprints of pollarded lime trees outside his London flat. One tree became a street, then an entire neighbourhood - each print revealing something about our often-overlooked relationship with urban ecology. After relocating to Devon, his focus expanded to trees shaped by climate and human intervention: ash threatened by disease, fire-scarred Joshua trees in the Mojave Desert, and the lichen-draped oaks of Dartmoor's edges. His larger pieces are composite Gelliplate monoprints, created through masking, stencils, and layered textures. Recently, time-limited, 15-minute studies have been made in response to the energy and flux of temperate rainforests. These prints subsequently raised over £1000 for the local charity, Moor Trees. Stewart’s gelliplate techniques were featured in Printmaking Today (Summer 2024). His work is held in the print collection of the V&A and the Jyväskylä Art Museum, and in private collections across the world.