Landscapes are shaped by continuous flows of materials and energy driven by anthropogenic and non-anthropogenic forces. Within constructed landscape systems, materials range from living to inert, from banal to innovative, from extracted to synthesized. Once installed in sites, these materials perform ecologically – engaging in dynamic relationships with abiotic and biotic elements. Essential functions include biogeochemical cycling, water infiltration, air filtration, soil remediation, soil stabilization, thermal regulation, and habitat creation. Apart from their often-brief stint installed in a site, materials are embedded with the energy, social relations and landscape effects of their own extraction, production, use, maintenance, and disposal, recycling or repurposing.This course will look at materials or material assemblies through two lenses: material histories – by tracing materials through various states and locales from extraction to repurposing to understand material life cycles and complex global material flows and micro-ecologies – investigating micro-ecological performance in constructed landscape systems. Together these two axes of investigation are necessary to explore the ecological performances and impacts of landscape constructions. Over the past decade, architectural culture has focused increasingly on the properties, performance criteria, and potentials for materials, evidenced in New York\’s Material ConneXions and the GSD???s Materials Collection, developed during Toshiko Mori\’s tenure as Chair of Architecture. The course will draw from and expand upon the resources in the GSD\’s Materials Collection.Structured as a collective research project, the course will be driven by independent student work, complemented with lectures, guest speakers, readings, and field studies. Drawing from industrial ecology, design practice and civil engineering, the course will be relevant to architects, landscape architects, and industrial designers interested in the ecological potentials and effects of material practice.