Biochemical and Sensory Dimensions of Plant–Human Interactions

This chapter examines the biochemical, sensory, spatial, and temporal dimensions of plant–human interactions within landscape architecture. Drawing on phytochemistry, forest medicine, environmental psychology, therapeutic landscape research, urban ecology, public health, and ethnobotany, it evaluates how plants may generate restorative, therapeutic, allergenic, toxic, and otherwise context-dependent effects. Species-based examples—including willow, linden, Russian olive, pine, juniper, plane, oleander, giant hogweed, and olive—demonstrate that plant effects cannot be reduced to visual qualities or single biochemical mechanisms. Instead, outcomes vary according to species composition, exposure pathway and duration, user characteristics, phenology, environmental conditions, and spatial scale. The chapter further distinguishes between evidence derived from extracts or controlled experiments and effects arising through direct landscape experience. It argues that landscape planning and design should integrate sensory and biochemical knowledge with ecological and aesthetic considerations while preserving scientific caution. A contextual, multiscale framework is proposed for evaluating both the potential benefits and risks of plants.