From one tree to the canopy: an evolutionary design trajectory for tethered robotics in forest environments

Forest robotics has largely evolved along a ground-first and flight-dominant trajectory, treating the canopy as a region to observe or briefly access rather than a habitat to inhabit. In this Perspective, we propose an alternative canopy-first framework in which robots operate through anchoring, suspension, and tension-mediated interaction with the environment. We trace the progression from ground and aerial systems to perching mechanisms, identifying their shared limitation as transient canopy interaction. Tether-based robots instead enable sustained presence by transforming branches into structural supports. Within this context, TreeSpider is presented as an early canopy-innate morphology. We argue that such systems point toward a broader class of structure-innate robotics, where behavior emerges through physical coupling with the environment rather than continuous free-space mobility.