Let the riverscape grow! Riverscape rewilding restores lateral connectivity and promotes geomorphic recovery in a...

Placement of in-channel large wood is a popular tool in process-based river restoration. In degraded streams lacking naturally recruited large wood, it can be used to reinstate fluvial processes and encourage a river to self-heal with minimal intervention. Its use is becoming common practice in regions where riverscape wood available for natural recruitment is sparse owing to long-term land management approaches. To re-establish wood supply, restoration of riparian woodland often accompanies in-channel large wood placement. Post-restoration monitoring is, however, rarely carried out to gather evidence on geomorphic responses to large wood placement and recruitment, and riverscape rewilding. To assess evolution of post-restoration riverscape wood dynamics, we use a decadal-scale morphological dataset of a "working with natural processes" restoration approach, with evidence from Allt Lorgy, Scotland. We apply automated geomorphic analysis tools to map geomorphic change and geomorphic units, orthomosaic aerial imagery to map in-channel large wood and LiDAR to map regenerating trees. Results show that process-based restoration with the addition of large wood enhances lateral connectivity and geomorphic recovery in a gravel-bed river with high recovery potential. Placed large wood reinstates natural processes, augmenting diagonal bar complexes, promoting channel widening, and forcing diverse geomorphic unit assemblages. Natural recruitment of large wood increases post-restoration, with storage occurring on diagonal bar complexes. Deer fencing of the scheme facilitates patches of regenerative growth of native tree species across the riverscape, predominantly on disturbed ground. Findings support the concept of riverscape rewilding in Scotland to encourage the development of healthy, self-sustaining, resilient riverscapes.