environment field landscape nature obstacle path stile wood barbed boundary country countryside cross fence handrail ladder over planks posts steps wire wooden England english exercise footpath Great Britain natural outdoors spring Sussex track trail trees walk access barrier hiking inviting meadow route rural Surrey walking winter gap green hedge neglected overgrown post ramble step Bedfordshire entrance open stone trailhead view wall explore footbridge forest natural environment public right of way woodland clouds farm gate hill hillside sky South Downs