chalk destination direction England english eroded erosion flower footpath Great Britain hill national park natural nature slope South Downs summer Sussex track trail travel Trek wild worn barrier bars boundary cattlegrid estate farm field forest house iron landscape livestock manor mansion meadow pasture rural sheep trees view Arun bridge cliff current flow green peaceful placid reeds river Salix tree water willow amber bare branches brown copper deciduous ghyll leaf leaves litter russet rusty shadows sunlight trunks winter wood woodland autumn bridleway countryside exercise fall lane path shade shady walk calm canal February reflections sky still sunny towpath tranquil Betula birch holly ilex peace quiet ramble shadow country grass hike hikers madow walkers beech bend british colour Fagus gold road route tawny uk