bracken deer green male park stag dense England english fern Great Britain habitat natural nature Pteridium aquilinum summer Surrey woodland brown cold dead golden hill hillside landscape Powys snow steep stems tawny wales welsh winter countryside heathland natural environment Natural landscape Pitch Hill trees view clouds heath meadow sky Sussex cliff coastline danger height high Pembrokeshire rock sea united kingdom water Calluna ecology heather Pteridium bridleway exercise path slippery track trail Trek walk conifer oak pine blue plants rocks shore coniferous footpath forest pines quality shade sunlight