“What unites the wisest trails, I have found, is a balance of three values: durability, efficiency, and flexibility. If a trail has only one of these qualities it will not persist for long: a trail that is too durable will be too fixed, and will fail when conditions change; a trail that is too flexible will be too flimsy, and will erode; and a trail that is too efficient will be too parsimonious, and so will lack resilience.”
